Fix wrong attachment download progress information after re-enqueueing items

Closes #232

README.md

@@ -16,7 +16,6 @@ Fork the repository and clone it to your computer (if you've never used git, you
 
 Folder organization:
 * `app/` contains a Visual Studio solution for the desktop app
-* `lib/` contains utilities required to build the project
 * `web/` contains source code of the [official website](https://dht.chylex.com), which can be used as a template when making your own website
 
 To start editing source code for the desktop app, install the [.NET 8 SDK](https://dotnet.microsoft.com/en-us/download/dotnet/8.0), and then open `app/DiscordHistoryTracker.sln` in [Visual Studio](https://visualstudio.microsoft.com/downloads/) or [Rider](https://www.jetbrains.com/rider/).
@@ -29,22 +28,13 @@ To build a `Release` version of the desktop app, follow the instructions for you
 
 #### Release – Windows (64-bit)
 
-1. Install [Python 3](https://www.python.org/downloads), and ensure the `python` executable is in your `PATH`
-2. Install [Powershell 5](https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell-on-windows) or newer (on Windows 10, the included version of Powershell should be enough)
-
-The `lib/` folder contains an installation of [Node](https://nodejs.org/en) and [uglify-js](https://www.npmjs.com/package/uglify-js), which are used to minify the tracking script. This installation will only work on 64-bit Windows; building on 32-bit Windows is not supported, but you can try.
+1. Install [Powershell 5](https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell-on-windows) or newer (on Windows 10, the included version of Powershell should be enough)
 
 Run the `app/build.bat` script, and read the [Distribution](#distribution) section below.
 
 #### Release – Other Operating Systems
 
-1. Install [Python 3](https://www.python.org/downloads), and ensure the `python` executable exists and launches Python 3
-   - On Debian and derivatives, you can install `python-is-python3`
-   - On other distributions, you can create a link manually, for ex. `ln -s /usr/bin/python3 /usr/bin/python`
-   - If you don't want `python` to mean Python 3, then edit `Desktop.csproj` and change `python` to `python3`
-2. Install [Node + npm](https://nodejs.org/en)
-3. Install [uglify-js](https://www.npmjs.com/package/uglify-js) globally (`npm install -g uglify-js`)
-4. Install the `zip` package from your repository
+1. Install the `zip` package from your repository
 
 Run the `app/build.sh` script, and read the [Distribution](#distribution) section below.
 
@@ -52,4 +42,4 @@ Run the `app/build.sh` script, and read the [Distribution](#distribution) sectio
 
 The mentioned build scripts will prepare `Release` builds ready for distribution. Once the script finishes, the `app/bin` folder will contain self-contained executables for each major operating system, and a portable version that works on all other systems but requires .NET 8 to be installed.
 
-Note that when building on Windows, the generated `.zip` files for Linux and Mac will not have correct file permissions, so it will not be possible to run them by double-clicking `DiscordHistoryTracker`. I tried using Python to re-create the archives with correct file permissions, but found that Linux `zip` tools could not see them. The only working solution is building the Windows + portable version on Windows, and Linux + Mac version on Linux.
+Note that when building on Windows, the generated `.zip` files for Linux and Mac will not have correct file permissions, so it will not be possible to run them by double-clicking the executable. Since .NET 8 fixed several issues with publishing Windows executables on Linux, I recommend using Linux to build the app for all operating systems.

app/.idea/.idea.DiscordHistoryTracker/.idea/codeStyles/Project.xml

@@ -29,9 +29,6 @@
     <H2CodeStyleSettings version="6">
       <option name="USE_GENERIC_STYLE" value="true" />
     </H2CodeStyleSettings>
-    <H2CodeStyleSettings version="6">
-      <option name="USE_GENERIC_STYLE" value="true" />
-    </H2CodeStyleSettings>
     <HSQLCodeStyleSettings version="6">
       <option name="USE_GENERIC_STYLE" value="true" />
     </HSQLCodeStyleSettings>

app/.idea/.idea.DiscordHistoryTracker/.idea/runConfigurations/Desktop.xml

@@ -1,8 +1,8 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="Desktop" type="DotNetProject" factoryName=".NET Project">
-    <option name="EXE_PATH" value="$PROJECT_DIR$/Desktop/bin/Debug/net5.0/DiscordHistoryTracker.exe" />
+    <option name="EXE_PATH" value="$PROJECT_DIR$/.artifacts/bin/Desktop/debug/DiscordHistoryTracker.exe" />
     <option name="PROGRAM_PARAMETERS" value="" />
-    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/Desktop/bin/Debug/net5.0" />
+    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/.artifacts/bin/Desktop/debug" />
     <option name="PASS_PARENT_ENVS" value="1" />
     <option name="USE_EXTERNAL_CONSOLE" value="0" />
     <option name="USE_MONO" value="0" />
@@ -12,7 +12,7 @@
     <option name="PROJECT_ARGUMENTS_TRACKING" value="1" />
     <option name="PROJECT_WORKING_DIRECTORY_TRACKING" value="1" />
     <option name="PROJECT_KIND" value="DotNetCore" />
-    <option name="PROJECT_TFM" value="net5.0" />
+    <option name="PROJECT_TFM" value="net8.0" />
     <method v="2">
       <option name="Build" />
     </method>

app/.idea/.idea.DiscordHistoryTracker/.idea/runConfigurations/Minify.xml

@@ -1,23 +0,0 @@
-<component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="Minify" type="PythonConfigurationType" factoryName="Python">
-    <module name="rider.module" />
-    <option name="INTERPRETER_OPTIONS" value="" />
-    <option name="PARENT_ENVS" value="true" />
-    <envs>
-      <env name="PYTHONUNBUFFERED" value="1" />
-    </envs>
-    <option name="SDK_HOME" value="" />
-    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$" />
-    <option name="IS_MODULE_SDK" value="false" />
-    <option name="ADD_CONTENT_ROOTS" value="false" />
-    <option name="ADD_SOURCE_ROOTS" value="false" />
-    <option name="SCRIPT_NAME" value="$PROJECT_DIR$/minify.py" />
-    <option name="PARAMETERS" value="" />
-    <option name="SHOW_COMMAND_LINE" value="false" />
-    <option name="EMULATE_TERMINAL" value="false" />
-    <option name="MODULE_MODE" value="false" />
-    <option name="REDIRECT_INPUT" value="false" />
-    <option name="INPUT_FILE" value="" />
-    <method v="2" />
-  </configuration>
-</component>

app/Desktop/App.axaml

@@ -2,7 +2,8 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:common="clr-namespace:DHT.Desktop.Common"
              xmlns:system="clr-namespace:System;assembly=System.Runtime"
-             x:Class="DHT.Desktop.App">
+             x:Class="DHT.Desktop.App"
+             RequestedThemeVariant="Light">
 
     <Application.Styles>
 

app/Desktop/App.axaml.cs

@@ -1,4 +1,3 @@
-using System;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
@@ -13,7 +12,7 @@ sealed class App : Application {
 
 	public override void OnFrameworkInitializationCompleted() {
 		if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop) {
-			desktop.MainWindow = new MainWindow(new Arguments(desktop.Args ?? Array.Empty<string>()));
+			desktop.MainWindow = new MainWindow(Program.Arguments);
 		}
 
 		base.OnFrameworkInitializationCompleted();

app/Desktop/Arguments.cs

@@ -5,26 +5,33 @@ namespace DHT.Desktop;
 
 sealed class Arguments {
 	private static readonly Log Log = Log.ForType<Arguments>();
+	
+	private const int FirstArgument = 1;
 
 	public static Arguments Empty => new(Array.Empty<string>());
 
+	public bool Console { get; }
 	public string? DatabaseFile { get; }
 	public ushort? ServerPort { get; }
 	public string? ServerToken { get; }
 
 	public Arguments(string[] args) {
-		for (int i = 0; i < args.Length; i++) {
+		for (int i = FirstArgument; i < args.Length; i++) {
 			string key = args[i];
 
 			switch (key) {
 				case "-debug":
 					Log.IsDebugEnabled = true;
 					continue;
+				
+				case "-console":
+					Console = true;
+					continue;
 			}
 
 			string value;
 
-			if (i == 0 && !key.StartsWith('-')) {
+			if (i == FirstArgument && !key.StartsWith('-')) {
 				value = key;
 				key = "-db";
 			}

app/Desktop/Common/DatabaseGui.cs

@@ -1,14 +1,17 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Threading;
 using System.Threading.Tasks;
 using Avalonia.Controls;
 using Avalonia.Platform.Storage;
+using Avalonia.Threading;
 using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Server.Database;
 using DHT.Server.Database.Exceptions;
 using DHT.Server.Database.Sqlite;
+using DHT.Server.Database.Sqlite.Utils;
 using DHT.Utils.Logging;
 
 namespace DHT.Desktop.Common;
@@ -18,9 +21,9 @@ static class DatabaseGui {
 
 	private const string DatabaseFileInitialName = "archive.dht";
 
-	private static readonly IReadOnlyList<FilePickerFileType> DatabaseFileDialogFilter = new List<FilePickerFileType> {
-		FileDialogs.CreateFilter("Discord History Tracker Database", new [] { "dht" })
-	};
+	private static readonly IReadOnlyList<FilePickerFileType> DatabaseFileDialogFilter = [
+		FileDialogs.CreateFilter("Discord History Tracker Database", ["dht"])
+	];
 
 	public static async Task<string[]> NewOpenDatabaseFilesDialog(Window window, string? suggestedDirectory) {
 		return await window.StorageProvider.OpenFiles(new FilePickerOpenOptions {
@@ -41,11 +44,16 @@ static class DatabaseGui {
 		});
 	}
 
-	public static async Task<IDatabaseFile?> TryOpenOrCreateDatabaseFromPath(string path, Window window, Func<Task<bool>> checkCanUpgradeDatabase) {
+	public static async Task<IDatabaseFile?> TryOpenOrCreateDatabaseFromPath(string path, Window window, ISchemaUpgradeCallbacks schemaUpgradeCallbacks) {
+		var prevSynchronizationContext = SynchronizationContext.Current;
+		SynchronizationContext.SetSynchronizationContext(new AvaloniaSynchronizationContext());
+		var taskScheduler = TaskScheduler.FromCurrentSynchronizationContext();
+		SynchronizationContext.SetSynchronizationContext(prevSynchronizationContext);
+		
 		IDatabaseFile? file = null;
 
 		try {
-			file = await SqliteDatabaseFile.OpenOrCreate(path, checkCanUpgradeDatabase);
+			file = await SqliteDatabaseFile.OpenOrCreate(path, schemaUpgradeCallbacks, taskScheduler);
 		} catch (InvalidDatabaseVersionException ex) {
 			await Dialog.ShowOk(window, "Database Error", "Database '" + Path.GetFileName(path) + "' appears to be corrupted (invalid version: " + ex.Version + ").");
 		} catch (DatabaseTooNewException ex) {

app/Desktop/Desktop.csproj

@@ -1,36 +1,34 @@
 <Project Sdk="Microsoft.NET.Sdk">
+  
+  <PropertyGroup>
+    <RootNamespace>DHT.Desktop</RootNamespace>
+    <AssemblyName>DiscordHistoryTracker</AssemblyName>
+    <PackageId>DiscordHistoryTracker</PackageId>
+  </PropertyGroup>
+  
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
-    <Nullable>enable</Nullable>
-    <AssemblyName>DiscordHistoryTracker</AssemblyName>
-    <RootNamespace>DHT.Desktop</RootNamespace>
-    <PackageId>DiscordHistoryTracker</PackageId>
-    <Authors>chylex</Authors>
-    <Company>DiscordHistoryTracker</Company>
-    <Product>DiscordHistoryTracker</Product>
     <ApplicationIcon>./Resources/icon.ico</ApplicationIcon>
+    <AvaloniaUseCompiledBindingsByDefault>true</AvaloniaUseCompiledBindingsByDefault>
     <CheckForOverflowUnderflow>true</CheckForOverflowUnderflow>
     <SatelliteResourceLanguages>en</SatelliteResourceLanguages>
-    <GenerateAssemblyVersionAttribute>false</GenerateAssemblyVersionAttribute>
-    <GenerateAssemblyFileVersionAttribute>false</GenerateAssemblyFileVersionAttribute>
-    <GenerateAssemblyInformationalVersionAttribute>false</GenerateAssemblyInformationalVersionAttribute>
-  </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
-    <DebugSymbols>true</DebugSymbols>
-    <DebugType>none</DebugType>
   </PropertyGroup>
+  
   <ItemGroup>
-    <PackageReference Include="Avalonia" Version="11.0.5" />
-    <PackageReference Include="Avalonia.Controls.DataGrid" Version="11.0.5" />
-    <PackageReference Include="Avalonia.Controls.ItemsRepeater" Version="11.0.5" />
-    <PackageReference Include="Avalonia.Desktop" Version="11.0.5" />
-    <PackageReference Include="Avalonia.Diagnostics" Version="11.0.5" Condition=" '$(Configuration)' == 'Debug' " />
-    <PackageReference Include="Avalonia.Fonts.Inter" Version="11.0.5" />
-    <PackageReference Include="Avalonia.Themes.Fluent" Version="11.0.5" />
+    <PackageReference Include="Avalonia" Version="11.0.6" />
+    <PackageReference Include="Avalonia.Controls.DataGrid" Version="11.0.6" />
+    <PackageReference Include="Avalonia.Controls.ItemsRepeater" Version="11.0.6" />
+    <PackageReference Include="Avalonia.Desktop" Version="11.0.6" />
+    <PackageReference Include="Avalonia.Diagnostics" Version="11.0.6" Condition=" '$(Configuration)' == 'Debug' " />
+    <PackageReference Include="Avalonia.Fonts.Inter" Version="11.0.6" />
+    <PackageReference Include="Avalonia.ReactiveUI" Version="11.0.6" />
+    <PackageReference Include="Avalonia.Themes.Fluent" Version="11.0.6" />
   </ItemGroup>
+  
   <ItemGroup>
     <ProjectReference Include="..\Server\Server.csproj" />
   </ItemGroup>
+  
   <ItemGroup>
     <Compile Include="..\Version.cs" Link="Version.cs" />
     <Compile Update="Dialogs\TextBox\TextBoxDialog.axaml.cs">
@@ -38,22 +36,11 @@
       <SubType>Code</SubType>
     </Compile>
   </ItemGroup>
+  
   <ItemGroup>
     <AvaloniaResource Include="Resources/icon.ico" />
-    <EmbeddedResource Include="../Resources/Tracker/bootstrap.js">
-      <LogicalName>Tracker\%(RecursiveDir)%(Filename)%(Extension)</LogicalName>
-      <Link>Resources/Tracker/%(RecursiveDir)%(Filename)%(Extension)</Link>
-      <Visible>false</Visible>
-    </EmbeddedResource>
-    <EmbeddedResource Include="../Resources/Tracker/scripts/**" Condition=" '$(Configuration)' == 'Debug' ">
-      <LogicalName>Tracker\scripts\%(RecursiveDir)%(Filename)%(Extension)</LogicalName>
-      <Link>Resources/Tracker/scripts/%(RecursiveDir)%(Filename)%(Extension)</Link>
-      <Visible>false</Visible>
-    </EmbeddedResource>
-    <EmbeddedResource Include="../Resources/Tracker/styles/**">
-      <LogicalName>Tracker\styles\%(RecursiveDir)%(Filename)%(Extension)</LogicalName>
-      <Link>Resources/Tracker/styles/%(RecursiveDir)%(Filename)%(Extension)</Link>
-      <Visible>false</Visible>
+    <EmbeddedResource Include="Resources/tracker-loader.js">
+      <LogicalName>tracker-loader.js</LogicalName>
     </EmbeddedResource>
     <EmbeddedResource Include="../Resources/Viewer/**">
       <LogicalName>Viewer\%(RecursiveDir)%(Filename)%(Extension)</LogicalName>
@@ -61,19 +48,5 @@
       <Visible>false</Visible>
     </EmbeddedResource>
   </ItemGroup>
-  <Target Name="MinifyResources" BeforeTargets="PrepareForBuild" Condition=" '$(Configuration)' == 'Release' ">
-    <PropertyGroup>
-      <MinifiedResourceDir>$(ProjectDir)bin/.res/scripts</MinifiedResourceDir>
-    </PropertyGroup>
-    <ItemGroup>
-      <UpToDateCheckInput Include="$(ProjectDir)../Resources/Tracker/scripts/**" Visible="false" />
-      <EmbeddedResource Include="$(MinifiedResourceDir)/discord.js" LogicalName="Tracker\scripts\discord.js" Visible="false" />
-      <EmbeddedResource Include="$(MinifiedResourceDir)/dom.js" LogicalName="Tracker\scripts\dom.js" Visible="false" />
-      <EmbeddedResource Include="$(MinifiedResourceDir)/gui.js" LogicalName="Tracker\scripts\gui.js" Visible="false" />
-      <EmbeddedResource Include="$(MinifiedResourceDir)/settings.js" LogicalName="Tracker\scripts\settings.js" Visible="false" />
-      <EmbeddedResource Include="$(MinifiedResourceDir)/state.js" LogicalName="Tracker\scripts\state.js" Visible="false" />
-    </ItemGroup>
-    <RemoveDir Directories="$(ProjectDir)bin/.res/scripts" />
-    <Exec Command="python $(ProjectDir)../Resources/minify.py" WorkingDirectory="$(ProjectDir)../Resources" IgnoreExitCode="false" />
-  </Target>
+  
 </Project>

app/Desktop/Dialogs/CheckBox/CheckBoxDialog.axaml

@@ -5,6 +5,7 @@
         xmlns:namespace="clr-namespace:DHT.Desktop.Dialogs.CheckBox"
         mc:Ignorable="d" d:DesignWidth="500"
         x:Class="DHT.Desktop.Dialogs.CheckBox.CheckBoxDialog"
+        x:DataType="namespace:CheckBoxDialogModel"
         Title="{Binding Title}"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
         Width="500" SizeToContent="Height" CanResize="False"

app/Desktop/Dialogs/Message/MessageDialog.axaml

@@ -5,6 +5,7 @@
         xmlns:namespace="clr-namespace:DHT.Desktop.Dialogs.Message"
         mc:Ignorable="d" d:DesignWidth="500"
         x:Class="DHT.Desktop.Dialogs.Message.MessageDialog"
+        x:DataType="namespace:MessageDialogModel"
         Title="{Binding Title}"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
         Width="500" SizeToContent="Height" CanResize="False"

app/Desktop/Dialogs/Progress/IProgressCallback.cs

@@ -4,4 +4,6 @@ namespace DHT.Desktop.Dialogs.Progress;
 
 interface IProgressCallback {
 	Task Update(string message, int finishedItems, int totalItems);
+	Task UpdateIndeterminate(string message);
+	Task Hide();
 }

app/Desktop/Dialogs/Progress/ProgressDialog.axaml

@@ -5,6 +5,7 @@
         xmlns:namespace="clr-namespace:DHT.Desktop.Dialogs.Progress"
         mc:Ignorable="d" d:DesignWidth="500"
         x:Class="DHT.Desktop.Dialogs.Progress.ProgressDialog"
+        x:DataType="namespace:ProgressDialogModel"
         Title="{Binding Title}"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
         Opened="OnOpened"
@@ -31,12 +32,18 @@
         </Style>
     </Window.Styles>
 
-    <StackPanel Margin="20">
-        <DockPanel>
-            <TextBlock DockPanel.Dock="Right" Text="{Binding Items}" Classes="items" />
-            <TextBlock DockPanel.Dock="Left" Text="{Binding Message}" />
-        </DockPanel>
-        <ProgressBar Value="{Binding Progress}" />
-    </StackPanel>
+    <ItemsRepeater ItemsSource="{Binding Items}" Margin="0 10">
+        <ItemsRepeater.ItemTemplate>
+            <DataTemplate>
+                <StackPanel Margin="20 10" IsHitTestVisible="{Binding IsVisible}" Opacity="{Binding Opacity}">
+                    <DockPanel>
+                        <TextBlock DockPanel.Dock="Right" Text="{Binding Items}" Classes="items" />
+                        <TextBlock DockPanel.Dock="Left" Text="{Binding Message}" />
+                    </DockPanel>
+                    <ProgressBar IsIndeterminate="{Binding IsIndeterminate}" Value="{Binding Progress}" />
+                </StackPanel>
+            </DataTemplate>
+        </ItemsRepeater.ItemTemplate>
+    </ItemsRepeater>
 
 </Window>

app/Desktop/Dialogs/Progress/ProgressDialog.axaml.cs

@@ -7,7 +7,60 @@ namespace DHT.Desktop.Dialogs.Progress;
 
 [SuppressMessage("ReSharper", "MemberCanBeInternal")]
 public sealed partial class ProgressDialog : Window {
+	internal static async Task Show(Window owner, string title, Func<ProgressDialog, IProgressCallback, Task> action) {
+		var taskCompletionSource = new TaskCompletionSource();
+		var dialog = new ProgressDialog();
+		
+		dialog.DataContext = new ProgressDialogModel(title, async callbacks => {
+			try {
+				await action(dialog, callbacks[0]);
+				taskCompletionSource.SetResult();
+			} catch (Exception e) {
+				taskCompletionSource.SetException(e);
+			}
+		});
+		
+		await dialog.ShowProgressDialog(owner);
+		await taskCompletionSource.Task;
+	}
+	
+	internal static async Task ShowIndeterminate(Window owner, string title, string message, Func<ProgressDialog, Task> action) {
+		var taskCompletionSource = new TaskCompletionSource();
+		var dialog = new ProgressDialog();
+		
+		dialog.DataContext = new ProgressDialogModel(title, async callbacks => {
+			await callbacks[0].UpdateIndeterminate(message);
+			try {
+				await action(dialog);
+				taskCompletionSource.SetResult();
+			} catch (Exception e) {
+				taskCompletionSource.SetException(e);
+			}
+		});
+		
+		await dialog.ShowProgressDialog(owner);
+		await taskCompletionSource.Task;
+	}
+	
+	internal static async Task<T> ShowIndeterminate<T>(Window owner, string title, string message, Func<ProgressDialog, Task<T>> action) {
+		var taskCompletionSource = new TaskCompletionSource<T>();
+		var dialog = new ProgressDialog();
+
+		dialog.DataContext = new ProgressDialogModel(title, async callbacks => {
+			await callbacks[0].UpdateIndeterminate(message);
+			try {
+				taskCompletionSource.SetResult(await action(dialog));
+			} catch (Exception e) {
+				taskCompletionSource.SetException(e);
+			}
+		});
+		
+		await dialog.ShowProgressDialog(owner);
+		return await taskCompletionSource.Task;
+	}
+
 	private bool isFinished = false;
+	private Task progressTask = Task.CompletedTask;
 
 	public ProgressDialog() {
 		InitializeComponent();
@@ -15,7 +68,8 @@ public sealed partial class ProgressDialog : Window {
 
 	public void OnOpened(object? sender, EventArgs e) {
 		if (DataContext is ProgressDialogModel model) {
-			Task.Run(model.StartTask).ContinueWith(OnFinished, TaskScheduler.FromCurrentSynchronizationContext());
+			progressTask = Task.Run(model.StartTask);
+			progressTask.ContinueWith(OnFinished, TaskScheduler.FromCurrentSynchronizationContext());
 		}
 	}
 
@@ -27,4 +81,9 @@ public sealed partial class ProgressDialog : Window {
 		isFinished = true;
 		Close();
 	}
+
+	public async Task ShowProgressDialog(Window owner) {
+		await ShowDialog(owner);
+		await progressTask;
+	}
 }

app/Desktop/Dialogs/Progress/ProgressDialogModel.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 using Avalonia.Threading;
 using DHT.Desktop.Common;
@@ -9,57 +11,54 @@ namespace DHT.Desktop.Dialogs.Progress;
 sealed class ProgressDialogModel : BaseModel {
 	public string Title { get; init; } = "";
 
-	private string message = "";
-
-	public string Message {
-		get => message;
-		private set => Change(ref message, value);
-	}
-
-	private string items = "";
-
-	public string Items {
-		get => items;
-		private set => Change(ref items, value);
-	}
-
-	private int progress = 0;
-
-	public int Progress {
-		get => progress;
-		private set => Change(ref progress, value);
-	}
+	public IReadOnlyList<ProgressItem> Items { get; } = Array.Empty<ProgressItem>();
 
 	private readonly TaskRunner? task;
 
 	[Obsolete("Designer")]
 	public ProgressDialogModel() {}
 
-	public ProgressDialogModel(TaskRunner task) {
+	public ProgressDialogModel(string title, TaskRunner task, int progressItems = 1) {
+		this.Title = title;
 		this.task = task;
+		this.Items = Enumerable.Range(0, progressItems).Select(static _ => new ProgressItem()).ToArray();
 	}
 
 	internal async Task StartTask() {
 		if (task != null) {
-			await task(new Callback(this));
+			await task(Items.Select(static item => new Callback(item)).ToArray());
 		}
 	}
 
-	public delegate Task TaskRunner(IProgressCallback callback);
+	public delegate Task TaskRunner(IReadOnlyList<IProgressCallback> callbacks);
 
 	private sealed class Callback : IProgressCallback {
-		private readonly ProgressDialogModel model;
+		private readonly ProgressItem item;
 
-		public Callback(ProgressDialogModel model) {
-			this.model = model;
+		public Callback(ProgressItem item) {
+			this.item = item;
 		}
 
-		async Task IProgressCallback.Update(string message, int finishedItems, int totalItems) {
+		public async Task Update(string message, int finishedItems, int totalItems) {
 			await Dispatcher.UIThread.InvokeAsync(() => {
-				model.Message = message;
-				model.Items = finishedItems.Format() + " / " + totalItems.Format();
-				model.Progress = 100 * finishedItems / totalItems;
+				item.Message = message;
+				item.Items = totalItems == 0 ? string.Empty : finishedItems.Format() + " / " + totalItems.Format();
+				item.Progress = totalItems == 0 ? 0 : 100 * finishedItems / totalItems;
+				item.IsIndeterminate = false;
 			});
 		}
+
+		public async Task UpdateIndeterminate(string message) {
+			await Dispatcher.UIThread.InvokeAsync(() => {
+				item.Message = message;
+				item.Items = string.Empty;
+				item.Progress = 0;
+				item.IsIndeterminate = true;
+			});
+		}
+
+		public Task Hide() {
+			return Update(string.Empty, 0, 0);
+		}
 	}
 }

app/Desktop/Dialogs/Progress/ProgressItem.cs

@@ -0,0 +1,48 @@
+using DHT.Utils.Models;
+
+namespace DHT.Desktop.Dialogs.Progress;
+
+sealed class ProgressItem : BaseModel {
+	private bool isVisible = false;
+
+	public bool IsVisible {
+		get => isVisible;
+		private set {
+			Change(ref isVisible, value);
+			OnPropertyChanged(nameof(Opacity));
+		}
+	}
+	
+	public double Opacity => IsVisible ? 1.0 : 0.0;
+
+	private string message = "";
+
+	public string Message {
+		get => message;
+		set {
+			Change(ref message, value);
+			IsVisible = !string.IsNullOrEmpty(value);
+		}
+	}
+
+	private string items = "";
+
+	public string Items {
+		get => items;
+		set => Change(ref items, value);
+	}
+
+	private int progress = 0;
+
+	public int Progress {
+		get => progress;
+		set => Change(ref progress, value);
+	}
+	
+	private bool isIndeterminate;
+
+	public bool IsIndeterminate {
+		get => isIndeterminate;
+		set => Change(ref isIndeterminate, value);
+	}
+}

app/Desktop/Dialogs/TextBox/TextBoxDialog.axaml

@@ -5,6 +5,7 @@
         xmlns:namespace="clr-namespace:DHT.Desktop.Dialogs.TextBox"
         mc:Ignorable="d" d:DesignWidth="500"
         x:Class="DHT.Desktop.Dialogs.TextBox.TextBoxDialog"
+        x:DataType="namespace:TextBoxDialogModel"
         Title="{Binding Title}"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
         Width="500" SizeToContent="Height" CanResize="False"

app/Desktop/Dialogs/TextBox/TextBoxDialog.axaml.cs

@@ -3,7 +3,7 @@ using Avalonia.Controls;
 using Avalonia.Interactivity;
 using DHT.Desktop.Dialogs.Message;
 
-namespace DHT.Desktop.Dialogs.TextBox; 
+namespace DHT.Desktop.Dialogs.TextBox;
 
 [SuppressMessage("ReSharper", "MemberCanBeInternal")]
 public sealed partial class TextBoxDialog : Window {

app/Desktop/Dialogs/TextBox/TextBoxDialogModel.cs

@@ -4,7 +4,7 @@ using System.ComponentModel;
 using System.Linq;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Dialogs.TextBox; 
+namespace DHT.Desktop.Dialogs.TextBox;
 
 class TextBoxDialogModel : BaseModel {
 	public string Title { get; init; } = "";

app/Desktop/Dialogs/TextBox/TextBoxItem.cs

@@ -3,7 +3,7 @@ using System.Collections;
 using System.ComponentModel;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Dialogs.TextBox; 
+namespace DHT.Desktop.Dialogs.TextBox;
 
 class TextBoxItem : BaseModel, INotifyDataErrorInfo {
 	public string Title { get; init; } = "";

app/Desktop/Discord/DiscordAppSettings.cs

@@ -1,9 +1,9 @@
 using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Runtime.InteropServices;
 using System.Text.Json;
+using System.Text.Json.Nodes;
 using System.Threading.Tasks;
 using DHT.Utils.Logging;
 using static System.Environment.SpecialFolder;
@@ -39,7 +39,8 @@ static class DiscordAppSettings {
 
 	public static async Task<bool?> AreDevToolsEnabled() {
 		try {
-			return AreDevToolsEnabled(await ReadSettingsJson());
+			var settingsJson = await ReadSettingsJson().ConfigureAwait(false);
+			return AreDevToolsEnabled(settingsJson);
 		} catch (Exception e) {
 			Log.Error("Cannot read settings file.");
 			Log.Error(e);
@@ -47,12 +48,12 @@ static class DiscordAppSettings {
 		}
 	}
 
-	private static bool AreDevToolsEnabled(Dictionary<string, object?> json) {
-		return json.TryGetValue(JsonKeyDevTools, out var value) && value is JsonElement { ValueKind: JsonValueKind.True };
+	private static bool AreDevToolsEnabled(JsonObject json) {
+		return json.TryGetPropertyValue(JsonKeyDevTools, out var node) && node?.GetValueKind() == JsonValueKind.True;
 	}
 
 	public static async Task<SettingsJsonResult> ConfigureDevTools(bool enable) {
-		Dictionary<string, object?> json;
+		JsonObject json;
 
 		try {
 			json = await ReadSettingsJson();
@@ -109,13 +110,13 @@ static class DiscordAppSettings {
 		return SettingsJsonResult.Success;
 	}
 
-	private static async Task<Dictionary<string, object?>> ReadSettingsJson() {
+	private static async Task<JsonObject> ReadSettingsJson() {
 		await using var stream = new FileStream(JsonFilePath, FileMode.Open, FileAccess.Read, FileShare.Read);
-		return await JsonSerializer.DeserializeAsync<Dictionary<string, object?>?>(stream) ?? throw new JsonException();
+		return await JsonSerializer.DeserializeAsync(stream, DiscordAppSettingsJsonContext.Default.JsonObject) ?? throw new JsonException();
 	}
 
-	private static async Task WriteSettingsJson(Dictionary<string, object?> json) {
+	private static async Task WriteSettingsJson(JsonObject json) {
 		await using var stream = new FileStream(JsonFilePath, FileMode.Truncate, FileAccess.Write, FileShare.None);
-		await JsonSerializer.SerializeAsync(stream, json, new JsonSerializerOptions { WriteIndented = true });
+		await JsonSerializer.SerializeAsync(stream, json, DiscordAppSettingsJsonContext.Default.JsonObject);
 	}
 }

app/Desktop/Discord/DiscordAppSettingsJsonContext.cs

@@ -0,0 +1,8 @@
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+
+namespace DHT.Desktop.Discord;
+
+[JsonSourceGenerationOptions(GenerationMode = JsonSourceGenerationMode.Default, WriteIndented = true)]
+[JsonSerializable(typeof(JsonObject))]
+sealed partial class DiscordAppSettingsJsonContext : JsonSerializerContext {}

app/Desktop/Main/AboutWindow.axaml

@@ -5,6 +5,7 @@
         xmlns:main="clr-namespace:DHT.Desktop.Main"
         mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="295"
         x:Class="DHT.Desktop.Main.AboutWindow"
+        x:DataType="main:AboutWindowModel"
         Title="About Discord History Tracker"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
         Width="480" Height="295" CanResize="False"

app/Desktop/Main/Controls/AttachmentFilterPanel.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              mc:Ignorable="d"
-             x:Class="DHT.Desktop.Main.Controls.AttachmentFilterPanel">
+             x:Class="DHT.Desktop.Main.Controls.AttachmentFilterPanel"
+             x:DataType="controls:AttachmentFilterPanelModel">
 
     <Design.DataContext>
         <controls:AttachmentFilterPanelModel />

app/Desktop/Main/Controls/AttachmentFilterPanelModel.cs

@@ -1,7 +1,9 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Threading.Tasks;
 using DHT.Desktop.Common;
+using DHT.Server;
 using DHT.Server.Data.Filters;
 using DHT.Server.Database;
 using DHT.Utils.Models;
@@ -12,17 +14,17 @@ namespace DHT.Desktop.Main.Controls;
 sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 	public sealed record Unit(string Name, uint Scale);
 
-	private static readonly Unit[] AllUnits = {
-		new ("B", 1),
-		new ("kB", 1024),
-		new ("MB", 1024 * 1024)
-	};
+	private static readonly Unit[] AllUnits = [
+		new Unit("B", 1),
+		new Unit("kB", 1024),
+		new Unit("MB", 1024 * 1024)
+	];
 
-	private static readonly HashSet<string> FilterProperties = new () {
+	private static readonly HashSet<string> FilterProperties = [
 		nameof(LimitSize),
 		nameof(MaximumSize),
 		nameof(MaximumSizeUnit)
-	};
+	];
 
 	public string FilterStatisticsText { get; private set; } = "";
 
@@ -47,30 +49,30 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 
 	public IEnumerable<Unit> Units => AllUnits;
 
-	private readonly IDatabaseFile db;
+	private readonly State state;
 	private readonly string verb;
 
-	private readonly AsyncValueComputer<long> matchingAttachmentCountComputer;
+	private readonly RestartableTask<long> matchingAttachmentCountTask;
 	private long? matchingAttachmentCount;
 	private long? totalAttachmentCount;
 
 	[Obsolete("Designer")]
-	public AttachmentFilterPanelModel() : this(DummyDatabaseFile.Instance) {}
+	public AttachmentFilterPanelModel() : this(State.Dummy) {}
 
-	public AttachmentFilterPanelModel(IDatabaseFile db, string verb = "Matches") {
-		this.db = db;
+	public AttachmentFilterPanelModel(State state, string verb = "Matches") {
+		this.state = state;
 		this.verb = verb;
 
-		this.matchingAttachmentCountComputer = AsyncValueComputer<long>.WithResultProcessor(SetAttachmentCounts).Build();
+		this.matchingAttachmentCountTask = new RestartableTask<long>(SetAttachmentCounts, TaskScheduler.FromCurrentSynchronizationContext());
 
 		UpdateFilterStatistics();
 
 		PropertyChanged += OnPropertyChanged;
-		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+		state.Db.Statistics.PropertyChanged += OnDbStatisticsChanged;
 	}
 
 	public void Dispose() {
-		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+		state.Db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
 	}
 
 	private void OnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
@@ -81,7 +83,7 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 
 	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
 		if (e.PropertyName == nameof(DatabaseStatistics.TotalAttachments)) {
-			totalAttachmentCount = db.Statistics.TotalAttachments;
+			totalAttachmentCount = state.Db.Statistics.TotalAttachments;
 			UpdateFilterStatistics();
 		}
 	}
@@ -89,14 +91,14 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 	private void UpdateFilterStatistics() {
 		var filter = CreateFilter();
 		if (filter.IsEmpty) {
-			matchingAttachmentCountComputer.Cancel();
+			matchingAttachmentCountTask.Cancel();
 			matchingAttachmentCount = totalAttachmentCount;
 			UpdateFilterStatisticsText();
 		}
 		else {
 			matchingAttachmentCount = null;
 			UpdateFilterStatisticsText();
-			matchingAttachmentCountComputer.Compute(() => db.CountAttachments(filter));
+			matchingAttachmentCountTask.Restart(cancellationToken => state.Db.Downloads.CountAttachments(filter, cancellationToken));
 		}
 	}
 
@@ -114,7 +116,7 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 	}
 
 	public AttachmentFilter CreateFilter() {
-		AttachmentFilter filter = new();
+		AttachmentFilter filter = new ();
 
 		if (LimitSize) {
 			try {

app/Desktop/Main/Controls/MessageFilterPanel.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              mc:Ignorable="d"
-             x:Class="DHT.Desktop.Main.Controls.MessageFilterPanel">
+             x:Class="DHT.Desktop.Main.Controls.MessageFilterPanel"
+             x:DataType="controls:MessageFilterPanelModel">
 
     <Design.DataContext>
         <controls:MessageFilterPanelModel />

app/Desktop/Main/Controls/MessageFilterPanelModel.cs

@@ -8,6 +8,8 @@ using Avalonia.Controls;
 using DHT.Desktop.Common;
 using DHT.Desktop.Dialogs.CheckBox;
 using DHT.Desktop.Dialogs.Message;
+using DHT.Desktop.Dialogs.Progress;
+using DHT.Server;
 using DHT.Server.Data;
 using DHT.Server.Data.Filters;
 using DHT.Server.Database;
@@ -17,7 +19,7 @@ using DHT.Utils.Tasks;
 namespace DHT.Desktop.Main.Controls;
 
 sealed class MessageFilterPanelModel : BaseModel, IDisposable {
-	private static readonly HashSet<string> FilterProperties = new () {
+	private static readonly HashSet<string> FilterProperties = [
 		nameof(FilterByDate),
 		nameof(StartDate),
 		nameof(EndDate),
@@ -25,7 +27,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		nameof(IncludedChannels),
 		nameof(FilterByUser),
 		nameof(IncludedUsers)
-	};
+	];
 
 	public string FilterStatisticsText { get; private set; } = "";
 
@@ -61,8 +63,8 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		set => Change(ref filterByChannel, value);
 	}
 
-	public HashSet<ulong> IncludedChannels {
-		get => includedChannels ?? db.GetAllChannels().Select(static channel => channel.Id).ToHashSet();
+	public HashSet<ulong>? IncludedChannels {
+		get => includedChannels;
 		set => Change(ref includedChannels, value);
 	}
 
@@ -71,8 +73,8 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		set => Change(ref filterByUser, value);
 	}
 
-	public HashSet<ulong> IncludedUsers {
-		get => includedUsers ?? db.GetAllUsers().Select(static user => user.Id).ToHashSet();
+	public HashSet<ulong>? IncludedUsers {
+		get => includedUsers;
 		set => Change(ref includedUsers, value);
 	}
 
@@ -91,33 +93,34 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 	}
 
 	private readonly Window window;
-	private readonly IDatabaseFile db;
+	private readonly State state;
 	private readonly string verb;
 
-	private readonly AsyncValueComputer<long> exportedMessageCountComputer;
+	private readonly RestartableTask<long> exportedMessageCountTask;
 	private long? exportedMessageCount;
 	private long? totalMessageCount;
 
 	[Obsolete("Designer")]
-	public MessageFilterPanelModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public MessageFilterPanelModel() : this(null!, State.Dummy) {}
 
-	public MessageFilterPanelModel(Window window, IDatabaseFile db, string verb = "Matches") {
+	public MessageFilterPanelModel(Window window, State state, string verb = "Matches") {
 		this.window = window;
-		this.db = db;
+		this.state = state;
 		this.verb = verb;
 
-		this.exportedMessageCountComputer = AsyncValueComputer<long>.WithResultProcessor(SetExportedMessageCount).Build();
+		this.exportedMessageCountTask = new RestartableTask<long>(SetExportedMessageCount, TaskScheduler.FromCurrentSynchronizationContext());
 
 		UpdateFilterStatistics();
 		UpdateChannelFilterLabel();
 		UpdateUserFilterLabel();
 
 		PropertyChanged += OnPropertyChanged;
-		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+		state.Db.Statistics.PropertyChanged += OnDbStatisticsChanged;
 	}
 
 	public void Dispose() {
-		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+		exportedMessageCountTask.Cancel();
+		state.Db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
 	}
 
 	private void OnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
@@ -136,7 +139,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 
 	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
 		if (e.PropertyName == nameof(DatabaseStatistics.TotalMessages)) {
-			totalMessageCount = db.Statistics.TotalMessages;
+			totalMessageCount = state.Db.Statistics.TotalMessages;
 			UpdateFilterStatistics();
 		}
 		else if (e.PropertyName == nameof(DatabaseStatistics.TotalChannels)) {
@@ -147,17 +150,29 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		}
 	}
 
+	private void UpdateChannelFilterLabel() {
+		long total = state.Db.Statistics.TotalChannels;
+		long included = FilterByChannel && IncludedChannels != null ? IncludedChannels.Count : total;
+		ChannelFilterLabel = "Selected " + included.Format() + " / " + total.Pluralize("channel") + ".";
+	}
+
+	private void UpdateUserFilterLabel() {
+		long total = state.Db.Statistics.TotalUsers;
+		long included = FilterByUser && IncludedUsers != null ? IncludedUsers.Count : total;
+		UserFilterLabel = "Selected " + included.Format() + " / " + total.Pluralize("user") + ".";
+	}
+
 	private void UpdateFilterStatistics() {
 		var filter = CreateFilter();
 		if (filter.IsEmpty) {
-			exportedMessageCountComputer.Cancel();
+			exportedMessageCountTask.Cancel();
 			exportedMessageCount = totalMessageCount;
 			UpdateFilterStatisticsText();
 		}
 		else {
 			exportedMessageCount = null;
 			UpdateFilterStatisticsText();
-			exportedMessageCountComputer.Compute(() => db.CountMessages(filter));
+			exportedMessageCountTask.Restart(cancellationToken => state.Db.Messages.Count(filter, cancellationToken));
 		}
 	}
 
@@ -174,103 +189,98 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		OnPropertyChanged(nameof(FilterStatisticsText));
 	}
 
-	public async void OpenChannelFilterDialog() {
-		var servers = db.GetAllServers().ToDictionary(static server => server.Id);
-		var items = new List<CheckBoxItem<ulong>>();
-		var included = IncludedChannels;
+	public async Task OpenChannelFilterDialog() {
+		async Task<List<CheckBoxItem<ulong>>> PrepareChannelItems(ProgressDialog dialog) {
+			var items = new List<CheckBoxItem<ulong>>();
+			var servers = await state.Db.Servers.Get().ToDictionaryAsync(static server => server.Id);
 
-		foreach (var channel in db.GetAllChannels()) {
-			var channelId = channel.Id;
-			var channelName = channel.Name;
+			await foreach (var channel in state.Db.Channels.Get()) {
+				var channelId = channel.Id;
+				var channelName = channel.Name;
 
-			string title;
-			if (servers.TryGetValue(channel.Server, out var server)) {
-				var titleBuilder = new StringBuilder();
-				var serverType = server.Type;
+				string title;
+				if (servers.TryGetValue(channel.Server, out var server)) {
+					var titleBuilder = new StringBuilder();
+					var serverType = server.Type;
 
-				titleBuilder.Append('[')
-				            .Append(ServerTypes.ToString(serverType))
-				            .Append("] ");
+					titleBuilder.Append('[')
+					            .Append(ServerTypes.ToString(serverType))
+					            .Append("] ");
 
-				if (serverType == ServerType.DirectMessage) {
-					titleBuilder.Append(channelName);
+					if (serverType == ServerType.DirectMessage) {
+						titleBuilder.Append(channelName);
+					}
+					else {
+						titleBuilder.Append(server.Name)
+						            .Append(" - ")
+						            .Append(channelName);
+					}
+
+					title = titleBuilder.ToString();
 				}
 				else {
-					titleBuilder.Append(server.Name)
-					            .Append(" - ")
-					            .Append(channelName);
+					title = channelName;
 				}
 
-				title = titleBuilder.ToString();
-			}
-			else {
-				title = channelName;
+				items.Add(new CheckBoxItem<ulong>(channelId) {
+					Title = title,
+					Checked = IncludedChannels == null || IncludedChannels.Contains(channelId)
+				});
 			}
 
-			items.Add(new CheckBoxItem<ulong>(channelId) {
-				Title = title,
-				Checked = included.Contains(channelId)
-			});
+			return items;
+		}
+		
+		const string Title = "Included Channels";
+
+		List<CheckBoxItem<ulong>> items;
+		try {
+			items = await ProgressDialog.ShowIndeterminate(window, Title, "Loading channels...", PrepareChannelItems);
+		} catch (Exception e) {
+			await Dialog.ShowOk(window, Title, "Error loading channels: " + e.Message);
+			return;
 		}
 
-		var result = await OpenIdFilterDialog(window, "Included Channels", items);
+		var result = await OpenIdFilterDialog(Title, items);
 		if (result != null) {
 			IncludedChannels = result;
 		}
 	}
 
-	public async void OpenUserFilterDialog() {
-		var items = new List<CheckBoxItem<ulong>>();
-		var included = IncludedUsers;
+	public async Task OpenUserFilterDialog() {
+		async Task<List<CheckBoxItem<ulong>>> PrepareUserItems(ProgressDialog dialog) {
+			var checkBoxItems = new List<CheckBoxItem<ulong>>();
 
-		foreach (var user in db.GetAllUsers()) {
-			var name = user.Name;
-			var discriminator = user.Discriminator;
+			await foreach (var user in state.Db.Users.Get()) {
+				var name = user.Name;
+				var discriminator = user.Discriminator;
 
-			items.Add(new CheckBoxItem<ulong>(user.Id) {
-				Title = discriminator == null ? name : name + " #" + discriminator,
-				Checked = included.Contains(user.Id)
-			});
+				checkBoxItems.Add(new CheckBoxItem<ulong>(user.Id) {
+					Title = discriminator == null ? name : name + " #" + discriminator,
+					Checked = IncludedUsers == null || IncludedUsers.Contains(user.Id)
+				});
+			}
+
+			return checkBoxItems;
 		}
 
-		var result = await OpenIdFilterDialog(window, "Included Users", items);
+		const string Title = "Included Users";
+		
+		List<CheckBoxItem<ulong>> items;
+		try {
+			items = await ProgressDialog.ShowIndeterminate(window, Title, "Loading users...", PrepareUserItems);
+		} catch (Exception e) {
+			await Dialog.ShowOk(window, Title, "Error loading users: " + e.Message);
+			return;
+		}
+
+		var result = await OpenIdFilterDialog(Title, items);
 		if (result != null) {
 			IncludedUsers = result;
 		}
 	}
 
-	private void UpdateChannelFilterLabel() {
-		long total = db.Statistics.TotalChannels;
-		long included = FilterByChannel ? IncludedChannels.Count : total;
-		ChannelFilterLabel = "Selected " + included.Format() + " / " + total.Pluralize("channel") + ".";
-	}
-
-	private void UpdateUserFilterLabel() {
-		long total = db.Statistics.TotalUsers;
-		long included = FilterByUser ? IncludedUsers.Count : total;
-		UserFilterLabel = "Selected " + included.Format() + " / " + total.Pluralize("user") + ".";
-	}
-
-	public MessageFilter CreateFilter() {
-		MessageFilter filter = new();
-
-		if (FilterByDate) {
-			filter.StartDate = StartDate;
-			filter.EndDate = EndDate?.AddDays(1).AddMilliseconds(-1);
-		}
-
-		if (FilterByChannel) {
-			filter.ChannelIds = new HashSet<ulong>(IncludedChannels);
-		}
-
-		if (FilterByUser) {
-			filter.UserIds = new HashSet<ulong>(IncludedUsers);
-		}
-
-		return filter;
-	}
-
-	private static async Task<HashSet<ulong>?> OpenIdFilterDialog(Window window, string title, List<CheckBoxItem<ulong>> items) {
+	private async Task<HashSet<ulong>?> OpenIdFilterDialog(string title, List<CheckBoxItem<ulong>> items) {
 		items.Sort(static (item1, item2) => item1.Title.CompareTo(item2.Title));
 
 		var model = new CheckBoxDialogModel<ulong>(items) {
@@ -282,4 +292,23 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 
 		return result == DialogResult.OkCancel.Ok ? model.SelectedItems.Select(static item => item.Item).ToHashSet() : null;
 	}
+
+	public MessageFilter CreateFilter() {
+		MessageFilter filter = new ();
+
+		if (FilterByDate) {
+			filter.StartDate = StartDate;
+			filter.EndDate = EndDate?.AddDays(1).AddMilliseconds(-1);
+		}
+
+		if (FilterByChannel && IncludedChannels != null) {
+			filter.ChannelIds = new HashSet<ulong>(IncludedChannels);
+		}
+
+		if (FilterByUser && IncludedUsers != null) {
+			filter.UserIds = new HashSet<ulong>(IncludedUsers);
+		}
+
+		return filter;
+	}
 }

app/Desktop/Main/Controls/ServerConfigurationPanel.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              mc:Ignorable="d"
-             x:Class="DHT.Desktop.Main.Controls.ServerConfigurationPanel">
+             x:Class="DHT.Desktop.Main.Controls.ServerConfigurationPanel"
+             x:DataType="controls:ServerConfigurationPanelModel">
 
     <Design.DataContext>
         <controls:ServerConfigurationPanelModel />

app/Desktop/Main/Controls/ServerConfigurationPanelModel.cs

@@ -1,14 +1,19 @@
 using System;
+using System.Threading.Tasks;
 using Avalonia.Controls;
+using Avalonia.Threading;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Server;
-using DHT.Server.Database;
+using DHT.Server;
 using DHT.Server.Service;
+using DHT.Utils.Logging;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main.Controls;
 
 sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
+	private static readonly Log Log = Log.ForType<ServerConfigurationPanelModel>();
+	
 	private string inputPort;
 
 	public string InputPort {
@@ -29,7 +34,7 @@ sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
 		}
 	}
 
-	public bool HasMadeChanges => ServerManager.Port.ToString() != InputPort || ServerManager.Token != InputToken;
+	public bool HasMadeChanges => ServerConfiguration.Port.ToString() != InputPort || ServerConfiguration.Token != InputToken;
 
 	private bool isToggleServerButtonEnabled = true;
 
@@ -38,59 +43,69 @@ sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
 		set => Change(ref isToggleServerButtonEnabled, value);
 	}
 
-	public string ToggleServerButtonText => serverManager.IsRunning ? "Stop Server" : "Start Server";
-
-	public event EventHandler<StatusBarModel.Status>? ServerStatusChanged;
+	public string ToggleServerButtonText => server.IsRunning ? "Stop Server" : "Start Server";
 
 	private readonly Window window;
-	private readonly ServerManager serverManager;
+	private readonly ServerManager server;
 
 	[Obsolete("Designer")]
-	public ServerConfigurationPanelModel() : this(null!, new ServerManager(DummyDatabaseFile.Instance)) {}
+	public ServerConfigurationPanelModel() : this(null!, State.Dummy) {}
 
-	public ServerConfigurationPanelModel(Window window, ServerManager serverManager) {
+	public ServerConfigurationPanelModel(Window window, State state) {
 		this.window = window;
-		this.serverManager = serverManager;
-		this.inputPort = ServerManager.Port.ToString();
-		this.inputToken = ServerManager.Token;
-	}
-
-	public void Initialize() {
-		ServerLauncher.ServerStatusChanged += ServerLauncherOnServerStatusChanged;
+		this.server = state.Server;
+		this.inputPort = ServerConfiguration.Port.ToString();
+		this.inputToken = ServerConfiguration.Token;
+		
+		server.StatusChanged += OnServerStatusChanged;
 	}
 
 	public void Dispose() {
-		ServerLauncher.ServerStatusChanged -= ServerLauncherOnServerStatusChanged;
+		server.StatusChanged -= OnServerStatusChanged;
 	}
 
-	private void ServerLauncherOnServerStatusChanged(object? sender, EventArgs e) {
-		ServerStatusChanged?.Invoke(this, serverManager.IsRunning ? StatusBarModel.Status.Ready : StatusBarModel.Status.Stopped);
+	private void OnServerStatusChanged(object? sender, ServerManager.Status e) {
+		Dispatcher.UIThread.InvokeAsync(UpdateServerStatus);
+	}
+
+	private void UpdateServerStatus() {
 		OnPropertyChanged(nameof(ToggleServerButtonText));
+	}
+
+	private async Task StartServer() {
+		IsToggleServerButtonEnabled = false;
+		
+		try {
+			await server.Start(ServerConfiguration.Port, ServerConfiguration.Token);
+		} catch (Exception e) {
+			Log.Error(e);
+			await Dialog.ShowOk(window, "Internal Server Error", e.Message);
+		}
+		
+		UpdateServerStatus();
 		IsToggleServerButtonEnabled = true;
 	}
 
-	private void BeforeServerStart() {
+	private async Task StopServer() {
 		IsToggleServerButtonEnabled = false;
-		ServerStatusChanged?.Invoke(this, StatusBarModel.Status.Starting);
+		
+		try {
+			await server.Stop();
+		} catch (Exception e) {
+			Log.Error(e);
+			await Dialog.ShowOk(window, "Internal Server Error", e.Message);
+		}
+		
+		UpdateServerStatus();
+		IsToggleServerButtonEnabled = true;
 	}
 
-	private void StartServer() {
-		BeforeServerStart();
-		serverManager.Launch();
-	}
-
-	private void StopServer() {
-		IsToggleServerButtonEnabled = false;
-		ServerStatusChanged?.Invoke(this, StatusBarModel.Status.Stopping);
-		serverManager.Stop();
-	}
-
-	public void OnClickToggleServerButton() {
-		if (serverManager.IsRunning) {
-			StopServer();
+	public async Task OnClickToggleServerButton() {
+		if (server.IsRunning) {
+			await StopServer();
 		}
 		else {
-			StartServer();
+			await StartServer();
 		}
 	}
 
@@ -98,19 +113,22 @@ sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
 		InputToken = ServerUtils.GenerateRandomToken(20);
 	}
 
-	public async void OnClickApplyChanges() {
+	public async Task OnClickApplyChanges() {
 		if (!ushort.TryParse(InputPort, out ushort port)) {
 			await Dialog.ShowOk(window, "Invalid Port", "Port must be a number between 0 and 65535.");
 			return;
 		}
 
-		BeforeServerStart();
-		serverManager.Relaunch(port, InputToken);
+		ServerConfiguration.Port = port;
+		ServerConfiguration.Token = inputToken;
+		
 		OnPropertyChanged(nameof(HasMadeChanges));
+		
+		await StartServer();
 	}
 
 	public void OnClickCancelChanges() {
-		InputPort = ServerManager.Port.ToString();
-		InputToken = ServerManager.Token;
+		InputPort = ServerConfiguration.Port.ToString();
+		InputToken = ServerConfiguration.Token;
 	}
 }

app/Desktop/Main/Controls/StatusBar.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              mc:Ignorable="d"
-             x:Class="DHT.Desktop.Main.Controls.StatusBar">
+             x:Class="DHT.Desktop.Main.Controls.StatusBar"
+             x:DataType="controls:StatusBarModel">
 
     <Design.DataContext>
         <controls:StatusBarModel />
@@ -39,22 +40,22 @@
     <StackPanel Orientation="Horizontal" Margin="6 3">
         <StackPanel Orientation="Vertical" Width="65">
             <TextBlock Classes="label">Status</TextBlock>
-            <TextBlock FontSize="12" Margin="0 3 0 0" Text="{Binding StatusText}" />
+            <TextBlock FontSize="12" Margin="0 3 0 0" Text="{Binding ServerStatusText}" />
         </StackPanel>
         <Rectangle />
         <StackPanel Orientation="Vertical">
             <TextBlock Classes="label">Servers</TextBlock>
-            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalServers, Converter={StaticResource NumberValueConverter}}" />
+            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalServers, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" />
         </StackPanel>
         <Rectangle />
         <StackPanel Orientation="Vertical">
             <TextBlock Classes="label">Channels</TextBlock>
-            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalChannels, Converter={StaticResource NumberValueConverter}}" />
+            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalChannels, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" />
         </StackPanel>
         <Rectangle />
         <StackPanel Orientation="Vertical">
             <TextBlock Classes="label">Messages</TextBlock>
-            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalMessages, Converter={StaticResource NumberValueConverter}}" />
+            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalMessages, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" />
         </StackPanel>
     </StackPanel>
 

app/Desktop/Main/Controls/StatusBarModel.cs

@@ -1,45 +1,46 @@
 using System;
+using Avalonia.Threading;
+using DHT.Server;
 using DHT.Server.Database;
+using DHT.Server.Service;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main.Controls;
 
-sealed class StatusBarModel : BaseModel {
+sealed class StatusBarModel : BaseModel, IDisposable {
 	public DatabaseStatistics DatabaseStatistics { get; }
 
-	private Status status = Status.Stopped;
+	private ServerManager.Status serverStatus;
 
-	public Status CurrentStatus {
-		get => status;
-		set {
-			status = value;
-			OnPropertyChanged(nameof(StatusText));
-		}
-	}
+	public string ServerStatusText => serverStatus switch {
+		ServerManager.Status.Starting => "STARTING",
+		ServerManager.Status.Started  => "READY",
+		ServerManager.Status.Stopping => "STOPPING",
+		ServerManager.Status.Stopped  => "STOPPED",
+		_                             => ""
+	};
 
-	public string StatusText {
-		get {
-			return CurrentStatus switch {
-				Status.Starting => "STARTING",
-				Status.Ready    => "READY",
-				Status.Stopping => "STOPPING",
-				Status.Stopped  => "STOPPED",
-				_               => ""
-			};
-		}
-	}
+	private readonly State state;
 
 	[Obsolete("Designer")]
-	public StatusBarModel() : this(new DatabaseStatistics()) {}
+	public StatusBarModel() : this(State.Dummy) {}
 
-	public StatusBarModel(DatabaseStatistics databaseStatistics) {
-		this.DatabaseStatistics = databaseStatistics;
+	public StatusBarModel(State state) {
+		this.state = state;
+		this.DatabaseStatistics = state.Db.Statistics;
+
+		state.Server.StatusChanged += OnServerStatusChanged;
+		serverStatus = state.Server.IsRunning ? ServerManager.Status.Started : ServerManager.Status.Stopped;
 	}
 
-	public enum Status {
-		Starting,
-		Ready,
-		Stopping,
-		Stopped
+	public void Dispose() {
+		state.Server.StatusChanged -= OnServerStatusChanged;
+	}
+
+	private void OnServerStatusChanged(object? sender, ServerManager.Status e) {
+		Dispatcher.UIThread.InvokeAsync(() => {
+			serverStatus = e;
+			OnPropertyChanged(nameof(ServerStatusText));
+		});
 	}
 }

app/Desktop/Main/MainWindow.axaml

@@ -5,12 +5,13 @@
         xmlns:main="clr-namespace:DHT.Desktop.Main"
         mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
         x:Class="DHT.Desktop.Main.MainWindow"
+        x:DataType="main:MainWindowModel"
         Title="{Binding Title}"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
         Width="800" Height="500"
         MinWidth="520" MinHeight="300"
         WindowStartupLocation="CenterScreen"
-        Closed="OnClosed">
+        Closing="OnClosing">
 
     <Design.DataContext>
         <main:MainWindowModel />

app/Desktop/Main/MainWindow.axaml.cs

@@ -1,14 +1,18 @@
 using System;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
+using System.Threading.Tasks;
 using Avalonia.Controls;
 using DHT.Desktop.Main.Pages;
+using DHT.Utils.Logging;
 using JetBrains.Annotations;
 
 namespace DHT.Desktop.Main;
 
 [SuppressMessage("ReSharper", "MemberCanBeInternal")]
 public sealed partial class MainWindow : Window {
+	private static readonly Log Log = Log.ForType<MainWindow>();
+	
 	[UsedImplicitly]
 	public MainWindow() {
 		InitializeComponent();
@@ -20,9 +24,24 @@ public sealed partial class MainWindow : Window {
 		DataContext = new MainWindowModel(this, args);
 	}
 
-	public void OnClosed(object? sender, EventArgs e) {
-		if (DataContext is IDisposable disposable) {
-			disposable.Dispose();
+	public async void OnClosing(object? sender, WindowClosingEventArgs e) {
+		e.Cancel = true;
+		Closing -= OnClosing;
+
+		try {
+			await Dispose();
+		} finally {
+			Close();
+		}
+	}
+
+	private async Task Dispose() {
+		if (DataContext is MainWindowModel model) {
+			try {
+				await model.DisposeAsync();
+			} catch (Exception ex) {
+				Log.Error("Caught exception while disposing window: " + ex);
+			}
 		}
 
 		foreach (var temporaryFile in ViewerPageModel.TemporaryFiles) {

app/Desktop/Main/MainWindowModel.cs

@@ -1,5 +1,4 @@
 using System;
-using System.ComponentModel;
 using System.IO;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
@@ -7,14 +6,18 @@ using Avalonia.Controls;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Screens;
 using DHT.Desktop.Server;
+using DHT.Server;
 using DHT.Server.Database;
+using DHT.Utils.Logging;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main;
 
-sealed class MainWindowModel : BaseModel, IDisposable {
+sealed class MainWindowModel : BaseModel, IAsyncDisposable {
 	private const string DefaultTitle = "Discord History Tracker";
 
+	private static readonly Log Log = Log.ForType<MainWindowModel>();
+
 	public string Title { get; private set; } = DefaultTitle;
 
 	public UserControl CurrentScreen { get; private set; }
@@ -22,12 +25,11 @@ sealed class MainWindowModel : BaseModel, IDisposable {
 	private readonly WelcomeScreen welcomeScreen;
 	private readonly WelcomeScreenModel welcomeScreenModel;
 
-	private MainContentScreen? mainContentScreen;
 	private MainContentScreenModel? mainContentScreenModel;
 
 	private readonly Window window;
 
-	private IDatabaseFile? db;
+	private State? state;
 
 	[Obsolete("Designer")]
 	public MainWindowModel() : this(null!, Arguments.Empty) {}
@@ -36,11 +38,11 @@ sealed class MainWindowModel : BaseModel, IDisposable {
 		this.window = window;
 
 		welcomeScreenModel = new WelcomeScreenModel(window);
+		welcomeScreenModel.DatabaseSelected += OnDatabaseSelected;
+
 		welcomeScreen = new WelcomeScreen { DataContext = welcomeScreenModel };
 		CurrentScreen = welcomeScreen;
 
-		welcomeScreenModel.PropertyChanged += WelcomeScreenModelOnPropertyChanged;
-
 		var dbFile = args.DatabaseFile;
 		if (!string.IsNullOrWhiteSpace(dbFile)) {
 			async void OnWindowOpened(object? o, EventArgs eventArgs) {
@@ -63,54 +65,67 @@ sealed class MainWindowModel : BaseModel, IDisposable {
 		}
 
 		if (args.ServerPort != null) {
-			ServerManager.Port = args.ServerPort.Value;
+			ServerConfiguration.Port = args.ServerPort.Value;
 		}
 
 		if (args.ServerToken != null) {
-			ServerManager.Token = args.ServerToken;
+			ServerConfiguration.Token = args.ServerToken;
 		}
 	}
 
-	private async void WelcomeScreenModelOnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
-		if (e.PropertyName == nameof(welcomeScreenModel.Db)) {
-			if (mainContentScreenModel != null) {
-				mainContentScreenModel.DatabaseClosed -= MainContentScreenModelOnDatabaseClosed;
-				mainContentScreenModel.Dispose();
-			}
+	private async void OnDatabaseSelected(object? sender, IDatabaseFile db) {
+		welcomeScreenModel.DatabaseSelected -= OnDatabaseSelected;
+		
+		await DisposeState();
+		
+		state = new State(db);
 
-			db?.Dispose();
-			db = welcomeScreenModel.Db;
+		try {
+			await state.Server.Start(ServerConfiguration.Port, ServerConfiguration.Token);
+		} catch (Exception ex) {
+			Log.Error(ex);
+			await Dialog.ShowOk(window, "Internal Server Error", ex.Message);
+		}
 
-			if (db == null) {
-				Title = DefaultTitle;
-				mainContentScreenModel = null;
-				mainContentScreen = null;
-				CurrentScreen = welcomeScreen;
-			}
-			else {
-				Title = Path.GetFileName(db.Path) + " - " + DefaultTitle;
-				mainContentScreenModel = new MainContentScreenModel(window, db);
-				await mainContentScreenModel.Initialize();
-				mainContentScreenModel.DatabaseClosed += MainContentScreenModelOnDatabaseClosed;
-				mainContentScreen = new MainContentScreen { DataContext = mainContentScreenModel };
-				CurrentScreen = mainContentScreen;
-			}
+		mainContentScreenModel = new MainContentScreenModel(window, state);
+		mainContentScreenModel.DatabaseClosed += MainContentScreenModelOnDatabaseClosed;
+		
+		Title = Path.GetFileName(state.Db.Path) + " - " + DefaultTitle;
+		CurrentScreen = new MainContentScreen { DataContext = mainContentScreenModel };
 
-			OnPropertyChanged(nameof(CurrentScreen));
-			OnPropertyChanged(nameof(Title));
+		OnPropertyChanged(nameof(Title));
+		OnPropertyChanged(nameof(CurrentScreen));
 
-			window.Focus();
+		window.Focus();
+	}
+
+	private async void MainContentScreenModelOnDatabaseClosed(object? sender, EventArgs e) {
+		if (mainContentScreenModel != null) {
+			mainContentScreenModel.DatabaseClosed -= MainContentScreenModelOnDatabaseClosed;
+			mainContentScreenModel.Dispose();
+			mainContentScreenModel = null;
+		}
+
+		await DisposeState();
+
+		Title = DefaultTitle;
+		CurrentScreen = welcomeScreen;
+
+		welcomeScreenModel.DatabaseSelected += OnDatabaseSelected;
+		
+		OnPropertyChanged(nameof(Title));
+		OnPropertyChanged(nameof(CurrentScreen));
+	}
+
+	private async Task DisposeState() {
+		if (state != null) {
+			await state.DisposeAsync();
+			state = null;
 		}
 	}
 
-	private void MainContentScreenModelOnDatabaseClosed(object? sender, EventArgs e) {
-		welcomeScreenModel.CloseDatabase();
-	}
-
-	public void Dispose() {
-		welcomeScreenModel.Dispose();
+	public async ValueTask DisposeAsync() {
 		mainContentScreenModel?.Dispose();
-		db?.Dispose();
-		db = null;
+		await DisposeState();
 	}
 }

app/Desktop/Main/Pages/AdvancedPage.axaml

@@ -5,7 +5,8 @@
              xmlns:pages="clr-namespace:DHT.Desktop.Main.Pages"
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Pages.AdvancedPage">
+             x:Class="DHT.Desktop.Main.Pages.AdvancedPage"
+             x:DataType="pages:AdvancedPageModel">
 
     <Design.DataContext>
         <pages:AdvancedPageModel />

app/Desktop/Main/Pages/AdvancedPageModel.cs

@@ -1,39 +1,37 @@
 using System;
+using System.Threading.Tasks;
 using Avalonia.Controls;
 using DHT.Desktop.Dialogs.Message;
+using DHT.Desktop.Dialogs.Progress;
 using DHT.Desktop.Main.Controls;
-using DHT.Desktop.Server;
-using DHT.Server.Database;
+using DHT.Server;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main.Pages;
 
 sealed class AdvancedPageModel : BaseModel, IDisposable {
 	public ServerConfigurationPanelModel ServerConfigurationModel { get; }
-
+	
 	private readonly Window window;
-	private readonly IDatabaseFile db;
+	private readonly State state;
 
 	[Obsolete("Designer")]
-	public AdvancedPageModel() : this(null!, DummyDatabaseFile.Instance, new ServerManager(DummyDatabaseFile.Instance)) {}
+	public AdvancedPageModel() : this(null!, State.Dummy) {}
 
-	public AdvancedPageModel(Window window, IDatabaseFile db, ServerManager serverManager) {
+	public AdvancedPageModel(Window window, State state) {
 		this.window = window;
-		this.db = db;
+		this.state = state;
 
-		ServerConfigurationModel = new ServerConfigurationPanelModel(window, serverManager);
-	}
-
-	public void Initialize() {
-		ServerConfigurationModel.Initialize();
+		ServerConfigurationModel = new ServerConfigurationPanelModel(window, state);
 	}
 
 	public void Dispose() {
 		ServerConfigurationModel.Dispose();
 	}
 
-	public async void VacuumDatabase() {
-		db.Vacuum();
-		await Dialog.ShowOk(window, "Vacuum Database", "Done.");
+	public async Task VacuumDatabase() {
+		const string Title = "Vacuum Database";
+		await ProgressDialog.ShowIndeterminate(window, Title, "Vacuuming database...", _ => state.Db.Vacuum());
+		await Dialog.ShowOk(window, Title, "Done.");
 	}
 }

app/Desktop/Main/Pages/AttachmentsPage.axaml

@@ -5,7 +5,8 @@
              xmlns:pages="clr-namespace:DHT.Desktop.Main.Pages"
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Pages.AttachmentsPage">
+             x:Class="DHT.Desktop.Main.Pages.AttachmentsPage"
+             x:DataType="pages:AttachmentsPageModel">
 
     <Design.DataContext>
         <pages:AttachmentsPageModel />
@@ -32,22 +33,22 @@
     <StackPanel Orientation="Vertical" Spacing="20">
         <DockPanel>
             <Button Command="{Binding OnClickToggleDownload}" Content="{Binding ToggleDownloadButtonText}" IsEnabled="{Binding IsToggleDownloadButtonEnabled}" DockPanel.Dock="Left" />
-            <TextBlock Text="{Binding DownloadMessage}" Margin="10 0 0 0" VerticalAlignment="Center" DockPanel.Dock="Left" />
+            <TextBlock Text="{Binding DownloadMessage}" MinWidth="100" Margin="10 0 0 0" VerticalAlignment="Center" TextAlignment="Right" DockPanel.Dock="Left" />
             <ProgressBar Value="{Binding DownloadProgress}" IsVisible="{Binding IsDownloading}" Margin="15 0" VerticalAlignment="Center" DockPanel.Dock="Right" />
         </DockPanel>
-        <controls:AttachmentFilterPanel DataContext="{Binding FilterModel}" IsEnabled="{Binding !DataContext.IsDownloading, RelativeSource={RelativeSource AncestorType=UserControl}}" />
+        <controls:AttachmentFilterPanel DataContext="{Binding FilterModel}" IsEnabled="{Binding !IsDownloading, RelativeSource={RelativeSource AncestorType=pages:AttachmentsPageModel}}" />
         <StackPanel Orientation="Vertical" Spacing="12">
             <Expander Header="Download Status" IsExpanded="True">
                 <DataGrid ItemsSource="{Binding StatisticsRows}" AutoGenerateColumns="False" CanUserReorderColumns="False" CanUserResizeColumns="False" CanUserSortColumns="False" IsReadOnly="True">
                     <DataGrid.Columns>
                         <DataGridTextColumn Header="State" Binding="{Binding State}" Width="*" />
-                        <DataGridTextColumn Header="Attachments" Binding="{Binding Items, Converter={StaticResource NumberValueConverter}}" Width="*" CellStyleClasses="right" />
-                        <DataGridTextColumn Header="Size" Binding="{Binding Size, Converter={StaticResource BytesValueConverter}}" Width="*" CellStyleClasses="right" />
+                        <DataGridTextColumn Header="Attachments" Binding="{Binding Items, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" Width="*" CellStyleClasses="right" />
+                        <DataGridTextColumn Header="Size" Binding="{Binding Size, Mode=OneWay, Converter={StaticResource BytesValueConverter}}" Width="*" CellStyleClasses="right" />
                     </DataGrid.Columns>
                 </DataGrid>
             </Expander>
             <StackPanel Orientation="Horizontal" Spacing="10">
-                <Button Command="{Binding OnClickRetryFailedDownloads}" IsEnabled="{Binding HasFailedDownloads}">Retry Failed Downloads</Button>
+                <Button Command="{Binding OnClickRetryFailedDownloads}" IsEnabled="{Binding IsRetryFailedOnDownloadsButtonEnabled}">Retry Failed Downloads</Button>
             </StackPanel>
         </StackPanel>
     </StackPanel>

app/Desktop/Main/Pages/AttachmentsPageModel.cs

@@ -1,38 +1,55 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
-using System.Threading;
-using Avalonia.Threading;
+using System.Reactive.Linq;
+using System.Threading.Tasks;
+using Avalonia.ReactiveUI;
 using DHT.Desktop.Common;
 using DHT.Desktop.Main.Controls;
+using DHT.Server;
 using DHT.Server.Data;
 using DHT.Server.Data.Aggregations;
 using DHT.Server.Data.Filters;
 using DHT.Server.Database;
-using DHT.Server.Download;
+using DHT.Utils.Logging;
 using DHT.Utils.Models;
 using DHT.Utils.Tasks;
 
 namespace DHT.Desktop.Main.Pages;
 
 sealed class AttachmentsPageModel : BaseModel, IDisposable {
-	private static readonly DownloadItemFilter EnqueuedItemFilter = new() {
+	private static readonly Log Log = Log.ForType<AttachmentsPageModel>();
+
+	private static readonly DownloadItemFilter EnqueuedItemFilter = new () {
 		IncludeStatuses = new HashSet<DownloadStatus> {
-			DownloadStatus.Enqueued
+			DownloadStatus.Enqueued,
+			DownloadStatus.Downloading
 		}
 	};
 
-	private bool isThreadDownloadButtonEnabled = true;
-
-	public string ToggleDownloadButtonText => downloadThread == null ? "Start Downloading" : "Stop Downloading";
+	private bool isToggleDownloadButtonEnabled = true;
 
 	public bool IsToggleDownloadButtonEnabled {
-		get => isThreadDownloadButtonEnabled;
-		set => Change(ref isThreadDownloadButtonEnabled, value);
+		get => isToggleDownloadButtonEnabled;
+		set => Change(ref isToggleDownloadButtonEnabled, value);
 	}
 
+	public string ToggleDownloadButtonText => IsDownloading ? "Stop Downloading" : "Start Downloading";
+
+	private bool isRetryingFailedDownloads = false;
+
+	public bool IsRetryingFailedDownloads {
+		get => isRetryingFailedDownloads;
+		set {
+			isRetryingFailedDownloads = value;
+			OnPropertyChanged(nameof(IsRetryFailedOnDownloadsButtonEnabled));
+		}
+	}
+
+	public bool IsRetryFailedOnDownloadsButtonEnabled => !IsRetryingFailedDownloads && HasFailedDownloads;
+
 	public string DownloadMessage { get; set; } = "";
-	public double DownloadProgress => allItemsCount is null or 0 ? 0.0 : 100.0 * doneItemsCount / allItemsCount.Value;
+	public double DownloadProgress => totalItemsToDownloadCount is null or 0 ? 0.0 : 100.0 * doneItemsCount / totalItemsToDownloadCount.Value;
 
 	public AttachmentFilterPanelModel FilterModel { get; }
 
@@ -41,66 +58,151 @@ sealed class AttachmentsPageModel : BaseModel, IDisposable {
 	private readonly StatisticsRow statisticsFailed = new ("Failed");
 	private readonly StatisticsRow statisticsSkipped = new ("Skipped");
 
-	public List<StatisticsRow> StatisticsRows {
-		get {
-			return new List<StatisticsRow> {
-				statisticsEnqueued,
-				statisticsDownloaded,
-				statisticsFailed,
-				statisticsSkipped
-			};
-		}
-	}
+	public List<StatisticsRow> StatisticsRows => [
+		statisticsEnqueued,
+		statisticsDownloaded,
+		statisticsFailed,
+		statisticsSkipped
+	];
 
-	public bool IsDownloading => downloadThread != null;
+	public bool IsDownloading => state.Downloader.IsDownloading;
 	public bool HasFailedDownloads => statisticsFailed.Items > 0;
 
-	private readonly IDatabaseFile db;
-	private readonly AsyncValueComputer<DownloadStatusStatistics>.Single downloadStatisticsComputer;
-	private BackgroundDownloadThread? downloadThread;
+	private readonly State state;
+	private readonly ThrottledTask<int> enqueueDownloadItemsTask;
+	private readonly ThrottledTask<DownloadStatusStatistics> downloadStatisticsTask;
 
+	private IDisposable? finishedItemsSubscription;
 	private int doneItemsCount;
-	private int? allItemsCount;
+	private int totalEnqueuedItemCount;
+	private int? totalItemsToDownloadCount;
 
-	public AttachmentsPageModel() : this(DummyDatabaseFile.Instance) {}
+	public AttachmentsPageModel() : this(State.Dummy) {}
 
-	public AttachmentsPageModel(IDatabaseFile db) {
-		this.db = db;
-		this.FilterModel = new AttachmentFilterPanelModel(db);
+	public AttachmentsPageModel(State state) {
+		this.state = state;
 
-		this.downloadStatisticsComputer = AsyncValueComputer<DownloadStatusStatistics>.WithResultProcessor(UpdateStatistics).WithOutdatedResults().BuildWithComputer(db.GetDownloadStatusStatistics);
-		this.downloadStatisticsComputer.Recompute();
+		FilterModel = new AttachmentFilterPanelModel(state);
 
-		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+		enqueueDownloadItemsTask = new ThrottledTask<int>(OnItemsEnqueued, TaskScheduler.FromCurrentSynchronizationContext());
+		downloadStatisticsTask = new ThrottledTask<DownloadStatusStatistics>(UpdateStatistics, TaskScheduler.FromCurrentSynchronizationContext());
+		RecomputeDownloadStatistics();
+
+		state.Db.Statistics.PropertyChanged += OnDbStatisticsChanged;
 	}
 
 	public void Dispose() {
-		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
-
+		state.Db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+		enqueueDownloadItemsTask.Dispose();
+		downloadStatisticsTask.Dispose();
+		finishedItemsSubscription?.Dispose();
 		FilterModel.Dispose();
-		DisposeDownloadThread();
 	}
 
 	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
 		if (e.PropertyName == nameof(DatabaseStatistics.TotalAttachments)) {
 			if (IsDownloading) {
-				EnqueueDownloadItems();
+				EnqueueDownloadItemsLater();
 			}
 			else {
-				downloadStatisticsComputer.Recompute();
+				RecomputeDownloadStatistics();
 			}
 		}
 		else if (e.PropertyName == nameof(DatabaseStatistics.TotalDownloads)) {
-			downloadStatisticsComputer.Recompute();
+			RecomputeDownloadStatistics();
 		}
 	}
 
-	private void EnqueueDownloadItems() {
+	private async Task EnqueueDownloadItems() {
+		OnItemsEnqueued(await state.Db.Downloads.EnqueueDownloadItems(CreateAttachmentFilter()));
+	}
+
+	private void EnqueueDownloadItemsLater() {
+		var filter = CreateAttachmentFilter();
+		enqueueDownloadItemsTask.Post(cancellationToken => state.Db.Downloads.EnqueueDownloadItems(filter, cancellationToken));
+	}
+
+	private void OnItemsEnqueued(int itemCount) {
+		totalEnqueuedItemCount += itemCount;
+		totalItemsToDownloadCount = totalEnqueuedItemCount;
+		UpdateDownloadMessage();
+		RecomputeDownloadStatistics();
+	}
+
+	private AttachmentFilter CreateAttachmentFilter() {
 		var filter = FilterModel.CreateFilter();
 		filter.DownloadItemRule = AttachmentFilter.DownloadItemRules.OnlyNotPresent;
-		db.EnqueueDownloadItems(filter);
+		return filter;
+	}
 
-		downloadStatisticsComputer.Recompute();
+	public async Task OnClickToggleDownload() {
+		IsToggleDownloadButtonEnabled = false;
+
+		if (IsDownloading) {
+			await state.Downloader.Stop();
+
+			finishedItemsSubscription?.Dispose();
+			finishedItemsSubscription = null;
+
+			RecomputeDownloadStatistics();
+
+			await state.Db.Downloads.RemoveDownloadItems(EnqueuedItemFilter, FilterRemovalMode.RemoveMatching);
+
+			doneItemsCount = 0;
+			totalEnqueuedItemCount = 0;
+			totalItemsToDownloadCount = null;
+			UpdateDownloadMessage();
+		}
+		else {
+			var finishedItems = await state.Downloader.Start();
+
+			finishedItemsSubscription = finishedItems.Select(static _ => true)
+			                                         .Buffer(TimeSpan.FromMilliseconds(100))
+			                                         .Select(static items => items.Count)
+			                                         .Where(static items => items > 0)
+			                                         .ObserveOn(AvaloniaScheduler.Instance)
+			                                         .Subscribe(OnItemsFinished);
+
+			await EnqueueDownloadItems();
+		}
+
+		OnPropertyChanged(nameof(ToggleDownloadButtonText));
+		OnPropertyChanged(nameof(IsDownloading));
+		IsToggleDownloadButtonEnabled = true;
+	}
+
+	private void OnItemsFinished(int finishedItemCount) {
+		doneItemsCount += finishedItemCount;
+		UpdateDownloadMessage();
+		RecomputeDownloadStatistics();
+	}
+
+	public async Task OnClickRetryFailedDownloads() {
+		IsRetryingFailedDownloads = true;
+
+		try {
+			var allExceptFailedFilter = new DownloadItemFilter {
+				IncludeStatuses = new HashSet<DownloadStatus> {
+					DownloadStatus.Enqueued,
+					DownloadStatus.Downloading,
+					DownloadStatus.Success
+				}
+			};
+
+			await state.Db.Downloads.RemoveDownloadItems(allExceptFailedFilter, FilterRemovalMode.KeepMatching);
+
+			if (IsDownloading) {
+				await EnqueueDownloadItems();
+			}
+		} catch (Exception e) {
+			Log.Error(e);
+		} finally {
+			IsRetryingFailedDownloads = false;
+		}
+	}
+
+	private void RecomputeDownloadStatistics() {
+		downloadStatisticsTask.Post(state.Db.Downloads.GetStatistics);
 	}
 
 	private void UpdateStatistics(DownloadStatusStatistics statusStatistics) {
@@ -122,77 +224,19 @@ sealed class AttachmentsPageModel : BaseModel, IDisposable {
 
 		if (hadFailedDownloads != HasFailedDownloads) {
 			OnPropertyChanged(nameof(HasFailedDownloads));
+			OnPropertyChanged(nameof(IsRetryFailedOnDownloadsButtonEnabled));
 		}
 
-		allItemsCount = doneItemsCount + statisticsEnqueued.Items;
 		UpdateDownloadMessage();
 	}
 
 	private void UpdateDownloadMessage() {
-		DownloadMessage = IsDownloading ? doneItemsCount.Format() + " / " + (allItemsCount?.Format() ?? "?") : "";
+		DownloadMessage = IsDownloading ? doneItemsCount.Format() + " / " + (totalItemsToDownloadCount?.Format() ?? "?") : "";
 
 		OnPropertyChanged(nameof(DownloadMessage));
 		OnPropertyChanged(nameof(DownloadProgress));
 	}
 
-	private void DownloadThreadOnOnItemFinished(object? sender, DownloadItem e) {
-		Interlocked.Increment(ref doneItemsCount);
-
-		Dispatcher.UIThread.Invoke(UpdateDownloadMessage);
-		downloadStatisticsComputer.Recompute();
-	}
-
-	private void DownloadThreadOnOnServerStopped(object? sender, EventArgs e) {
-		downloadStatisticsComputer.Recompute();
-		IsToggleDownloadButtonEnabled = true;
-	}
-
-	public void OnClickToggleDownload() {
-		if (downloadThread == null) {
-			EnqueueDownloadItems();
-			downloadThread = new BackgroundDownloadThread(db);
-			downloadThread.OnItemFinished += DownloadThreadOnOnItemFinished;
-			downloadThread.OnServerStopped += DownloadThreadOnOnServerStopped;
-		}
-		else {
-			IsToggleDownloadButtonEnabled = false;
-			DisposeDownloadThread();
-
-			db.RemoveDownloadItems(EnqueuedItemFilter, FilterRemovalMode.RemoveMatching);
-
-			doneItemsCount = 0;
-			allItemsCount = null;
-			UpdateDownloadMessage();
-		}
-
-		OnPropertyChanged(nameof(ToggleDownloadButtonText));
-		OnPropertyChanged(nameof(IsDownloading));
-	}
-
-	public void OnClickRetryFailedDownloads() {
-		var allExceptFailedFilter = new DownloadItemFilter {
-			IncludeStatuses = new HashSet<DownloadStatus> {
-				DownloadStatus.Enqueued,
-				DownloadStatus.Success
-			}
-		};
-
-		db.RemoveDownloadItems(allExceptFailedFilter, FilterRemovalMode.KeepMatching);
-
-		if (IsDownloading) {
-			EnqueueDownloadItems();
-		}
-	}
-
-	private void DisposeDownloadThread() {
-		if (downloadThread != null) {
-			downloadThread.OnItemFinished -= DownloadThreadOnOnItemFinished;
-			downloadThread.StopThread();
-		}
-
-		downloadThread = null;
-	}
-
 	public sealed class StatisticsRow {
 		public string State { get; }
 		public int Items { get; set; }

app/Desktop/Main/Pages/DatabasePage.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:pages="clr-namespace:DHT.Desktop.Main.Pages"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Pages.DatabasePage">
+             x:Class="DHT.Desktop.Main.Pages.DatabasePage"
+             x:DataType="pages:DatabasePageModel">
 
     <Design.DataContext>
         <pages:DatabasePageModel />

app/Desktop/Main/Pages/DatabasePageModel.cs

@@ -14,13 +14,15 @@ using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Dialogs.Progress;
 using DHT.Desktop.Dialogs.TextBox;
+using DHT.Server;
 using DHT.Server.Data;
 using DHT.Server.Database;
 using DHT.Server.Database.Import;
+using DHT.Server.Database.Sqlite.Utils;
 using DHT.Utils.Logging;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Main.Pages; 
+namespace DHT.Desktop.Main.Pages;
 
 sealed class DatabasePageModel : BaseModel {
 	private static readonly Log Log = Log.ForType<DatabasePageModel>();
@@ -32,14 +34,14 @@ sealed class DatabasePageModel : BaseModel {
 	private readonly Window window;
 
 	[Obsolete("Designer")]
-	public DatabasePageModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public DatabasePageModel() : this(null!, State.Dummy) {}
 
-	public DatabasePageModel(Window window, IDatabaseFile db) {
+	public DatabasePageModel(Window window, State state) {
 		this.window = window;
-		this.Db = db;
+		this.Db = state.Db;
 	}
 
-	public async void OpenDatabaseFolder() {
+	public async Task OpenDatabaseFolder() {
 		string file = Db.Path;
 		string? folder = Path.GetDirectoryName(file);
 
@@ -70,45 +72,25 @@ sealed class DatabasePageModel : BaseModel {
 		DatabaseClosed?.Invoke(this, EventArgs.Empty);
 	}
 
-	public async void MergeWithDatabase() {
+	public async Task MergeWithDatabase() {
 		var paths = await DatabaseGui.NewOpenDatabaseFilesDialog(window, Path.GetDirectoryName(Db.Path));
-		if (paths.Length == 0) {
-			return;
+		if (paths.Length > 0) {
+			await ProgressDialog.Show(window, "Database Merge", async (dialog, callback) => await MergeWithDatabaseFromPaths(Db, paths, dialog, callback));
 		}
-
-		ProgressDialog progressDialog = new ProgressDialog();
-		progressDialog.DataContext = new ProgressDialogModel(async callback => await MergeWithDatabaseFromPaths(Db, paths, progressDialog, callback)) {
-			Title = "Database Merge"
-		};
-
-		await progressDialog.ShowDialog(window);
 	}
 
 	private static async Task MergeWithDatabaseFromPaths(IDatabaseFile target, string[] paths, ProgressDialog dialog, IProgressCallback callback) {
-		int total = paths.Length;
-
-		DialogResult.YesNo? upgradeResult = null;
-
-		async Task<bool> CheckCanUpgradeDatabase() {
-			upgradeResult ??= total > 1
-				                  ? await DatabaseGui.ShowCanUpgradeMultipleDatabaseDialog(dialog)
-				                  : await DatabaseGui.ShowCanUpgradeDatabaseDialog(dialog);
-
-			return DialogResult.YesNo.Yes == upgradeResult;
-		}
-
+		var schemaUpgradeCallbacks = new SchemaUpgradeCallbacks(dialog, paths.Length);
+		
 		await PerformImport(target, paths, dialog, callback, "Database Merge", "Database Error", "database file", async path => {
-			SynchronizationContext? prevSyncContext = SynchronizationContext.Current;
-			SynchronizationContext.SetSynchronizationContext(new AvaloniaSynchronizationContext());
-			IDatabaseFile? db = await DatabaseGui.TryOpenOrCreateDatabaseFromPath(path, dialog, CheckCanUpgradeDatabase);
-			SynchronizationContext.SetSynchronizationContext(prevSyncContext);
+			IDatabaseFile? db = await DatabaseGui.TryOpenOrCreateDatabaseFromPath(path, dialog, schemaUpgradeCallbacks);
 
 			if (db == null) {
 				return false;
 			}
 
 			try {
-				target.AddFrom(db);
+				await target.AddFrom(db);
 				return true;
 			} finally {
 				db.Dispose();
@@ -116,23 +98,51 @@ sealed class DatabasePageModel : BaseModel {
 		});
 	}
 
-	public async void ImportLegacyArchive() {
+	private sealed class SchemaUpgradeCallbacks : ISchemaUpgradeCallbacks {
+		private readonly ProgressDialog dialog;
+		private readonly int total;
+		private bool? decision;
+		
+		public SchemaUpgradeCallbacks(ProgressDialog dialog, int total) {
+			this.total = total;
+			this.dialog = dialog;
+		}
+
+		public async Task<bool> CanUpgrade() {
+			return decision ??= (total > 1
+				                     ? await DatabaseGui.ShowCanUpgradeMultipleDatabaseDialog(dialog)
+				                     : await DatabaseGui.ShowCanUpgradeDatabaseDialog(dialog)) == DialogResult.YesNo.Yes;
+		}
+
+		public Task Start(int versionSteps, Func<ISchemaUpgradeCallbacks.IProgressReporter, Task> doUpgrade) {
+			return doUpgrade(new NullReporter());
+		}
+
+		private sealed class NullReporter : ISchemaUpgradeCallbacks.IProgressReporter {
+			public Task NextVersion() {
+				return Task.CompletedTask;
+			}
+
+			public Task MainWork(string message, int finishedItems, int totalItems) {
+				return Task.CompletedTask;
+			}
+
+			public Task SubWork(string message, int finishedItems, int totalItems) {
+				return Task.CompletedTask;
+			}
+		}
+	}
+
+	public async Task ImportLegacyArchive() {
 		var paths = await window.StorageProvider.OpenFiles(new FilePickerOpenOptions {
 			Title = "Open Legacy DHT Archive",
 			SuggestedStartLocation = await FileDialogs.GetSuggestedStartLocation(window, Path.GetDirectoryName(Db.Path)),
 			AllowMultiple = true
 		});
-			
-		if (paths.Length == 0) {
-			return;
+
+		if (paths.Length > 0) {
+			await ProgressDialog.Show(window, "Legacy Archive Import", async (dialog, callback) => await ImportLegacyArchiveFromPaths(Db, paths, dialog, callback));
 		}
-
-		ProgressDialog progressDialog = new ProgressDialog();
-		progressDialog.DataContext = new ProgressDialogModel(async callback => await ImportLegacyArchiveFromPaths(Db, paths, progressDialog, callback)) {
-			Title = "Legacy Archive Import"
-		};
-
-		await progressDialog.ShowDialog(window);
 	}
 
 	private static async Task ImportLegacyArchiveFromPaths(IDatabaseFile target, string[] paths, ProgressDialog dialog, IProgressCallback callback) {
@@ -184,7 +194,7 @@ sealed class DatabasePageModel : BaseModel {
 
 	private static async Task PerformImport(IDatabaseFile target, string[] paths, ProgressDialog dialog, IProgressCallback callback, string neutralDialogTitle, string errorDialogTitle, string itemName, Func<string, Task<bool>> performImport) {
 		int total = paths.Length;
-		var oldStatistics = target.SnapshotStatistics();
+		var oldStatistics = await target.SnapshotStatistics();
 
 		int successful = 0;
 		int finished = 0;
@@ -215,7 +225,8 @@ sealed class DatabasePageModel : BaseModel {
 			return;
 		}
 
-		await Dialog.ShowOk(dialog, neutralDialogTitle, GetImportDialogMessage(oldStatistics, target.SnapshotStatistics(), successful, total, itemName));
+		var newStatistics = await target.SnapshotStatistics();
+		await Dialog.ShowOk(dialog, neutralDialogTitle, GetImportDialogMessage(oldStatistics, newStatistics, successful, total, itemName));
 	}
 
 	private static string GetImportDialogMessage(DatabaseStatisticsSnapshot oldStatistics, DatabaseStatisticsSnapshot newStatistics, int successfulItems, int totalItems, string itemName) {

app/Desktop/Main/Pages/DebugPage.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:pages="clr-namespace:DHT.Desktop.Main.Pages"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Pages.DebugPage">
+             x:Class="DHT.Desktop.Main.Pages.DebugPage"
+             x:DataType="pages:DebugPageModel">
     
     <Design.DataContext>
         <pages:DebugPageModel />

app/Desktop/Main/Pages/DebugPageModel.cs

@@ -6,8 +6,8 @@ using System.Threading.Tasks;
 using Avalonia.Controls;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Dialogs.Progress;
+using DHT.Server;
 using DHT.Server.Data;
-using DHT.Server.Database;
 using DHT.Server.Service;
 using DHT.Utils.Models;
 
@@ -18,14 +18,14 @@ namespace DHT.Desktop.Main.Pages {
 		public string GenerateMessages { get; set; } = "0";
 
 		private readonly Window window;
-		private readonly IDatabaseFile db;
+		private readonly State state;
 
 		[Obsolete("Designer")]
-		public DebugPageModel() : this(null!, DummyDatabaseFile.Instance) {}
+		public DebugPageModel() : this(null!, State.Dummy) {}
 
-		public DebugPageModel(Window window, IDatabaseFile db) {
+		public DebugPageModel(Window window, State state) {
 			this.window = window;
-			this.db = db;
+			this.state = state;
 		}
 
 		public async void OnClickAddRandomDataToDatabase() {
@@ -44,13 +44,7 @@ namespace DHT.Desktop.Main.Pages {
 				return;
 			}
 
-			ProgressDialog progressDialog = new ProgressDialog {
-				DataContext = new ProgressDialogModel(async callback => await GenerateRandomData(channels, users, messages, callback)) {
-					Title = "Generating Random Data"
-				}
-			};
-
-			await progressDialog.ShowDialog(window);
+			await ProgressDialog.Show(window, "Generating Random Data", async (_, callback) => await GenerateRandomData(channels, users, messages, callback));
 		}
 
 		private const int BatchSize = 500;
@@ -83,12 +77,9 @@ namespace DHT.Desktop.Main.Pages {
 				Discriminator = rand.Next(0, 9999).ToString(),
 			}).ToArray();
 
-			db.AddServer(server);
-			db.AddUsers(users);
-
-			foreach (var channel in channels) {
-				db.AddChannel(channel);
-			}
+			await state.Db.Users.Add(users);
+			await state.Db.Servers.Add([server]);
+			await state.Db.Channels.Add(channels);
 
 			var now = DateTimeOffset.Now;
 			int batchIndex = 0;
@@ -111,13 +102,13 @@ namespace DHT.Desktop.Main.Pages {
 						Timestamp = timeMillis,
 						EditTimestamp = editMillis,
 						RepliedToId = null,
-						Attachments = ImmutableArray<Attachment>.Empty,
-						Embeds = ImmutableArray<Embed>.Empty,
-						Reactions = ImmutableArray<Reaction>.Empty,
+						Attachments = ImmutableList<Attachment>.Empty,
+						Embeds = ImmutableList<Embed>.Empty,
+						Reactions = ImmutableList<Reaction>.Empty,
 					};
 				}).ToArray();
 
-				db.AddMessages(messages);
+				await state.Db.Messages.Add(messages);
 
 				messageCount -= BatchSize;
 				await callback.Update("Adding messages in batches of " + BatchSize, ++batchIndex, batchCount);

app/Desktop/Main/Pages/TrackingPage.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:pages="clr-namespace:DHT.Desktop.Main.Pages"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Pages.TrackingPage">
+             x:Class="DHT.Desktop.Main.Pages.TrackingPage"
+             x:DataType="pages:TrackingPageModel">
 
     <Design.DataContext>
         <pages:TrackingPageModel />
@@ -15,7 +16,7 @@
             To start tracking messages, copy the tracking script and paste it into the console of either the Discord app, or your browser. The console is usually opened by pressing Ctrl+Shift+I.
         </TextBlock>
         <StackPanel DockPanel.Dock="Left" Orientation="Horizontal" Spacing="10">
-            <Button x:Name="CopyTrackingScript" Click="CopyTrackingScriptButton_OnClick">Copy Tracking Script</Button>
+            <Button x:Name="CopyTrackingScript" Click="CopyTrackingScriptButton_OnClick" IsEnabled="{Binding IsCopyTrackingScriptButtonEnabled}">Copy Tracking Script</Button>
         </StackPanel>
         <TextBlock TextWrapping="Wrap" Margin="0 5 0 0">
             By default, the Discord app does not allow opening the console. The button below will change a hidden setting in the Discord app that controls whether the Ctrl+Shift+I shortcut is enabled.

app/Desktop/Main/Pages/TrackingPageModel.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 using System.Web;
 using Avalonia.Controls;
@@ -11,9 +12,16 @@ using static DHT.Desktop.Program;
 namespace DHT.Desktop.Main.Pages;
 
 sealed class TrackingPageModel : BaseModel {
-	private bool areDevToolsEnabled;
+	private bool isCopyTrackingScriptButtonEnabled = true;
 
-	private bool AreDevToolsEnabled {
+	public bool IsCopyTrackingScriptButtonEnabled {
+		get => isCopyTrackingScriptButtonEnabled;
+		set => Change(ref isCopyTrackingScriptButtonEnabled, value);
+	}
+
+	private bool? areDevToolsEnabled;
+
+	private bool? AreDevToolsEnabled {
 		get => areDevToolsEnabled;
 		set {
 			Change(ref areDevToolsEnabled, value);
@@ -21,15 +29,19 @@ sealed class TrackingPageModel : BaseModel {
 		}
 	}
 
-	public bool IsToggleAppDevToolsButtonEnabled { get; private set; } = true;
+	public bool IsToggleAppDevToolsButtonEnabled { get; private set; } = false;
 
 	public string ToggleAppDevToolsButtonText {
 		get {
+			if (!AreDevToolsEnabled.HasValue) {
+				return "Loading...";
+			}
+
 			if (!IsToggleAppDevToolsButtonEnabled) {
 				return "Unavailable";
 			}
 
-			return AreDevToolsEnabled ? "Disable Ctrl+Shift+I" : "Enable Ctrl+Shift+I";
+			return AreDevToolsEnabled.Value ? "Disable Ctrl+Shift+I" : "Enable Ctrl+Shift+I";
 		}
 	}
 
@@ -40,26 +52,23 @@ sealed class TrackingPageModel : BaseModel {
 
 	public TrackingPageModel(Window window) {
 		this.window = window;
-	}
 
-	public async Task Initialize() {
-		bool? devToolsEnabled = await DiscordAppSettings.AreDevToolsEnabled();
-		if (devToolsEnabled.HasValue) {
-			AreDevToolsEnabled = devToolsEnabled.Value;
-		}
-		else {
-			IsToggleAppDevToolsButtonEnabled = false;
-			OnPropertyChanged(nameof(IsToggleAppDevToolsButtonEnabled));
-		}
+		Task.Factory.StartNew(InitializeDevToolsToggle, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.FromCurrentSynchronizationContext());
 	}
 
 	public async Task<bool> OnClickCopyTrackingScript() {
-		string bootstrap = await Resources.ReadTextAsync("Tracker/bootstrap.js");
-		string script = bootstrap.Replace("= 0; /*[PORT]*/", "= " + ServerManager.Port + ";")
-		                         .Replace("/*[TOKEN]*/", HttpUtility.JavaScriptStringEncode(ServerManager.Token))
-		                         .Replace("/*[IMPORTS]*/", await Resources.ReadJoinedAsync("Tracker/scripts/", '\n'))
-		                         .Replace("/*[CSS-CONTROLLER]*/", await Resources.ReadTextAsync("Tracker/styles/controller.css"))
-		                         .Replace("/*[CSS-SETTINGS]*/", await Resources.ReadTextAsync("Tracker/styles/settings.css"));
+		IsCopyTrackingScriptButtonEnabled = false;
+
+		try {
+			return await CopyTrackingScript();
+		} finally {
+			IsCopyTrackingScriptButtonEnabled = true;
+		}
+	}
+
+	private async Task<bool> CopyTrackingScript() {
+		string url = $"http://127.0.0.1:{ServerConfiguration.Port}/get-tracking-script?token={HttpUtility.UrlEncode(ServerConfiguration.Token)}";
+		string script = (await Resources.ReadTextAsync("tracker-loader.js")).Trim().Replace("{url}", url);
 
 		var clipboard = window.Clipboard;
 		if (clipboard == null) {
@@ -76,10 +85,28 @@ sealed class TrackingPageModel : BaseModel {
 		}
 	}
 
-	public async void OnClickToggleAppDevTools() {
+	private async Task InitializeDevToolsToggle() {
+		bool? devToolsEnabled = await DiscordAppSettings.AreDevToolsEnabled();
+
+		if (devToolsEnabled.HasValue) {
+			IsToggleAppDevToolsButtonEnabled = true;
+			AreDevToolsEnabled = devToolsEnabled.Value;
+		}
+		else {
+			IsToggleAppDevToolsButtonEnabled = false;
+		}
+
+		OnPropertyChanged(nameof(IsToggleAppDevToolsButtonEnabled));
+	}
+
+	public async Task OnClickToggleAppDevTools() {
 		const string DialogTitle = "Discord App Settings File";
 
-		bool oldState = AreDevToolsEnabled;
+		if (!AreDevToolsEnabled.HasValue) {
+			return;
+		}
+
+		bool oldState = AreDevToolsEnabled.Value;
 		bool newState = !oldState;
 
 		switch (await DiscordAppSettings.ConfigureDevTools(newState)) {

app/Desktop/Main/Pages/ViewerPage.axaml

@@ -5,7 +5,8 @@
              xmlns:pages="clr-namespace:DHT.Desktop.Main.Pages"
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Pages.ViewerPage">
+             x:Class="DHT.Desktop.Main.Pages.ViewerPage"
+             x:DataType="pages:ViewerPageModel">
 
     <Design.DataContext>
         <pages:ViewerPageModel />

app/Desktop/Main/Pages/ViewerPageModel.cs

@@ -11,10 +11,11 @@ using Avalonia.Platform.Storage;
 using DHT.Desktop.Common;
 using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
+using DHT.Desktop.Dialogs.Progress;
 using DHT.Desktop.Main.Controls;
 using DHT.Desktop.Server;
+using DHT.Server;
 using DHT.Server.Data.Filters;
-using DHT.Server.Database;
 using DHT.Server.Database.Export;
 using DHT.Server.Database.Export.Strategy;
 using DHT.Utils.Models;
@@ -23,7 +24,11 @@ using static DHT.Desktop.Program;
 namespace DHT.Desktop.Main.Pages;
 
 sealed class ViewerPageModel : BaseModel, IDisposable {
-	public static readonly ConcurrentBag<string> TemporaryFiles = new ();
+	public static readonly ConcurrentBag<string> TemporaryFiles = [];
+
+	private static readonly FilePickerFileType[] ViewerFileTypes = [
+		FileDialogs.CreateFilter("Discord History Viewer", ["html"])
+	];
 
 	public bool DatabaseToolFilterModeKeep { get; set; } = true;
 	public bool DatabaseToolFilterModeRemove { get; set; } = false;
@@ -35,19 +40,19 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		set => Change(ref hasFilters, value);
 	}
 
-	private MessageFilterPanelModel FilterModel { get; }
+	public MessageFilterPanelModel FilterModel { get; }
 
 	private readonly Window window;
-	private readonly IDatabaseFile db;
+	private readonly State state;
 
 	[Obsolete("Designer")]
-	public ViewerPageModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public ViewerPageModel() : this(null!, State.Dummy) {}
 
-	public ViewerPageModel(Window window, IDatabaseFile db) {
+	public ViewerPageModel(Window window, State state) {
 		this.window = window;
-		this.db = db;
+		this.state = state;
 
-		FilterModel = new MessageFilterPanelModel(window, db, "Will export");
+		FilterModel = new MessageFilterPanelModel(window, state, "Will export");
 		FilterModel.FilterPropertyChanged += OnFilterPropertyChanged;
 	}
 
@@ -59,6 +64,58 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		HasFilters = FilterModel.HasAnyFilters;
 	}
 
+	public async void OnClickOpenViewer() {
+		try {
+			var fullPath = await PrepareTemporaryViewerFile();
+			var strategy = new LiveViewerExportStrategy(ServerConfiguration.Port, ServerConfiguration.Token);
+
+			await WriteViewerFile(fullPath, strategy);
+			Process.Start(new ProcessStartInfo(fullPath) { UseShellExecute = true });
+		} catch (Exception e) {
+			await Dialog.ShowOk(window, "Open Viewer", "Could not save viewer: " + e.Message);
+		}
+	}
+
+	private async Task<string> PrepareTemporaryViewerFile() {
+		return await Task.Run(() => {
+			string rootPath = Path.Combine(Path.GetTempPath(), "DiscordHistoryTracker");
+			string filenameBase = Path.GetFileNameWithoutExtension(state.Db.Path) + "-" + DateTime.Now.ToString("yyyy-MM-dd");
+			string fullPath = Path.Combine(rootPath, filenameBase + ".html");
+			
+			int counter = 0;
+
+			while (File.Exists(fullPath)) {
+				++counter;
+				fullPath = Path.Combine(rootPath, filenameBase + "-" + counter + ".html");
+			}
+
+			TemporaryFiles.Add(fullPath);
+
+			Directory.CreateDirectory(rootPath);
+
+			return fullPath;
+		});
+	}
+
+	public async void OnClickSaveViewer() {
+		string? path = await window.StorageProvider.SaveFile(new FilePickerSaveOptions {
+			Title = "Save Viewer",
+			FileTypeChoices = ViewerFileTypes,
+			SuggestedFileName = Path.GetFileNameWithoutExtension(state.Db.Path) + ".html",
+			SuggestedStartLocation = await FileDialogs.GetSuggestedStartLocation(window, Path.GetDirectoryName(state.Db.Path)),
+		});
+
+		if (path == null) {
+			return;
+		}
+
+		try {
+			await WriteViewerFile(path, StandaloneViewerExportStrategy.Instance);
+		} catch (Exception e) {
+			await Dialog.ShowOk(window, "Save Viewer", "Could not save viewer: " + e.Message);
+		}
+	}
+
 	private async Task WriteViewerFile(string path, IViewerExportStrategy strategy) {
 		const string ArchiveTag = "/*[ARCHIVE]*/";
 
@@ -72,7 +129,7 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		string jsonTempFile = path + ".tmp";
 
 		await using (var jsonStream = new FileStream(jsonTempFile, FileMode.Create, FileAccess.ReadWrite, FileShare.Read)) {
-			await ViewerJsonExport.Generate(jsonStream, strategy, db, FilterModel.CreateFilter());
+			await ViewerJsonExport.Generate(jsonStream, strategy, state.Db, FilterModel.CreateFilter());
 
 			char[] jsonBuffer = new char[Math.Min(32768, jsonStream.Position)];
 			jsonStream.Position = 0;
@@ -96,54 +153,23 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		File.Delete(jsonTempFile);
 	}
 
-	public async void OnClickOpenViewer() {
-		string rootPath = Path.Combine(Path.GetTempPath(), "DiscordHistoryTracker");
-		string filenameBase = Path.GetFileNameWithoutExtension(db.Path) + "-" + DateTime.Now.ToString("yyyy-MM-dd");
-		string fullPath = Path.Combine(rootPath, filenameBase + ".html");
-		int counter = 0;
-
-		while (File.Exists(fullPath)) {
-			++counter;
-			fullPath = Path.Combine(rootPath, filenameBase + "-" + counter + ".html");
-		}
-
-		TemporaryFiles.Add(fullPath);
-
-		Directory.CreateDirectory(rootPath);
-		await WriteViewerFile(fullPath, new LiveViewerExportStrategy(ServerManager.Port, ServerManager.Token));
-
-		Process.Start(new ProcessStartInfo(fullPath) { UseShellExecute = true });
-	}
-
-	private static readonly FilePickerFileType[] ViewerFileTypes = {
-		FileDialogs.CreateFilter("Discord History Viewer", new string[] { "html" }),
-	};
-	
-	public async void OnClickSaveViewer() {
-		string? path = await window.StorageProvider.SaveFile(new FilePickerSaveOptions {
-			Title = "Save Viewer",
-			FileTypeChoices = ViewerFileTypes,
-			SuggestedFileName = Path.GetFileNameWithoutExtension(db.Path) + ".html",
-			SuggestedStartLocation = await FileDialogs.GetSuggestedStartLocation(window, Path.GetDirectoryName(db.Path)),
-		});
-
-		if (path != null) {
-			await WriteViewerFile(path, StandaloneViewerExportStrategy.Instance);
-		}
-	}
-
-	public async void OnClickApplyFiltersToDatabase() {
+	public async Task OnClickApplyFiltersToDatabase() {
 		var filter = FilterModel.CreateFilter();
+		var messageCount = await ProgressDialog.ShowIndeterminate(window, "Apply Filters", "Counting matching messages...", _ => state.Db.Messages.Count(filter));
 
 		if (DatabaseToolFilterModeKeep) {
-			if (DialogResult.YesNo.Yes == await Dialog.ShowYesNo(window, "Keep Matching Messages in This Database", db.CountMessages(filter).Pluralize("message") + " will be kept, and the rest will be removed from this database. This action cannot be undone. Proceed?")) {
-				db.RemoveMessages(filter, FilterRemovalMode.KeepMatching);
+			if (DialogResult.YesNo.Yes == await Dialog.ShowYesNo(window, "Keep Matching Messages in This Database", messageCount.Pluralize("message") + " will be kept, and the rest will be removed from this database. This action cannot be undone. Proceed?")) {
+				await ApplyFilterToDatabase(filter, FilterRemovalMode.KeepMatching);
 			}
 		}
 		else if (DatabaseToolFilterModeRemove) {
-			if (DialogResult.YesNo.Yes == await Dialog.ShowYesNo(window, "Remove Matching Messages in This Database", db.CountMessages(filter).Pluralize("message") + " will be removed from this database. This action cannot be undone. Proceed?")) {
-				db.RemoveMessages(filter, FilterRemovalMode.RemoveMatching);
+			if (DialogResult.YesNo.Yes == await Dialog.ShowYesNo(window, "Remove Matching Messages in This Database", messageCount.Pluralize("message") + " will be removed from this database. This action cannot be undone. Proceed?")) {
+				await ApplyFilterToDatabase(filter, FilterRemovalMode.RemoveMatching);
 			}
 		}
 	}
+
+	private async Task ApplyFilterToDatabase(MessageFilter filter, FilterRemovalMode removalMode) {
+		await ProgressDialog.ShowIndeterminate(window, "Apply Filters", "Removing messages...", _ => state.Db.Messages.Remove(filter, removalMode));
+	}
 }

app/Desktop/Main/Screens/MainContentScreen.axaml

@@ -5,7 +5,8 @@
              xmlns:controls="clr-namespace:DHT.Desktop.Main.Controls"
              xmlns:screens="clr-namespace:DHT.Desktop.Main.Screens"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Screens.MainContentScreen">
+             x:Class="DHT.Desktop.Main.Screens.MainContentScreen"
+             x:DataType="screens:MainContentScreenModel">
 
     <Design.DataContext>
         <screens:MainContentScreenModel />

app/Desktop/Main/Screens/MainContentScreenModel.cs

@@ -1,19 +1,12 @@
 using System;
-using System.Threading.Tasks;
 using Avalonia.Controls;
-using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Controls;
 using DHT.Desktop.Main.Pages;
-using DHT.Desktop.Server;
-using DHT.Server.Database;
-using DHT.Server.Service;
-using DHT.Utils.Logging;
+using DHT.Server;
 
 namespace DHT.Desktop.Main.Screens;
 
 sealed class MainContentScreenModel : IDisposable {
-	private static readonly Log Log = Log.ForType<MainContentScreenModel>();
-
 	public DatabasePage DatabasePage { get; }
 	private DatabasePageModel DatabasePageModel { get; }
 
@@ -35,7 +28,7 @@ sealed class MainContentScreenModel : IDisposable {
 	public bool HasDebugPage => true;
 	private DebugPageModel DebugPageModel { get; }
 	#else
-		public bool HasDebugPage => false;
+	public bool HasDebugPage => false;
 	#endif
 
 	public StatusBarModel StatusBarModel { get; }
@@ -49,71 +42,39 @@ sealed class MainContentScreenModel : IDisposable {
 		}
 	}
 
-	private readonly Window window;
-	private readonly ServerManager serverManager;
-
 	[Obsolete("Designer")]
-	public MainContentScreenModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public MainContentScreenModel() : this(null!, State.Dummy) {}
 
-	public MainContentScreenModel(Window window, IDatabaseFile db) {
-		this.window = window;
-		this.serverManager = new ServerManager(db);
-
-		ServerLauncher.ServerManagementExceptionCaught += ServerLauncherOnServerManagementExceptionCaught;
-
-		DatabasePageModel = new DatabasePageModel(window, db);
+	public MainContentScreenModel(Window window, State state) {
+		DatabasePageModel = new DatabasePageModel(window, state);
 		DatabasePage = new DatabasePage { DataContext = DatabasePageModel };
 
 		TrackingPageModel = new TrackingPageModel(window);
 		TrackingPage = new TrackingPage { DataContext = TrackingPageModel };
 
-		AttachmentsPageModel = new AttachmentsPageModel(db);
+		AttachmentsPageModel = new AttachmentsPageModel(state);
 		AttachmentsPage = new AttachmentsPage { DataContext = AttachmentsPageModel };
 
-		ViewerPageModel = new ViewerPageModel(window, db);
+		ViewerPageModel = new ViewerPageModel(window, state);
 		ViewerPage = new ViewerPage { DataContext = ViewerPageModel };
 
-		AdvancedPageModel = new AdvancedPageModel(window, db, serverManager);
+		AdvancedPageModel = new AdvancedPageModel(window, state);
 		AdvancedPage = new AdvancedPage { DataContext = AdvancedPageModel };
 
 		#if DEBUG
-		DebugPageModel = new DebugPageModel(window, db);
+		DebugPageModel = new DebugPageModel(window, state);
 		DebugPage = new DebugPage { DataContext = DebugPageModel };
 		#else
-			DebugPage = null;
+		DebugPage = null;
 		#endif
 
-		StatusBarModel = new StatusBarModel(db.Statistics);
-
-		AdvancedPageModel.ServerConfigurationModel.ServerStatusChanged += OnServerStatusChanged;
-		DatabaseClosed += OnDatabaseClosed;
-
-		StatusBarModel.CurrentStatus = serverManager.IsRunning ? StatusBarModel.Status.Ready : StatusBarModel.Status.Stopped;
-	}
-
-	public async Task Initialize() {
-		await TrackingPageModel.Initialize();
-		AdvancedPageModel.Initialize();
-		serverManager.Launch();
+		StatusBarModel = new StatusBarModel(state);
 	}
 
 	public void Dispose() {
-		ServerLauncher.ServerManagementExceptionCaught -= ServerLauncherOnServerManagementExceptionCaught;
 		AttachmentsPageModel.Dispose();
 		ViewerPageModel.Dispose();
-		serverManager.Dispose();
-	}
-
-	private void OnServerStatusChanged(object? sender, StatusBarModel.Status e) {
-		StatusBarModel.CurrentStatus = e;
-	}
-
-	private void OnDatabaseClosed(object? sender, EventArgs e) {
-		serverManager.Stop();
-	}
-
-	private async void ServerLauncherOnServerManagementExceptionCaught(object? sender, Exception ex) {
-		Log.Error(ex);
-		await Dialog.ShowOk(window, "Internal Server Error", ex.Message);
+		AdvancedPageModel.Dispose();
+		StatusBarModel.Dispose();
 	}
 }

app/Desktop/Main/Screens/WelcomeScreen.axaml

@@ -4,7 +4,8 @@
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:screens="clr-namespace:DHT.Desktop.Main.Screens"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="DHT.Desktop.Main.Screens.WelcomeScreen">
+             x:Class="DHT.Desktop.Main.Screens.WelcomeScreen"
+             x:DataType="screens:WelcomeScreenModel">
 
     <Design.DataContext>
         <screens:WelcomeScreenModel />
@@ -31,7 +32,7 @@
             <TextBlock Text="{Binding Version, StringFormat=Discord History Tracker v{0}}" FontSize="25" Margin="0 0 0 30" HorizontalAlignment="Center" />
 
             <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
-                <Button Command="{Binding OpenOrCreateDatabase}">Open or Create Database</Button>
+                <Button Command="{Binding OpenOrCreateDatabase}" IsEnabled="{Binding IsOpenOrCreateDatabaseButtonEnabled}">Open or Create Database</Button>
                 <Button Command="{Binding ShowAboutDialog}">About</Button>
                 <Button Command="{Binding Exit}">Exit</Button>
             </StackPanel>

app/Desktop/Main/Screens/WelcomeScreenModel.cs

@@ -1,20 +1,29 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Threading.Tasks;
 using Avalonia.Controls;
 using DHT.Desktop.Common;
 using DHT.Desktop.Dialogs.Message;
+using DHT.Desktop.Dialogs.Progress;
 using DHT.Server.Database;
+using DHT.Server.Database.Sqlite.Utils;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main.Screens;
 
-sealed class WelcomeScreenModel : BaseModel, IDisposable {
+sealed class WelcomeScreenModel : BaseModel {
 	public string Version => Program.Version;
-
-	public IDatabaseFile? Db { get; private set; }
-	public bool HasDatabase => Db != null;
-
+	
+	private bool isOpenOrCreateDatabaseButtonEnabled = true;
+	
+	public bool IsOpenOrCreateDatabaseButtonEnabled {
+		get => isOpenOrCreateDatabaseButtonEnabled;
+		set => Change(ref isOpenOrCreateDatabaseButtonEnabled, value);
+	}
+	
+	public event EventHandler<IDatabaseFile>? DatabaseSelected; 
+	
 	private readonly Window window;
 
 	private string? dbFilePath;
@@ -26,45 +35,89 @@ sealed class WelcomeScreenModel : BaseModel, IDisposable {
 		this.window = window;
 	}
 
-	public async void OpenOrCreateDatabase() {
-		var path = await DatabaseGui.NewOpenOrCreateDatabaseFileDialog(window, Path.GetDirectoryName(dbFilePath));
-		if (path != null) {
-			await OpenOrCreateDatabaseFromPath(path);
+	public async Task OpenOrCreateDatabase() {
+		IsOpenOrCreateDatabaseButtonEnabled = false;
+		try {
+			var path = await DatabaseGui.NewOpenOrCreateDatabaseFileDialog(window, Path.GetDirectoryName(dbFilePath));
+			if (path != null) {
+				await OpenOrCreateDatabaseFromPath(path);
+			}
+		} finally {
+			IsOpenOrCreateDatabaseButtonEnabled = true;
 		}
 	}
 
 	public async Task OpenOrCreateDatabaseFromPath(string path) {
-		if (Db != null) {
-			Db = null;
+		dbFilePath = path;
+		
+		var db = await DatabaseGui.TryOpenOrCreateDatabaseFromPath(path, window, new SchemaUpgradeCallbacks(window));
+		if (db != null) {
+			DatabaseSelected?.Invoke(this, db);
+		}
+	}
+
+	private sealed class SchemaUpgradeCallbacks : ISchemaUpgradeCallbacks {
+		private readonly Window window;
+		
+		public SchemaUpgradeCallbacks(Window window) {
+			this.window = window;
 		}
 
-		dbFilePath = path;
-		Db = await DatabaseGui.TryOpenOrCreateDatabaseFromPath(path, window, CheckCanUpgradeDatabase);
+		public async Task<bool> CanUpgrade() {
+			return DialogResult.YesNo.Yes == await DatabaseGui.ShowCanUpgradeDatabaseDialog(window);
+		}
 
-		OnPropertyChanged(nameof(Db));
-		OnPropertyChanged(nameof(HasDatabase));
+		public async Task Start(int versionSteps, Func<ISchemaUpgradeCallbacks.IProgressReporter, Task> doUpgrade) {
+			async Task StartUpgrade(IReadOnlyList<IProgressCallback> callbacks) {
+				var reporter = new ProgressReporter(versionSteps, callbacks);
+				await reporter.NextVersion();
+				await Task.Delay(TimeSpan.FromMilliseconds(800));
+				await doUpgrade(reporter);
+				await Task.Delay(TimeSpan.FromMilliseconds(600));
+			}
+			
+			await new ProgressDialog { DataContext = new ProgressDialogModel("Upgrading Database", StartUpgrade, progressItems: 3) }.ShowProgressDialog(window);
+		}
+
+		private sealed class ProgressReporter : ISchemaUpgradeCallbacks.IProgressReporter {
+			private readonly IReadOnlyList<IProgressCallback> callbacks;
+			
+			private readonly int versionSteps;
+			private int versionProgress = 0;
+			
+			public ProgressReporter(int versionSteps, IReadOnlyList<IProgressCallback> callbacks) {
+				this.callbacks = callbacks;
+				this.versionSteps = versionSteps;
+			}
+
+			public async Task NextVersion() {
+				await callbacks[0].Update("Upgrading schema version...", versionProgress++, versionSteps);
+				await HideChildren(0);
+			}
+
+			public async Task MainWork(string message, int finishedItems, int totalItems) {
+				await callbacks[1].Update(message, finishedItems, totalItems);
+				await HideChildren(1);
+			}
+
+			public async Task SubWork(string message, int finishedItems, int totalItems) {
+				await callbacks[2].Update(message, finishedItems, totalItems);
+				await HideChildren(2);
+			}
+
+			private async Task HideChildren(int parentIndex) {
+				for (int i = parentIndex + 1; i < callbacks.Count; i++) {
+					await callbacks[i].Hide();
+				}
+			}
+		}
 	}
 
-	private async Task<bool> CheckCanUpgradeDatabase() {
-		return DialogResult.YesNo.Yes == await DatabaseGui.ShowCanUpgradeDatabaseDialog(window);
-	}
-
-	public void CloseDatabase() {
-		Dispose();
-		OnPropertyChanged(nameof(Db));
-		OnPropertyChanged(nameof(HasDatabase));
-	}
-
-	public async void ShowAboutDialog() {
-		await new AboutWindow { DataContext = new AboutWindowModel() }.ShowDialog(this.window);
+	public async Task ShowAboutDialog() {
+		await new AboutWindow { DataContext = new AboutWindowModel() }.ShowDialog(window);
 	}
 
 	public void Exit() {
 		window.Close();
 	}
-
-	public void Dispose() {
-		Db?.Dispose();
-		Db = null;
-	}
 }

app/Desktop/Program.cs

@@ -1,6 +1,8 @@
-using System.Globalization;
+using System;
+using System.Globalization;
 using System.Reflection;
 using Avalonia;
+using DHT.Utils.Logging;
 using DHT.Utils.Resources;
 
 namespace DHT.Desktop;
@@ -9,6 +11,7 @@ static class Program {
 	public static string Version { get; }
 	public static CultureInfo Culture { get; }
 	public static ResourceLoader Resources { get; }
+	public static Arguments Arguments { get; }
 
 	static Program() {
 		var assembly = Assembly.GetExecutingAssembly();
@@ -25,10 +28,21 @@ static class Program {
 		CultureInfo.DefaultThreadCurrentUICulture = CultureInfo.InvariantCulture;
 
 		Resources = new ResourceLoader(assembly);
+		Arguments = new Arguments(Environment.GetCommandLineArgs());
 	}
 
 	public static void Main(string[] args) {
-		BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);
+		if (Arguments.Console && OperatingSystem.IsWindows()) {
+			WindowsConsole.AllocConsole();
+		}
+
+		try {
+			BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);
+		} finally {
+			if (Arguments.Console && OperatingSystem.IsWindows()) {
+				WindowsConsole.FreeConsole();
+			}
+		}
 	}
 
 	private static AppBuilder BuildAvaloniaApp() {

app/Desktop/Resources/tracker-loader.js

@@ -0,0 +1 @@
+fetch("{url}").then(r => r.ok ? (r.headers.get("X-DHT") === "1" ? r.text() : Promise.reject("Invalid response")) : Promise.reject(r.status + " " + r.statusText)).then(s => eval(s)).catch(e => alert("Could not load tracking script:\n" + e));

app/Desktop/Server/ServerConfiguration.cs

@@ -0,0 +1,8 @@
+using DHT.Server.Service;
+
+namespace DHT.Desktop.Server;
+
+static class ServerConfiguration {
+	public static ushort Port { get; set; } = ServerUtils.FindAvailablePort(50000, 60000);
+	public static string Token { get; set; } = ServerUtils.GenerateRandomToken(20);
+}

app/Desktop/Server/ServerManager.cs

@@ -1,50 +0,0 @@
-using System;
-using DHT.Server.Database;
-using DHT.Server.Service;
-
-namespace DHT.Desktop.Server;
-
-sealed class ServerManager : IDisposable {
-	public static ushort Port { get; set; } = ServerUtils.FindAvailablePort(50000, 60000);
-	public static string Token { get; set; } = ServerUtils.GenerateRandomToken(20);
-
-	private static ServerManager? instance;
-
-	public bool IsRunning => ServerLauncher.IsRunning;
-
-	private readonly IDatabaseFile db;
-
-	public ServerManager(IDatabaseFile db) {
-		if (db != DummyDatabaseFile.Instance) {
-			if (instance != null) {
-				throw new InvalidOperationException("Only one instance of ServerManager can exist at the same time!");
-			}
-
-			instance = this;
-		}
-
-		this.db = db;
-	}
-
-	public void Launch() {
-		ServerLauncher.Relaunch(Port, Token, db);
-	}
-
-	public void Relaunch(ushort port, string token) {
-		Port = port;
-		Token = token;
-		Launch();
-	}
-
-	public void Stop() {
-		ServerLauncher.Stop();
-	}
-
-	public void Dispose() {
-		Stop();
-
-		if (instance == this) {
-			instance = null;
-		}
-	}
-}

app/Directory.Build.props

@@ -0,0 +1,49 @@
+<Project>
+  
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <LangVersion>12</LangVersion>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+  
+  <PropertyGroup>
+    <Authors>chylex</Authors>
+    <Company>DiscordHistoryTracker</Company>
+    <Product>DiscordHistoryTracker</Product>
+  </PropertyGroup>
+  
+  <PropertyGroup>
+    <GenerateAssemblyVersionAttribute>false</GenerateAssemblyVersionAttribute>
+    <GenerateAssemblyFileVersionAttribute>false</GenerateAssemblyFileVersionAttribute>
+    <GenerateAssemblyInformationalVersionAttribute>false</GenerateAssemblyInformationalVersionAttribute>
+  </PropertyGroup>
+  
+  <PropertyGroup>
+    <SuppressTrimAnalysisWarnings>false</SuppressTrimAnalysisWarnings>
+    <PublishTrimmed>true</PublishTrimmed>
+    <TrimMode>partial</TrimMode>
+    <EnableUnsafeBinaryFormatterSerialization>false</EnableUnsafeBinaryFormatterSerialization>
+    <EnableUnsafeUTF7Encoding>false</EnableUnsafeUTF7Encoding>
+    <EventSourceSupport>false</EventSourceSupport>
+    <HttpActivityPropagationSupport>false</HttpActivityPropagationSupport>
+    <JsonSerializerIsReflectionEnabledByDefault>false</JsonSerializerIsReflectionEnabledByDefault>
+  </PropertyGroup>
+  
+  <PropertyGroup>
+    <PublishSingleFile>true</PublishSingleFile>
+    <PublishReadyToRun>false</PublishReadyToRun>
+    <EnableCompressionInSingleFile>true</EnableCompressionInSingleFile>
+    <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
+  </PropertyGroup>
+  
+  <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
+    <DebugSymbols>false</DebugSymbols>
+    <DebugType>none</DebugType>
+  </PropertyGroup>
+  
+  <PropertyGroup>
+    <UseArtifactsOutput>true</UseArtifactsOutput>
+    <ArtifactsPath>$(MSBuildThisFileDirectory).artifacts</ArtifactsPath>
+  </PropertyGroup>
+  
+</Project>

app/Directory.build.props

@@ -1,8 +0,0 @@
-<Project>
-  
-  <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
-    <LangVersion>11</LangVersion>
-  </PropertyGroup>
-  
-</Project>

app/Resources/Tracker/bootstrap.js

@@ -64,9 +64,11 @@
 			let action = null;
 			
 			if (!DISCORD.hasMoreMessages()) {
+				console.debug("[DHT] Reached first message.");
 				action = SETTINGS.afterFirstMsg;
 			}
 			if (isNoAction(action) && !anyNewMessages) {
+				console.debug("[DHT] No new messages.");
 				action = SETTINGS.afterSavedMsg;
 			}
 			
@@ -121,7 +123,7 @@
 				onTrackingContinued(false);
 			}
 			else {
-				const anyNewMessages = await STATE.addDiscordMessages(info.id, messages);
+				const anyNewMessages = await STATE.addDiscordMessages(messages);
 				onTrackingContinued(anyNewMessages);
 			}
 		} catch (e) {
@@ -156,3 +158,4 @@
 		GUI.showSettings();
 	}
 })();
+/*[DEBUGGER]*/

app/Resources/Tracker/scripts/discord.js

@@ -1,5 +1,23 @@
 // noinspection JSUnresolvedVariable
+// noinspection LocalVariableNamingConventionJS
 class DISCORD {
+	
+	// https://discord.com/developers/docs/resources/channel#channel-object-channel-types
+	static CHANNEL_TYPE = {
+		DM: 1,
+		GROUP_DM: 3,
+		ANNOUNCEMENT_THREAD: 10,
+		PUBLIC_THREAD: 11,
+		PRIVATE_THREAD: 12
+	};
+	
+	// https://discord.com/developers/docs/resources/channel#message-object-message-types
+	static MESSAGE_TYPE = {
+		DEFAULT: 0,
+		REPLY: 19,
+		THREAD_STARTER: 21
+	};
+	
 	static getMessageOuterElement() {
 		return DOM.queryReactClass("messagesWrapper");
 	}
@@ -28,46 +46,11 @@ class DISCORD {
 	 * Calls the provided function with a list of messages whenever the currently loaded messages change.
 	 */
 	static setupMessageCallback(callback) {
-		let skipsLeft = 0;
-		let waitForCleanup = false;
 		const previousMessages = new Set();
 		
-		const timer = window.setInterval(() => {
-			if (skipsLeft > 0) {
-				--skipsLeft;
-				return;
-			}
-			
-			const view = this.getMessageOuterElement();
-			
-			if (!view) {
-				skipsLeft = 2;
-				return;
-			}
-			
-			const anyMessage = DOM.queryReactClass("message", this.getMessageOuterElement());
-			const messageCount = anyMessage ? anyMessage.parentElement.children.length : 0;
-			
-			if (messageCount > 300) {
-				if (waitForCleanup) {
-					return;
-				}
-				
-				skipsLeft = 3;
-				waitForCleanup = true;
-				
-				window.setTimeout(() => {
-					const view = this.getMessageScrollerElement();
-					// noinspection JSUnusedGlobalSymbols
-					view.scrollTop = view.scrollHeight / 2;
-				}, 1);
-			}
-			else {
-				waitForCleanup = false;
-			}
-			
-			const messages = this.getMessages();
-			const hasChanged = messages.some(message => !previousMessages.has(message.id)) || !this.hasMoreMessages();
+		const onMessageElementsChanged = function() {
+			const messages = DISCORD.getMessages();
+			const hasChanged = messages.some(message => !previousMessages.has(message.id)) || !DISCORD.hasMoreMessages();
 			
 			if (!hasChanged) {
 				return;
@@ -79,24 +62,74 @@ class DISCORD {
 			}
 			
 			callback(messages);
-		}, 200);
+		};
 		
-		window.DHT_ON_UNLOAD.push(() => window.clearInterval(timer));
+		let debounceTimer;
+		
+		/**
+		 * Do not trigger the callback too often due to autoscrolling.
+		 */
+		const onMessageElementsChangedLater = function() {
+			window.clearTimeout(debounceTimer);
+			debounceTimer = window.setTimeout(onMessageElementsChanged, 100);
+		};
+		
+		const observer = new MutationObserver(function () {
+			onMessageElementsChangedLater();
+		});
+		
+		let skipsLeft = 0;
+		let observedElement = null;
+		
+		const observerTimer = window.setInterval(() => {
+			if (skipsLeft > 0) {
+				--skipsLeft;
+				return;
+			}
+			
+			const view = this.getMessageOuterElement();
+			
+			if (!view) {
+				skipsLeft = 1;
+				return;
+			}
+			
+			if (observedElement !== null && observedElement.isConnected) {
+				return;
+			}
+			
+			observedElement = view.querySelector("[data-list-id='chat-messages']");
+			
+			if (observedElement) {
+				console.debug("[DHT] Observed message container.");
+				observer.observe(observedElement, { childList: true });
+				onMessageElementsChangedLater();
+			}
+		}, 400);
+		
+		window.DHT_ON_UNLOAD.push(() => {
+			observer.disconnect();
+			observedElement = null;
+			window.clearInterval(observerTimer);
+		});
 	}
 	
 	/**
-	 * Returns the property object of a message element.
-	 * @returns { null | { message: DiscordMessage, channel: Object } }
+	 * Returns the message from a message element.
+	 * @returns { null | DiscordMessage } }
 	 */
-	static getMessageElementProps(ele) {
+	static getMessageFromElement(ele) {
 		const props = DOM.getReactProps(ele);
 		
-		if (props.children && props.children.length) {
-			for (let i = 3; i < props.children.length; i++) {
-				const childProps = props.children[i].props;
+		if (props && Array.isArray(props.children)) {
+			for (const child of props.children) {
+				if (!(child instanceof Object)) {
+					continue;
+				}
 				
-				if (childProps && "message" in childProps && "channel" in childProps) {
-					return childProps;
+				const childProps = child.props;
+				if (childProps instanceof Object && "message" in childProps) {
+					return childProps.message;
 				}
 			}
 		}
@@ -113,10 +146,10 @@ class DISCORD {
 			
 			for (const ele of this.getMessageElements()) {
 				try {
-					const props = this.getMessageElementProps(ele);
+					const message = this.getMessageFromElement(ele);
 					
-					if (props != null) {
-						messages.push(props.message);
+					if (message != null) {
+						messages.push(message);
 					}
 				} catch (e) {
 					console.error("[DHT] Error extracing message data, skipping it.", e, ele, DOM.tryGetReactProps(ele));
@@ -137,7 +170,7 @@ class DISCORD {
 	 */
 	static getSelectedChannel() {
 		try {
-			let obj;
+			let obj = null;
 			
 			try {
 				for (const child of DOM.getReactProps(DOM.queryReactClass("chatContent")).children) {
@@ -148,15 +181,6 @@ class DISCORD {
 				}
 			} catch (e) {
 				console.error("[DHT] Error retrieving selected channel from 'chatContent' element.", e);
-				
-				for (const ele of this.getMessageElements()) {
-					const props = this.getMessageElementProps(ele);
-					
-					if (props != null) {
-						obj = props.channel;
-						break;
-					}
-				}
 			}
 			
 			if (!obj || typeof obj.id !== "string") {
@@ -185,8 +209,8 @@ class DISCORD {
 				
 				// https://discord.com/developers/docs/resources/channel#channel-object-channel-types
 				switch (obj.type) {
-					case 1: type = "DM"; break;
-					case 3: type = "GROUP"; break;
+					case DISCORD.CHANNEL_TYPE.DM: type = "DM"; break;
+					case DISCORD.CHANNEL_TYPE.GROUP_DM: type = "GROUP"; break;
 					default: return null;
 				}
 				
@@ -224,7 +248,7 @@ class DISCORD {
 					}
 				};
 				
-				if (obj.parent_id) {
+				if (obj.type === DISCORD.CHANNEL_TYPE.ANNOUNCEMENT_THREAD || obj.type === DISCORD.CHANNEL_TYPE.PUBLIC_THREAD || obj.type === DISCORD.CHANNEL_TYPE.PRIVATE_THREAD) {
 					channel["extra"]["parent"] = obj.parent_id;
 				}
 				else {

app/Resources/Tracker/scripts/gui.js

@@ -86,12 +86,12 @@ const GUI = (function() {
 <label><input id='dht-cfg-autoscroll' type='checkbox'> Autoscroll</label><br>
 <br>
 <label>After reaching the first message in channel...</label><br>
-${radio("afm", "nothing", "Do Nothing")}
+${radio("afm", "nothing", "Continue Tracking")}
 ${radio("afm", "pause", "Pause Tracking")}
 ${radio("afm", "switch", "Switch to Next Channel")}
 <br>
 <label>After reaching a previously saved message...</label><br>
-${radio("asm", "nothing", "Do Nothing")}
+${radio("asm", "nothing", "Continue Tracking")}
 ${radio("asm", "pause", "Pause Tracking")}
 ${radio("asm", "switch", "Switch to Next Channel")}
 <p id='dht-cfg-note'>It is recommended to disable link and image previews to avoid putting unnecessary strain on your browser.</p>`;

app/Resources/Tracker/scripts/state.js

@@ -174,12 +174,10 @@ const STATE = (function() {
 		},
 		
 		/**
-		 * @param {String} channelId
 		 * @param {DiscordMessage[]} discordMessageArray
 		 */
-		async addDiscordMessages(channelId, discordMessageArray) {
-			// https://discord.com/developers/docs/resources/channel#message-object-message-types
-			discordMessageArray = discordMessageArray.filter(msg => (msg.type === 0 || msg.type === 19 || msg.type === 21) && msg.state === "SENT");
+		async addDiscordMessages(discordMessageArray) {
+			discordMessageArray = discordMessageArray.filter(msg => (msg.type === DISCORD.MESSAGE_TYPE.DEFAULT || msg.type === DISCORD.MESSAGE_TYPE.REPLY || msg.type === DISCORD.MESSAGE_TYPE.THREAD_STARTER) && msg.state === "SENT");
 			
 			if (discordMessageArray.length === 0) {
 				return false;

app/Resources/Viewer/scripts/discord.js

@@ -1,7 +1,8 @@
 const DISCORD = (function() {
 	const regex = {
 		formatBold: /\*\*([\s\S]+?)\*\*(?!\*)/g,
-		formatItalic: /(.)?([_*])([\s\S]+?)\2(?!\2)/g,
+		formatItalic1: /\*([\s\S]+?)\*(?!\*)/g,
+		formatItalic2: /_([\s\S]+?)_(?!_)\b/g,
 		formatUnderline: /__([\s\S]+?)__(?!_)/g,
 		formatStrike: /~~([\s\S]+?)~~(?!~)/g,
 		formatCodeInline: /(`+)\s*([\s\S]*?[^`])\s*\1(?!`)/g,
@@ -48,7 +49,8 @@ const DISCORD = (function() {
 				.replace(regex.specialEscapedDouble, full => full.replace(/\\/g, "").replace(/(.)/g, escapeHtmlMatch))
 				.replace(regex.formatBold, "<b>$1</b>")
 				.replace(regex.formatUnderline, "<u>$1</u>")
-				.replace(regex.formatItalic, (full, pre, char, match) => pre === "\\" ? full : (pre || "") + "<i>" + match + "</i>")
+				.replace(regex.formatItalic1, "<i>$1</i>")
+				.replace(regex.formatItalic2, "<i>$1</i>")
 				.replace(regex.formatStrike, "<s>$1</s>");
 		}
 		

app/Resources/minify.py

@@ -1,27 +0,0 @@
-#!/usr/bin/env python3
-
-import glob
-import os
-import shutil
-import sys
-
-if os.name == "nt":
-    uglifyjs = os.path.abspath("../../lib/uglifyjs.cmd")
-else:
-    uglifyjs = "uglifyjs"
-
-if shutil.which(uglifyjs) is None:
-    print("Cannot find executable: {0}".format(uglifyjs))
-    sys.exit(1)
-
-input_dir = os.path.abspath("./Tracker/scripts")
-output_dir = os.path.abspath("../Desktop/bin/.res/scripts")
-
-os.makedirs(output_dir, exist_ok=True)
-
-for file in glob.glob(input_dir + "/*.js"):
-    name = os.path.basename(file)
-    print("Minifying {0}...".format(name))
-    os.system("{0} {1} -o {2}/{3}".format(uglifyjs, file, output_dir, name))
-
-print("Done!")

app/Server/Data/Attachment.cs

@@ -4,7 +4,8 @@ public readonly struct Attachment {
 	public ulong Id { get; internal init; }
 	public string Name { get; internal init; }
 	public string? Type { get; internal init; }
-	public string Url { get; internal init; }
+	public string NormalizedUrl { get; internal init; }
+	public string DownloadUrl { get; internal init; }
 	public ulong Size { get; internal init; }
 	public int? Width { get; internal init; }
 	public int? Height { get; internal init; }

app/Server/Data/Download.cs

@@ -1,30 +1,33 @@
 using System;
 using System.Net;
+using DHT.Server.Download;
 
 namespace DHT.Server.Data;
 
 public readonly struct Download {
-	internal static Download NewSuccess(string url, byte[] data) {
-		return new Download(url, DownloadStatus.Success, (ulong) Math.Max(data.LongLength, 0), data);
+	internal static Download NewSuccess(DownloadItem item, byte[] data) {
+		return new Download(item.NormalizedUrl, item.DownloadUrl, DownloadStatus.Success, (ulong) Math.Max(data.LongLength, 0), data);
 	}
 
-	internal static Download NewFailure(string url, HttpStatusCode? statusCode, ulong size) {
-		return new Download(url, statusCode.HasValue ? (DownloadStatus) (int) statusCode : DownloadStatus.GenericError, size);
+	internal static Download NewFailure(DownloadItem item, HttpStatusCode? statusCode, ulong size) {
+		return new Download(item.NormalizedUrl, item.DownloadUrl, statusCode.HasValue ? (DownloadStatus) (int) statusCode : DownloadStatus.GenericError, size);
 	}
 
-	public string Url { get; }
+	public string NormalizedUrl { get; }
+	public string DownloadUrl { get; }
 	public DownloadStatus Status { get; }
 	public ulong Size { get; }
 	public byte[]? Data { get; }
 
-	internal Download(string url, DownloadStatus status, ulong size, byte[]? data = null) {
-		Url = url;
+	internal Download(string normalizedUrl, string downloadUrl, DownloadStatus status, ulong size, byte[]? data = null) {
+		NormalizedUrl = normalizedUrl;
+		DownloadUrl = downloadUrl;
 		Status = status;
 		Size = size;
 		Data = data;
 	}
 
 	internal Download WithData(byte[] data) {
-		return new Download(Url, Status, Size, data);
+		return new Download(NormalizedUrl, DownloadUrl, Status, Size, data);
 	}
 }

app/Server/Data/DownloadStatus.cs

@@ -8,5 +8,6 @@ namespace DHT.Server.Data;
 public enum DownloadStatus {
 	Enqueued = 0,
 	GenericError = 1,
+	Downloading = 2,
 	Success = HttpStatusCode.OK
 }

app/Server/Data/Message.cs

@@ -10,7 +10,7 @@ public readonly struct Message {
 	public long Timestamp { get; init; }
 	public long? EditTimestamp { get; init; }
 	public ulong? RepliedToId { get; init; }
-	public ImmutableArray<Attachment> Attachments { get; init; }
-	public ImmutableArray<Embed> Embeds { get; init; }
-	public ImmutableArray<Reaction> Reactions { get; init; }
+	public ImmutableList<Attachment> Attachments { get; init; }
+	public ImmutableList<Embed> Embeds { get; init; }
+	public ImmutableList<Reaction> Reactions { get; init; }
 }

app/Server/Database/DatabaseExtensions.cs

@@ -1,29 +1,32 @@
 using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
 using DHT.Server.Data;
 
 namespace DHT.Server.Database;
 
 public static class DatabaseExtensions {
-	public static void AddFrom(this IDatabaseFile target, IDatabaseFile source) {
-		target.AddServers(source.GetAllServers());
-		target.AddChannels(source.GetAllChannels());
-		target.AddUsers(source.GetAllUsers().ToArray());
-		target.AddMessages(source.GetMessages().ToArray());
+	public static async Task AddFrom(this IDatabaseFile target, IDatabaseFile source) {
+		await target.Users.Add(await source.Users.Get().ToListAsync());
+		await target.Servers.Add(await source.Servers.Get().ToListAsync());
+		await target.Channels.Add(await source.Channels.Get().ToListAsync());
 
-		foreach (var download in source.GetDownloadsWithoutData()) {
-			target.AddDownload(download.Status == DownloadStatus.Success ? source.GetDownloadWithData(download) : download);
+		const int MessageBatchSize = 100;
+		List<Message> batchedMessages = new (MessageBatchSize);
+		
+		await foreach (var message in source.Messages.Get()) {
+			batchedMessages.Add(message);
+
+			if (batchedMessages.Count >= MessageBatchSize) {
+				await target.Messages.Add(batchedMessages);
+				batchedMessages.Clear();
+			}
 		}
-	}
+		
+		await target.Messages.Add(batchedMessages);
 
-	internal static void AddServers(this IDatabaseFile target, IEnumerable<Data.Server> servers) {
-		foreach (var server in servers) {
-			target.AddServer(server);
-		}
-	}
-
-	internal static void AddChannels(this IDatabaseFile target, IEnumerable<Channel> channels) {
-		foreach (var channel in channels) {
-			target.AddChannel(channel);
+		await foreach (var download in source.Downloads.GetWithoutData()) {
+			await target.Downloads.AddDownload(download.Status == DownloadStatus.Success ? await source.Downloads.HydrateWithData(download) : download);
 		}
 	}
 }

app/Server/Database/DummyDatabaseFile.cs

@@ -1,90 +1,31 @@
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using DHT.Server.Data;
-using DHT.Server.Data.Aggregations;
-using DHT.Server.Data.Filters;
-using DHT.Server.Download;
+using System.Threading.Tasks;
+using DHT.Server.Database.Repositories;
 
 namespace DHT.Server.Database;
 
 [SuppressMessage("ReSharper", "ArrangeObjectCreationWhenTypeNotEvident")]
-public sealed class DummyDatabaseFile : IDatabaseFile {
-	public static DummyDatabaseFile Instance { get; } = new();
+sealed class DummyDatabaseFile : IDatabaseFile {
+	public static DummyDatabaseFile Instance { get; } = new ();
 
 	public string Path => "";
-	public DatabaseStatistics Statistics { get; } = new();
-
+	public DatabaseStatistics Statistics { get; } = new ();
+	
+	public IUserRepository Users { get; } = new IUserRepository.Dummy();
+	public IServerRepository Servers { get; } = new IServerRepository.Dummy();
+	public IChannelRepository Channels { get; } = new IChannelRepository.Dummy();
+	public IMessageRepository Messages { get; } = new IMessageRepository.Dummy();
+	public IDownloadRepository Downloads { get; } = new IDownloadRepository.Dummy();
+	
 	private DummyDatabaseFile() {}
 
-	public DatabaseStatisticsSnapshot SnapshotStatistics() {
-		return new();
+	public Task<DatabaseStatisticsSnapshot> SnapshotStatistics() {
+		return Task.FromResult(new DatabaseStatisticsSnapshot());
 	}
 
-	public void AddServer(Data.Server server) {}
-
-	public List<Data.Server> GetAllServers() {
-		return new();
+	public Task Vacuum() {
+		return Task.CompletedTask;
 	}
 
-	public void AddChannel(Channel channel) {}
-
-	public List<Channel> GetAllChannels() {
-		return new();
-	}
-
-	public void AddUsers(User[] users) {}
-
-	public List<User> GetAllUsers() {
-		return new();
-	}
-
-	public void AddMessages(Message[] messages) {}
-
-	public int CountMessages(MessageFilter? filter = null) {
-		return 0;
-	}
-
-	public List<Message> GetMessages(MessageFilter? filter = null) {
-		return new();
-	}
-
-	public HashSet<ulong> GetMessageIds(MessageFilter? filter = null) {
-		return new();
-	}
-
-	public void RemoveMessages(MessageFilter filter, FilterRemovalMode mode) {}
-
-	public int CountAttachments(AttachmentFilter? filter = null) {
-		return new();
-	}
-
-	public List<Data.Download> GetDownloadsWithoutData() {
-		return new();
-	}
-
-	public Data.Download GetDownloadWithData(Data.Download download) {
-		return download;
-	}
-
-	public DownloadedAttachment? GetDownloadedAttachment(string url) {
-		return null;
-	}
-
-	public void AddDownload(Data.Download download) {}
-
-	public void EnqueueDownloadItems(AttachmentFilter? filter = null) {}
-
-	public List<DownloadItem> GetEnqueuedDownloadItems(int count) {
-		return new();
-	}
-
-	public void RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode) {}
-
-	public DownloadStatusStatistics GetDownloadStatusStatistics() {
-		return new();
-	}
-
-	public void Vacuum() {}
-
 	public void Dispose() {}
 }

app/Server/Database/Export/Snowflake.cs

@@ -0,0 +1,3 @@
+namespace DHT.Server.Database.Export;
+
+readonly record struct Snowflake(ulong Id);

app/Server/Database/Export/SnowflakeJsonSerializer.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace DHT.Server.Database.Export;
+
+sealed class SnowflakeJsonSerializer : JsonConverter<Snowflake> {
+	public override Snowflake Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+		return new Snowflake(ulong.Parse(reader.GetString()!));
+	}
+
+	public override void Write(Utf8JsonWriter writer, Snowflake value, JsonSerializerOptions options) {
+		writer.WriteStringValue(value.Id.ToString());
+	}
+
+	public override Snowflake ReadAsPropertyName(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+		return new Snowflake(ulong.Parse(reader.GetString()!));
+	}
+
+	public override void WriteAsPropertyName(Utf8JsonWriter writer, Snowflake value, JsonSerializerOptions options) {
+		writer.WritePropertyName(value.Id.ToString());
+	}
+}

app/Server/Database/Export/Strategy/LiveViewerExportStrategy.cs

@@ -13,6 +13,6 @@ public sealed class LiveViewerExportStrategy : IViewerExportStrategy {
 	}
 
 	public string GetAttachmentUrl(Attachment attachment) {
-		return "http://127.0.0.1:" + safePort + "/get-attachment/" + WebUtility.UrlEncode(attachment.Url) + "?token=" + safeToken;
+		return "http://127.0.0.1:" + safePort + "/get-attachment/" + WebUtility.UrlEncode(attachment.NormalizedUrl) + "?token=" + safeToken;
 	}
 }

app/Server/Database/Export/Strategy/StandaloneViewerExportStrategy.cs

@@ -8,6 +8,11 @@ public sealed class StandaloneViewerExportStrategy : IViewerExportStrategy {
 	private StandaloneViewerExportStrategy() {}
 
 	public string GetAttachmentUrl(Attachment attachment) {
-		return attachment.Url;
+		// The normalized URL will not load files from Discord CDN once the time limit is enforced.
+		
+		// The downloaded URL would work, but only for a limited time, so it is better for the links to not work
+		// rather than give users a false sense of security.
+		
+		return attachment.NormalizedUrl;
 	}
 }

app/Server/Database/Export/ViewerJson.cs

@@ -0,0 +1,93 @@
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace DHT.Server.Database.Export;
+
+sealed class ViewerJson {
+	public required JsonMeta Meta { get; init; }
+	public required Dictionary<Snowflake, Dictionary<Snowflake, JsonMessage>> Data { get; init; }
+
+	public sealed class JsonMeta {
+		public required Dictionary<Snowflake, JsonUser> Users { get; init; }
+		public required List<Snowflake> Userindex { get; init; }
+		public required List<JsonServer> Servers { get; init; }
+		public required Dictionary<Snowflake, JsonChannel> Channels { get; init; }
+	}
+	
+	public sealed class JsonUser {
+		public required string Name { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? Avatar { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? Tag { get; init; }
+	}
+
+	public sealed class JsonServer {
+		public required string Name { get; init; }
+		public required string Type { get; init; }
+	}
+
+	public sealed class JsonChannel {
+		public required int Server { get; init; }
+		public required string Name { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? Parent { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public int? Position { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? Topic { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public bool? Nsfw { get; init; }
+	}
+
+	public sealed class JsonMessage {
+		public required int U { get; init; }
+		public required long T { get; init; }
+
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? M { get; init; }
+
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public long? Te { get; init; }
+
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? R { get; init; }
+
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public JsonMessageAttachment[]? A { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string[]? E { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public JsonMessageReaction[]? Re { get; init; }
+	}
+
+	public sealed class JsonMessageAttachment {
+		public required string Url { get; init; }
+		public required string Name { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public int? Width { get; set; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public int? Height { get; set; }
+	}
+
+	public sealed class JsonMessageReaction {
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? Id { get; init; }
+		
+		[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+		public string? N { get; init; }
+
+		public required bool A { get; init; }
+		public required int C { get; init; }
+	}
+}

app/Server/Database/Export/ViewerJsonContext.cs

@@ -0,0 +1,11 @@
+using System.Text.Json.Serialization;
+
+namespace DHT.Server.Database.Export;
+
+[JsonSourceGenerationOptions(
+	Converters = new [] { typeof(SnowflakeJsonSerializer) },
+	PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
+	GenerationMode = JsonSourceGenerationMode.Default
+)]
+[JsonSerializable(typeof(ViewerJson))]
+sealed partial class ViewerJsonContext : JsonSerializerContext {}

app/Server/Database/Export/ViewerJsonExport.cs

@@ -21,7 +21,7 @@ public static class ViewerJsonExport {
 		var includedChannelIds = new HashSet<ulong>();
 		var includedServerIds = new HashSet<ulong>();
 
-		var includedMessages = db.GetMessages(filter);
+		var includedMessages = await db.Messages.Get(filter).ToListAsync();
 		var includedChannels = new List<Channel>();
 
 		foreach (var message in includedMessages) {
@@ -29,185 +29,145 @@ public static class ViewerJsonExport {
 			includedChannelIds.Add(message.Channel);
 		}
 
-		foreach (var channel in db.GetAllChannels()) {
+		await foreach (var channel in db.Channels.Get()) {
 			if (includedChannelIds.Contains(channel.Id)) {
 				includedChannels.Add(channel);
 				includedServerIds.Add(channel.Server);
 			}
 		}
 
-		var users = GenerateUserList(db, includedUserIds, out var userindex, out var userIndices);
-		var servers = GenerateServerList(db, includedServerIds, out var serverindex);
-		var channels = GenerateChannelList(includedChannels, serverindex);
+		var (users, userIndex, userIndices) = await GenerateUserList(db, includedUserIds);
+		var (servers, serverIndices) = await GenerateServerList(db, includedServerIds);
+		var channels = GenerateChannelList(includedChannels, serverIndices);
 
 		perf.Step("Collect database data");
 
-		var value = new {
-			meta = new { users, userindex, servers, channels },
-			data = GenerateMessageList(includedMessages, userIndices, strategy),
+		var value = new ViewerJson {
+			Meta = new ViewerJson.JsonMeta {
+				Users = users,
+				Userindex = userIndex,
+				Servers = servers,
+				Channels = channels
+			},
+			Data = GenerateMessageList(includedMessages, userIndices, strategy)
 		};
 
 		perf.Step("Generate value object");
 
-		var opts = new JsonSerializerOptions();
-		opts.Converters.Add(new ViewerJsonSnowflakeSerializer());
-
-		await JsonSerializer.SerializeAsync(stream, value, opts);
+		await JsonSerializer.SerializeAsync(stream, value, ViewerJsonContext.Default.ViewerJson);
 
 		perf.Step("Serialize to JSON");
 		perf.End();
 	}
 
-	private static Dictionary<string, object> GenerateUserList(IDatabaseFile db, HashSet<ulong> userIds, out List<string> userindex, out Dictionary<ulong, object> userIndices) {
-		var users = new Dictionary<string, object>();
-		userindex = new List<string>();
-		userIndices = new Dictionary<ulong, object>();
+	private static async Task<(Dictionary<Snowflake, ViewerJson.JsonUser> Users, List<Snowflake> UserIndex, Dictionary<ulong, int> UserIndices)> GenerateUserList(IDatabaseFile db, HashSet<ulong> userIds) {
+		var users = new Dictionary<Snowflake, ViewerJson.JsonUser>();
+		var userIndex = new List<Snowflake>();
+		var userIndices = new Dictionary<ulong, int>();
 
-		foreach (var user in db.GetAllUsers()) {
+		await foreach (var user in db.Users.Get()) {
 			var id = user.Id;
 			if (!userIds.Contains(id)) {
 				continue;
 			}
 
-			var obj = new Dictionary<string, object> {
-				["name"] = user.Name
-			};
-
-			if (user.AvatarUrl != null) {
-				obj["avatar"] = user.AvatarUrl;
-			}
-
-			if (user.Discriminator != null) {
-				obj["tag"] = user.Discriminator;
-			}
-
-			var idStr = id.ToString();
+			var idSnowflake = new Snowflake(id);
 			userIndices[id] = users.Count;
-			userindex.Add(idStr);
-			users[idStr] = obj;
+			userIndex.Add(idSnowflake);
+			
+			users[idSnowflake] = new ViewerJson.JsonUser {
+				Name = user.Name,
+				Avatar = user.AvatarUrl,
+				Tag = user.Discriminator
+			};
 		}
 
-		return users;
+		return (users, userIndex, userIndices);
 	}
 
-	private static List<object> GenerateServerList(IDatabaseFile db, HashSet<ulong> serverIds, out Dictionary<ulong, object> serverIndices) {
-		var servers = new List<object>();
-		serverIndices = new Dictionary<ulong, object>();
+	private static async Task<(List<ViewerJson.JsonServer> Servers, Dictionary<ulong, int> ServerIndices)> GenerateServerList(IDatabaseFile db, HashSet<ulong> serverIds) {
+		var servers = new List<ViewerJson.JsonServer>();
+		var serverIndices = new Dictionary<ulong, int>();
 
-		foreach (var server in db.GetAllServers()) {
+		await foreach (var server in db.Servers.Get()) {
 			var id = server.Id;
 			if (!serverIds.Contains(id)) {
 				continue;
 			}
 
 			serverIndices[id] = servers.Count;
-			servers.Add(new Dictionary<string, object> {
-				["name"] = server.Name,
-				["type"] = ServerTypes.ToJsonViewerString(server.Type),
+			
+			servers.Add(new ViewerJson.JsonServer {
+				Name = server.Name,
+				Type = ServerTypes.ToJsonViewerString(server.Type)
 			});
 		}
 
-		return servers;
+		return (servers, serverIndices);
 	}
 
-	private static Dictionary<string, object> GenerateChannelList(List<Channel> includedChannels, Dictionary<ulong, object> serverIndices) {
-		var channels = new Dictionary<string, object>();
+	private static Dictionary<Snowflake, ViewerJson.JsonChannel> GenerateChannelList(List<Channel> includedChannels, Dictionary<ulong, int> serverIndices) {
+		var channels = new Dictionary<Snowflake, ViewerJson.JsonChannel>();
 
 		foreach (var channel in includedChannels) {
-			var obj = new Dictionary<string, object> {
-				["server"] = serverIndices[channel.Server],
-				["name"] = channel.Name,
+			var channelIdSnowflake = new Snowflake(channel.Id);
+			
+			channels[channelIdSnowflake] = new ViewerJson.JsonChannel {
+				Server = serverIndices[channel.Server],
+				Name = channel.Name,
+				Parent = channel.ParentId?.ToString(),
+				Position = channel.Position,
+				Topic = channel.Topic,
+				Nsfw = channel.Nsfw
 			};
-
-			if (channel.ParentId != null) {
-				obj["parent"] = channel.ParentId;
-			}
-
-			if (channel.Position != null) {
-				obj["position"] = channel.Position;
-			}
-
-			if (channel.Topic != null) {
-				obj["topic"] = channel.Topic;
-			}
-
-			if (channel.Nsfw != null) {
-				obj["nsfw"] = channel.Nsfw;
-			}
-
-			channels[channel.Id.ToString()] = obj;
 		}
 
 		return channels;
 	}
 
-	private static Dictionary<string, Dictionary<string, object>> GenerateMessageList( List<Message> includedMessages, Dictionary<ulong, object> userIndices, IViewerExportStrategy strategy) {
-		var data = new Dictionary<string, Dictionary<string, object>>();
+	private static Dictionary<Snowflake, Dictionary<Snowflake, ViewerJson.JsonMessage>> GenerateMessageList(List<Message> includedMessages, Dictionary<ulong, int> userIndices, IViewerExportStrategy strategy) {
+		var data = new Dictionary<Snowflake, Dictionary<Snowflake, ViewerJson.JsonMessage>>();
 
 		foreach (var grouping in includedMessages.GroupBy(static message => message.Channel)) {
-			var channel = grouping.Key.ToString();
-			var channelData = new Dictionary<string, object>();
+			var channelIdSnowflake = new Snowflake(grouping.Key);
+			var channelData = new Dictionary<Snowflake, ViewerJson.JsonMessage>();
 
 			foreach (var message in grouping) {
-				var obj = new Dictionary<string, object> {
-					["u"] = userIndices[message.Sender],
-					["t"] = message.Timestamp,
-				};
-
-				if (!string.IsNullOrEmpty(message.Text)) {
-					obj["m"] = message.Text;
-				}
-
-				if (message.EditTimestamp != null) {
-					obj["te"] = message.EditTimestamp;
-				}
-
-				if (message.RepliedToId != null) {
-					obj["r"] = message.RepliedToId.Value;
-				}
-
-				if (!message.Attachments.IsEmpty) {
-					obj["a"] = message.Attachments.Select(attachment => {
-						var a = new Dictionary<string, object> {
-							{ "url", strategy.GetAttachmentUrl(attachment) },
-							{ "name", Uri.TryCreate(attachment.Url, UriKind.Absolute, out var uri) ? Path.GetFileName(uri.LocalPath) : attachment.Url },
+				var messageIdSnowflake = new Snowflake(message.Id);
+				
+				channelData[messageIdSnowflake] = new ViewerJson.JsonMessage {
+					U = userIndices[message.Sender],
+					T = message.Timestamp,
+					M = string.IsNullOrEmpty(message.Text) ? null : message.Text,
+					Te = message.EditTimestamp,
+					R = message.RepliedToId?.ToString(),
+					
+					A = message.Attachments.IsEmpty ? null : message.Attachments.Select(attachment => {
+						var a = new ViewerJson.JsonMessageAttachment {
+							Url = strategy.GetAttachmentUrl(attachment),
+							Name = Uri.TryCreate(attachment.NormalizedUrl, UriKind.Absolute, out var uri) ? Path.GetFileName(uri.LocalPath) : attachment.NormalizedUrl
 						};
 
 						if (attachment is { Width: not null, Height: not null }) {
-							a["width"] = attachment.Width;
-							a["height"] = attachment.Height;
+							a.Width = attachment.Width;
+							a.Height = attachment.Height;
 						}
 
 						return a;
-					}).ToArray();
-				}
-
-				if (!message.Embeds.IsEmpty) {
-					obj["e"] = message.Embeds.Select(static embed => embed.Json).ToArray();
-				}
-
-				if (!message.Reactions.IsEmpty) {
-					obj["re"] = message.Reactions.Select(static reaction => {
-						var r = new Dictionary<string, object>();
-
-						if (reaction.EmojiId != null) {
-							r["id"] = reaction.EmojiId.Value;
-						}
-
-						if (reaction.EmojiName != null) {
-							r["n"] = reaction.EmojiName;
-						}
-
-						r["a"] = reaction.EmojiFlags.HasFlag(EmojiFlags.Animated);
-						r["c"] = reaction.Count;
-						return r;
-					}).ToArray();
-				}
-
-				channelData[message.Id.ToString()] = obj;
+					}).ToArray(),
+					
+					E = message.Embeds.IsEmpty ? null : message.Embeds.Select(static embed => embed.Json).ToArray(),
+					
+					Re = message.Reactions.IsEmpty ? null : message.Reactions.Select(static reaction => new ViewerJson.JsonMessageReaction {
+						Id = reaction.EmojiId?.ToString(),
+						N = reaction.EmojiName,
+						A = reaction.EmojiFlags.HasFlag(EmojiFlags.Animated),
+						C = reaction.Count
+					}).ToArray()
+				};
 			}
 
-			data[channel] = channelData;
+			data[channelIdSnowflake] = channelData;
 		}
 
 		return data;

app/Server/Database/Export/ViewerJsonSnowflakeSerializer.cs

@@ -1,15 +0,0 @@
-using System;
-using System.Text.Json;
-using System.Text.Json.Serialization;
-
-namespace DHT.Server.Database.Export;
-
-sealed class ViewerJsonSnowflakeSerializer : JsonConverter<ulong> {
-	public override ulong Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
-		return ulong.Parse(reader.GetString()!);
-	}
-
-	public override void Write(Utf8JsonWriter writer, ulong value, JsonSerializerOptions options) {
-		writer.WriteStringValue(value.ToString());
-	}
-}

app/Server/Database/IDatabaseFile.cs

@@ -1,43 +1,19 @@
 using System;
-using System.Collections.Generic;
-using DHT.Server.Data;
-using DHT.Server.Data.Aggregations;
-using DHT.Server.Data.Filters;
-using DHT.Server.Download;
+using System.Threading.Tasks;
+using DHT.Server.Database.Repositories;
 
 namespace DHT.Server.Database;
 
 public interface IDatabaseFile : IDisposable {
 	string Path { get; }
 	DatabaseStatistics Statistics { get; }
-	DatabaseStatisticsSnapshot SnapshotStatistics();
+	Task<DatabaseStatisticsSnapshot> SnapshotStatistics();
 
-	void AddServer(Data.Server server);
-	List<Data.Server> GetAllServers();
+	IUserRepository Users { get; }
+	IServerRepository Servers { get; }
+	IChannelRepository Channels { get; }
+	IMessageRepository Messages { get; }
+	IDownloadRepository Downloads { get; }
 
-	void AddChannel(Channel channel);
-	List<Channel> GetAllChannels();
-
-	void AddUsers(User[] users);
-	List<User> GetAllUsers();
-
-	void AddMessages(Message[] messages);
-	int CountMessages(MessageFilter? filter = null);
-	List<Message> GetMessages(MessageFilter? filter = null);
-	HashSet<ulong> GetMessageIds(MessageFilter? filter = null);
-	void RemoveMessages(MessageFilter filter, FilterRemovalMode mode);
-
-	int CountAttachments(AttachmentFilter? filter = null);
-
-	void AddDownload(Data.Download download);
-	List<Data.Download> GetDownloadsWithoutData();
-	Data.Download GetDownloadWithData(Data.Download download);
-	DownloadedAttachment? GetDownloadedAttachment(string url);
-
-	void EnqueueDownloadItems(AttachmentFilter? filter = null);
-	List<DownloadItem> GetEnqueuedDownloadItems(int count);
-	void RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode);
-	DownloadStatusStatistics GetDownloadStatusStatistics();
-
-	void Vacuum();
+	Task Vacuum();
 }

app/Server/Database/Import/DiscordEmbedLegacyJson.cs

@@ -0,0 +1,23 @@
+using System.Text.Json.Serialization;
+
+namespace DHT.Server.Database.Import;
+
+sealed class DiscordEmbedLegacyJson {
+	public required string Url { get; init; }
+	public required string Type { get; init; }
+	
+	public bool DhtLegacy { get; } = true;
+
+	[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+	public string? Title { get; init; }
+	
+	[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+	public string? Description { get; init; }
+
+	[JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+	public ImageJson? Image { get; init; }
+
+	public sealed class ImageJson {
+		public required string Url { get; init; }
+	}
+}

app/Server/Database/Import/DiscordEmbedLegacyJsonContext.cs

@@ -0,0 +1,7 @@
+using System.Text.Json.Serialization;
+
+namespace DHT.Server.Database.Import;
+
+[JsonSourceGenerationOptions(PropertyNamingPolicy = JsonKnownNamingPolicy.SnakeCaseLower, GenerationMode = JsonSourceGenerationMode.Default)]
+[JsonSerializable(typeof(DiscordEmbedLegacyJson))]
+sealed partial class DiscordEmbedLegacyJsonContext : JsonSerializerContext {}

app/Server/Database/Import/LegacyArchiveImport.cs

@@ -21,7 +21,7 @@ public static class LegacyArchiveImport {
 
 	public static async Task<bool> Read(Stream stream, IDatabaseFile db, FakeSnowflake fakeSnowflake, Func<Data.Server[], Task<Dictionary<Data.Server, ulong>?>> askForServerIds) {
 		var perf = Log.Start();
-		var root = await JsonSerializer.DeserializeAsync<JsonElement>(stream);
+		var root = await JsonSerializer.DeserializeAsync(stream, JsonElementContext.Default.JsonElement);
 
 		try {
 			var meta = root.RequireObject("meta");
@@ -33,10 +33,8 @@ public static class LegacyArchiveImport {
 			var servers = ReadServerList(meta, fakeSnowflake);
 
 			var newServersOnly = new HashSet<Data.Server>(servers);
-			var oldServersById = db.GetAllServers().ToDictionary(static server => server.Id, static server => server);
-
-			var oldChannels = db.GetAllChannels();
-			var oldChannelsById = oldChannels.ToDictionary(static channel => channel.Id, static channel => channel);
+			var oldServersById = await db.Servers.Get().ToDictionaryAsync(static server => server.Id, static server => server);
+			var oldChannelsById = await db.Channels.Get().ToDictionaryAsync(static channel => channel.Id, static channel => channel);
 
 			foreach (var (channelId, serverIndex) in ReadChannelToServerIndexMapping(meta, servers)) {
 				if (oldChannelsById.TryGetValue(channelId, out var oldChannel) && oldServersById.TryGetValue(oldChannel.Server, out var oldServer) && newServersOnly.Remove(servers[serverIndex])) {
@@ -66,17 +64,17 @@ public static class LegacyArchiveImport {
 
 			perf.Step("Read channel list");
 
-			var oldMessageIds = db.GetMessageIds();
+			var oldMessageIds = await db.Messages.GetIds().ToHashSetAsync();
 			var newMessages = channels.SelectMany(channel => ReadMessages(data, channel, users, fakeSnowflake))
 			                          .Where(message => !oldMessageIds.Contains(message.Id))
 			                          .ToArray();
 
 			perf.Step("Read messages");
 
-			db.AddUsers(users);
-			db.AddServers(servers);
-			db.AddChannels(channels);
-			db.AddMessages(newMessages);
+			await db.Users.Add(users);
+			await db.Servers.Add(servers);
+			await db.Channels.Add(channels);
+			await db.Messages.Add(newMessages);
 
 			perf.Step("Import into database");
 		} catch (HttpException e) {
@@ -179,9 +177,9 @@ public static class LegacyArchiveImport {
 				Timestamp = messageObj.RequireLong("t", path),
 				EditTimestamp = messageObj.HasKey("te") ? messageObj.RequireLong("te", path) : null,
 				RepliedToId = messageObj.HasKey("r") ? messageObj.RequireSnowflake("r", path) : null,
-				Attachments = messageObj.HasKey("a") ? ReadMessageAttachments(messageObj.RequireArray("a", path), fakeSnowflake, path + ".a[]").ToImmutableArray() : ImmutableArray<Attachment>.Empty,
-				Embeds = messageObj.HasKey("e") ? ReadMessageEmbeds(messageObj.RequireArray("e", path), path + ".e[]").ToImmutableArray() : ImmutableArray<Embed>.Empty,
-				Reactions = messageObj.HasKey("re") ? ReadMessageReactions(messageObj.RequireArray("re", path), path + ".re[]").ToImmutableArray() : ImmutableArray<Reaction>.Empty,
+				Attachments = messageObj.HasKey("a") ? ReadMessageAttachments(messageObj.RequireArray("a", path), fakeSnowflake, path + ".a[]").ToImmutableList() : ImmutableList<Attachment>.Empty,
+				Embeds = messageObj.HasKey("e") ? ReadMessageEmbeds(messageObj.RequireArray("e", path), path + ".e[]").ToImmutableList() : ImmutableList<Embed>.Empty,
+				Reactions = messageObj.HasKey("re") ? ReadMessageReactions(messageObj.RequireArray("re", path), path + ".re[]").ToImmutableList() : ImmutableList<Reaction>.Empty,
 			};
 		}).ToArray();
 	}
@@ -197,7 +195,8 @@ public static class LegacyArchiveImport {
 				Id = fakeSnowflake.Next(),
 				Name = name,
 				Type = type,
-				Url = url,
+				NormalizedUrl = url,
+				DownloadUrl = url,
 				Size = 0, // unknown size
 			};
 		}).DistinctByKeyStable(static attachment => {
@@ -211,30 +210,17 @@ public static class LegacyArchiveImport {
 		return embedsArray.Where(static embedObj => embedObj.HasKey("url")).Select(embedObj => {
 			string url = embedObj.RequireString("url", path);
 			string type = embedObj.RequireString("type", path);
-
-			var embedJson = new Dictionary<string, object> {
-				{ "url", url },
-				{ "type", type },
-				{ "dht_legacy", true },
+			
+			var embed = new DiscordEmbedLegacyJson {
+				Url = url,
+				Type = type,
+				Title = type == "rich" && embedObj.HasKey("t") ? embedObj.RequireString("t", path) : null,
+				Description = type == "rich" && embedObj.HasKey("d") ? embedObj.RequireString("d", path) : null,
+				Image = type == "image" ? new DiscordEmbedLegacyJson.ImageJson { Url = url } : null
 			};
 
-			if (type == "image") {
-				embedJson["image"] = new Dictionary<string, string> {
-					{ "url", url }
-				};
-			}
-			else if (type == "rich") {
-				if (embedObj.HasKey("t")) {
-					embedJson["title"] = embedObj.RequireString("t", path);
-				}
-
-				if (embedObj.HasKey("d")) {
-					embedJson["description"] = embedObj.RequireString("d", path);
-				}
-			}
-
 			return new Embed {
-				Json = JsonSerializer.Serialize(embedJson)
+				Json = JsonSerializer.Serialize(embed, DiscordEmbedLegacyJsonContext.Default.DiscordEmbedLegacyJson)
 			};
 		});
 	}

app/Server/Database/Repositories/IChannelRepository.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+
+namespace DHT.Server.Database.Repositories;
+
+public interface IChannelRepository {
+	Task Add(IReadOnlyList<Channel> channels);
+	
+	IAsyncEnumerable<Channel> Get();
+
+	internal sealed class Dummy : IChannelRepository {
+		public Task Add(IReadOnlyList<Channel> channels) {
+			return Task.CompletedTask;
+		}
+
+		public IAsyncEnumerable<Channel> Get() {
+			return AsyncEnumerable.Empty<Channel>();
+		}
+	}
+}

app/Server/Database/Repositories/IDownloadRepository.cs

@@ -0,0 +1,68 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Data.Aggregations;
+using DHT.Server.Data.Filters;
+using DHT.Server.Download;
+
+namespace DHT.Server.Database.Repositories;
+
+public interface IDownloadRepository {
+	Task<long> CountAttachments(AttachmentFilter? filter = null, CancellationToken cancellationToken = default);
+
+	Task AddDownload(Data.Download download);
+
+	Task<DownloadStatusStatistics> GetStatistics(CancellationToken cancellationToken = default);
+	
+	IAsyncEnumerable<Data.Download> GetWithoutData();
+
+	Task<Data.Download> HydrateWithData(Data.Download download);
+
+	Task<DownloadedAttachment?> GetDownloadedAttachment(string normalizedUrl);
+
+	Task<int> EnqueueDownloadItems(AttachmentFilter? filter = null, CancellationToken cancellationToken = default);
+
+	IAsyncEnumerable<DownloadItem> PullEnqueuedDownloadItems(int count, CancellationToken cancellationToken = default);
+
+	Task RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode);
+
+	internal sealed class Dummy : IDownloadRepository {
+		public Task<long> CountAttachments(AttachmentFilter? filter, CancellationToken cancellationToken) {
+			return Task.FromResult(0L);
+		}
+
+		public Task AddDownload(Data.Download download) {
+			return Task.CompletedTask;
+		}
+
+		public Task<DownloadStatusStatistics> GetStatistics(CancellationToken cancellationToken) {
+			return Task.FromResult(new DownloadStatusStatistics());
+		}
+
+		public IAsyncEnumerable<Data.Download> GetWithoutData() {
+			return AsyncEnumerable.Empty<Data.Download>();
+		}
+
+		public Task<Data.Download> HydrateWithData(Data.Download download) {
+			return Task.FromResult(download);
+		}
+
+		public Task<DownloadedAttachment?> GetDownloadedAttachment(string normalizedUrl) {
+			return Task.FromResult<DownloadedAttachment?>(null);
+		}
+
+		public Task<int> EnqueueDownloadItems(AttachmentFilter? filter, CancellationToken cancellationToken) {
+			return Task.FromResult(0);
+		}
+
+		public IAsyncEnumerable<DownloadItem> PullEnqueuedDownloadItems(int count, CancellationToken cancellationToken) {
+			return AsyncEnumerable.Empty<DownloadItem>();
+		}
+
+		public Task RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode) {
+			return Task.CompletedTask;
+		}
+	}
+}

app/Server/Database/Repositories/IMessageRepository.cs

@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Data.Filters;
+
+namespace DHT.Server.Database.Repositories;
+
+public interface IMessageRepository {
+	Task Add(IReadOnlyList<Message> messages);
+	
+	Task<long> Count(MessageFilter? filter = null, CancellationToken cancellationToken = default);
+	
+	IAsyncEnumerable<Message> Get(MessageFilter? filter = null);
+	
+	IAsyncEnumerable<ulong> GetIds(MessageFilter? filter = null);
+	
+	Task Remove(MessageFilter filter, FilterRemovalMode mode);
+
+	internal sealed class Dummy : IMessageRepository {
+		public Task Add(IReadOnlyList<Message> messages) {
+			return Task.CompletedTask;
+		}
+
+		public Task<long> Count(MessageFilter? filter, CancellationToken cancellationToken) {
+			return Task.FromResult(0L);
+		}
+
+		public IAsyncEnumerable<Message> Get(MessageFilter? filter) {
+			return AsyncEnumerable.Empty<Message>();
+		}
+
+		public IAsyncEnumerable<ulong> GetIds(MessageFilter? filter) {
+			return AsyncEnumerable.Empty<ulong>();
+		}
+
+		public Task Remove(MessageFilter filter, FilterRemovalMode mode) {
+			return Task.CompletedTask;
+		}
+	}
+}

app/Server/Database/Repositories/IServerRepository.cs

@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace DHT.Server.Database.Repositories;
+
+public interface IServerRepository {
+	Task Add(IReadOnlyList<Data.Server> servers);
+	
+	IAsyncEnumerable<Data.Server> Get();
+
+	internal sealed class Dummy : IServerRepository {
+		public Task Add(IReadOnlyList<Data.Server> servers) {
+			return Task.CompletedTask;
+		}
+
+		public IAsyncEnumerable<Data.Server> Get() {
+			return AsyncEnumerable.Empty<Data.Server>();
+		}
+	}
+}

app/Server/Database/Repositories/IUserRepository.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+
+namespace DHT.Server.Database.Repositories;
+
+public interface IUserRepository {
+	Task Add(IReadOnlyList<User> users);
+	
+	IAsyncEnumerable<User> Get();
+
+	internal sealed class Dummy : IUserRepository {
+		public Task Add(IReadOnlyList<User> users) {
+			return Task.CompletedTask;
+		}
+
+		public IAsyncEnumerable<User> Get() {
+			return AsyncEnumerable.Empty<User>();
+		}
+	}
+}

app/Server/Database/Sqlite/Repositories/SqliteChannelRepository.cs

@@ -0,0 +1,77 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Database.Repositories;
+using DHT.Server.Database.Sqlite.Utils;
+using Microsoft.Data.Sqlite;
+
+namespace DHT.Server.Database.Sqlite.Repositories;
+
+sealed class SqliteChannelRepository : IChannelRepository {
+	private readonly SqliteConnectionPool pool;
+	private readonly DatabaseStatistics statistics;
+
+	public SqliteChannelRepository(SqliteConnectionPool pool, DatabaseStatistics statistics) {
+		this.pool = pool;
+		this.statistics = statistics;
+	}
+
+	internal async Task Initialize() {
+		using var conn = pool.Take();
+		await UpdateChannelStatistics(conn);
+	}
+
+	private async Task UpdateChannelStatistics(ISqliteConnection conn) {
+		statistics.TotalChannels = await conn.ExecuteReaderAsync("SELECT COUNT(*) FROM channels", static reader => reader?.GetInt64(0) ?? 0L);
+	}
+
+	public async Task Add(IReadOnlyList<Channel> channels) {
+		using var conn = pool.Take();
+
+		await using (var tx = await conn.BeginTransactionAsync()) {
+			await using var cmd = conn.Upsert("channels", [
+				("id", SqliteType.Integer),
+				("server", SqliteType.Integer),
+				("name", SqliteType.Text),
+				("parent_id", SqliteType.Integer),
+				("position", SqliteType.Integer),
+				("topic", SqliteType.Text),
+				("nsfw", SqliteType.Integer)
+			]);
+
+			foreach (var channel in channels) {
+				cmd.Set(":id", channel.Id);
+				cmd.Set(":server", channel.Server);
+				cmd.Set(":name", channel.Name);
+				cmd.Set(":parent_id", channel.ParentId);
+				cmd.Set(":position", channel.Position);
+				cmd.Set(":topic", channel.Topic);
+				cmd.Set(":nsfw", channel.Nsfw);
+				await cmd.ExecuteNonQueryAsync();
+			}
+
+			await tx.CommitAsync();
+		}
+
+		await UpdateChannelStatistics(conn);
+	}
+
+	public async IAsyncEnumerable<Channel> Get() {
+		using var conn = pool.Take();
+
+		await using var cmd = conn.Command("SELECT id, server, name, parent_id, position, topic, nsfw FROM channels");
+		await using var reader = await cmd.ExecuteReaderAsync();
+
+		while (reader.Read()) {
+			yield return new Channel {
+				Id = reader.GetUint64(0),
+				Server = reader.GetUint64(1),
+				Name = reader.GetString(2),
+				ParentId = reader.IsDBNull(3) ? null : reader.GetUint64(3),
+				Position = reader.IsDBNull(4) ? null : reader.GetInt32(4),
+				Topic = reader.IsDBNull(5) ? null : reader.GetString(5),
+				Nsfw = reader.IsDBNull(6) ? null : reader.GetBoolean(6),
+			};
+		}
+	}
+}

app/Server/Database/Sqlite/Repositories/SqliteDownloadRepository.cs

@@ -0,0 +1,233 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Data.Aggregations;
+using DHT.Server.Data.Filters;
+using DHT.Server.Database.Repositories;
+using DHT.Server.Database.Sqlite.Utils;
+using DHT.Server.Download;
+using DHT.Utils.Tasks;
+using Microsoft.Data.Sqlite;
+
+namespace DHT.Server.Database.Sqlite.Repositories;
+
+sealed class SqliteDownloadRepository : IDownloadRepository {
+	private readonly SqliteConnectionPool pool;
+	private readonly AsyncValueComputer<long>.Single totalDownloadsComputer;
+
+	public SqliteDownloadRepository(SqliteConnectionPool pool, AsyncValueComputer<long>.Single totalDownloadsComputer) {
+		this.pool = pool;
+		this.totalDownloadsComputer = totalDownloadsComputer;
+	}
+
+	public async Task<long> CountAttachments(AttachmentFilter? filter, CancellationToken cancellationToken) {
+		using var conn = pool.Take();
+		return await conn.ExecuteReaderAsync("SELECT COUNT(DISTINCT normalized_url) FROM attachments a" + filter.GenerateWhereClause("a"), static reader => reader?.GetInt64(0) ?? 0L, cancellationToken);
+	}
+
+	public async Task AddDownload(Data.Download download) {
+		using (var conn = pool.Take()) {
+			await using var cmd = conn.Upsert("downloads", [
+				("normalized_url", SqliteType.Text),
+				("download_url", SqliteType.Text),
+				("status", SqliteType.Integer),
+				("size", SqliteType.Integer),
+				("blob", SqliteType.Blob)
+			]);
+
+			cmd.Set(":normalized_url", download.NormalizedUrl);
+			cmd.Set(":download_url", download.DownloadUrl);
+			cmd.Set(":status", (int) download.Status);
+			cmd.Set(":size", download.Size);
+			cmd.Set(":blob", download.Data);
+			await cmd.ExecuteNonQueryAsync();
+		}
+
+		totalDownloadsComputer.Recompute();
+	}
+
+	public async Task<DownloadStatusStatistics> GetStatistics(CancellationToken cancellationToken) {
+		static async Task LoadUndownloadedStatistics(ISqliteConnection conn, DownloadStatusStatistics result, CancellationToken cancellationToken) {
+			await using var cmd = conn.Command(
+				"""
+				SELECT IFNULL(COUNT(size), 0), IFNULL(SUM(size), 0)
+				FROM (SELECT MAX(a.size) size
+				      FROM attachments a
+				      WHERE a.normalized_url NOT IN (SELECT d.normalized_url FROM downloads d)
+				      GROUP BY a.normalized_url)
+				""");
+
+			await using var reader = await cmd.ExecuteReaderAsync(cancellationToken);
+
+			if (reader.Read()) {
+				result.SkippedCount = reader.GetInt32(0);
+				result.SkippedSize = reader.GetUint64(1);
+			}
+		}
+
+		static async Task LoadSuccessStatistics(ISqliteConnection conn, DownloadStatusStatistics result, CancellationToken cancellationToken) {
+			await using var cmd = conn.Command(
+				"""
+				SELECT
+				IFNULL(SUM(CASE WHEN status IN (:enqueued, :downloading) THEN 1 ELSE 0 END), 0),
+				IFNULL(SUM(CASE WHEN status IN (:enqueued, :downloading) THEN size ELSE 0 END), 0),
+				IFNULL(SUM(CASE WHEN status = :success THEN 1 ELSE 0 END), 0),
+				IFNULL(SUM(CASE WHEN status = :success THEN size ELSE 0 END), 0),
+				IFNULL(SUM(CASE WHEN status NOT IN (:enqueued, :downloading) AND status != :success THEN 1 ELSE 0 END), 0),
+				IFNULL(SUM(CASE WHEN status NOT IN (:enqueued, :downloading) AND status != :success THEN size ELSE 0 END), 0)
+				FROM downloads
+				"""
+			);
+			
+			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
+			cmd.AddAndSet(":downloading", SqliteType.Integer, (int) DownloadStatus.Downloading);
+			cmd.AddAndSet(":success", SqliteType.Integer, (int) DownloadStatus.Success);
+
+			await using var reader = await cmd.ExecuteReaderAsync(cancellationToken);
+
+			if (reader.Read()) {
+				result.EnqueuedCount = reader.GetInt32(0);
+				result.EnqueuedSize = reader.GetUint64(1);
+				result.SuccessfulCount = reader.GetInt32(2);
+				result.SuccessfulSize = reader.GetUint64(3);
+				result.FailedCount = reader.GetInt32(4);
+				result.FailedSize = reader.GetUint64(5);
+			}
+		}
+
+		var result = new DownloadStatusStatistics();
+
+		using var conn = pool.Take();
+		await LoadUndownloadedStatistics(conn, result, cancellationToken);
+		await LoadSuccessStatistics(conn, result, cancellationToken);
+		return result;
+	}
+
+	public async IAsyncEnumerable<Data.Download> GetWithoutData() {
+		using var conn = pool.Take();
+
+		await using var cmd = conn.Command("SELECT normalized_url, download_url, status, size FROM downloads");
+		await using var reader = await cmd.ExecuteReaderAsync();
+
+		while (reader.Read()) {
+			string normalizedUrl = reader.GetString(0);
+			string downloadUrl = reader.GetString(1);
+			var status = (DownloadStatus) reader.GetInt32(2);
+			ulong size = reader.GetUint64(3);
+
+			yield return new Data.Download(normalizedUrl, downloadUrl, status, size);
+		}
+	}
+
+	public async Task<Data.Download> HydrateWithData(Data.Download download) {
+		using var conn = pool.Take();
+
+		await using var cmd = conn.Command("SELECT blob FROM downloads WHERE normalized_url = :url");
+		cmd.AddAndSet(":url", SqliteType.Text, download.NormalizedUrl);
+
+		await using var reader = await cmd.ExecuteReaderAsync();
+
+		if (reader.Read() && !reader.IsDBNull(0)) {
+			return download.WithData((byte[]) reader["blob"]);
+		}
+		else {
+			return download;
+		}
+	}
+
+	public async Task<DownloadedAttachment?> GetDownloadedAttachment(string normalizedUrl) {
+		using var conn = pool.Take();
+
+		await using var cmd = conn.Command(
+			"""
+			SELECT a.type, d.blob FROM downloads d
+			LEFT JOIN attachments a ON d.normalized_url = a.normalized_url
+			WHERE d.normalized_url = :normalized_url AND d.status = :success AND d.blob IS NOT NULL
+			"""
+		);
+
+		cmd.AddAndSet(":normalized_url", SqliteType.Text, normalizedUrl);
+		cmd.AddAndSet(":success", SqliteType.Integer, (int) DownloadStatus.Success);
+
+		await using var reader = await cmd.ExecuteReaderAsync();
+
+		if (!reader.Read()) {
+			return null;
+		}
+
+		return new DownloadedAttachment {
+			Type = reader.IsDBNull(0) ? null : reader.GetString(0),
+			Data = (byte[]) reader["blob"],
+		};
+	}
+
+	public async Task<int> EnqueueDownloadItems(AttachmentFilter? filter, CancellationToken cancellationToken) {
+		using var conn = pool.Take();
+
+		await using var cmd = conn.Command(
+			$"""
+			 INSERT INTO downloads (normalized_url, download_url, status, size)
+			 SELECT a.normalized_url, a.download_url, :enqueued, MAX(a.size)
+			 FROM attachments a
+			 {filter.GenerateWhereClause("a")}
+			 GROUP BY a.normalized_url
+			 """
+		);
+
+		cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
+		return await cmd.ExecuteNonQueryAsync(cancellationToken);
+	}
+
+	public async IAsyncEnumerable<DownloadItem> PullEnqueuedDownloadItems(int count, [EnumeratorCancellation] CancellationToken cancellationToken) {
+		var found = new List<DownloadItem>();
+
+		using var conn = pool.Take();
+
+		await using (var cmd = conn.Command("SELECT normalized_url, download_url, size FROM downloads WHERE status = :enqueued LIMIT :limit")) {
+			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
+			cmd.AddAndSet(":limit", SqliteType.Integer, Math.Max(0, count));
+
+			await using var reader = await cmd.ExecuteReaderAsync(cancellationToken);
+
+			while (reader.Read()) {
+				found.Add(new DownloadItem {
+					NormalizedUrl = reader.GetString(0),
+					DownloadUrl = reader.GetString(1),
+					Size = reader.GetUint64(2),
+				});
+			}
+		}
+
+		if (found.Count != 0) {
+			await using var cmd = conn.Command("UPDATE downloads SET status = :downloading WHERE normalized_url = :normalized_url AND status = :enqueued");
+			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
+			cmd.AddAndSet(":downloading", SqliteType.Integer, (int) DownloadStatus.Downloading);
+			cmd.Add(":normalized_url", SqliteType.Text);
+
+			foreach (var item in found) {
+				cmd.Set(":normalized_url", item.NormalizedUrl);
+
+				if (await cmd.ExecuteNonQueryAsync(cancellationToken) == 1) {
+					yield return item;
+				}
+			}
+		}
+	}
+
+	public async Task RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode) {
+		using (var conn = pool.Take()) {
+			await conn.ExecuteAsync(
+				$"""
+				 -- noinspection SqlWithoutWhere
+				 DELETE FROM downloads
+				 {filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching)}
+				 """
+			);
+		}
+
+		totalDownloadsComputer.Recompute();
+	}
+}

app/Server/Database/Sqlite/Repositories/SqliteMessageRepository.cs

@@ -0,0 +1,306 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Data.Filters;
+using DHT.Server.Database.Repositories;
+using DHT.Server.Database.Sqlite.Utils;
+using DHT.Utils.Tasks;
+using Microsoft.Data.Sqlite;
+
+namespace DHT.Server.Database.Sqlite.Repositories;
+
+sealed class SqliteMessageRepository : IMessageRepository {
+	private readonly SqliteConnectionPool pool;
+	private readonly AsyncValueComputer<long>.Single totalMessagesComputer;
+	private readonly AsyncValueComputer<long>.Single totalAttachmentsComputer;
+
+	public SqliteMessageRepository(SqliteConnectionPool pool, AsyncValueComputer<long>.Single totalMessagesComputer, AsyncValueComputer<long>.Single totalAttachmentsComputer) {
+		this.pool = pool;
+		this.totalMessagesComputer = totalMessagesComputer;
+		this.totalAttachmentsComputer = totalAttachmentsComputer;
+	}
+
+	public async Task Add(IReadOnlyList<Message> messages) {
+		if (messages.Count == 0) {
+			return;
+		}
+
+		static SqliteCommand DeleteByMessageId(ISqliteConnection conn, string tableName) {
+			return conn.Delete(tableName, ("message_id", SqliteType.Integer));
+		}
+
+		static async Task ExecuteDeleteByMessageId(SqliteCommand cmd, object id) {
+			cmd.Set(":message_id", id);
+			await cmd.ExecuteNonQueryAsync();
+		}
+
+		bool addedAttachments = false;
+
+		using (var conn = pool.Take()) {
+			await using var tx = await conn.BeginTransactionAsync();
+
+			await using var messageCmd = conn.Upsert("messages", [
+				("message_id", SqliteType.Integer),
+				("sender_id", SqliteType.Integer),
+				("channel_id", SqliteType.Integer),
+				("text", SqliteType.Text),
+				("timestamp", SqliteType.Integer)
+			]);
+
+			await using var deleteEditTimestampCmd = DeleteByMessageId(conn, "edit_timestamps");
+			await using var deleteRepliedToCmd = DeleteByMessageId(conn, "replied_to");
+
+			await using var deleteAttachmentsCmd = DeleteByMessageId(conn, "attachments");
+			await using var deleteEmbedsCmd = DeleteByMessageId(conn, "embeds");
+			await using var deleteReactionsCmd = DeleteByMessageId(conn, "reactions");
+
+			await using var editTimestampCmd = conn.Insert("edit_timestamps", [
+				("message_id", SqliteType.Integer),
+				("edit_timestamp", SqliteType.Integer)
+			]);
+
+			await using var repliedToCmd = conn.Insert("replied_to", [
+				("message_id", SqliteType.Integer),
+				("replied_to_id", SqliteType.Integer)
+			]);
+
+			await using var attachmentCmd = conn.Insert("attachments", [
+				("message_id", SqliteType.Integer),
+				("attachment_id", SqliteType.Integer),
+				("name", SqliteType.Text),
+				("type", SqliteType.Text),
+				("normalized_url", SqliteType.Text),
+				("download_url", SqliteType.Text),
+				("size", SqliteType.Integer),
+				("width", SqliteType.Integer),
+				("height", SqliteType.Integer)
+			]);
+
+			await using var embedCmd = conn.Insert("embeds", [
+				("message_id", SqliteType.Integer),
+				("json", SqliteType.Text)
+			]);
+
+			await using var reactionCmd = conn.Insert("reactions", [
+				("message_id", SqliteType.Integer),
+				("emoji_id", SqliteType.Integer),
+				("emoji_name", SqliteType.Text),
+				("emoji_flags", SqliteType.Integer),
+				("count", SqliteType.Integer)
+			]);
+
+			foreach (var message in messages) {
+				object messageId = message.Id;
+
+				messageCmd.Set(":message_id", messageId);
+				messageCmd.Set(":sender_id", message.Sender);
+				messageCmd.Set(":channel_id", message.Channel);
+				messageCmd.Set(":text", message.Text);
+				messageCmd.Set(":timestamp", message.Timestamp);
+				await messageCmd.ExecuteNonQueryAsync();
+
+				await ExecuteDeleteByMessageId(deleteEditTimestampCmd, messageId);
+				await ExecuteDeleteByMessageId(deleteRepliedToCmd, messageId);
+
+				await ExecuteDeleteByMessageId(deleteAttachmentsCmd, messageId);
+				await ExecuteDeleteByMessageId(deleteEmbedsCmd, messageId);
+				await ExecuteDeleteByMessageId(deleteReactionsCmd, messageId);
+
+				if (message.EditTimestamp is {} timestamp) {
+					editTimestampCmd.Set(":message_id", messageId);
+					editTimestampCmd.Set(":edit_timestamp", timestamp);
+					await editTimestampCmd.ExecuteNonQueryAsync();
+				}
+
+				if (message.RepliedToId is {} repliedToId) {
+					repliedToCmd.Set(":message_id", messageId);
+					repliedToCmd.Set(":replied_to_id", repliedToId);
+					await repliedToCmd.ExecuteNonQueryAsync();
+				}
+
+				if (!message.Attachments.IsEmpty) {
+					addedAttachments = true;
+
+					foreach (var attachment in message.Attachments) {
+						attachmentCmd.Set(":message_id", messageId);
+						attachmentCmd.Set(":attachment_id", attachment.Id);
+						attachmentCmd.Set(":name", attachment.Name);
+						attachmentCmd.Set(":type", attachment.Type);
+						attachmentCmd.Set(":normalized_url", attachment.NormalizedUrl);
+						attachmentCmd.Set(":download_url", attachment.DownloadUrl);
+						attachmentCmd.Set(":size", attachment.Size);
+						attachmentCmd.Set(":width", attachment.Width);
+						attachmentCmd.Set(":height", attachment.Height);
+						await attachmentCmd.ExecuteNonQueryAsync();
+					}
+				}
+
+				if (!message.Embeds.IsEmpty) {
+					foreach (var embed in message.Embeds) {
+						embedCmd.Set(":message_id", messageId);
+						embedCmd.Set(":json", embed.Json);
+						await embedCmd.ExecuteNonQueryAsync();
+					}
+				}
+
+				if (!message.Reactions.IsEmpty) {
+					foreach (var reaction in message.Reactions) {
+						reactionCmd.Set(":message_id", messageId);
+						reactionCmd.Set(":emoji_id", reaction.EmojiId);
+						reactionCmd.Set(":emoji_name", reaction.EmojiName);
+						reactionCmd.Set(":emoji_flags", (int) reaction.EmojiFlags);
+						reactionCmd.Set(":count", reaction.Count);
+						await reactionCmd.ExecuteNonQueryAsync();
+					}
+				}
+			}
+
+			await tx.CommitAsync();
+		}
+
+		totalMessagesComputer.Recompute();
+
+		if (addedAttachments) {
+			totalAttachmentsComputer.Recompute();
+		}
+	}
+
+	public async Task<long> Count(MessageFilter? filter, CancellationToken cancellationToken) {
+		using var conn = pool.Take();
+		return await conn.ExecuteReaderAsync("SELECT COUNT(*) FROM messages" + filter.GenerateWhereClause(), static reader => reader?.GetInt64(0) ?? 0L, cancellationToken);
+	}
+
+	private sealed class MesageToManyCommand<T> : IAsyncDisposable {
+		private readonly SqliteCommand cmd;
+		private readonly Func<SqliteDataReader, T> readItem;
+
+		public MesageToManyCommand(ISqliteConnection conn, string sql, Func<SqliteDataReader, T> readItem) {
+			this.cmd = conn.Command(sql);
+			this.cmd.Add(":message_id", SqliteType.Integer);
+
+			this.readItem = readItem;
+		}
+
+		public async Task<ImmutableList<T>> GetItems(ulong messageId) {
+			cmd.Set(":message_id", messageId);
+
+			var items = ImmutableList<T>.Empty;
+
+			await using var reader = await cmd.ExecuteReaderAsync();
+
+			while (await reader.ReadAsync()) {
+				items = items.Add(readItem(reader));
+			}
+
+			return items;
+		}
+
+		public async ValueTask DisposeAsync() {
+			await cmd.DisposeAsync();
+		}
+	}
+
+	public async IAsyncEnumerable<Message> Get(MessageFilter? filter) {
+		using var conn = pool.Take();
+
+		const string AttachmentSql =
+			"""
+			SELECT attachment_id, name, type, normalized_url, download_url, size, width, height
+			FROM attachments
+			WHERE message_id = :message_id
+			""";
+
+		await using var attachmentCmd = new MesageToManyCommand<Attachment>(conn, AttachmentSql, static reader => new Attachment {
+			Id = reader.GetUint64(0),
+			Name = reader.GetString(1),
+			Type = reader.IsDBNull(2) ? null : reader.GetString(2),
+			NormalizedUrl = reader.GetString(3),
+			DownloadUrl = reader.GetString(4),
+			Size = reader.GetUint64(5),
+			Width = reader.IsDBNull(6) ? null : reader.GetInt32(6),
+			Height = reader.IsDBNull(7) ? null : reader.GetInt32(7),
+		});
+
+		const string EmbedSql =
+			"""
+			SELECT json
+			FROM embeds
+			WHERE message_id = :message_id
+			""";
+
+		await using var embedCmd = new MesageToManyCommand<Embed>(conn, EmbedSql, static reader => new Embed {
+			Json = reader.GetString(0)
+		});
+
+		const string ReactionSql =
+			"""
+			SELECT emoji_id, emoji_name, emoji_flags, count
+			FROM reactions
+			WHERE message_id = :message_id
+			""";
+
+		await using var reactionsCmd = new MesageToManyCommand<Reaction>(conn, ReactionSql, static reader => new Reaction {
+			EmojiId = reader.IsDBNull(0) ? null : reader.GetUint64(0),
+			EmojiName = reader.IsDBNull(1) ? null : reader.GetString(1),
+			EmojiFlags = (EmojiFlags) reader.GetInt16(2),
+			Count = reader.GetInt32(3),
+		});
+
+		await using var messageCmd = conn.Command(
+			$"""
+			 SELECT m.message_id, m.sender_id, m.channel_id, m.text, m.timestamp, et.edit_timestamp, rt.replied_to_id
+			 FROM messages m
+			 LEFT JOIN edit_timestamps et ON m.message_id = et.message_id
+			 LEFT JOIN replied_to rt ON m.message_id = rt.message_id
+			 {filter.GenerateWhereClause("m")}
+			 """
+		);
+
+		await using var reader = await messageCmd.ExecuteReaderAsync();
+
+		while (await reader.ReadAsync()) {
+			ulong messageId = reader.GetUint64(0);
+
+			yield return new Message {
+				Id = messageId,
+				Sender = reader.GetUint64(1),
+				Channel = reader.GetUint64(2),
+				Text = reader.GetString(3),
+				Timestamp = reader.GetInt64(4),
+				EditTimestamp = reader.IsDBNull(5) ? null : reader.GetInt64(5),
+				RepliedToId = reader.IsDBNull(6) ? null : reader.GetUint64(6),
+				Attachments = await attachmentCmd.GetItems(messageId),
+				Embeds = await embedCmd.GetItems(messageId),
+				Reactions = await reactionsCmd.GetItems(messageId)
+			};
+		}
+	}
+
+	public async IAsyncEnumerable<ulong> GetIds(MessageFilter? filter) {
+		using var conn = pool.Take();
+		
+		await using var cmd = conn.Command("SELECT message_id FROM messages" + filter.GenerateWhereClause());
+		await using var reader = await cmd.ExecuteReaderAsync();
+
+		while (await reader.ReadAsync()) {
+			yield return reader.GetUint64(0);
+		}
+	}
+
+	public async Task Remove(MessageFilter filter, FilterRemovalMode mode) {
+		using (var conn = pool.Take()) {
+			await conn.ExecuteAsync(
+				$"""
+				 -- noinspection SqlWithoutWhere
+				 DELETE FROM messages
+				 {filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching)}
+				 """
+			);
+		}
+
+		totalMessagesComputer.Recompute();
+	}
+}

app/Server/Database/Sqlite/Repositories/SqliteServerRepository.cs

@@ -0,0 +1,65 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Database.Repositories;
+using DHT.Server.Database.Sqlite.Utils;
+using Microsoft.Data.Sqlite;
+
+namespace DHT.Server.Database.Sqlite.Repositories;
+
+sealed class SqliteServerRepository : IServerRepository {
+	private readonly SqliteConnectionPool pool;
+	private readonly DatabaseStatistics statistics;
+
+	public SqliteServerRepository(SqliteConnectionPool pool, DatabaseStatistics statistics) {
+		this.pool = pool;
+		this.statistics = statistics;
+	}
+
+	internal async Task Initialize() {
+		using var conn = pool.Take();
+		await UpdateServerStatistics(conn);
+	}
+
+	private async Task UpdateServerStatistics(ISqliteConnection conn) {
+		statistics.TotalServers = await conn.ExecuteReaderAsync("SELECT COUNT(*) FROM servers", static reader => reader?.GetInt64(0) ?? 0L);
+	}
+
+	public async Task Add(IReadOnlyList<Data.Server> servers) {
+		using var conn = pool.Take();
+
+		await using (var tx = await conn.BeginTransactionAsync()) {
+			await using var cmd = conn.Upsert("servers", [
+				("id", SqliteType.Integer),
+				("name", SqliteType.Text),
+				("type", SqliteType.Text)
+			]);
+
+			foreach (var server in servers) {
+				cmd.Set(":id", server.Id);
+				cmd.Set(":name", server.Name);
+				cmd.Set(":type", ServerTypes.ToString(server.Type));
+				await cmd.ExecuteNonQueryAsync();
+			}
+
+			await tx.CommitAsync();
+		}
+
+		await UpdateServerStatistics(conn);
+	}
+
+	public async IAsyncEnumerable<Data.Server> Get() {
+		using var conn = pool.Take();
+
+		await using var cmd = conn.Command("SELECT id, name, type FROM servers");
+		await using var reader = await cmd.ExecuteReaderAsync();
+
+		while (reader.Read()) {
+			yield return new Data.Server {
+				Id = reader.GetUint64(0),
+				Name = reader.GetString(1),
+				Type = ServerTypes.FromString(reader.GetString(2)),
+			};
+		}
+	}
+}

app/Server/Database/Sqlite/Repositories/SqliteUserRepository.cs

@@ -0,0 +1,68 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using DHT.Server.Data;
+using DHT.Server.Database.Repositories;
+using DHT.Server.Database.Sqlite.Utils;
+using Microsoft.Data.Sqlite;
+
+namespace DHT.Server.Database.Sqlite.Repositories;
+
+sealed class SqliteUserRepository : IUserRepository {
+	private readonly SqliteConnectionPool pool;
+	private readonly DatabaseStatistics statistics;
+	
+	public SqliteUserRepository(SqliteConnectionPool pool, DatabaseStatistics statistics) {
+		this.pool = pool;
+		this.statistics = statistics;
+	}
+
+	internal async Task Initialize() {
+		using var conn = pool.Take();
+		await UpdateUserStatistics(conn);
+	}
+	
+	private async Task UpdateUserStatistics(ISqliteConnection conn) {
+		statistics.TotalUsers = await conn.ExecuteReaderAsync("SELECT COUNT(*) FROM users", static reader => reader?.GetInt64(0) ?? 0L);
+	}
+
+	public async Task Add(IReadOnlyList<User> users) {
+		using var conn = pool.Take();
+
+		await using (var tx = await conn.BeginTransactionAsync()) {
+			await using var cmd = conn.Upsert("users", [
+				("id", SqliteType.Integer),
+				("name", SqliteType.Text),
+				("avatar_url", SqliteType.Text),
+				("discriminator", SqliteType.Text)
+			]);
+
+			foreach (var user in users) {
+				cmd.Set(":id", user.Id);
+				cmd.Set(":name", user.Name);
+				cmd.Set(":avatar_url", user.AvatarUrl);
+				cmd.Set(":discriminator", user.Discriminator);
+				await cmd.ExecuteNonQueryAsync();
+			}
+
+			await tx.CommitAsync();
+		}
+		
+		await UpdateUserStatistics(conn);
+	}
+
+	public async IAsyncEnumerable<User> Get() {
+		using var conn = pool.Take();
+		
+		await using var cmd = conn.Command("SELECT id, name, avatar_url, discriminator FROM users");
+		await using var reader = await cmd.ExecuteReaderAsync();
+
+		while (reader.Read()) {
+			yield return new User {
+				Id = reader.GetUint64(0),
+				Name = reader.GetString(1),
+				AvatarUrl = reader.IsDBNull(2) ? null : reader.GetString(2),
+				Discriminator = reader.IsDBNull(3) ? null : reader.GetString(3),
+			};
+		}
+	}
+}

app/Server/Database/Sqlite/Schema.cs

@@ -1,13 +1,16 @@
-using System;
+using System.Collections.Generic;
+using System.Data.Common;
 using System.Threading.Tasks;
 using DHT.Server.Database.Exceptions;
 using DHT.Server.Database.Sqlite.Utils;
+using DHT.Server.Download;
 using DHT.Utils.Logging;
+using Microsoft.Data.Sqlite;
 
 namespace DHT.Server.Database.Sqlite;
 
 sealed class Schema {
-	internal const int Version = 5;
+	internal const int Version = 6;
 
 	private static readonly Log Log = Log.ForType<Schema>();
 
@@ -17,155 +20,337 @@ sealed class Schema {
 		this.conn = conn;
 	}
 
-	private void Execute(string sql) {
-		conn.Command(sql).ExecuteNonQuery();
-	}
+	public async Task<bool> Setup(ISchemaUpgradeCallbacks callbacks) {
+		await conn.ExecuteAsync("CREATE TABLE IF NOT EXISTS metadata (key TEXT PRIMARY KEY, value TEXT)");
 
-	public async Task<bool> Setup(Func<Task<bool>> checkCanUpgradeSchemas) {
-		Execute(@"CREATE TABLE IF NOT EXISTS metadata (key TEXT PRIMARY KEY, value TEXT)");
-
-		var dbVersionStr = conn.SelectScalar("SELECT value FROM metadata WHERE key = 'version'");
+		var dbVersionStr = await conn.ExecuteReaderAsync("SELECT value FROM metadata WHERE key = 'version'", static reader => reader?.GetString(0));
 		if (dbVersionStr == null) {
-			InitializeSchemas();
+			await InitializeSchemas();
 		}
-		else if (!int.TryParse(dbVersionStr.ToString(), out int dbVersion) || dbVersion < 1) {
-			throw new InvalidDatabaseVersionException(dbVersionStr.ToString() ?? "<null>");
+		else if (!int.TryParse(dbVersionStr, out int dbVersion) || dbVersion < 1) {
+			throw new InvalidDatabaseVersionException(dbVersionStr);
 		}
 		else if (dbVersion > Version) {
 			throw new DatabaseTooNewException(dbVersion);
 		}
 		else if (dbVersion < Version) {
-			var proceed = await checkCanUpgradeSchemas();
+			var proceed = await callbacks.CanUpgrade();
 			if (!proceed) {
 				return false;
 			}
 
-			UpgradeSchemas(dbVersion);
+			await callbacks.Start(Version - dbVersion, async reporter => await UpgradeSchemas(dbVersion, reporter));
 		}
 
 		return true;
 	}
 
-	private void InitializeSchemas() {
-		Execute(@"CREATE TABLE users (
-			          id INTEGER PRIMARY KEY NOT NULL,
-			          name TEXT NOT NULL,
-			          avatar_url TEXT,
-			          discriminator TEXT)");
+	private async Task InitializeSchemas() {
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE users (
+		                        	id            INTEGER PRIMARY KEY NOT NULL,
+		                        	name          TEXT NOT NULL,
+		                        	avatar_url    TEXT,
+		                        	discriminator TEXT
+		                        )
+		                        """);
 
-		Execute(@"CREATE TABLE servers (
-			          id INTEGER PRIMARY KEY NOT NULL,
-			          name TEXT NOT NULL,
-			          type TEXT NOT NULL)");
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE servers (
+		                        	id   INTEGER PRIMARY KEY NOT NULL,
+		                        	name TEXT NOT NULL,
+		                        	type TEXT NOT NULL
+		                        )
+		                        """);
 
-		Execute(@"CREATE TABLE channels (
-			          id INTEGER PRIMARY KEY NOT NULL,
-			          server INTEGER NOT NULL,
-			          name TEXT NOT NULL,
-			          parent_id INTEGER,
-			          position INTEGER,
-			          topic TEXT,
-			          nsfw INTEGER)");
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE channels (
+		                        	id        INTEGER PRIMARY KEY NOT NULL,
+		                        	server    INTEGER NOT NULL,
+		                        	name      TEXT NOT NULL,
+		                        	parent_id INTEGER,
+		                        	position  INTEGER,
+		                        	topic     TEXT,
+		                        	nsfw      INTEGER
+		                        )
+		                        """);
 
-		Execute(@"CREATE TABLE messages (
-			        message_id INTEGER PRIMARY KEY NOT NULL,
-			        sender_id INTEGER NOT NULL,
-			        channel_id INTEGER NOT NULL,
-			        text TEXT NOT NULL,
-			        timestamp INTEGER NOT NULL)");
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE messages (
+		                        	message_id INTEGER PRIMARY KEY NOT NULL,
+		                        	sender_id  INTEGER NOT NULL,
+		                        	channel_id INTEGER NOT NULL,
+		                        	text       TEXT NOT NULL,
+		                        	timestamp  INTEGER NOT NULL
+		                        )
+		                        """);
 
-		Execute(@"CREATE TABLE attachments (
-			        message_id INTEGER NOT NULL,
-			        attachment_id INTEGER NOT NULL PRIMARY KEY NOT NULL,
-			        name TEXT NOT NULL,
-			        type TEXT,
-			        url TEXT NOT NULL,
-			        size INTEGER NOT NULL,
-			        width INTEGER,
-			        height INTEGER)");
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE attachments (
+		                        	message_id     INTEGER NOT NULL,
+		                        	attachment_id  INTEGER NOT NULL PRIMARY KEY NOT NULL,
+		                        	name           TEXT NOT NULL,
+		                        	type           TEXT,
+		                        	normalized_url TEXT NOT NULL,
+		                        	download_url   TEXT,
+		                        	size           INTEGER NOT NULL,
+		                        	width          INTEGER,
+		                        	height         INTEGER
+		                        )
+		                        """);
 
-		Execute(@"CREATE TABLE embeds (
-			        message_id INTEGER NOT NULL,
-			        json TEXT NOT NULL)");
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE embeds (
+		                        	message_id INTEGER NOT NULL,
+		                        	json       TEXT NOT NULL
+		                        )
+		                        """);
 
-		Execute(@"CREATE TABLE reactions (
-					message_id INTEGER NOT NULL,
-					emoji_id INTEGER,
-					emoji_name TEXT,
-					emoji_flags INTEGER NOT NULL,
-					count INTEGER NOT NULL)");
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE downloads (
+		                        	normalized_url TEXT NOT NULL PRIMARY KEY,
+		                        	download_url   TEXT,
+		                        	status         INTEGER NOT NULL,
+		                        	size           INTEGER NOT NULL,
+		                        	blob           BLOB
+		                        )
+		                        """);
 
-		CreateMessageEditTimestampTable();
-		CreateMessageRepliedToTable();
-		CreateDownloadsTable();
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE reactions (
+		                        	message_id  INTEGER NOT NULL,
+		                        	emoji_id    INTEGER,
+		                        	emoji_name  TEXT,
+		                        	emoji_flags INTEGER NOT NULL,
+		                        	count       INTEGER NOT NULL
+		                        )
+		                        """);
 
-		Execute("CREATE INDEX attachments_message_ix ON attachments(message_id)");
-		Execute("CREATE INDEX embeds_message_ix ON embeds(message_id)");
-		Execute("CREATE INDEX reactions_message_ix ON reactions(message_id)");
+		await CreateMessageEditTimestampTable();
+		await CreateMessageRepliedToTable();
 
-		Execute("INSERT INTO metadata (key, value) VALUES ('version', " + Version + ")");
+		await conn.ExecuteAsync("CREATE INDEX attachments_message_ix ON attachments(message_id)");
+		await conn.ExecuteAsync("CREATE INDEX embeds_message_ix ON embeds(message_id)");
+		await conn.ExecuteAsync("CREATE INDEX reactions_message_ix ON reactions(message_id)");
+
+		await conn.ExecuteAsync("INSERT INTO metadata (key, value) VALUES ('version', " + Version + ")");
 	}
 
-	private void CreateMessageEditTimestampTable() {
-		Execute(@"CREATE TABLE edit_timestamps (
-			        message_id INTEGER PRIMARY KEY NOT NULL,
-			        edit_timestamp INTEGER NOT NULL)");
+	private async Task CreateMessageEditTimestampTable() {
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE edit_timestamps (
+		                        	message_id     INTEGER PRIMARY KEY NOT NULL,
+		                        	edit_timestamp INTEGER NOT NULL
+		                        )
+		                        """);
 	}
 
-	private void CreateMessageRepliedToTable() {
-		Execute(@"CREATE TABLE replied_to (
-			        message_id INTEGER PRIMARY KEY NOT NULL,
-			        replied_to_id INTEGER NOT NULL)");
+	private async Task CreateMessageRepliedToTable() {
+		await conn.ExecuteAsync("""
+		                        CREATE TABLE replied_to (
+		                        	message_id    INTEGER PRIMARY KEY NOT NULL,
+		                        	replied_to_id INTEGER NOT NULL
+		                        )
+		                        """);
 	}
 
-	private void CreateDownloadsTable() {
-		Execute(@"CREATE TABLE downloads (
-                      url TEXT NOT NULL PRIMARY KEY,
-                      status INTEGER NOT NULL,
-                      size INTEGER NOT NULL,
-                      blob BLOB)");
+	private async Task NormalizeAttachmentUrls(ISchemaUpgradeCallbacks.IProgressReporter reporter) {
+		await reporter.SubWork("Preparing attachments...", 0, 0);
+
+		var normalizedUrls = new Dictionary<long, string>();
+
+		await using (var selectCmd = conn.Command("SELECT attachment_id, url FROM attachments")) {
+			await using var reader = await selectCmd.ExecuteReaderAsync();
+
+			while (reader.Read()) {
+				var attachmentId = reader.GetInt64(0);
+				var originalUrl = reader.GetString(1);
+				normalizedUrls[attachmentId] = DiscordCdn.NormalizeUrl(originalUrl);
+			}
+		}
+
+		await using var tx = await conn.BeginTransactionAsync();
+
+		int totalUrls = normalizedUrls.Count;
+		int processedUrls = -1;
+
+		await using (var updateCmd = conn.Command("UPDATE attachments SET download_url = url, url = :normalized_url WHERE attachment_id = :attachment_id")) {
+			updateCmd.Add(":attachment_id", SqliteType.Integer);
+			updateCmd.Add(":normalized_url", SqliteType.Text);
+
+			foreach (var (attachmentId, normalizedUrl) in normalizedUrls) {
+				if (++processedUrls % 1000 == 0) {
+					await reporter.SubWork("Updating URLs...", processedUrls, totalUrls);
+				}
+
+				updateCmd.Set(":attachment_id", attachmentId);
+				updateCmd.Set(":normalized_url", normalizedUrl);
+				updateCmd.ExecuteNonQuery();
+			}
+		}
+
+		await reporter.SubWork("Updating URLs...", totalUrls, totalUrls);
+
+		await tx.CommitAsync();
 	}
 
-	private void UpgradeSchemas(int dbVersion) {
+	private async Task NormalizeDownloadUrls(ISchemaUpgradeCallbacks.IProgressReporter reporter) {
+		await reporter.SubWork("Preparing downloads...", 0, 0);
+
+		var normalizedUrlsToOriginalUrls = new Dictionary<string, string>();
+		var duplicateUrlsToDelete = new HashSet<string>();
+
+		await using (var selectCmd = conn.Command("SELECT url FROM downloads ORDER BY CASE WHEN status = 200 THEN 0 ELSE 1 END")) {
+			await using var reader = await selectCmd.ExecuteReaderAsync();
+
+			while (reader.Read()) {
+				var originalUrl = reader.GetString(0);
+				var normalizedUrl = DiscordCdn.NormalizeUrl(originalUrl);
+
+				if (!normalizedUrlsToOriginalUrls.TryAdd(normalizedUrl, originalUrl)) {
+					duplicateUrlsToDelete.Add(originalUrl);
+				}
+			}
+		}
+
+		await conn.ExecuteAsync("PRAGMA cache_size = -20000");
+
+		DbTransaction tx;
+
+		await using (tx = await conn.BeginTransactionAsync()) {
+			await reporter.SubWork("Deleting duplicates...", 0, 0);
+
+			await using (var deleteCmd = conn.Delete("downloads", ("url", SqliteType.Text))) {
+				foreach (var duplicateUrl in duplicateUrlsToDelete) {
+					deleteCmd.Set(":url", duplicateUrl);
+					deleteCmd.ExecuteNonQuery();
+				}
+			}
+
+			await tx.CommitAsync();
+		}
+
+		int totalUrls = normalizedUrlsToOriginalUrls.Count;
+		int processedUrls = -1;
+
+		tx = await conn.BeginTransactionAsync();
+
+		await using (var updateCmd = conn.Command("UPDATE downloads SET download_url = :download_url, url = :normalized_url WHERE url = :download_url")) {
+			updateCmd.Add(":normalized_url", SqliteType.Text);
+			updateCmd.Add(":download_url", SqliteType.Text);
+
+			foreach (var (normalizedUrl, downloadUrl) in normalizedUrlsToOriginalUrls) {
+				if (++processedUrls % 100 == 0) {
+					await reporter.SubWork("Updating URLs...", processedUrls, totalUrls);
+
+					// Not proper way of dealing with transactions, but it avoids a long commit at the end.
+					// Schema upgrades are already non-atomic anyways, so this doesn't make it worse.
+					await tx.CommitAsync();
+					await tx.DisposeAsync();
+
+					tx = await conn.BeginTransactionAsync();
+					updateCmd.Transaction = (SqliteTransaction) tx;
+				}
+
+				updateCmd.Set(":normalized_url", normalizedUrl);
+				updateCmd.Set(":download_url", downloadUrl);
+				updateCmd.ExecuteNonQuery();
+			}
+		}
+
+		await reporter.SubWork("Updating URLs...", totalUrls, totalUrls);
+
+		await tx.CommitAsync();
+		await tx.DisposeAsync();
+
+		await conn.ExecuteAsync("PRAGMA cache_size = -2000");
+	}
+
+	private async Task UpgradeSchemas(int dbVersion, ISchemaUpgradeCallbacks.IProgressReporter reporter) {
 		var perf = Log.Start("from version " + dbVersion);
 
-		Execute("UPDATE metadata SET value = " + Version + " WHERE key = 'version'");
+		await conn.ExecuteAsync("UPDATE metadata SET value = " + Version + " WHERE key = 'version'");
 
 		if (dbVersion <= 1) {
-			Execute("ALTER TABLE channels ADD parent_id INTEGER");
+			await reporter.MainWork("Applying schema changes...", 0, 1);
+			await conn.ExecuteAsync("ALTER TABLE channels ADD parent_id INTEGER");
+
 			perf.Step("Upgrade to version 2");
+			await reporter.NextVersion();
 		}
 
 		if (dbVersion <= 2) {
-			CreateMessageEditTimestampTable();
-			CreateMessageRepliedToTable();
+			await reporter.MainWork("Applying schema changes...", 0, 1);
 
-			Execute(@"INSERT INTO edit_timestamps (message_id, edit_timestamp)
-						SELECT message_id, edit_timestamp FROM messages
-						WHERE edit_timestamp IS NOT NULL");
+			await CreateMessageEditTimestampTable();
+			await CreateMessageRepliedToTable();
 
-			Execute(@"INSERT INTO replied_to (message_id, replied_to_id)
-						SELECT message_id, replied_to_id FROM messages
-						WHERE replied_to_id IS NOT NULL");
+			await conn.ExecuteAsync("""
+			                        INSERT INTO edit_timestamps (message_id, edit_timestamp)
+			                        SELECT message_id, edit_timestamp
+			                        FROM messages
+			                        WHERE edit_timestamp IS NOT NULL
+			                        """);
 
-			Execute("ALTER TABLE messages DROP COLUMN replied_to_id");
-			Execute("ALTER TABLE messages DROP COLUMN edit_timestamp");
+			await conn.ExecuteAsync("""
+			                        INSERT INTO replied_to (message_id, replied_to_id)
+			                        SELECT message_id, replied_to_id
+			                        FROM messages
+			                        WHERE replied_to_id IS NOT NULL
+			                        """);
+
+			await conn.ExecuteAsync("ALTER TABLE messages DROP COLUMN replied_to_id");
+			await conn.ExecuteAsync("ALTER TABLE messages DROP COLUMN edit_timestamp");
 
 			perf.Step("Upgrade to version 3");
 
-			Execute("VACUUM");
+			await reporter.MainWork("Vacuuming the database...", 1, 1);
+			await conn.ExecuteAsync("VACUUM");
 			perf.Step("Vacuum");
+
+			await reporter.NextVersion();
 		}
 
 		if (dbVersion <= 3) {
-			CreateDownloadsTable();
+			await conn.ExecuteAsync("""
+			                        CREATE TABLE downloads (
+			                        	url    TEXT NOT NULL PRIMARY KEY,
+			                        	status INTEGER NOT NULL,
+			                        	size   INTEGER NOT NULL,
+			                        	blob   BLOB
+			                        )
+			                        """);
+
 			perf.Step("Upgrade to version 4");
+			await reporter.NextVersion();
 		}
 
 		if (dbVersion <= 4) {
-			Execute("ALTER TABLE attachments ADD width INTEGER");
-			Execute("ALTER TABLE attachments ADD height INTEGER");
+			await reporter.MainWork("Applying schema changes...", 0, 1);
+			await conn.ExecuteAsync("ALTER TABLE attachments ADD width INTEGER");
+			await conn.ExecuteAsync("ALTER TABLE attachments ADD height INTEGER");
+
 			perf.Step("Upgrade to version 5");
+			await reporter.NextVersion();
+		}
+
+		if (dbVersion <= 5) {
+			await reporter.MainWork("Applying schema changes...", 0, 3);
+			await conn.ExecuteAsync("ALTER TABLE attachments ADD download_url TEXT");
+			await conn.ExecuteAsync("ALTER TABLE downloads ADD download_url TEXT");
+
+			await reporter.MainWork("Updating attachments...", 1, 3);
+			await NormalizeAttachmentUrls(reporter);
+
+			await reporter.MainWork("Updating downloads...", 2, 3);
+			await NormalizeDownloadUrls(reporter);
+
+			await reporter.MainWork("Applying schema changes...", 3, 3);
+			await conn.ExecuteAsync("ALTER TABLE attachments RENAME COLUMN url TO normalized_url");
+			await conn.ExecuteAsync("ALTER TABLE downloads RENAME COLUMN url TO normalized_url");
+
+			perf.Step("Upgrade to version 6");
+			await reporter.NextVersion();
 		}
 
 		perf.End();

app/Server/Database/Sqlite/SqliteDatabaseFile.cs

@@ -1,15 +1,8 @@
 using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Text;
 using System.Threading.Tasks;
-using DHT.Server.Data;
-using DHT.Server.Data.Aggregations;
-using DHT.Server.Data.Filters;
+using DHT.Server.Database.Repositories;
+using DHT.Server.Database.Sqlite.Repositories;
 using DHT.Server.Database.Sqlite.Utils;
-using DHT.Server.Download;
-using DHT.Utils.Collections;
-using DHT.Utils.Logging;
 using DHT.Utils.Tasks;
 using Microsoft.Data.Sqlite;
 
@@ -18,7 +11,7 @@ namespace DHT.Server.Database.Sqlite;
 public sealed class SqliteDatabaseFile : IDatabaseFile {
 	private const int DefaultPoolSize = 5;
 
-	public static async Task<SqliteDatabaseFile?> OpenOrCreate(string path, Func<Task<bool>> checkCanUpgradeSchemas) {
+	public static async Task<SqliteDatabaseFile?> OpenOrCreate(string path, ISchemaUpgradeCallbacks schemaUpgradeCallbacks, TaskScheduler computeTaskResultScheduler) {
 		var connectionString = new SqliteConnectionStringBuilder {
 			DataSource = path,
 			Mode = SqliteOpenMode.ReadWriteCreate,
@@ -27,12 +20,18 @@ public sealed class SqliteDatabaseFile : IDatabaseFile {
 		var pool = new SqliteConnectionPool(connectionString, DefaultPoolSize);
 		bool wasOpened;
 
-		using (var conn = pool.Take()) {
-			wasOpened = await new Schema(conn).Setup(checkCanUpgradeSchemas);
+		try {
+			using var conn = pool.Take();
+			wasOpened = await new Schema(conn).Setup(schemaUpgradeCallbacks);
+		} catch (Exception) {
+			pool.Dispose();
+			throw;
 		}
 
 		if (wasOpened) {
-			return new SqliteDatabaseFile(path, pool);
+			var db = new SqliteDatabaseFile(path, pool, computeTaskResultScheduler);
+			await db.Initialize();
+			return db;
 		}
 		else {
 			pool.Dispose();
@@ -42,651 +41,94 @@ public sealed class SqliteDatabaseFile : IDatabaseFile {
 
 	public string Path { get; }
 	public DatabaseStatistics Statistics { get; }
-
-	private readonly Log log;
+	
+	public IUserRepository Users => users;
+	public IServerRepository Servers => servers;
+	public IChannelRepository Channels => channels;
+	public IMessageRepository Messages => messages;
+	public IDownloadRepository Downloads => downloads;
+	
 	private readonly SqliteConnectionPool pool;
+	
+	private readonly SqliteUserRepository users;
+	private readonly SqliteServerRepository servers;
+	private readonly SqliteChannelRepository channels;
+	private readonly SqliteMessageRepository messages;
+	private readonly SqliteDownloadRepository downloads;
+	
 	private readonly AsyncValueComputer<long>.Single totalMessagesComputer;
 	private readonly AsyncValueComputer<long>.Single totalAttachmentsComputer;
 	private readonly AsyncValueComputer<long>.Single totalDownloadsComputer;
 
-	private SqliteDatabaseFile(string path, SqliteConnectionPool pool) {
-		this.log = Log.ForType(typeof(SqliteDatabaseFile), System.IO.Path.GetFileName(path));
+	private SqliteDatabaseFile(string path, SqliteConnectionPool pool, TaskScheduler computeTaskResultScheduler) {
 		this.pool = pool;
 
-		this.totalMessagesComputer = AsyncValueComputer<long>.WithResultProcessor(UpdateMessageStatistics).WithOutdatedResults().BuildWithComputer(ComputeMessageStatistics);
-		this.totalAttachmentsComputer = AsyncValueComputer<long>.WithResultProcessor(UpdateAttachmentStatistics).WithOutdatedResults().BuildWithComputer(ComputeAttachmentStatistics);
-		this.totalDownloadsComputer = AsyncValueComputer<long>.WithResultProcessor(UpdateDownloadStatistics).WithOutdatedResults().BuildWithComputer(ComputeDownloadStatistics);
+		this.totalMessagesComputer = AsyncValueComputer<long>.WithResultProcessor(UpdateMessageStatistics, computeTaskResultScheduler).WithOutdatedResults().BuildWithComputer(ComputeMessageStatistics);
+		this.totalAttachmentsComputer = AsyncValueComputer<long>.WithResultProcessor(UpdateAttachmentStatistics, computeTaskResultScheduler).WithOutdatedResults().BuildWithComputer(ComputeAttachmentStatistics);
+		this.totalDownloadsComputer = AsyncValueComputer<long>.WithResultProcessor(UpdateDownloadStatistics, computeTaskResultScheduler).WithOutdatedResults().BuildWithComputer(ComputeDownloadStatistics);
 
 		this.Path = path;
 		this.Statistics = new DatabaseStatistics();
 
-		using (var conn = pool.Take()) {
-			UpdateServerStatistics(conn);
-			UpdateChannelStatistics(conn);
-			UpdateUserStatistics(conn);
-		}
+		this.users = new SqliteUserRepository(pool, Statistics);
+		this.servers = new SqliteServerRepository(pool, Statistics);
+		this.channels = new SqliteChannelRepository(pool, Statistics);
+		this.messages = new SqliteMessageRepository(pool, totalMessagesComputer, totalAttachmentsComputer);
+		this.downloads = new SqliteDownloadRepository(pool, totalDownloadsComputer);
 
 		totalMessagesComputer.Recompute();
 		totalAttachmentsComputer.Recompute();
 		totalDownloadsComputer.Recompute();
 	}
 
+	private async Task Initialize() {
+		await users.Initialize();
+		await servers.Initialize();
+		await channels.Initialize();
+	}
+
 	public void Dispose() {
+		totalMessagesComputer.Cancel();
+		totalAttachmentsComputer.Cancel();
+		totalDownloadsComputer.Cancel();
 		pool.Dispose();
 	}
 
-	public DatabaseStatisticsSnapshot SnapshotStatistics() {
+	public async Task<DatabaseStatisticsSnapshot> SnapshotStatistics() {
 		return new DatabaseStatisticsSnapshot {
 			TotalServers = Statistics.TotalServers,
 			TotalChannels = Statistics.TotalChannels,
 			TotalUsers = Statistics.TotalUsers,
-			TotalMessages = ComputeMessageStatistics(),
+			TotalMessages = await ComputeMessageStatistics(),
 		};
 	}
 
-	public void AddServer(Data.Server server) {
+	public async Task Vacuum() {
 		using var conn = pool.Take();
-		using var cmd = conn.Upsert("servers", new[] {
-			("id", SqliteType.Integer),
-			("name", SqliteType.Text),
-			("type", SqliteType.Text),
-		});
-
-		cmd.Set(":id", server.Id);
-		cmd.Set(":name", server.Name);
-		cmd.Set(":type", ServerTypes.ToString(server.Type));
-		cmd.ExecuteNonQuery();
-		UpdateServerStatistics(conn);
+		await conn.ExecuteAsync("VACUUM");
 	}
 
-	public List<Data.Server> GetAllServers() {
-		var perf = log.Start();
-		var list = new List<Data.Server>();
-
+	private async Task<long> ComputeMessageStatistics() {
 		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT id, name, type FROM servers");
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			list.Add(new Data.Server {
-				Id = reader.GetUint64(0),
-				Name = reader.GetString(1),
-				Type = ServerTypes.FromString(reader.GetString(2)),
-			});
-		}
-
-		perf.End();
-		return list;
-	}
-
-	public void AddChannel(Channel channel) {
-		using var conn = pool.Take();
-		using var cmd = conn.Upsert("channels", new[] {
-			("id", SqliteType.Integer),
-			("server", SqliteType.Integer),
-			("name", SqliteType.Text),
-			("parent_id", SqliteType.Integer),
-			("position", SqliteType.Integer),
-			("topic", SqliteType.Text),
-			("nsfw", SqliteType.Integer),
-		});
-
-		cmd.Set(":id", channel.Id);
-		cmd.Set(":server", channel.Server);
-		cmd.Set(":name", channel.Name);
-		cmd.Set(":parent_id", channel.ParentId);
-		cmd.Set(":position", channel.Position);
-		cmd.Set(":topic", channel.Topic);
-		cmd.Set(":nsfw", channel.Nsfw);
-		cmd.ExecuteNonQuery();
-		UpdateChannelStatistics(conn);
-	}
-
-	public List<Channel> GetAllChannels() {
-		var list = new List<Channel>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT id, server, name, parent_id, position, topic, nsfw FROM channels");
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			list.Add(new Channel {
-				Id = reader.GetUint64(0),
-				Server = reader.GetUint64(1),
-				Name = reader.GetString(2),
-				ParentId = reader.IsDBNull(3) ? null : reader.GetUint64(3),
-				Position = reader.IsDBNull(4) ? null : reader.GetInt32(4),
-				Topic = reader.IsDBNull(5) ? null : reader.GetString(5),
-				Nsfw = reader.IsDBNull(6) ? null : reader.GetBoolean(6),
-			});
-		}
-
-		return list;
-	}
-
-	public void AddUsers(User[] users) {
-		using var conn = pool.Take();
-		using var tx = conn.BeginTransaction();
-		using var cmd = conn.Upsert("users", new[] {
-			("id", SqliteType.Integer),
-			("name", SqliteType.Text),
-			("avatar_url", SqliteType.Text),
-			("discriminator", SqliteType.Text),
-		});
-
-		foreach (var user in users) {
-			cmd.Set(":id", user.Id);
-			cmd.Set(":name", user.Name);
-			cmd.Set(":avatar_url", user.AvatarUrl);
-			cmd.Set(":discriminator", user.Discriminator);
-			cmd.ExecuteNonQuery();
-		}
-
-		tx.Commit();
-		UpdateUserStatistics(conn);
-	}
-
-	public List<User> GetAllUsers() {
-		var perf = log.Start();
-		var list = new List<User>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT id, name, avatar_url, discriminator FROM users");
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			list.Add(new User {
-				Id = reader.GetUint64(0),
-				Name = reader.GetString(1),
-				AvatarUrl = reader.IsDBNull(2) ? null : reader.GetString(2),
-				Discriminator = reader.IsDBNull(3) ? null : reader.GetString(3),
-			});
-		}
-
-		perf.End();
-		return list;
-	}
-
-	public void AddMessages(Message[] messages) {
-		static SqliteCommand DeleteByMessageId(ISqliteConnection conn, string tableName) {
-			return conn.Delete(tableName, ("message_id", SqliteType.Integer));
-		}
-
-		static void ExecuteDeleteByMessageId(SqliteCommand cmd, object id) {
-			cmd.Set(":message_id", id);
-			cmd.ExecuteNonQuery();
-		}
-
-		bool addedAttachments = false;
-
-		using (var conn = pool.Take()) {
-			using var tx = conn.BeginTransaction();
-
-			using var messageCmd = conn.Upsert("messages", new[] {
-				("message_id", SqliteType.Integer),
-				("sender_id", SqliteType.Integer),
-				("channel_id", SqliteType.Integer),
-				("text", SqliteType.Text),
-				("timestamp", SqliteType.Integer),
-			});
-
-			using var deleteEditTimestampCmd = DeleteByMessageId(conn, "edit_timestamps");
-			using var deleteRepliedToCmd = DeleteByMessageId(conn, "replied_to");
-
-			using var deleteAttachmentsCmd = DeleteByMessageId(conn, "attachments");
-			using var deleteEmbedsCmd = DeleteByMessageId(conn, "embeds");
-			using var deleteReactionsCmd = DeleteByMessageId(conn, "reactions");
-
-			using var editTimestampCmd = conn.Insert("edit_timestamps", new [] {
-				("message_id", SqliteType.Integer),
-				("edit_timestamp", SqliteType.Integer),
-			});
-
-			using var repliedToCmd = conn.Insert("replied_to", new [] {
-				("message_id", SqliteType.Integer),
-				("replied_to_id", SqliteType.Integer),
-			});
-
-			using var attachmentCmd = conn.Insert("attachments", new[] {
-				("message_id", SqliteType.Integer),
-				("attachment_id", SqliteType.Integer),
-				("name", SqliteType.Text),
-				("type", SqliteType.Text),
-				("url", SqliteType.Text),
-				("size", SqliteType.Integer),
-				("width", SqliteType.Integer),
-				("height", SqliteType.Integer),
-			});
-
-			using var embedCmd = conn.Insert("embeds", new[] {
-				("message_id", SqliteType.Integer),
-				("json", SqliteType.Text),
-			});
-
-			using var reactionCmd = conn.Insert("reactions", new[] {
-				("message_id", SqliteType.Integer),
-				("emoji_id", SqliteType.Integer),
-				("emoji_name", SqliteType.Text),
-				("emoji_flags", SqliteType.Integer),
-				("count", SqliteType.Integer),
-			});
-
-			foreach (var message in messages) {
-				object messageId = message.Id;
-
-				messageCmd.Set(":message_id", messageId);
-				messageCmd.Set(":sender_id", message.Sender);
-				messageCmd.Set(":channel_id", message.Channel);
-				messageCmd.Set(":text", message.Text);
-				messageCmd.Set(":timestamp", message.Timestamp);
-				messageCmd.ExecuteNonQuery();
-
-				ExecuteDeleteByMessageId(deleteEditTimestampCmd, messageId);
-				ExecuteDeleteByMessageId(deleteRepliedToCmd, messageId);
-
-				ExecuteDeleteByMessageId(deleteAttachmentsCmd, messageId);
-				ExecuteDeleteByMessageId(deleteEmbedsCmd, messageId);
-				ExecuteDeleteByMessageId(deleteReactionsCmd, messageId);
-
-				if (message.EditTimestamp is {} timestamp) {
-					editTimestampCmd.Set(":message_id", messageId);
-					editTimestampCmd.Set(":edit_timestamp", timestamp);
-					editTimestampCmd.ExecuteNonQuery();
-				}
-
-				if (message.RepliedToId is {} repliedToId) {
-					repliedToCmd.Set(":message_id", messageId);
-					repliedToCmd.Set(":replied_to_id", repliedToId);
-					repliedToCmd.ExecuteNonQuery();
-				}
-
-				if (!message.Attachments.IsEmpty) {
-					addedAttachments = true;
-
-					foreach (var attachment in message.Attachments) {
-						attachmentCmd.Set(":message_id", messageId);
-						attachmentCmd.Set(":attachment_id", attachment.Id);
-						attachmentCmd.Set(":name", attachment.Name);
-						attachmentCmd.Set(":type", attachment.Type);
-						attachmentCmd.Set(":url", attachment.Url);
-						attachmentCmd.Set(":size", attachment.Size);
-						attachmentCmd.Set(":width", attachment.Width);
-						attachmentCmd.Set(":height", attachment.Height);
-						attachmentCmd.ExecuteNonQuery();
-					}
-				}
-
-				if (!message.Embeds.IsEmpty) {
-					foreach (var embed in message.Embeds) {
-						embedCmd.Set(":message_id", messageId);
-						embedCmd.Set(":json", embed.Json);
-						embedCmd.ExecuteNonQuery();
-					}
-				}
-
-				if (!message.Reactions.IsEmpty) {
-					foreach (var reaction in message.Reactions) {
-						reactionCmd.Set(":message_id", messageId);
-						reactionCmd.Set(":emoji_id", reaction.EmojiId);
-						reactionCmd.Set(":emoji_name", reaction.EmojiName);
-						reactionCmd.Set(":emoji_flags", (int) reaction.EmojiFlags);
-						reactionCmd.Set(":count", reaction.Count);
-						reactionCmd.ExecuteNonQuery();
-					}
-				}
-			}
-
-			tx.Commit();
-		}
-
-		totalMessagesComputer.Recompute();
-
-		if (addedAttachments) {
-			totalAttachmentsComputer.Recompute();
-		}
-	}
-
-	public int CountMessages(MessageFilter? filter = null) {
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT COUNT(*) FROM messages" + filter.GenerateWhereClause());
-		using var reader = cmd.ExecuteReader();
-
-		return reader.Read() ? reader.GetInt32(0) : 0;
-	}
-
-	public List<Message> GetMessages(MessageFilter? filter = null) {
-		var perf = log.Start();
-		var list = new List<Message>();
-
-		var attachments = GetAllAttachments();
-		var embeds = GetAllEmbeds();
-		var reactions = GetAllReactions();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command(@"
-SELECT m.message_id, m.sender_id, m.channel_id, m.text, m.timestamp, et.edit_timestamp, rt.replied_to_id
-FROM messages m
-LEFT JOIN edit_timestamps et ON m.message_id = et.message_id
-LEFT JOIN replied_to rt ON m.message_id = rt.message_id" + filter.GenerateWhereClause("m"));
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			ulong id = reader.GetUint64(0);
-
-			list.Add(new Message {
-				Id = id,
-				Sender = reader.GetUint64(1),
-				Channel = reader.GetUint64(2),
-				Text = reader.GetString(3),
-				Timestamp = reader.GetInt64(4),
-				EditTimestamp = reader.IsDBNull(5) ? null : reader.GetInt64(5),
-				RepliedToId = reader.IsDBNull(6) ? null : reader.GetUint64(6),
-				Attachments = attachments.GetListOrNull(id)?.ToImmutableArray() ?? ImmutableArray<Attachment>.Empty,
-				Embeds = embeds.GetListOrNull(id)?.ToImmutableArray() ?? ImmutableArray<Embed>.Empty,
-				Reactions = reactions.GetListOrNull(id)?.ToImmutableArray() ?? ImmutableArray<Reaction>.Empty,
-			});
-		}
-
-		perf.End();
-		return list;
-	}
-
-	public HashSet<ulong> GetMessageIds(MessageFilter? filter = null) {
-		var perf = log.Start();
-		var ids = new HashSet<ulong>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT message_id FROM messages" + filter.GenerateWhereClause());
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			ids.Add(reader.GetUint64(0));
-		}
-
-		perf.End();
-		return ids;
-	}
-
-	public void RemoveMessages(MessageFilter filter, FilterRemovalMode mode) {
-		var perf = log.Start();
-
-		DeleteFromTable("messages", filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching));
-		totalMessagesComputer.Recompute();
-
-		perf.End();
-	}
-
-	public int CountAttachments(AttachmentFilter? filter = null) {
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT COUNT(DISTINCT url) FROM attachments a" + filter.GenerateWhereClause("a"));
-		using var reader = cmd.ExecuteReader();
-
-		return reader.Read() ? reader.GetInt32(0) : 0;
-	}
-
-	public void AddDownload(Data.Download download) {
-		using var conn = pool.Take();
-		using var cmd = conn.Upsert("downloads", new[] {
-			("url", SqliteType.Text),
-			("status", SqliteType.Integer),
-			("size", SqliteType.Integer),
-			("blob", SqliteType.Blob),
-		});
-
-		cmd.Set(":url", download.Url);
-		cmd.Set(":status", (int) download.Status);
-		cmd.Set(":size", download.Size);
-		cmd.Set(":blob", download.Data);
-		cmd.ExecuteNonQuery();
-
-		totalDownloadsComputer.Recompute();
-	}
-
-	public List<Data.Download> GetDownloadsWithoutData() {
-		var list = new List<Data.Download>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT url, status, size FROM downloads");
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			string url = reader.GetString(0);
-			var status = (DownloadStatus) reader.GetInt32(1);
-			ulong size = reader.GetUint64(2);
-
-			list.Add(new Data.Download(url, status, size));
-		}
-
-		return list;
-	}
-
-	public Data.Download GetDownloadWithData(Data.Download download) {
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT blob FROM downloads WHERE url = :url");
-		cmd.AddAndSet(":url", SqliteType.Text, download.Url);
-
-		using var reader = cmd.ExecuteReader();
-
-		if (reader.Read() && !reader.IsDBNull(0)) {
-			return download.WithData((byte[]) reader["blob"]);
-		}
-		else {
-			return download;
-		}
-	}
-
-	public DownloadedAttachment? GetDownloadedAttachment(string url) {
-		using var conn = pool.Take();
-		using var cmd = conn.Command(@"
-SELECT a.type, d.blob FROM downloads d
-LEFT JOIN attachments a ON d.url = a.url
-WHERE d.url = :url AND d.status = :success AND d.blob IS NOT NULL");
-
-		cmd.AddAndSet(":url", SqliteType.Text, url);
-		cmd.AddAndSet(":success", SqliteType.Integer, (int) DownloadStatus.Success);
-
-		using var reader = cmd.ExecuteReader();
-
-		if (!reader.Read()) {
-			return null;
-		}
-
-		return new DownloadedAttachment {
-			Type = reader.IsDBNull(0) ? null : reader.GetString(0),
-			Data = (byte[]) reader["blob"],
-		};
-	}
-
-	public void EnqueueDownloadItems(AttachmentFilter? filter = null) {
-		using var conn = pool.Take();
-		using var cmd = conn.Command("INSERT INTO downloads (url, status, size) SELECT a.url, :enqueued, MAX(a.size) FROM attachments a" + filter.GenerateWhereClause("a") + " GROUP BY a.url");
-		cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
-		cmd.ExecuteNonQuery();
-	}
-
-	public List<DownloadItem> GetEnqueuedDownloadItems(int count) {
-		var list = new List<DownloadItem>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT url, size FROM downloads WHERE status = :enqueued LIMIT :limit");
-		cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
-		cmd.AddAndSet(":limit", SqliteType.Integer, Math.Max(0, count));
-
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			list.Add(new DownloadItem {
-				Url = reader.GetString(0),
-				Size = reader.GetUint64(1),
-			});
-		}
-
-		return list;
-	}
-
-	public void RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode) {
-		DeleteFromTable("downloads", filter.GenerateWhereClause(invert: mode == FilterRemovalMode.KeepMatching));
-		totalDownloadsComputer.Recompute();
-	}
-
-	public DownloadStatusStatistics GetDownloadStatusStatistics() {
-		static void LoadUndownloadedStatistics(ISqliteConnection conn, DownloadStatusStatistics result) {
-			using var cmd = conn.Command("SELECT IFNULL(COUNT(size), 0), IFNULL(SUM(size), 0) FROM (SELECT MAX(a.size) size FROM attachments a WHERE a.url NOT IN (SELECT d.url FROM downloads d) GROUP BY a.url)");
-			using var reader = cmd.ExecuteReader();
-
-			if (reader.Read()) {
-				result.SkippedCount = reader.GetInt32(0);
-				result.SkippedSize = reader.GetUint64(1);
-			}
-		}
-
-		static void LoadSuccessStatistics(ISqliteConnection conn, DownloadStatusStatistics result) {
-			using var cmd = conn.Command(@"SELECT
-IFNULL(SUM(CASE WHEN status = :enqueued THEN 1 ELSE 0 END), 0),
-IFNULL(SUM(CASE WHEN status = :enqueued THEN size ELSE 0 END), 0),
-IFNULL(SUM(CASE WHEN status = :success THEN 1 ELSE 0 END), 0),
-IFNULL(SUM(CASE WHEN status = :success THEN size ELSE 0 END), 0),
-IFNULL(SUM(CASE WHEN status != :enqueued AND status != :success THEN 1 ELSE 0 END), 0),
-IFNULL(SUM(CASE WHEN status != :enqueued AND status != :success THEN size ELSE 0 END), 0)
-FROM downloads");
-			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
-			cmd.AddAndSet(":success", SqliteType.Integer, (int) DownloadStatus.Success);
-
-			using var reader = cmd.ExecuteReader();
-
-			if (reader.Read()) {
-				result.EnqueuedCount = reader.GetInt32(0);
-				result.EnqueuedSize = reader.GetUint64(1);
-				result.SuccessfulCount = reader.GetInt32(2);
-				result.SuccessfulSize = reader.GetUint64(3);
-				result.FailedCount = reader.GetInt32(4);
-				result.FailedSize = reader.GetUint64(5);
-			}
-		}
-
-		var result = new DownloadStatusStatistics();
-
-		using var conn = pool.Take();
-		LoadUndownloadedStatistics(conn, result);
-		LoadSuccessStatistics(conn, result);
-		return result;
-	}
-
-	private MultiDictionary<ulong, Attachment> GetAllAttachments() {
-		var dict = new MultiDictionary<ulong, Attachment>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT message_id, attachment_id, name, type, url, size, width, height FROM attachments");
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			ulong messageId = reader.GetUint64(0);
-
-			dict.Add(messageId, new Attachment {
-				Id = reader.GetUint64(1),
-				Name = reader.GetString(2),
-				Type = reader.IsDBNull(3) ? null : reader.GetString(3),
-				Url = reader.GetString(4),
-				Size = reader.GetUint64(5),
-				Width = reader.IsDBNull(6) ? null : reader.GetInt32(6),
-				Height = reader.IsDBNull(7) ? null : reader.GetInt32(7),
-			});
-		}
-
-		return dict;
-	}
-
-	private MultiDictionary<ulong, Embed> GetAllEmbeds() {
-		var dict = new MultiDictionary<ulong, Embed>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT message_id, json FROM embeds");
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			ulong messageId = reader.GetUint64(0);
-
-			dict.Add(messageId, new Embed {
-				Json = reader.GetString(1),
-			});
-		}
-
-		return dict;
-	}
-
-	private MultiDictionary<ulong, Reaction> GetAllReactions() {
-		var dict = new MultiDictionary<ulong, Reaction>();
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT message_id, emoji_id, emoji_name, emoji_flags, count FROM reactions");
-		using var reader = cmd.ExecuteReader();
-
-		while (reader.Read()) {
-			ulong messageId = reader.GetUint64(0);
-
-			dict.Add(messageId, new Reaction {
-				EmojiId = reader.IsDBNull(1) ? null : reader.GetUint64(1),
-				EmojiName = reader.IsDBNull(2) ? null : reader.GetString(2),
-				EmojiFlags = (EmojiFlags) reader.GetInt16(3),
-				Count = reader.GetInt32(4),
-			});
-		}
-
-		return dict;
-	}
-
-	private void DeleteFromTable(string table, string whereClause) {
-		// Rider is being stupid...
-		StringBuilder build = new StringBuilder()
-		                      .Append("DELETE ")
-		                      .Append("FROM ")
-		                      .Append(table)
-		                      .Append(whereClause);
-
-		using var conn = pool.Take();
-		using var cmd = conn.Command(build.ToString());
-		cmd.ExecuteNonQuery();
-	}
-
-	public void Vacuum() {
-		using var conn = pool.Take();
-		using var cmd = conn.Command("VACUUM");
-		cmd.ExecuteNonQuery();
-	}
-
-	private void UpdateServerStatistics(ISqliteConnection conn) {
-		Statistics.TotalServers = conn.SelectScalar("SELECT COUNT(*) FROM servers") as long? ?? 0;
-	}
-
-	private void UpdateChannelStatistics(ISqliteConnection conn) {
-		Statistics.TotalChannels = conn.SelectScalar("SELECT COUNT(*) FROM channels") as long? ?? 0;
-	}
-
-	private void UpdateUserStatistics(ISqliteConnection conn) {
-		Statistics.TotalUsers = conn.SelectScalar("SELECT COUNT(*) FROM users") as long? ?? 0;
-	}
-
-	private long ComputeMessageStatistics() {
-		using var conn = pool.Take();
-		return conn.SelectScalar("SELECT COUNT(*) FROM messages") as long? ?? 0L;
+		return await conn.ExecuteReaderAsync("SELECT COUNT(*) FROM messages", static reader => reader?.GetInt64(0) ?? 0L);
 	}
 
 	private void UpdateMessageStatistics(long totalMessages) {
 		Statistics.TotalMessages = totalMessages;
 	}
 
-	private long ComputeAttachmentStatistics() {
+	private async Task<long> ComputeAttachmentStatistics() {
 		using var conn = pool.Take();
-		return conn.SelectScalar("SELECT COUNT(DISTINCT url) FROM attachments") as long? ?? 0L;
+		return await conn.ExecuteReaderAsync("SELECT COUNT(DISTINCT normalized_url) FROM attachments", static reader => reader?.GetInt64(0) ?? 0L);
 	}
 
 	private void UpdateAttachmentStatistics(long totalAttachments) {
 		Statistics.TotalAttachments = totalAttachments;
 	}
 
-	private long ComputeDownloadStatistics() {
+	private async Task<long> ComputeDownloadStatistics() {
 		using var conn = pool.Take();
-		return conn.SelectScalar("SELECT COUNT(*) FROM downloads") as long? ?? 0L;
+		return await conn.ExecuteReaderAsync("SELECT COUNT(*) FROM downloads", static reader => reader?.GetInt64(0) ?? 0L);
 	}
 
 	private void UpdateDownloadStatistics(long totalDownloads) {

app/Server/Database/Sqlite/SqliteFilters.cs

@@ -8,9 +8,13 @@ using DHT.Server.Database.Sqlite.Utils;
 namespace DHT.Server.Database.Sqlite;
 
 static class SqliteFilters {
+	private static string WhereAll(bool invert) {
+		return invert ? "WHERE FALSE" : "";
+	}
+
 	public static string GenerateWhereClause(this MessageFilter? filter, string? tableAlias = null, bool invert = false) {
-		if (filter == null) {
-			return "";
+		if (filter == null || filter.IsEmpty) {
+			return WhereAll(invert);
 		}
 
 		var where = new SqliteWhereGenerator(tableAlias, invert);
@@ -39,8 +43,8 @@ static class SqliteFilters {
 	}
 
 	public static string GenerateWhereClause(this AttachmentFilter? filter, string? tableAlias = null, bool invert = false) {
-		if (filter == null) {
-			return "";
+		if (filter == null || filter.IsEmpty) {
+			return WhereAll(invert);
 		}
 
 		var where = new SqliteWhereGenerator(tableAlias, invert);
@@ -50,18 +54,18 @@ static class SqliteFilters {
 		}
 
 		if (filter.DownloadItemRule == AttachmentFilter.DownloadItemRules.OnlyNotPresent) {
-			where.AddCondition("url NOT IN (SELECT url FROM downloads)");
+			where.AddCondition("normalized_url NOT IN (SELECT normalized_url FROM downloads)");
 		}
 		else if (filter.DownloadItemRule == AttachmentFilter.DownloadItemRules.OnlyPresent) {
-			where.AddCondition("url IN (SELECT url FROM downloads)");
+			where.AddCondition("normalized_url IN (SELECT normalized_url FROM downloads)");
 		}
 
 		return where.Generate();
 	}
 
 	public static string GenerateWhereClause(this DownloadItemFilter? filter, string? tableAlias = null, bool invert = false) {
-		if (filter == null) {
-			return "";
+		if (filter == null || filter.IsEmpty) {
+			return WhereAll(invert);
 		}
 
 		var where = new SqliteWhereGenerator(tableAlias, invert);

app/Server/Database/Sqlite/Utils/ISchemaUpgradeCallbacks.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Threading.Tasks;
+
+namespace DHT.Server.Database.Sqlite.Utils;
+
+public interface ISchemaUpgradeCallbacks {
+	Task<bool> CanUpgrade();
+	Task Start(int versionSteps, Func<IProgressReporter, Task> doUpgrade);
+
+	public interface IProgressReporter {
+		Task NextVersion();
+		Task MainWork(string message, int finishedItems, int totalItems);
+		Task SubWork(string message, int finishedItems, int totalItems);
+	}
+}

app/Server/Database/Sqlite/Utils/SqliteExtensions.cs

@@ -1,23 +1,34 @@
 using System;
+using System.Data.Common;
 using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using JetBrains.Annotations;
 using Microsoft.Data.Sqlite;
 
 namespace DHT.Server.Database.Sqlite.Utils;
 
 static class SqliteExtensions {
+	public static ValueTask<DbTransaction> BeginTransactionAsync(this ISqliteConnection conn) {
+		return conn.InnerConnection.BeginTransactionAsync();
+	}
+
 	public static SqliteCommand Command(this ISqliteConnection conn, string sql) {
 		var cmd = conn.InnerConnection.CreateCommand();
 		cmd.CommandText = sql;
 		return cmd;
 	}
 
-	public static SqliteTransaction BeginTransaction(this ISqliteConnection conn) {
-		return conn.InnerConnection.BeginTransaction();
+	public static async Task<int> ExecuteAsync(this ISqliteConnection conn, [LanguageInjection("sql")] string sql, CancellationToken cancellationToken = default) {
+		await using var cmd = conn.Command(sql);
+		return await cmd.ExecuteNonQueryAsync(cancellationToken);
 	}
+	
+	public static async Task<T> ExecuteReaderAsync<T>(this ISqliteConnection conn, string sql, Func<SqliteDataReader?, T> readFunction, CancellationToken cancellationToken = default) {
+		await using var cmd = conn.Command(sql);
+		await using var reader = await cmd.ExecuteReaderAsync(cancellationToken);
 
-	public static object? SelectScalar(this ISqliteConnection conn, string sql) {
-		using var cmd = conn.Command(sql);
-		return cmd.ExecuteScalar();
+		return reader.Read() ? readFunction(reader) : readFunction(null);
 	}
 
 	public static SqliteCommand Insert(this ISqliteConnection conn, string tableName, (string Name, SqliteType Type)[] columns) {
@@ -47,7 +58,7 @@ static class SqliteExtensions {
 
 	public static SqliteCommand Delete(this ISqliteConnection conn, string tableName, (string Name, SqliteType Type) column) {
 		var cmd = conn.Command("DELETE FROM " + tableName + " WHERE " + column.Name + " = :" + column.Name);
-		CreateParameters(cmd, new [] { column });
+		CreateParameters(cmd, new[] { column });
 		return cmd;
 	}
 
@@ -57,6 +68,10 @@ static class SqliteExtensions {
 		}
 	}
 
+	public static void Add(this SqliteCommand cmd, string key, SqliteType type) {
+		cmd.Parameters.Add(key, type);
+	}
+
 	public static void AddAndSet(this SqliteCommand cmd, string key, SqliteType type, object? value) {
 		cmd.Parameters.Add(key, type).Value = value ?? DBNull.Value;
 	}

app/Server/Download/BackgroundDownloadThread.cs

@@ -1,130 +0,0 @@
-using System;
-using System.Collections.Concurrent;
-using System.Net.Http;
-using System.Threading;
-using DHT.Server.Database;
-using DHT.Utils.Logging;
-using DHT.Utils.Models;
-
-namespace DHT.Server.Download;
-
-public sealed class BackgroundDownloadThread : BaseModel {
-	private static readonly Log Log = Log.ForType<BackgroundDownloadThread>();
-
-	public event EventHandler<DownloadItem>? OnItemFinished {
-		add => parameters.OnItemFinished += value;
-		remove => parameters.OnItemFinished -= value;
-	}
-
-	public event EventHandler? OnServerStopped {
-		add => parameters.OnServerStopped += value;
-		remove => parameters.OnServerStopped -= value;
-	}
-
-	private readonly CancellationTokenSource cancellationTokenSource;
-	private readonly ThreadInstance.Parameters parameters;
-
-	public BackgroundDownloadThread(IDatabaseFile db) {
-		this.cancellationTokenSource = new CancellationTokenSource();
-		this.parameters = new ThreadInstance.Parameters(db, cancellationTokenSource);
-
-		var thread = new Thread(new ThreadInstance().Work) {
-			Name = "DHT download thread"
-		};
-
-		thread.Start(parameters);
-	}
-
-	public void StopThread() {
-		try {
-			cancellationTokenSource.Cancel();
-		} catch (ObjectDisposedException) {
-			Log.Warn("Attempted to stop background download thread after the cancellation token has been disposed.");
-		}
-	}
-
-	private sealed class ThreadInstance {
-		private const int QueueSize = 32;
-
-		public sealed class Parameters {
-			public event EventHandler<DownloadItem>? OnItemFinished;
-			public event EventHandler? OnServerStopped;
-
-			public IDatabaseFile Db { get; }
-			public CancellationTokenSource CancellationTokenSource { get; }
-
-			public Parameters(IDatabaseFile db, CancellationTokenSource cancellationTokenSource) {
-				Db = db;
-				CancellationTokenSource = cancellationTokenSource;
-			}
-
-			public void FireOnItemFinished(DownloadItem item) {
-				OnItemFinished?.Invoke(null, item);
-			}
-
-			public void FireOnServerStopped() {
-				OnServerStopped?.Invoke(null, EventArgs.Empty);
-			}
-		}
-
-		private readonly HttpClient client = new ();
-
-		public ThreadInstance() {
-			client.DefaultRequestHeaders.UserAgent.ParseAdd("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36");
-		}
-
-		public async void Work(object? obj) {
-			var parameters = (Parameters) obj!;
-
-			var cancellationTokenSource = parameters.CancellationTokenSource;
-			var cancellationToken = cancellationTokenSource.Token;
-
-			var db = parameters.Db;
-			var queue = new ConcurrentQueue<DownloadItem>();
-
-			try {
-				while (!cancellationToken.IsCancellationRequested) {
-					FillQueue(db, queue, cancellationToken);
-
-					while (!cancellationToken.IsCancellationRequested && queue.TryDequeue(out var item)) {
-						var url = item.Url;
-						Log.Debug("Downloading " + url + "...");
-
-						try {
-							db.AddDownload(Data.Download.NewSuccess(url, await client.GetByteArrayAsync(url, cancellationToken)));
-						} catch (HttpRequestException e) {
-							db.AddDownload(Data.Download.NewFailure(url, e.StatusCode, item.Size));
-							Log.Error(e);
-						} catch (Exception e) {
-							db.AddDownload(Data.Download.NewFailure(url, null, item.Size));
-							Log.Error(e);
-						} finally {
-							parameters.FireOnItemFinished(item);
-						}
-					}
-				}
-			} catch (OperationCanceledException) {
-				//
-			} catch (ObjectDisposedException) {
-				//
-			} finally {
-				cancellationTokenSource.Dispose();
-				parameters.FireOnServerStopped();
-			}
-		}
-
-		private static void FillQueue(IDatabaseFile db, ConcurrentQueue<DownloadItem> queue, CancellationToken cancellationToken) {
-			while (!cancellationToken.IsCancellationRequested && queue.IsEmpty) {
-				var newItems = db.GetEnqueuedDownloadItems(QueueSize);
-				if (newItems.Count == 0) {
-					Thread.Sleep(TimeSpan.FromMilliseconds(50));
-				}
-				else {
-					foreach (var item in newItems) {
-						queue.Enqueue(item);
-					}
-				}
-			}
-		}
-	}
-}

app/Server/Download/DiscordCdn.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Frozen;
+
+namespace DHT.Server.Download;
+
+static class DiscordCdn {
+	private static FrozenSet<string> CdnHosts { get; } = new [] {
+		"cdn.discordapp.com",
+		"cdn.discord.com",
+	}.ToFrozenSet();
+
+	public static string NormalizeUrl(string originalUrl) {
+		return Uri.TryCreate(originalUrl, UriKind.Absolute, out var uri) && CdnHosts.Contains(uri.Host) ? uri.GetLeftPart(UriPartial.Path) : originalUrl;
+	}
+}

app/Server/Download/DownloadItem.cs

@@ -1,6 +1,7 @@
 namespace DHT.Server.Download;
 
 public readonly struct DownloadItem {
-	public string Url { get; init; }
+	public string NormalizedUrl { get; init; }
+	public string DownloadUrl { get; init; }
 	public ulong Size { get; init; }
 }

app/Server/Download/Downloader.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Database;
+
+namespace DHT.Server.Download;
+
+public sealed class Downloader {
+	private DownloaderTask? current;
+	public bool IsDownloading => current != null;
+	
+	private readonly IDatabaseFile db;
+	private readonly SemaphoreSlim semaphore = new (1, 1);
+	
+	internal Downloader(IDatabaseFile db) {
+		this.db = db;
+	}
+
+	public async Task<IObservable<DownloadItem>> Start() {
+		await semaphore.WaitAsync();
+		try {
+			current ??= new DownloaderTask(db);
+			return current.FinishedItems;
+		} finally {
+			semaphore.Release();
+		}
+	}
+
+	public async Task Stop() {
+		await semaphore.WaitAsync();
+		try {
+			if (current != null) {
+				await current.DisposeAsync();
+				current = null;
+			}
+		} finally {
+			semaphore.Release();
+		}
+	}
+}

app/Server/Download/DownloaderTask.cs

@@ -0,0 +1,110 @@
+using System;
+using System.Linq;
+using System.Net.Http;
+using System.Reactive.Subjects;
+using System.Threading;
+using System.Threading.Channels;
+using System.Threading.Tasks;
+using DHT.Server.Database;
+using DHT.Utils.Logging;
+using DHT.Utils.Tasks;
+
+namespace DHT.Server.Download;
+
+sealed class DownloaderTask : IAsyncDisposable {
+	private static readonly Log Log = Log.ForType<DownloaderTask>();
+
+	private const int DownloadTasks = 4;
+	private const int QueueSize = 25;
+	private const string UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36";
+
+	private readonly Channel<DownloadItem> downloadQueue = Channel.CreateBounded<DownloadItem>(new BoundedChannelOptions(QueueSize) {
+		SingleReader = false,
+		SingleWriter = true,
+		AllowSynchronousContinuations = false,
+		FullMode = BoundedChannelFullMode.Wait
+	});
+
+	private readonly CancellationTokenSource cancellationTokenSource = new ();
+	private readonly CancellationToken cancellationToken;
+
+	private readonly IDatabaseFile db;
+	private readonly Subject<DownloadItem> finishedItemPublisher = new ();
+
+	private readonly Task queueWriterTask;
+	private readonly Task[] downloadTasks;
+
+	public IObservable<DownloadItem> FinishedItems => finishedItemPublisher;
+
+	internal DownloaderTask(IDatabaseFile db) {
+		this.db = db;
+		this.cancellationToken = cancellationTokenSource.Token;
+		this.queueWriterTask = Task.Run(RunQueueWriterTask);
+		this.downloadTasks = Enumerable.Range(1, DownloadTasks).Select(taskIndex => Task.Run(() => RunDownloadTask(taskIndex))).ToArray();
+	}
+
+	private async Task RunQueueWriterTask() {
+		while (await downloadQueue.Writer.WaitToWriteAsync(cancellationToken)) {
+			var newItems = await db.Downloads.PullEnqueuedDownloadItems(QueueSize, cancellationToken).ToListAsync(cancellationToken);
+			if (newItems.Count == 0) {
+				await Task.Delay(TimeSpan.FromMilliseconds(50), cancellationToken);
+				continue;
+			}
+
+			foreach (var newItem in newItems) {
+				await downloadQueue.Writer.WriteAsync(newItem, cancellationToken);
+			}
+		}
+	}
+
+	private async Task RunDownloadTask(int taskIndex) {
+		var log = Log.ForType<DownloaderTask>("Task " + taskIndex);
+
+		var client = new HttpClient();
+		client.DefaultRequestHeaders.UserAgent.ParseAdd(UserAgent);
+		client.Timeout = TimeSpan.FromSeconds(30);
+
+		while (!cancellationToken.IsCancellationRequested) {
+			var item = await downloadQueue.Reader.ReadAsync(cancellationToken);
+			log.Debug("Downloading " + item.DownloadUrl + "...");
+
+			try {
+				var downloadedBytes = await client.GetByteArrayAsync(item.DownloadUrl, cancellationToken);
+				await db.Downloads.AddDownload(Data.Download.NewSuccess(item, downloadedBytes));
+			} catch (OperationCanceledException) {
+				// Ignore.
+			} catch (HttpRequestException e) {
+				await db.Downloads.AddDownload(Data.Download.NewFailure(item, e.StatusCode, item.Size));
+				log.Error(e);
+			} catch (Exception e) {
+				await db.Downloads.AddDownload(Data.Download.NewFailure(item, null, item.Size));
+				log.Error(e);
+			} finally {
+				try {
+					finishedItemPublisher.OnNext(item);
+				} catch (Exception e) {
+					log.Error("Caught exception in event handler: " + e);
+				}
+			}
+		}
+	}
+
+	public async ValueTask DisposeAsync() {
+		try {
+			await cancellationTokenSource.CancelAsync();
+		} catch (Exception) {
+			Log.Warn("Attempted to stop background download twice.");
+			return;
+		}
+
+		downloadQueue.Writer.Complete();
+
+		try {
+			await queueWriterTask.WaitIgnoringCancellation();
+			await Task.WhenAll(downloadTasks).WaitIgnoringCancellation();
+		} finally {
+			cancellationTokenSource.Dispose();
+			finishedItemPublisher.OnCompleted();
+		}
+	}
+}