Release v38.0

Closes #226

README.md

@@ -19,7 +19,7 @@ Folder organization:
 * `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 5 SDK](https://dotnet.microsoft.com/en-us/download/dotnet/5.0), and then open `app/DiscordHistoryTracker.sln` in [Visual Studio](https://visualstudio.microsoft.com/downloads/) or [Rider](https://www.jetbrains.com/rider/).
+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/).
 
 ### Building
 
@@ -50,6 +50,6 @@ Run the `app/build.sh` script, and read the [Distribution](#distribution) sectio
 
 #### Distribution
 
-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 5 to be installed.
+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.

app/.idea/.idea.DiscordHistoryTracker/.idea/avalonia.xml

@@ -7,12 +7,15 @@
         <entry key="Desktop/Dialogs/CheckBox/CheckBoxDialog.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Dialogs/Message/MessageDialog.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Dialogs/Progress/ProgressDialog.axaml" value="Desktop/Desktop.csproj" />
+        <entry key="Desktop/Dialogs/TextBox/TextBoxDialog.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/AboutWindow.axaml" value="Desktop/Desktop.csproj" />
-        <entry key="Desktop/Main/Controls/FilterPanel.axaml" value="Desktop/Desktop.csproj" />
+        <entry key="Desktop/Main/Controls/AttachmentFilterPanel.axaml" value="Desktop/Desktop.csproj" />
+        <entry key="Desktop/Main/Controls/MessageFilterPanel.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Controls/ServerConfigurationPanel.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Controls/StatusBar.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/MainWindow.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Pages/AdvancedPage.axaml" value="Desktop/Desktop.csproj" />
+        <entry key="Desktop/Main/Pages/AttachmentsPage.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Pages/DatabasePage.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Pages/DebugPage.axaml" value="Desktop/Desktop.csproj" />
         <entry key="Desktop/Main/Pages/TrackingPage.axaml" value="Desktop/Desktop.csproj" />

app/Desktop/App.axaml

@@ -6,7 +6,8 @@
 
     <Application.Styles>
 
-        <FluentTheme Mode="Light" />
+        <FluentTheme />
+        <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Simple.xaml" />
 
         <Style Selector="Button, CheckBox, RadioButton, Expander /template/ ToggleButton#ExpanderHeader">
             <Setter Property="Cursor" Value="Hand" />
@@ -32,72 +33,24 @@
         <Style Selector="TextBox:focus /template/ Border#PART_BorderElement">
             <Setter Property="BorderThickness" Value="1" />
         </Style>
-        <Style Selector="TextBox:disabled"><!-- TODO bug in Avalonia (https://github.com/AvaloniaUI/Avalonia/pull/7792) -->
-            <Setter Property="Foreground" Value="{DynamicResource TextControlForegroundDisabled}" />
+        <Style Selector="TextBox:error DataValidationErrors">
+            <Style.Resources>
+                <ControlTemplate x:Key="InlineDataValidationContentTemplate" TargetType="DataValidationErrors">
+                    <ContentPresenter Name="PART_ContentPresenter"
+                                      Padding="{TemplateBinding Padding}"
+                                      Background="{TemplateBinding Background}"
+                                      BorderThickness="{TemplateBinding BorderThickness}"
+                                      CornerRadius="{TemplateBinding CornerRadius}"
+                                      Content="{TemplateBinding Content}"
+                                      ContentTemplate="{TemplateBinding ContentTemplate}" />
+                </ControlTemplate>
+            </Style.Resources>
+            <Setter Property="Template" Value="{StaticResource InlineDataValidationContentTemplate}" />
         </Style>
 
-        <Style Selector="Expander /template/ ToggleButton#ExpanderHeader">
-            <Setter Property="HorizontalContentAlignment" Value="Left" />
-            <Setter Property="Template">
-                <ControlTemplate>
-                    <Border x:Name="ToggleButtonBackground">
-                        <Grid ColumnDefinitions="Auto,*" RowDefinitions="35">
-                            <Border x:Name="ExpandCollapseChevronBorder"
-                                    Grid.Column="0"
-                                    Width="35"
-                                    Height="35"
-                                    Margin="2,0"
-                                    RenderTransformOrigin="50%,50%">
-                                <Path x:Name="ExpandCollapseChevron"
-                                      HorizontalAlignment="Center"
-                                      VerticalAlignment="Center"
-                                      RenderTransformOrigin="50%,50%"
-                                      Stretch="None"
-                                      Stroke="{DynamicResource ExpanderChevronForeground}"
-                                      StrokeThickness="1" />
-                                <Border.RenderTransform>
-                                    <RotateTransform />
-                                </Border.RenderTransform>
-                            </Border>
-                            <ContentPresenter x:Name="PART_ContentPresenter"
-                                              Grid.Column="1"
-                                              Margin="0"
-                                              HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
-                                              VerticalContentAlignment="Center"
-                                              Background="Transparent"
-                                              BorderBrush="Transparent"
-                                              BorderThickness="0"
-                                              Content="{TemplateBinding Content}"
-                                              ContentTemplate="{TemplateBinding ContentTemplate}"
-                                              TextBlock.Foreground="{DynamicResource ExpanderForeground}" />
-                        </Grid>
-                    </Border>
-                </ControlTemplate>
-            </Setter>
-        </Style>
-        <Style Selector="Expander:expanded /template/ ToggleButton#ExpanderHeader /template/ Border#ExpandCollapseChevronBorder">
-            <Style.Animations>
-                <Animation FillMode="Both" Duration="0:0:0.0625">
-                    <KeyFrame Cue="0%">
-                        <Setter Property="RotateTransform.Angle" Value="180" />
-                    </KeyFrame>
-                    <KeyFrame Cue="100%">
-                        <Setter Property="RotateTransform.Angle" Value="180" />
-                    </KeyFrame>
-                </Animation>
-            </Style.Animations>
-        </Style>
-        <Style Selector="Expander:not(:expanded) /template/ ToggleButton#ExpanderHeader /template/ Border#ExpandCollapseChevronBorder">
-            <Style.Animations>
-                <Animation FillMode="Both" Duration="0:0:0.0625">
-                    <KeyFrame Cue="0%">
-                        <Setter Property="RotateTransform.Angle" Value="0" />
-                    </KeyFrame>
-                    <KeyFrame Cue="100%">
-                        <Setter Property="RotateTransform.Angle" Value="0" />
-                    </KeyFrame>
-                </Animation>
-            </Style.Animations>
+        <Style Selector="Expander">
+            <Setter Property="MinHeight" Value="40" />
+            <Setter Property="HorizontalAlignment" Value="Stretch" />
         </Style>
         
     </Application.Styles>
@@ -105,6 +58,7 @@
     <Application.Resources>
 
         <common:NumberValueConverter x:Key="NumberValueConverter" />
+        <common:BytesValueConverter x:Key="BytesValueConverter" />
 
         <system:Double x:Key="ControlContentThemeFontSize">14</system:Double>
         <CornerRadius x:Key="ControlCornerRadius">0</CornerRadius>
@@ -154,13 +108,27 @@
         <SolidColorBrush x:Key="TextControlPlaceholderForegroundDisabled" Color="#AAAAAA" />
         
         <Thickness x:Key="ExpanderHeaderPadding">15,0</Thickness>
-        <Thickness x:Key="ExpanderContentPadding">15</Thickness>
-        <SolidColorBrush x:Key="ExpanderBorderBrush" Color="#697DAB" />
-        <SolidColorBrush x:Key="ExpanderBackground" Color="#697DAB" />
-        <SolidColorBrush x:Key="ExpanderForeground" Color="#FFFFFF" />
+        <Thickness x:Key="ExpanderContentPadding">12</Thickness>
+        <SolidColorBrush x:Key="ExpanderHeaderBorderBrush" Color="#697DAB" />
+        <SolidColorBrush x:Key="ExpanderHeaderBorderBrushPointerOver" Color="#697DAB" />
+        <SolidColorBrush x:Key="ExpanderHeaderBorderBrushPressed" Color="#697DAB" />
+        <SolidColorBrush x:Key="ExpanderHeaderBorderBrushDisabled" Color="#697DAB" />
+        <SolidColorBrush x:Key="ExpanderHeaderBackground" Color="#697DAB" />
+        <SolidColorBrush x:Key="ExpanderHeaderBackgroundPointerOver" Color="#536794" />
+        <SolidColorBrush x:Key="ExpanderHeaderBackgroundPressed" Color="#47587F" />
+        <SolidColorBrush x:Key="ExpanderHeaderBackgroundDisabled" Color="#697DAB" />
+        <SolidColorBrush x:Key="ExpanderHeaderForeground" Color="#FFFFFF" />
+        <SolidColorBrush x:Key="ExpanderHeaderForegroundPointerOver" Color="#FFFFFF" />
+        <SolidColorBrush x:Key="ExpanderHeaderForegroundPressed" Color="#FFFFFF" />
+        <SolidColorBrush x:Key="ExpanderHeaderForegroundDisabled" Color="#FFFFFF" />
+        <SolidColorBrush x:Key="ExpanderChevronBackground" Color="Transparent" />
+        <SolidColorBrush x:Key="ExpanderChevronBackgroundPointerOver" Color="#536794" />
+        <SolidColorBrush x:Key="ExpanderChevronBackgroundPressed" Color="#47587F" />
+        <SolidColorBrush x:Key="ExpanderChevronBackgroundDisabled" Color="Transparent" />
         <SolidColorBrush x:Key="ExpanderChevronForeground" Color="#FFFFFF" />
-        <SolidColorBrush x:Key="ExpanderDropDownBorderBrush" Color="#697DAB" />
-        <SolidColorBrush x:Key="ExpanderDropDownBackground" Color="#FFFFFF" />
+        <SolidColorBrush x:Key="ExpanderChevronForegroundPointerOver" Color="#FFFFFF" />
+        <SolidColorBrush x:Key="ExpanderChevronForegroundPressed" Color="#FFFFFF" />
+        <SolidColorBrush x:Key="ExpanderChevronForegroundDisabled" Color="#FFFFFF" />
 
     </Application.Resources>
 

app/Desktop/App.axaml.cs

@@ -1,20 +1,21 @@
+using System;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
 using DHT.Desktop.Main;
 
-namespace DHT.Desktop {
-	sealed class App : Application {
+namespace DHT.Desktop;
+
+sealed class App : Application {
 	public override void Initialize() {
 		AvaloniaXamlLoader.Load(this);
 	}
 
 	public override void OnFrameworkInitializationCompleted() {
 		if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop) {
-				desktop.MainWindow = new MainWindow(new Arguments(desktop.Args));
+			desktop.MainWindow = new MainWindow(new Arguments(desktop.Args ?? Array.Empty<string>()));
 		}
 
 		base.OnFrameworkInitializationCompleted();
 	}
-	}
 }

app/Desktop/Arguments.cs

@@ -1,8 +1,9 @@
 using System;
 using DHT.Utils.Logging;
 
-namespace DHT.Desktop {
-	sealed class Arguments {
+namespace DHT.Desktop;
+
+sealed class Arguments {
 	private static readonly Log Log = Log.ForType<Arguments>();
 
 	public static Arguments Empty => new(Array.Empty<string>());
@@ -61,5 +62,4 @@ namespace DHT.Desktop {
 			}
 		}
 	}
-	}
 }

app/Desktop/Common/BytesValueConverter.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Globalization;
+using Avalonia.Data.Converters;
+
+namespace DHT.Desktop.Common;
+
+sealed class BytesValueConverter : IValueConverter {
+	private sealed class Unit {
+		private readonly string label;
+		private readonly string numberFormat;
+
+		public Unit(string label, int decimalPlaces) {
+			this.label = label;
+			this.numberFormat = "{0:n" + decimalPlaces + "}";
+		}
+
+		public string Format(double size) {
+			return string.Format(Program.Culture, numberFormat, size) + " " + label;
+		}
+	}
+
+	private static readonly Unit[] Units = {
+		new ("B", decimalPlaces: 0),
+		new ("kB", decimalPlaces: 0),
+		new ("MB", decimalPlaces: 1),
+		new ("GB", decimalPlaces: 1),
+		new ("TB", decimalPlaces: 1)
+	};
+
+	private const int Scale = 1000;
+
+	private static string Convert(ulong size) {
+		int power = size == 0L ? 0 : (int) Math.Log(size, Scale);
+		int unit = power >= Units.Length ? Units.Length - 1 : power;
+		return Units[unit].Format(unit == 0 ? size : size / Math.Pow(Scale, unit));
+	}
+
+	public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture) {
+		if (value is long size and >= 0L) {
+			return Convert((ulong) size);
+		}
+		else if (value is ulong usize) {
+			return Convert(usize);
+		}
+		else {
+			return "-";
+		}
+	}
+
+	public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture) {
+		throw new NotSupportedException();
+	}
+}

app/Desktop/Common/DatabaseGui.cs

@@ -3,39 +3,42 @@ using System.Collections.Generic;
 using System.IO;
 using System.Threading.Tasks;
 using Avalonia.Controls;
+using Avalonia.Platform.Storage;
+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.Utils.Logging;
 
-namespace DHT.Desktop.Common {
-	static class DatabaseGui {
+namespace DHT.Desktop.Common;
+
+static class DatabaseGui {
 	private static readonly Log Log = Log.ForType(typeof(DatabaseGui));
 
 	private const string DatabaseFileInitialName = "archive.dht";
 
-		private static readonly List<FileDialogFilter> DatabaseFileDialogFilter = new() {
-			new FileDialogFilter {
-				Name = "Discord History Tracker Database",
-				Extensions = { "dht" }
-			}
+	private static readonly IReadOnlyList<FilePickerFileType> DatabaseFileDialogFilter = new List<FilePickerFileType> {
+		FileDialogs.CreateFilter("Discord History Tracker Database", new [] { "dht" })
 	};
 
-		public static OpenFileDialog NewOpenDatabaseFileDialog() {
-			return new OpenFileDialog {
+	public static async Task<string[]> NewOpenDatabaseFilesDialog(Window window, string? suggestedDirectory) {
+		return await window.StorageProvider.OpenFiles(new FilePickerOpenOptions {
 			Title = "Open Database File",
-				InitialFileName = DatabaseFileInitialName,
-				Filters = DatabaseFileDialogFilter
-			};
+			FileTypeFilter = DatabaseFileDialogFilter,
+			SuggestedStartLocation = await FileDialogs.GetSuggestedStartLocation(window, suggestedDirectory),
+			AllowMultiple = true
+		});
 	}
 
-		public static SaveFileDialog NewOpenOrCreateDatabaseFileDialog() {
-			return new SaveFileDialog {
+	public static async Task<string?> NewOpenOrCreateDatabaseFileDialog(Window window, string? suggestedDirectory) {
+		return await window.StorageProvider.SaveFile(new FilePickerSaveOptions {
 			Title = "Open or Create Database File",
-				InitialFileName = DatabaseFileInitialName,
-				Filters = DatabaseFileDialogFilter
-			};
+			FileTypeChoices = DatabaseFileDialogFilter,
+			SuggestedFileName = DatabaseFileInitialName,
+			SuggestedStartLocation = await FileDialogs.GetSuggestedStartLocation(window, suggestedDirectory),
+			ShowOverwritePrompt = false
+		});
 	}
 
 	public static async Task<IDatabaseFile?> TryOpenOrCreateDatabaseFromPath(string path, Window window, Func<Task<bool>> checkCanUpgradeDatabase) {
@@ -62,5 +65,4 @@ namespace DHT.Desktop.Common {
 	public static async Task<DialogResult.YesNo> ShowCanUpgradeMultipleDatabaseDialog(Window window) {
 		return await Dialog.ShowYesNo(window, "Database Upgrade", "One or more databases were created with an older version of DHT. If you proceed, these databases will be upgraded and will no longer open in previous versions of DHT. Otherwise, these databases will be skipped.\n\nPlease ensure you have a backup of the databases. Do you want to proceed with the upgrade?");
 	}
-	}
 }

app/Desktop/Common/NumberValueConverter.cs

@@ -2,8 +2,9 @@ using System;
 using System.Globalization;
 using Avalonia.Data.Converters;
 
-namespace DHT.Desktop.Common {
-	sealed class NumberValueConverter : IValueConverter {
+namespace DHT.Desktop.Common;
+
+sealed class NumberValueConverter : IValueConverter {
 	public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture) {
 		return value == null ? "-" : string.Format(Program.Culture, "{0:n0}", value);
 	}
@@ -11,5 +12,4 @@ namespace DHT.Desktop.Common {
 	public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture) {
 		throw new NotSupportedException();
 	}
-	}
 }

app/Desktop/Common/TextFormat.cs

@@ -1,5 +1,6 @@
-namespace DHT.Desktop.Common {
-	static class TextFormat {
+namespace DHT.Desktop.Common;
+
+static class TextFormat {
 	public static string Format(this int number) {
 		return number.ToString("N0", Program.Culture);
 	}
@@ -15,5 +16,4 @@ namespace DHT.Desktop.Common {
 	public static string Pluralize(this long number, string singular) {
 		return number.Format() + "\u00A0" + (number == 1 ? singular : singular + "s");
 	}
-	}
 }

app/Desktop/Desktop.csproj

@@ -1,7 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
-    <TargetFramework>net5.0</TargetFramework>
     <Nullable>enable</Nullable>
     <AssemblyName>DiscordHistoryTracker</AssemblyName>
     <RootNamespace>DHT.Desktop</RootNamespace>
@@ -21,15 +20,23 @@
     <DebugType>none</DebugType>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Avalonia" Version="0.10.13" />
-    <PackageReference Include="Avalonia.Desktop" Version="0.10.13" />
-    <PackageReference Include="Avalonia.Diagnostics" Version="0.10.13" Condition=" '$(Configuration)' == 'Debug' " />
+    <PackageReference Include="Avalonia" Version="11.0.5" />
+    <PackageReference Include="Avalonia.Controls.DataGrid" Version="11.0.5" />
+    <PackageReference Include="Avalonia.Controls.ItemsRepeater" Version="11.0.5" />
+    <PackageReference Include="Avalonia.Desktop" Version="11.0.5" />
+    <PackageReference Include="Avalonia.Diagnostics" Version="11.0.5" Condition=" '$(Configuration)' == 'Debug' " />
+    <PackageReference Include="Avalonia.Fonts.Inter" Version="11.0.5" />
+    <PackageReference Include="Avalonia.Themes.Fluent" Version="11.0.5" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Server\Server.csproj" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\Version.cs" Link="Version.cs" />
+    <Compile Update="Dialogs\TextBox\TextBoxDialog.axaml.cs">
+      <DependentUpon>CheckBoxDialog.axaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Compile>
   </ItemGroup>
   <ItemGroup>
     <AvaloniaResource Include="Resources/icon.ico" />

app/Desktop/Dialogs/CheckBox/CheckBoxDialog.axaml

@@ -34,8 +34,8 @@
 
     <StackPanel Margin="20">
         <ScrollViewer MaxHeight="400">
-            <ItemsControl Items="{Binding Items}">
-                <ItemsControl.ItemTemplate>
+            <ItemsRepeater ItemsSource="{Binding Items}">
+                <ItemsRepeater.ItemTemplate>
                     <DataTemplate>
                         <CheckBox IsChecked="{Binding Checked}">
                             <Label>
@@ -43,8 +43,8 @@
                             </Label>
                         </CheckBox>
                     </DataTemplate>
-                </ItemsControl.ItemTemplate>
-            </ItemsControl>
+                </ItemsRepeater.ItemTemplate>
+            </ItemsRepeater>
         </ScrollViewer>
         <Panel Classes="buttons">
             <WrapPanel Classes="left">

app/Desktop/Dialogs/CheckBox/CheckBoxDialog.axaml.cs

@@ -1,22 +1,14 @@
 using System.Diagnostics.CodeAnalysis;
-using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
-using Avalonia.Markup.Xaml;
 using DHT.Desktop.Dialogs.Message;
 
-namespace DHT.Desktop.Dialogs.CheckBox {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class CheckBoxDialog : Window {
+namespace DHT.Desktop.Dialogs.CheckBox;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class CheckBoxDialog : Window {
 	public CheckBoxDialog() {
 		InitializeComponent();
-			#if DEBUG
-			this.AttachDevTools();
-			#endif
-		}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
 	}
 
 	public void ClickOk(object? sender, RoutedEventArgs e) {
@@ -26,6 +18,4 @@ namespace DHT.Desktop.Dialogs.CheckBox {
 	public void ClickCancel(object? sender, RoutedEventArgs e) {
 		Close(DialogResult.OkCancel.Cancel);
 	}
-	}
 }
-

app/Desktop/Dialogs/CheckBox/CheckBoxDialogModel.cs

@@ -4,8 +4,9 @@ using System.ComponentModel;
 using System.Linq;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Dialogs.CheckBox {
-	class CheckBoxDialogModel : BaseModel {
+namespace DHT.Desktop.Dialogs.CheckBox;
+
+class CheckBoxDialogModel : BaseModel {
 	public string Title { get; init; } = "";
 
 	private IReadOnlyList<CheckBoxItem> items = Array.Empty<CheckBoxItem>();
@@ -55,9 +56,9 @@ namespace DHT.Desktop.Dialogs.CheckBox {
 			UpdateBulkButtons();
 		}
 	}
-	}
+}
 
-	sealed class CheckBoxDialogModel<T> : CheckBoxDialogModel {
+sealed class CheckBoxDialogModel<T> : CheckBoxDialogModel {
 	public new IReadOnlyList<CheckBoxItem<T>> Items { get; }
 
 	public IEnumerable<CheckBoxItem<T>> SelectedItems => Items.Where(static item => item.Checked);
@@ -66,5 +67,4 @@ namespace DHT.Desktop.Dialogs.CheckBox {
 		this.Items = new List<CheckBoxItem<T>>(items);
 		base.Items = this.Items;
 	}
-	}
 }

app/Desktop/Dialogs/CheckBox/CheckBoxItem.cs

@@ -1,7 +1,8 @@
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Dialogs.CheckBox {
-	class CheckBoxItem : BaseModel {
+namespace DHT.Desktop.Dialogs.CheckBox;
+
+class CheckBoxItem : BaseModel {
 	public string Title { get; init; } = "";
 	public object? Item { get; init; } = null;
 
@@ -11,14 +12,13 @@ namespace DHT.Desktop.Dialogs.CheckBox {
 		get => isChecked;
 		set => Change(ref isChecked, value);
 	}
-	}
+}
 
-	sealed class CheckBoxItem<T> : CheckBoxItem {
+sealed class CheckBoxItem<T> : CheckBoxItem {
 	public new T Item { get; }
 
 	public CheckBoxItem(T item) {
 		this.Item = item;
 		base.Item = item;
 	}
-	}
 }

app/Desktop/Dialogs/File/FileDialogs.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Avalonia.Controls;
+using Avalonia.Platform.Storage;
+
+namespace DHT.Desktop.Dialogs.File;
+
+static class FileDialogs {
+	public static async Task<string[]> OpenFiles(this IStorageProvider storageProvider, FilePickerOpenOptions options) {
+		return (await storageProvider.OpenFilePickerAsync(options)).ToLocalPaths();
+	}
+
+	public static async Task<string?> SaveFile(this IStorageProvider storageProvider, FilePickerSaveOptions options) {
+		return (await storageProvider.SaveFilePickerAsync(options))?.ToLocalPath();
+	}
+
+	public static FilePickerFileType CreateFilter(string name, string[] extensions) {
+		return new FilePickerFileType(name) {
+			Patterns = extensions.Select(static ext => "*." + ext).ToArray()
+		};
+	}
+
+	public static Task<IStorageFolder?> GetSuggestedStartLocation(Window window, string? suggestedDirectory) {
+		return suggestedDirectory == null ? Task.FromResult<IStorageFolder?>(null) : window.StorageProvider.TryGetFolderFromPathAsync(suggestedDirectory);
+	}
+
+	private static string ToLocalPath(this IStorageFile file) {
+		return file.TryGetLocalPath() ?? throw new NotSupportedException("Local filesystem is not supported.");
+	}
+
+	private static string[] ToLocalPaths(this IReadOnlyList<IStorageFile> files) {
+		return files.Select(ToLocalPath).ToArray();
+	}
+}

app/Desktop/Dialogs/Message/Dialog.cs

@@ -2,8 +2,9 @@ using System.Threading.Tasks;
 using Avalonia.Controls;
 using Avalonia.Threading;
 
-namespace DHT.Desktop.Dialogs.Message {
-	static class Dialog {
+namespace DHT.Desktop.Dialogs.Message;
+
+static class Dialog {
 	public static async Task ShowOk(Window owner, string title, string message) {
 		if (!Dispatcher.UIThread.CheckAccess()) {
 			await Dispatcher.UIThread.InvokeAsync(() => ShowOk(owner, title, message));
@@ -70,5 +71,4 @@ namespace DHT.Desktop.Dialogs.Message {
 
 		return result.ToYesNoCancel();
 	}
-	}
 }

app/Desktop/Dialogs/Message/DialogResult.cs

@@ -1,7 +1,8 @@
 using System;
 
-namespace DHT.Desktop.Dialogs.Message {
-	static class DialogResult {
+namespace DHT.Desktop.Dialogs.Message;
+
+static class DialogResult {
 	public enum All {
 		Ok,
 		Yes,
@@ -55,5 +56,4 @@ namespace DHT.Desktop.Dialogs.Message {
 			_          => throw new ArgumentException("Cannot convert dialog result " + result + " to yes/no/cancel.")
 		};
 	}
-	}
 }

app/Desktop/Dialogs/Message/MessageDialog.axaml.cs

@@ -1,21 +1,13 @@
 using System.Diagnostics.CodeAnalysis;
-using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Dialogs.Message {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class MessageDialog : Window {
+namespace DHT.Desktop.Dialogs.Message;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class MessageDialog : Window {
 	public MessageDialog() {
 		InitializeComponent();
-			#if DEBUG
-			this.AttachDevTools();
-			#endif
-		}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
 	}
 
 	public void ClickOk(object? sender, RoutedEventArgs e) {
@@ -33,5 +25,4 @@ namespace DHT.Desktop.Dialogs.Message {
 	public void ClickCancel(object? sender, RoutedEventArgs e) {
 		Close(DialogResult.All.Cancel);
 	}
-	}
 }

app/Desktop/Dialogs/Message/MessageDialogModel.cs

@@ -1,5 +1,6 @@
-namespace DHT.Desktop.Dialogs.Message {
-	sealed class MessageDialogModel {
+namespace DHT.Desktop.Dialogs.Message;
+
+sealed class MessageDialogModel {
 	public string Title { get; init; } = "";
 	public string Message { get; init; } = "";
 
@@ -7,5 +8,4 @@ namespace DHT.Desktop.Dialogs.Message {
 	public bool IsYesVisible { get; init; } = false;
 	public bool IsNoVisible { get; init; } = false;
 	public bool IsCancelVisible { get; init; } = false;
-	}
 }

app/Desktop/Dialogs/Progress/IProgressCallback.cs

@@ -1,7 +1,7 @@
 using System.Threading.Tasks;
 
-namespace DHT.Desktop.Dialogs.Progress {
-	interface IProgressCallback {
+namespace DHT.Desktop.Dialogs.Progress;
+
+interface IProgressCallback {
 	Task Update(string message, int finishedItems, int totalItems);
-	}
 }

app/Desktop/Dialogs/Progress/ProgressDialog.axaml

@@ -7,7 +7,7 @@
         x:Class="DHT.Desktop.Dialogs.Progress.ProgressDialog"
         Title="{Binding Title}"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
-        Opened="Loaded"
+        Opened="OnOpened"
         Closing="OnClosing"
         Width="500" SizeToContent="Height" CanResize="False"
         WindowStartupLocation="CenterOwner">

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

@@ -1,40 +1,30 @@
 using System;
-using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Threading.Tasks;
-using Avalonia;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Dialogs.Progress {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class ProgressDialog : Window {
+namespace DHT.Desktop.Dialogs.Progress;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class ProgressDialog : Window {
 	private bool isFinished = false;
 
 	public ProgressDialog() {
 		InitializeComponent();
-			#if DEBUG
-			this.AttachDevTools();
-			#endif
 	}
 
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-
-		public void OnClosing(object? sender, CancelEventArgs e) {
-			e.Cancel = !isFinished;
-		}
-
-		public void Loaded(object? sender, EventArgs e) {
+	public void OnOpened(object? sender, EventArgs e) {
 		if (DataContext is ProgressDialogModel model) {
 			Task.Run(model.StartTask).ContinueWith(OnFinished, TaskScheduler.FromCurrentSynchronizationContext());
 		}
 	}
 
+	public void OnClosing(object? sender, WindowClosingEventArgs e) {
+		e.Cancel = !isFinished;
+	}
+
 	private void OnFinished(Task task) {
 		isFinished = true;
 		Close();
 	}
-	}
 }

app/Desktop/Dialogs/Progress/ProgressDialogModel.cs

@@ -4,8 +4,9 @@ using Avalonia.Threading;
 using DHT.Desktop.Common;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Dialogs.Progress {
-	sealed class ProgressDialogModel : BaseModel {
+namespace DHT.Desktop.Dialogs.Progress;
+
+sealed class ProgressDialogModel : BaseModel {
 	public string Title { get; init; } = "";
 
 	private string message = "";
@@ -61,5 +62,4 @@ namespace DHT.Desktop.Dialogs.Progress {
 			});
 		}
 	}
-	}
 }

app/Desktop/Dialogs/TextBox/TextBoxDialog.axaml

@@ -0,0 +1,56 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:namespace="clr-namespace:DHT.Desktop.Dialogs.TextBox"
+        mc:Ignorable="d" d:DesignWidth="500"
+        x:Class="DHT.Desktop.Dialogs.TextBox.TextBoxDialog"
+        Title="{Binding Title}"
+        Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
+        Width="500" SizeToContent="Height" CanResize="False"
+        WindowStartupLocation="CenterOwner">
+
+    <Window.DataContext>
+        <namespace:TextBoxDialogModel />
+    </Window.DataContext>
+
+    <Window.Styles>
+        <Style Selector="Panel.buttons">
+            <Setter Property="Margin" Value="0 20 0 0" />
+        </Style>
+        <Style Selector="Panel.buttons > WrapPanel.right">
+            <Setter Property="HorizontalAlignment" Value="Right" />
+        </Style>
+        <Style Selector="Panel.buttons Button">
+            <Setter Property="MinWidth" Value="80" />
+            <Setter Property="Margin" Value="8 0 0 0" />
+        </Style>
+    </Window.Styles>
+
+    <StackPanel Margin="20">
+        <ScrollViewer MaxHeight="400">
+            <StackPanel Spacing="10">
+                <TextBlock Text="{Binding Description}" TextWrapping="Wrap" />
+                <ItemsRepeater ItemsSource="{Binding Items}">
+                    <ItemsRepeater.ItemTemplate>
+                        <DataTemplate>
+                            <DockPanel Margin="0 5 25 0">
+                                <TextBox Name="Input" Text="{Binding Value}" Width="180" VerticalAlignment="Top" DockPanel.Dock="Right" />
+                                <Label Target="Input" VerticalAlignment="Center" DockPanel.Dock="Left">
+                                    <TextBlock Text="{Binding Title}" TextWrapping="Wrap" />
+                                </Label>
+                            </DockPanel>
+                        </DataTemplate>
+                    </ItemsRepeater.ItemTemplate>
+                </ItemsRepeater>
+            </StackPanel>
+        </ScrollViewer>
+        <Panel Classes="buttons">
+            <WrapPanel Classes="right">
+                <Button Click="ClickOk" IsEnabled="{Binding !HasErrors}">OK</Button>
+                <Button Click="ClickCancel">Cancel</Button>
+            </WrapPanel>
+        </Panel>
+    </StackPanel>
+
+</Window>

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

@@ -0,0 +1,21 @@
+using System.Diagnostics.CodeAnalysis;
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using DHT.Desktop.Dialogs.Message;
+
+namespace DHT.Desktop.Dialogs.TextBox; 
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class TextBoxDialog : Window {
+	public TextBoxDialog() {
+		InitializeComponent();
+	}
+
+	public void ClickOk(object? sender, RoutedEventArgs e) {
+		Close(DialogResult.OkCancel.Ok);
+	}
+
+	public void ClickCancel(object? sender, RoutedEventArgs e) {
+		Close(DialogResult.OkCancel.Cancel);
+	}
+}

app/Desktop/Dialogs/TextBox/TextBoxDialogModel.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using DHT.Utils.Models;
+
+namespace DHT.Desktop.Dialogs.TextBox; 
+
+class TextBoxDialogModel : BaseModel {
+	public string Title { get; init; } = "";
+	public string Description { get; init; } = "";
+
+	private IReadOnlyList<TextBoxItem> items = Array.Empty<TextBoxItem>();
+
+	public IReadOnlyList<TextBoxItem> Items {
+		get => items;
+
+		protected set {
+			foreach (var item in items) {
+				item.ErrorsChanged -= OnItemErrorsChanged;
+			}
+
+			items = value;
+
+			foreach (var item in items) {
+				item.ErrorsChanged += OnItemErrorsChanged;
+			}
+		}
+	}
+		
+	public bool HasErrors => Items.Any(static item => !item.IsValid);
+
+	private void OnItemErrorsChanged(object? sender, DataErrorsChangedEventArgs e) {
+		OnPropertyChanged(nameof(HasErrors));
+	}
+}
+
+sealed class TextBoxDialogModel<T> : TextBoxDialogModel {
+	public new IReadOnlyList<TextBoxItem<T>> Items { get; }
+
+	public IEnumerable<TextBoxItem<T>> ValidItems => Items.Where(static item => item.IsValid);
+
+	public TextBoxDialogModel(IEnumerable<TextBoxItem<T>> items) {
+		this.Items = new List<TextBoxItem<T>>(items);
+		base.Items = this.Items;
+	}
+}

app/Desktop/Dialogs/TextBox/TextBoxItem.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections;
+using System.ComponentModel;
+using DHT.Utils.Models;
+
+namespace DHT.Desktop.Dialogs.TextBox; 
+
+class TextBoxItem : BaseModel, INotifyDataErrorInfo {
+	public string Title { get; init; } = "";
+	public object? Item { get; init; } = null;
+		
+	public Func<string, bool> ValidityCheck { get; init; } = static _ => true;
+	public bool IsValid => ValidityCheck(Value);
+
+	private string value = string.Empty;
+
+	public string Value {
+		get => this.value;
+		set {
+			Change(ref this.value, value);
+			ErrorsChanged?.Invoke(this, new DataErrorsChangedEventArgs(nameof(Value)));
+		}
+	}
+
+	public IEnumerable GetErrors(string? propertyName) {
+		if (propertyName == nameof(Value) && !IsValid) {
+			yield return string.Empty;
+		}
+	}
+
+	public bool HasErrors => !IsValid;
+	public event EventHandler<DataErrorsChangedEventArgs>? ErrorsChanged;
+}
+
+sealed class TextBoxItem<T> : TextBoxItem {
+	public new T Item { get; }
+
+	public TextBoxItem(T item) {
+		this.Item = item;
+		base.Item = item;
+	}
+}

app/Desktop/Discord/DiscordAppSettings.cs

@@ -9,8 +9,9 @@ using DHT.Utils.Logging;
 using static System.Environment.SpecialFolder;
 using static System.Environment.SpecialFolderOption;
 
-namespace DHT.Desktop.Discord {
-	static class DiscordAppSettings {
+namespace DHT.Desktop.Discord;
+
+static class DiscordAppSettings {
 	private static readonly Log Log = Log.ForType(typeof(DiscordAppSettings));
 
 	private const string JsonKeyDevTools = "DANGEROUS_ENABLE_DEVTOOLS_ONLY_ENABLE_IF_YOU_KNOW_WHAT_YOURE_DOING";
@@ -39,7 +40,9 @@ namespace DHT.Desktop.Discord {
 	public static async Task<bool?> AreDevToolsEnabled() {
 		try {
 			return AreDevToolsEnabled(await ReadSettingsJson());
-			} catch (Exception) {
+		} catch (Exception e) {
+			Log.Error("Cannot read settings file.");
+			Log.Error(e);
 			return null;
 		}
 	}
@@ -115,5 +118,4 @@ namespace DHT.Desktop.Discord {
 		await using var stream = new FileStream(JsonFilePath, FileMode.Truncate, FileAccess.Write, FileShare.None);
 		await JsonSerializer.SerializeAsync(stream, json, new JsonSerializerOptions { WriteIndented = true });
 	}
-	}
 }

app/Desktop/Discord/SettingsJsonResult.cs

@@ -1,10 +1,10 @@
-namespace DHT.Desktop.Discord {
-	enum SettingsJsonResult {
+namespace DHT.Desktop.Discord;
+
+enum SettingsJsonResult {
 	Success,
 	AlreadySet,
 	FileNotFound,
 	ReadError,
 	InvalidJson,
 	WriteError
-	}
 }

app/Desktop/Main/AboutWindow.axaml

@@ -46,7 +46,7 @@
             <TextBlock Grid.Row="0" Grid.Column="1" FontWeight="Bold">License</TextBlock>
             <TextBlock Grid.Row="0" Grid.Column="2" FontWeight="Bold">Link</TextBlock>
 
-            <TextBlock Grid.Row="2" Grid.Column="0">.NET 5</TextBlock>
+            <TextBlock Grid.Row="2" Grid.Column="0">.NET 8</TextBlock>
             <TextBlock Grid.Row="2" Grid.Column="1">MIT</TextBlock>
             <Button Grid.Row="2" Grid.Column="2" Command="{Binding ShowLibraryNetCore}">GitHub</Button>
 

app/Desktop/Main/AboutWindow.axaml.cs

@@ -1,20 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
-using Avalonia;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class AboutWindow : Window {
+namespace DHT.Desktop.Main;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class AboutWindow : Window {
 	public AboutWindow() {
 		InitializeComponent();
-			#if DEBUG
-			this.AttachDevTools();
-			#endif
-		}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
 	}
 }

app/Desktop/Main/AboutWindowModel.cs

@@ -1,7 +1,8 @@
 using System.Diagnostics;
 
-namespace DHT.Desktop.Main {
-	sealed class AboutWindowModel {
+namespace DHT.Desktop.Main;
+
+sealed class AboutWindowModel {
 	public void ShowOfficialWebsite() {
 		OpenUrl("https://dht.chylex.com");
 	}
@@ -29,5 +30,4 @@ namespace DHT.Desktop.Main {
 	private static void OpenUrl(string url) {
 		Process.Start(new ProcessStartInfo { FileName = url, UseShellExecute = true });
 	}
-	}
 }

app/Desktop/Main/Controls/AttachmentFilterPanel.axaml

@@ -0,0 +1,51 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             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">
+
+    <Design.DataContext>
+        <controls:AttachmentFilterPanelModel />
+    </Design.DataContext>
+
+    <UserControl.Styles>
+        <Style Selector="WrapPanel > StackPanel">
+            <Setter Property="Margin" Value="0 20 40 0" />
+            <Setter Property="Spacing" Value="4" />
+        </Style>
+        <Style Selector="WrapPanel > StackPanel:nth-last-child(1)">
+            <Setter Property="Margin" Value="0 20 0 0" />
+        </Style>
+        <Style Selector="Grid > Label">
+            <Setter Property="VerticalAlignment" Value="Center" />
+        </Style>
+        <Style Selector="ComboBox">
+            <Setter Property="Margin" Value="8 0 0 0" />
+        </Style>
+        <Style Selector="Button">
+            <Setter Property="Margin" Value="0 0 0 8" />
+        </Style>
+    </UserControl.Styles>
+
+    <StackPanel>
+        <TextBlock Text="{Binding FilterStatisticsText}" />
+        <WrapPanel>
+            <StackPanel>
+                <CheckBox IsChecked="{Binding LimitSize}">Limit Size</CheckBox>
+                <StackPanel Orientation="Horizontal">
+                    <TextBox Text="{Binding MaximumSize}" IsEnabled="{Binding LimitSize}" HorizontalContentAlignment="Right" />
+                    <ComboBox IsEnabled="{Binding LimitSize}" ItemsSource="{Binding Units}" SelectedItem="{Binding MaximumSizeUnit}">
+                        <ComboBox.ItemTemplate>
+                            <DataTemplate>
+                                <TextBlock Text="{Binding Name}" />
+                            </DataTemplate>
+                        </ComboBox.ItemTemplate>
+                    </ComboBox>
+                </StackPanel>
+            </StackPanel>
+        </WrapPanel>
+    </StackPanel>
+
+</UserControl>

app/Desktop/Main/Controls/AttachmentFilterPanel.axaml.cs

@@ -0,0 +1,11 @@
+using System.Diagnostics.CodeAnalysis;
+using Avalonia.Controls;
+
+namespace DHT.Desktop.Main.Controls;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class AttachmentFilterPanel : UserControl {
+	public AttachmentFilterPanel() {
+		InitializeComponent();
+	}
+}

app/Desktop/Main/Controls/AttachmentFilterPanelModel.cs

@@ -0,0 +1,129 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using DHT.Desktop.Common;
+using DHT.Server.Data.Filters;
+using DHT.Server.Database;
+using DHT.Utils.Models;
+using DHT.Utils.Tasks;
+
+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 HashSet<string> FilterProperties = new () {
+		nameof(LimitSize),
+		nameof(MaximumSize),
+		nameof(MaximumSizeUnit)
+	};
+
+	public string FilterStatisticsText { get; private set; } = "";
+
+	private bool limitSize = false;
+	private ulong maximumSize = 0L;
+	private Unit maximumSizeUnit = AllUnits[0];
+
+	public bool LimitSize {
+		get => limitSize;
+		set => Change(ref limitSize, value);
+	}
+
+	public ulong MaximumSize {
+		get => maximumSize;
+		set => Change(ref maximumSize, value);
+	}
+
+	public Unit MaximumSizeUnit {
+		get => maximumSizeUnit;
+		set => Change(ref maximumSizeUnit, value);
+	}
+
+	public IEnumerable<Unit> Units => AllUnits;
+
+	private readonly IDatabaseFile db;
+	private readonly string verb;
+
+	private readonly AsyncValueComputer<long> matchingAttachmentCountComputer;
+	private long? matchingAttachmentCount;
+	private long? totalAttachmentCount;
+
+	[Obsolete("Designer")]
+	public AttachmentFilterPanelModel() : this(DummyDatabaseFile.Instance) {}
+
+	public AttachmentFilterPanelModel(IDatabaseFile db, string verb = "Matches") {
+		this.db = db;
+		this.verb = verb;
+
+		this.matchingAttachmentCountComputer = AsyncValueComputer<long>.WithResultProcessor(SetAttachmentCounts).Build();
+
+		UpdateFilterStatistics();
+
+		PropertyChanged += OnPropertyChanged;
+		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+	}
+
+	public void Dispose() {
+		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+	}
+
+	private void OnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
+		if (e.PropertyName != null && FilterProperties.Contains(e.PropertyName)) {
+			UpdateFilterStatistics();
+		}
+	}
+
+	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
+		if (e.PropertyName == nameof(DatabaseStatistics.TotalAttachments)) {
+			totalAttachmentCount = db.Statistics.TotalAttachments;
+			UpdateFilterStatistics();
+		}
+	}
+
+	private void UpdateFilterStatistics() {
+		var filter = CreateFilter();
+		if (filter.IsEmpty) {
+			matchingAttachmentCountComputer.Cancel();
+			matchingAttachmentCount = totalAttachmentCount;
+			UpdateFilterStatisticsText();
+		}
+		else {
+			matchingAttachmentCount = null;
+			UpdateFilterStatisticsText();
+			matchingAttachmentCountComputer.Compute(() => db.CountAttachments(filter));
+		}
+	}
+
+	private void SetAttachmentCounts(long matchingAttachmentCount) {
+		this.matchingAttachmentCount = matchingAttachmentCount;
+		UpdateFilterStatisticsText();
+	}
+
+	private void UpdateFilterStatisticsText() {
+		var matchingAttachmentCountStr = matchingAttachmentCount?.Format() ?? "(...)";
+		var totalAttachmentCountStr = totalAttachmentCount?.Format() ?? "(...)";
+
+		FilterStatisticsText = verb + " " + matchingAttachmentCountStr + " out of " + totalAttachmentCountStr + " attachment" + (totalAttachmentCount is null or 1 ? "." : "s.");
+		OnPropertyChanged(nameof(FilterStatisticsText));
+	}
+
+	public AttachmentFilter CreateFilter() {
+		AttachmentFilter filter = new();
+
+		if (LimitSize) {
+			try {
+				filter.MaxBytes = maximumSize * maximumSizeUnit.Scale;
+			} catch (ArithmeticException) {
+				// set no size limit, because the overflown size is larger than any file could possibly be
+			}
+		}
+
+		return filter;
+	}
+}

app/Desktop/Main/Controls/FilterPanel.axaml

@@ -1,60 +0,0 @@
-<UserControl xmlns="https://github.com/avaloniaui"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-             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.FilterPanel">
-
-    <Design.DataContext>
-        <controls:FilterPanelModel />
-    </Design.DataContext>
-
-    <UserControl.Styles>
-        <Style Selector="WrapPanel > StackPanel">
-            <Setter Property="Margin" Value="0 20 40 0" />
-            <Setter Property="Spacing" Value="4" />
-        </Style>
-        <Style Selector="WrapPanel > StackPanel:nth-last-child(1)">
-            <Setter Property="Margin" Value="0 20 0 0" />
-        </Style>
-        <Style Selector="Grid > Label">
-            <Setter Property="VerticalAlignment" Value="Center" />
-        </Style>
-        <Style Selector="Grid > CalendarDatePicker">
-            <Setter Property="CornerRadius" Value="0" />
-            <Setter Property="HorizontalAlignment" Value="Stretch" />
-            <Setter Property="HorizontalContentAlignment" Value="Center" />
-            <Setter Property="VerticalAlignment" Value="Center" />
-            <Setter Property="VerticalContentAlignment" Value="Center" />
-            <Setter Property="IsTodayHighlighted" Value="True" />
-            <Setter Property="SelectedDateFormat" Value="Short" />
-        </Style>
-        <Style Selector="Button">
-            <Setter Property="Margin" Value="0 0 0 8" />
-        </Style>
-    </UserControl.Styles>
-
-    <WrapPanel>
-        <StackPanel>
-            <CheckBox IsChecked="{Binding FilterByDate}">Filter by Date</CheckBox>
-            <Grid ColumnDefinitions="Auto, 4, 125" RowDefinitions="Auto, 4, Auto" Margin="4 0">
-                <Label Grid.Row="0" Grid.Column="0">From:</Label>
-                <CalendarDatePicker Grid.Row="0" Grid.Column="2" x:Name="StartDatePicker" IsEnabled="{Binding FilterByDate}" SelectedDateChanged="CalendarDatePicker_OnSelectedDateChanged" />
-                <Label Grid.Row="2" Grid.Column="0">To:</Label>
-                <CalendarDatePicker Grid.Row="2" Grid.Column="2" x:Name="EndDatePicker" IsEnabled="{Binding FilterByDate}" SelectedDateChanged="CalendarDatePicker_OnSelectedDateChanged" />
-            </Grid>
-        </StackPanel>
-        <StackPanel>
-            <CheckBox IsChecked="{Binding FilterByChannel}">Filter by Channel</CheckBox>
-            <Button Command="{Binding OpenChannelFilterDialog}" IsEnabled="{Binding FilterByChannel}">Select Channels...</Button>
-            <TextBlock Text="{Binding ChannelFilterLabel}" />
-        </StackPanel>
-        <StackPanel>
-            <CheckBox IsChecked="{Binding FilterByUser}">Filter by User</CheckBox>
-            <Button Command="{Binding OpenUserFilterDialog}" IsEnabled="{Binding FilterByUser}">Select Users...</Button>
-            <TextBlock Text="{Binding UserFilterLabel}" />
-        </StackPanel>
-    </WrapPanel>
-
-</UserControl>

app/Desktop/Main/Controls/FilterPanel.axaml.cs

@@ -1,34 +0,0 @@
-using System.Diagnostics.CodeAnalysis;
-using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
-
-namespace DHT.Desktop.Main.Controls {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class FilterPanel : UserControl {
-		private CalendarDatePicker StartDatePicker => this.FindControl<CalendarDatePicker>("StartDatePicker");
-		private CalendarDatePicker EndDatePicker => this.FindControl<CalendarDatePicker>("EndDatePicker");
-
-		public FilterPanel() {
-			InitializeComponent();
-		}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-
-			var culture = Program.Culture;
-			foreach (var picker in new CalendarDatePicker[] { StartDatePicker, EndDatePicker }) {
-				picker.FirstDayOfWeek = culture.DateTimeFormat.FirstDayOfWeek;
-				picker.SelectedDateFormat = CalendarDatePickerFormat.Custom;
-				picker.CustomDateFormatString = culture.DateTimeFormat.ShortDatePattern;
-				picker.Watermark = culture.DateTimeFormat.ShortDatePattern;
-			}
-		}
-
-		public void CalendarDatePicker_OnSelectedDateChanged(object? sender, SelectionChangedEventArgs e) {
-			if (DataContext is FilterPanelModel model) {
-				model.StartDate = StartDatePicker.SelectedDate;
-				model.EndDate = EndDatePicker.SelectedDate;
-			}
-		}
-	}
-}

app/Desktop/Main/Controls/FilterPanelModel.cs

@@ -1,241 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Avalonia.Controls;
-using DHT.Desktop.Common;
-using DHT.Desktop.Dialogs.CheckBox;
-using DHT.Desktop.Dialogs.Message;
-using DHT.Server.Data;
-using DHT.Server.Data.Filters;
-using DHT.Server.Database;
-using DHT.Utils.Models;
-
-namespace DHT.Desktop.Main.Controls {
-	sealed class FilterPanelModel : BaseModel, IDisposable {
-		private static readonly HashSet<string> FilterProperties = new () {
-			nameof(FilterByDate),
-			nameof(StartDate),
-			nameof(EndDate),
-			nameof(FilterByChannel),
-			nameof(IncludedChannels),
-			nameof(FilterByUser),
-			nameof(IncludedUsers)
-		};
-
-		public event PropertyChangedEventHandler? FilterPropertyChanged;
-
-		public bool HasAnyFilters => FilterByDate || FilterByChannel || FilterByUser;
-
-		private bool filterByDate = false;
-		private DateTime? startDate = null;
-		private DateTime? endDate = null;
-		private bool filterByChannel = false;
-		private HashSet<ulong>? includedChannels = null;
-		private bool filterByUser = false;
-		private HashSet<ulong>? includedUsers = null;
-
-		public bool FilterByDate {
-			get => filterByDate;
-			set => Change(ref filterByDate, value);
-		}
-
-		public DateTime? StartDate {
-			get => startDate;
-			set => Change(ref startDate, value);
-		}
-
-		public DateTime? EndDate {
-			get => endDate;
-			set => Change(ref endDate, value);
-		}
-
-		public bool FilterByChannel {
-			get => filterByChannel;
-			set => Change(ref filterByChannel, value);
-		}
-
-		public HashSet<ulong> IncludedChannels {
-			get => includedChannels ?? db.GetAllChannels().Select(static channel => channel.Id).ToHashSet();
-			set => Change(ref includedChannels, value);
-		}
-
-		public bool FilterByUser {
-			get => filterByUser;
-			set => Change(ref filterByUser, value);
-		}
-
-		public HashSet<ulong> IncludedUsers {
-			get => includedUsers ?? db.GetAllUsers().Select(static user => user.Id).ToHashSet();
-			set => Change(ref includedUsers, value);
-		}
-
-		private string channelFilterLabel = "";
-
-		public string ChannelFilterLabel {
-			get => channelFilterLabel;
-			set => Change(ref channelFilterLabel, value);
-		}
-
-		private string userFilterLabel = "";
-
-		public string UserFilterLabel {
-			get => userFilterLabel;
-			set => Change(ref userFilterLabel, value);
-		}
-
-		private readonly Window window;
-		private readonly IDatabaseFile db;
-
-		[Obsolete("Designer")]
-		public FilterPanelModel() : this(null!, DummyDatabaseFile.Instance) {}
-
-		public FilterPanelModel(Window window, IDatabaseFile db) {
-			this.window = window;
-			this.db = db;
-
-			UpdateChannelFilterLabel();
-			UpdateUserFilterLabel();
-
-			PropertyChanged += OnPropertyChanged;
-			db.Statistics.PropertyChanged += OnDbStatisticsChanged;
-		}
-
-		public void Dispose() {
-			db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
-		}
-
-		private void OnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
-			if (e.PropertyName != null && FilterProperties.Contains(e.PropertyName)) {
-				FilterPropertyChanged?.Invoke(sender, e);
-			}
-
-			if (e.PropertyName is nameof(FilterByChannel) or nameof(IncludedChannels)) {
-				UpdateChannelFilterLabel();
-			}
-			else if (e.PropertyName is nameof(FilterByUser) or nameof(IncludedUsers)) {
-				UpdateUserFilterLabel();
-			}
-		}
-
-		private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
-			if (e.PropertyName == nameof(DatabaseStatistics.TotalChannels)) {
-				UpdateChannelFilterLabel();
-			}
-			else if (e.PropertyName == nameof(DatabaseStatistics.TotalUsers)) {
-				UpdateUserFilterLabel();
-			}
-		}
-
-		public async void OpenChannelFilterDialog() {
-			var servers = db.GetAllServers().ToDictionary(static server => server.Id);
-			var items = new List<CheckBoxItem<ulong>>();
-			var included = IncludedChannels;
-
-			foreach (var channel in db.GetAllChannels()) {
-				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;
-
-					titleBuilder.Append('[')
-					            .Append(ServerTypes.ToString(serverType))
-					            .Append("] ");
-
-					if (serverType == ServerType.DirectMessage) {
-						titleBuilder.Append(channelName);
-					}
-					else {
-						titleBuilder.Append(server.Name)
-						            .Append(" - ")
-						            .Append(channelName);
-					}
-
-					title = titleBuilder.ToString();
-				}
-				else {
-					title = channelName;
-				}
-
-				items.Add(new CheckBoxItem<ulong>(channelId) {
-					Title = title,
-					Checked = included.Contains(channelId)
-				});
-			}
-
-			var result = await OpenIdFilterDialog(window, "Included Channels", items);
-			if (result != null) {
-				IncludedChannels = result;
-			}
-		}
-
-		public async void OpenUserFilterDialog() {
-			var items = new List<CheckBoxItem<ulong>>();
-			var included = IncludedUsers;
-
-			foreach (var user in db.GetAllUsers()) {
-				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)
-				});
-			}
-
-			var result = await OpenIdFilterDialog(window, "Included Users", 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) {
-			items.Sort(static (item1, item2) => item1.Title.CompareTo(item2.Title));
-
-			var model = new CheckBoxDialogModel<ulong>(items) {
-				Title = title
-			};
-
-			var dialog = new CheckBoxDialog { DataContext = model };
-			var result = await dialog.ShowDialog<DialogResult.OkCancel>(window);
-
-			return result == DialogResult.OkCancel.Ok ? model.SelectedItems.Select(static item => item.Item).ToHashSet() : null;
-		}
-	}
-}

app/Desktop/Main/Controls/MessageFilterPanel.axaml

@@ -0,0 +1,63 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             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">
+
+    <Design.DataContext>
+        <controls:MessageFilterPanelModel />
+    </Design.DataContext>
+
+    <UserControl.Styles>
+        <Style Selector="WrapPanel > StackPanel">
+            <Setter Property="Margin" Value="0 20 40 0" />
+            <Setter Property="Spacing" Value="4" />
+        </Style>
+        <Style Selector="WrapPanel > StackPanel:nth-last-child(1)">
+            <Setter Property="Margin" Value="0 20 0 0" />
+        </Style>
+        <Style Selector="Grid > Label">
+            <Setter Property="VerticalAlignment" Value="Center" />
+        </Style>
+        <Style Selector="Grid > CalendarDatePicker">
+            <Setter Property="CornerRadius" Value="0" />
+            <Setter Property="HorizontalAlignment" Value="Stretch" />
+            <Setter Property="HorizontalContentAlignment" Value="Center" />
+            <Setter Property="VerticalAlignment" Value="Center" />
+            <Setter Property="VerticalContentAlignment" Value="Center" />
+            <Setter Property="IsTodayHighlighted" Value="True" />
+            <Setter Property="SelectedDateFormat" Value="Short" />
+        </Style>
+        <Style Selector="Button">
+            <Setter Property="Margin" Value="0 0 0 8" />
+        </Style>
+    </UserControl.Styles>
+
+    <StackPanel>
+        <TextBlock Text="{Binding FilterStatisticsText}" />
+        <WrapPanel>
+            <StackPanel>
+                <CheckBox IsChecked="{Binding FilterByDate}">Filter by Date</CheckBox>
+                <Grid ColumnDefinitions="Auto, 4, 125" RowDefinitions="Auto, 4, Auto" Margin="4 0">
+                    <Label Grid.Row="0" Grid.Column="0">From:</Label>
+                    <CalendarDatePicker Grid.Row="0" Grid.Column="2" x:Name="StartDatePicker" IsEnabled="{Binding FilterByDate}" SelectedDateChanged="CalendarDatePicker_OnSelectedDateChanged" />
+                    <Label Grid.Row="2" Grid.Column="0">To:</Label>
+                    <CalendarDatePicker Grid.Row="2" Grid.Column="2" x:Name="EndDatePicker" IsEnabled="{Binding FilterByDate}" SelectedDateChanged="CalendarDatePicker_OnSelectedDateChanged" />
+                </Grid>
+            </StackPanel>
+            <StackPanel>
+                <CheckBox IsChecked="{Binding FilterByChannel}">Filter by Channel</CheckBox>
+                <Button Command="{Binding OpenChannelFilterDialog}" IsEnabled="{Binding FilterByChannel}">Select Channels...</Button>
+                <TextBlock Text="{Binding ChannelFilterLabel}" />
+            </StackPanel>
+            <StackPanel>
+                <CheckBox IsChecked="{Binding FilterByUser}">Filter by User</CheckBox>
+                <Button Command="{Binding OpenUserFilterDialog}" IsEnabled="{Binding FilterByUser}">Select Users...</Button>
+                <TextBlock Text="{Binding UserFilterLabel}" />
+            </StackPanel>
+        </WrapPanel>
+    </StackPanel>
+
+</UserControl>

app/Desktop/Main/Controls/MessageFilterPanel.axaml.cs

@@ -0,0 +1,26 @@
+using System.Diagnostics.CodeAnalysis;
+using Avalonia.Controls;
+
+namespace DHT.Desktop.Main.Controls;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class MessageFilterPanel : UserControl {
+	public MessageFilterPanel() {
+		InitializeComponent();
+
+		var culture = Program.Culture;
+		foreach (var picker in new CalendarDatePicker[] { StartDatePicker, EndDatePicker }) {
+			picker.FirstDayOfWeek = culture.DateTimeFormat.FirstDayOfWeek;
+			picker.SelectedDateFormat = CalendarDatePickerFormat.Custom;
+			picker.CustomDateFormatString = culture.DateTimeFormat.ShortDatePattern;
+			picker.Watermark = culture.DateTimeFormat.ShortDatePattern;
+		}
+	}
+
+	public void CalendarDatePicker_OnSelectedDateChanged(object? sender, SelectionChangedEventArgs e) {
+		if (DataContext is MessageFilterPanelModel model) {
+			model.StartDate = StartDatePicker.SelectedDate;
+			model.EndDate = EndDatePicker.SelectedDate;
+		}
+	}
+}

app/Desktop/Main/Controls/MessageFilterPanelModel.cs

@@ -0,0 +1,285 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Avalonia.Controls;
+using DHT.Desktop.Common;
+using DHT.Desktop.Dialogs.CheckBox;
+using DHT.Desktop.Dialogs.Message;
+using DHT.Server.Data;
+using DHT.Server.Data.Filters;
+using DHT.Server.Database;
+using DHT.Utils.Models;
+using DHT.Utils.Tasks;
+
+namespace DHT.Desktop.Main.Controls;
+
+sealed class MessageFilterPanelModel : BaseModel, IDisposable {
+	private static readonly HashSet<string> FilterProperties = new () {
+		nameof(FilterByDate),
+		nameof(StartDate),
+		nameof(EndDate),
+		nameof(FilterByChannel),
+		nameof(IncludedChannels),
+		nameof(FilterByUser),
+		nameof(IncludedUsers)
+	};
+
+	public string FilterStatisticsText { get; private set; } = "";
+
+	public event PropertyChangedEventHandler? FilterPropertyChanged;
+
+	public bool HasAnyFilters => FilterByDate || FilterByChannel || FilterByUser;
+
+	private bool filterByDate = false;
+	private DateTime? startDate = null;
+	private DateTime? endDate = null;
+	private bool filterByChannel = false;
+	private HashSet<ulong>? includedChannels = null;
+	private bool filterByUser = false;
+	private HashSet<ulong>? includedUsers = null;
+
+	public bool FilterByDate {
+		get => filterByDate;
+		set => Change(ref filterByDate, value);
+	}
+
+	public DateTime? StartDate {
+		get => startDate;
+		set => Change(ref startDate, value);
+	}
+
+	public DateTime? EndDate {
+		get => endDate;
+		set => Change(ref endDate, value);
+	}
+
+	public bool FilterByChannel {
+		get => filterByChannel;
+		set => Change(ref filterByChannel, value);
+	}
+
+	public HashSet<ulong> IncludedChannels {
+		get => includedChannels ?? db.GetAllChannels().Select(static channel => channel.Id).ToHashSet();
+		set => Change(ref includedChannels, value);
+	}
+
+	public bool FilterByUser {
+		get => filterByUser;
+		set => Change(ref filterByUser, value);
+	}
+
+	public HashSet<ulong> IncludedUsers {
+		get => includedUsers ?? db.GetAllUsers().Select(static user => user.Id).ToHashSet();
+		set => Change(ref includedUsers, value);
+	}
+
+	private string channelFilterLabel = "";
+
+	public string ChannelFilterLabel {
+		get => channelFilterLabel;
+		set => Change(ref channelFilterLabel, value);
+	}
+
+	private string userFilterLabel = "";
+
+	public string UserFilterLabel {
+		get => userFilterLabel;
+		set => Change(ref userFilterLabel, value);
+	}
+
+	private readonly Window window;
+	private readonly IDatabaseFile db;
+	private readonly string verb;
+
+	private readonly AsyncValueComputer<long> exportedMessageCountComputer;
+	private long? exportedMessageCount;
+	private long? totalMessageCount;
+
+	[Obsolete("Designer")]
+	public MessageFilterPanelModel() : this(null!, DummyDatabaseFile.Instance) {}
+
+	public MessageFilterPanelModel(Window window, IDatabaseFile db, string verb = "Matches") {
+		this.window = window;
+		this.db = db;
+		this.verb = verb;
+
+		this.exportedMessageCountComputer = AsyncValueComputer<long>.WithResultProcessor(SetExportedMessageCount).Build();
+
+		UpdateFilterStatistics();
+		UpdateChannelFilterLabel();
+		UpdateUserFilterLabel();
+
+		PropertyChanged += OnPropertyChanged;
+		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+	}
+
+	public void Dispose() {
+		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+	}
+
+	private void OnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
+		if (e.PropertyName != null && FilterProperties.Contains(e.PropertyName)) {
+			UpdateFilterStatistics();
+			FilterPropertyChanged?.Invoke(sender, e);
+		}
+
+		if (e.PropertyName is nameof(FilterByChannel) or nameof(IncludedChannels)) {
+			UpdateChannelFilterLabel();
+		}
+		else if (e.PropertyName is nameof(FilterByUser) or nameof(IncludedUsers)) {
+			UpdateUserFilterLabel();
+		}
+	}
+
+	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
+		if (e.PropertyName == nameof(DatabaseStatistics.TotalMessages)) {
+			totalMessageCount = db.Statistics.TotalMessages;
+			UpdateFilterStatistics();
+		}
+		else if (e.PropertyName == nameof(DatabaseStatistics.TotalChannels)) {
+			UpdateChannelFilterLabel();
+		}
+		else if (e.PropertyName == nameof(DatabaseStatistics.TotalUsers)) {
+			UpdateUserFilterLabel();
+		}
+	}
+
+	private void UpdateFilterStatistics() {
+		var filter = CreateFilter();
+		if (filter.IsEmpty) {
+			exportedMessageCountComputer.Cancel();
+			exportedMessageCount = totalMessageCount;
+			UpdateFilterStatisticsText();
+		}
+		else {
+			exportedMessageCount = null;
+			UpdateFilterStatisticsText();
+			exportedMessageCountComputer.Compute(() => db.CountMessages(filter));
+		}
+	}
+
+	private void SetExportedMessageCount(long exportedMessageCount) {
+		this.exportedMessageCount = exportedMessageCount;
+		UpdateFilterStatisticsText();
+	}
+
+	private void UpdateFilterStatisticsText() {
+		var exportedMessageCountStr = exportedMessageCount?.Format() ?? "(...)";
+		var totalMessageCountStr = totalMessageCount?.Format() ?? "(...)";
+
+		FilterStatisticsText = verb + " " + exportedMessageCountStr + " out of " + totalMessageCountStr + " message" + (totalMessageCount is null or 1 ? "." : "s.");
+		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;
+
+		foreach (var channel in db.GetAllChannels()) {
+			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;
+
+				titleBuilder.Append('[')
+				            .Append(ServerTypes.ToString(serverType))
+				            .Append("] ");
+
+				if (serverType == ServerType.DirectMessage) {
+					titleBuilder.Append(channelName);
+				}
+				else {
+					titleBuilder.Append(server.Name)
+					            .Append(" - ")
+					            .Append(channelName);
+				}
+
+				title = titleBuilder.ToString();
+			}
+			else {
+				title = channelName;
+			}
+
+			items.Add(new CheckBoxItem<ulong>(channelId) {
+				Title = title,
+				Checked = included.Contains(channelId)
+			});
+		}
+
+		var result = await OpenIdFilterDialog(window, "Included Channels", items);
+		if (result != null) {
+			IncludedChannels = result;
+		}
+	}
+
+	public async void OpenUserFilterDialog() {
+		var items = new List<CheckBoxItem<ulong>>();
+		var included = IncludedUsers;
+
+		foreach (var user in db.GetAllUsers()) {
+			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)
+			});
+		}
+
+		var result = await OpenIdFilterDialog(window, "Included Users", 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) {
+		items.Sort(static (item1, item2) => item1.Title.CompareTo(item2.Title));
+
+		var model = new CheckBoxDialogModel<ulong>(items) {
+			Title = title
+		};
+
+		var dialog = new CheckBoxDialog { DataContext = model };
+		var result = await dialog.ShowDialog<DialogResult.OkCancel>(window);
+
+		return result == DialogResult.OkCancel.Ok ? model.SelectedItems.Select(static item => item.Item).ToHashSet() : null;
+	}
+}

app/Desktop/Main/Controls/ServerConfigurationPanel.axaml

@@ -24,7 +24,7 @@
     <StackPanel>
         <Button Command="{Binding OnClickToggleServerButton}" Content="{Binding ToggleServerButtonText}" IsEnabled="{Binding IsToggleServerButtonEnabled}" />
         <TextBlock TextWrapping="Wrap" Margin="0 15">
-            The following settings determine how the tracking script communicates with this application. If you change them, you will have to copy and apply the tracking script again.
+            The following settings determine how the tracking script communicates with this application. If you change them, you will have to copy/paste the tracking script again.
         </TextBlock>
         <WrapPanel>
             <StackPanel>

app/Desktop/Main/Controls/ServerConfigurationPanel.axaml.cs

@@ -1,16 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Controls {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class ServerConfigurationPanel : UserControl {
+namespace DHT.Desktop.Main.Controls;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class ServerConfigurationPanel : UserControl {
 	public ServerConfigurationPanel() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-	}
 }

app/Desktop/Main/Controls/ServerConfigurationPanelModel.cs

@@ -6,8 +6,9 @@ using DHT.Server.Database;
 using DHT.Server.Service;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Main.Controls {
-	sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
+namespace DHT.Desktop.Main.Controls;
+
+sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
 	private string inputPort;
 
 	public string InputPort {
@@ -112,5 +113,4 @@ namespace DHT.Desktop.Main.Controls {
 		InputPort = ServerManager.Port.ToString();
 		InputToken = ServerManager.Token;
 	}
-	}
 }

app/Desktop/Main/Controls/StatusBar.axaml.cs

@@ -1,16 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Controls {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class StatusBar : UserControl {
+namespace DHT.Desktop.Main.Controls;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class StatusBar : UserControl {
 	public StatusBar() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-	}
 }

app/Desktop/Main/Controls/StatusBarModel.cs

@@ -2,8 +2,9 @@ using System;
 using DHT.Server.Database;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Main.Controls {
-	sealed class StatusBarModel : BaseModel {
+namespace DHT.Desktop.Main.Controls;
+
+sealed class StatusBarModel : BaseModel {
 	public DatabaseStatistics DatabaseStatistics { get; }
 
 	private Status status = Status.Stopped;
@@ -41,5 +42,4 @@ namespace DHT.Desktop.Main.Controls {
 		Stopping,
 		Stopped
 	}
-	}
 }

app/Desktop/Main/MainWindow.axaml

@@ -8,7 +8,7 @@
         Title="{Binding Title}"
         Icon="avares://DiscordHistoryTracker/Resources/icon.ico"
         Width="800" Height="500"
-        MinWidth="500" MinHeight="275"
+        MinWidth="520" MinHeight="300"
         WindowStartupLocation="CenterScreen"
         Closed="OnClosed">
 

app/Desktop/Main/MainWindow.axaml.cs

@@ -1,35 +1,36 @@
 using System;
 using System.Diagnostics.CodeAnalysis;
-using Avalonia;
+using System.IO;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
+using DHT.Desktop.Main.Pages;
 using JetBrains.Annotations;
 
-namespace DHT.Desktop.Main {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class MainWindow : Window {
+namespace DHT.Desktop.Main;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class MainWindow : Window {
 	[UsedImplicitly]
 	public MainWindow() {
-			InitializeComponent(Arguments.Empty);
+		InitializeComponent();
+		DataContext = new MainWindowModel(this, Arguments.Empty);
 	}
 
 	internal MainWindow(Arguments args) {
-			InitializeComponent(args);
-		}
-
-		private void InitializeComponent(Arguments args) {
-			AvaloniaXamlLoader.Load(this);
+		InitializeComponent();
 		DataContext = new MainWindowModel(this, args);
-
-			#if DEBUG
-			this.AttachDevTools();
-			#endif
 	}
 
 	public void OnClosed(object? sender, EventArgs e) {
 		if (DataContext is IDisposable disposable) {
 			disposable.Dispose();
 		}
+
+		foreach (var temporaryFile in ViewerPageModel.TemporaryFiles) {
+			try {
+				File.Delete(temporaryFile);
+			} catch (Exception) {
+				// ignored
+			}
 		}
 	}
 }

app/Desktop/Main/MainWindowModel.cs

@@ -10,8 +10,9 @@ using DHT.Desktop.Server;
 using DHT.Server.Database;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Main {
-	sealed class MainWindowModel : BaseModel, IDisposable {
+namespace DHT.Desktop.Main;
+
+sealed class MainWindowModel : BaseModel, IDisposable {
 	private const string DefaultTitle = "Discord History Tracker";
 
 	public string Title { get; private set; } = DefaultTitle;
@@ -112,5 +113,4 @@ namespace DHT.Desktop.Main {
 		db?.Dispose();
 		db = null;
 	}
-	}
 }

app/Desktop/Main/Pages/AdvancedPage.axaml.cs

@@ -1,16 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Pages {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class AdvancedPage : UserControl {
+namespace DHT.Desktop.Main.Pages;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class AdvancedPage : UserControl {
 	public AdvancedPage() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-	}
 }

app/Desktop/Main/Pages/AdvancedPageModel.cs

@@ -6,8 +6,9 @@ using DHT.Desktop.Server;
 using DHT.Server.Database;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Main.Pages {
-	sealed class AdvancedPageModel : BaseModel, IDisposable {
+namespace DHT.Desktop.Main.Pages;
+
+sealed class AdvancedPageModel : BaseModel, IDisposable {
 	public ServerConfigurationPanelModel ServerConfigurationModel { get; }
 
 	private readonly Window window;
@@ -35,5 +36,4 @@ namespace DHT.Desktop.Main.Pages {
 		db.Vacuum();
 		await Dialog.ShowOk(window, "Vacuum Database", "Done.");
 	}
-	}
 }

app/Desktop/Main/Pages/AttachmentsPage.axaml

@@ -0,0 +1,54 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             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">
+
+    <Design.DataContext>
+        <pages:AttachmentsPageModel />
+    </Design.DataContext>
+
+    <UserControl.Styles>
+        <Style Selector="Expander">
+            <Setter Property="Margin" Value="0 5 0 0" />
+        </Style>
+        <Style Selector="DataGridColumnHeader">
+            <Setter Property="FontWeight" Value="Medium" />
+        </Style>
+        <Style Selector="DataGridColumnHeader:nth-child(2)">
+            <Setter Property="HorizontalContentAlignment" Value="Right" />
+        </Style>
+        <Style Selector="DataGridColumnHeader:nth-child(3)">
+            <Setter Property="HorizontalContentAlignment" Value="Right" />
+        </Style>
+        <Style Selector="DataGridCell.right">
+            <Setter Property="HorizontalContentAlignment" Value="Right" />
+        </Style>
+    </UserControl.Styles>
+
+    <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" />
+            <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}}" />
+        <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" />
+                    </DataGrid.Columns>
+                </DataGrid>
+            </Expander>
+            <StackPanel Orientation="Horizontal" Spacing="10">
+                <Button Command="{Binding OnClickRetryFailedDownloads}" IsEnabled="{Binding HasFailedDownloads}">Retry Failed Downloads</Button>
+            </StackPanel>
+        </StackPanel>
+    </StackPanel>
+</UserControl>

app/Desktop/Main/Pages/AttachmentsPage.axaml.cs

@@ -0,0 +1,11 @@
+using System.Diagnostics.CodeAnalysis;
+using Avalonia.Controls;
+
+namespace DHT.Desktop.Main.Pages;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class AttachmentsPage : UserControl {
+	public AttachmentsPage() {
+		InitializeComponent();
+	}
+}

app/Desktop/Main/Pages/AttachmentsPageModel.cs

@@ -0,0 +1,205 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Threading;
+using Avalonia.Threading;
+using DHT.Desktop.Common;
+using DHT.Desktop.Main.Controls;
+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.Models;
+using DHT.Utils.Tasks;
+
+namespace DHT.Desktop.Main.Pages;
+
+sealed class AttachmentsPageModel : BaseModel, IDisposable {
+	private static readonly DownloadItemFilter EnqueuedItemFilter = new() {
+		IncludeStatuses = new HashSet<DownloadStatus> {
+			DownloadStatus.Enqueued
+		}
+	};
+
+	private bool isThreadDownloadButtonEnabled = true;
+
+	public string ToggleDownloadButtonText => downloadThread == null ? "Start Downloading" : "Stop Downloading";
+
+	public bool IsToggleDownloadButtonEnabled {
+		get => isThreadDownloadButtonEnabled;
+		set => Change(ref isThreadDownloadButtonEnabled, value);
+	}
+
+	public string DownloadMessage { get; set; } = "";
+	public double DownloadProgress => allItemsCount is null or 0 ? 0.0 : 100.0 * doneItemsCount / allItemsCount.Value;
+
+	public AttachmentFilterPanelModel FilterModel { get; }
+
+	private readonly StatisticsRow statisticsEnqueued = new ("Enqueued");
+	private readonly StatisticsRow statisticsDownloaded = new ("Downloaded");
+	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 bool IsDownloading => downloadThread != null;
+	public bool HasFailedDownloads => statisticsFailed.Items > 0;
+
+	private readonly IDatabaseFile db;
+	private readonly AsyncValueComputer<DownloadStatusStatistics>.Single downloadStatisticsComputer;
+	private BackgroundDownloadThread? downloadThread;
+
+	private int doneItemsCount;
+	private int? allItemsCount;
+
+	public AttachmentsPageModel() : this(DummyDatabaseFile.Instance) {}
+
+	public AttachmentsPageModel(IDatabaseFile db) {
+		this.db = db;
+		this.FilterModel = new AttachmentFilterPanelModel(db);
+
+		this.downloadStatisticsComputer = AsyncValueComputer<DownloadStatusStatistics>.WithResultProcessor(UpdateStatistics).WithOutdatedResults().BuildWithComputer(db.GetDownloadStatusStatistics);
+		this.downloadStatisticsComputer.Recompute();
+
+		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+	}
+
+	public void Dispose() {
+		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+
+		FilterModel.Dispose();
+		DisposeDownloadThread();
+	}
+
+	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
+		if (e.PropertyName == nameof(DatabaseStatistics.TotalAttachments)) {
+			if (IsDownloading) {
+				EnqueueDownloadItems();
+			}
+			else {
+				downloadStatisticsComputer.Recompute();
+			}
+		}
+		else if (e.PropertyName == nameof(DatabaseStatistics.TotalDownloads)) {
+			downloadStatisticsComputer.Recompute();
+		}
+	}
+
+	private void EnqueueDownloadItems() {
+		var filter = FilterModel.CreateFilter();
+		filter.DownloadItemRule = AttachmentFilter.DownloadItemRules.OnlyNotPresent;
+		db.EnqueueDownloadItems(filter);
+
+		downloadStatisticsComputer.Recompute();
+	}
+
+	private void UpdateStatistics(DownloadStatusStatistics statusStatistics) {
+		var hadFailedDownloads = HasFailedDownloads;
+
+		statisticsEnqueued.Items = statusStatistics.EnqueuedCount;
+		statisticsEnqueued.Size = statusStatistics.EnqueuedSize;
+
+		statisticsDownloaded.Items = statusStatistics.SuccessfulCount;
+		statisticsDownloaded.Size = statusStatistics.SuccessfulSize;
+
+		statisticsFailed.Items = statusStatistics.FailedCount;
+		statisticsFailed.Size = statusStatistics.FailedSize;
+
+		statisticsSkipped.Items = statusStatistics.SkippedCount;
+		statisticsSkipped.Size = statusStatistics.SkippedSize;
+
+		OnPropertyChanged(nameof(StatisticsRows));
+
+		if (hadFailedDownloads != HasFailedDownloads) {
+			OnPropertyChanged(nameof(HasFailedDownloads));
+		}
+
+		allItemsCount = doneItemsCount + statisticsEnqueued.Items;
+		UpdateDownloadMessage();
+	}
+
+	private void UpdateDownloadMessage() {
+		DownloadMessage = IsDownloading ? doneItemsCount.Format() + " / " + (allItemsCount?.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; }
+		public ulong? Size { get; set; }
+
+		public StatisticsRow(string state) {
+			State = state;
+		}
+	}
+}

app/Desktop/Main/Pages/DatabasePage.axaml

@@ -24,6 +24,7 @@
         <WrapPanel>
             <Button Command="{Binding OpenDatabaseFolder}">Open Database Folder</Button>
             <Button Command="{Binding MergeWithDatabase}">Merge with Database(s)...</Button>
+            <Button Command="{Binding ImportLegacyArchive}">Import Legacy Archive(s)...</Button>
         </WrapPanel>
     </StackPanel>
 

app/Desktop/Main/Pages/DatabasePage.axaml.cs

@@ -1,16 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Pages {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class DatabasePage : UserControl {
+namespace DHT.Desktop.Main.Pages;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class DatabasePage : UserControl {
 	public DatabasePage() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-	}
 }

app/Desktop/Main/Pages/DatabasePageModel.cs

@@ -1,18 +1,28 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 using Avalonia.Controls;
+using Avalonia.Platform.Storage;
+using Avalonia.Threading;
 using DHT.Desktop.Common;
+using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Dialogs.Progress;
+using DHT.Desktop.Dialogs.TextBox;
+using DHT.Server.Data;
 using DHT.Server.Database;
+using DHT.Server.Database.Import;
 using DHT.Utils.Logging;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Main.Pages {
-	sealed class DatabasePageModel : BaseModel {
+namespace DHT.Desktop.Main.Pages; 
+
+sealed class DatabasePageModel : BaseModel {
 	private static readonly Log Log = Log.ForType<DatabasePageModel>();
 
 	public IDatabaseFile Db { get; }
@@ -56,13 +66,13 @@ namespace DHT.Desktop.Main.Pages {
 		}
 	}
 
-		public async void MergeWithDatabase() {
-			var fileDialog = DatabaseGui.NewOpenDatabaseFileDialog();
-			fileDialog.Directory = Path.GetDirectoryName(Db.Path);
-			fileDialog.AllowMultiple = true;
+	public void CloseDatabase() {
+		DatabaseClosed?.Invoke(this, EventArgs.Empty);
+	}
 
-			string[]? paths = await fileDialog.ShowAsync(window);
-			if (paths == null || paths.Length == 0) {
+	public async void MergeWithDatabase() {
+		var paths = await DatabaseGui.NewOpenDatabaseFilesDialog(window, Path.GetDirectoryName(Db.Path));
+		if (paths.Length == 0) {
 			return;
 		}
 
@@ -74,10 +84,6 @@ namespace DHT.Desktop.Main.Pages {
 		await progressDialog.ShowDialog(window);
 	}
 
-		public void CloseDatabase() {
-			DatabaseClosed?.Invoke(this, EventArgs.Empty);
-		}
-
 	private static async Task MergeWithDatabaseFromPaths(IDatabaseFile target, string[] paths, ProgressDialog dialog, IProgressCallback callback) {
 		int total = paths.Length;
 
@@ -91,8 +97,94 @@ namespace DHT.Desktop.Main.Pages {
 			return DialogResult.YesNo.Yes == upgradeResult;
 		}
 
-			var oldStatistics = target.Statistics.Clone();
-			var oldMessageCount = target.CountMessages();
+		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);
+
+			if (db == null) {
+				return false;
+			}
+
+			try {
+				target.AddFrom(db);
+				return true;
+			} finally {
+				db.Dispose();
+			}
+		});
+	}
+
+	public async void 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;
+		}
+
+		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) {
+		var fakeSnowflake = new FakeSnowflake();
+
+		await PerformImport(target, paths, dialog, callback, "Legacy Archive Import", "Legacy Archive Error", "archive file", async path => {
+			await using var jsonStream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
+				
+			return await LegacyArchiveImport.Read(jsonStream, target, fakeSnowflake, async servers => {
+				SynchronizationContext? prevSyncContext = SynchronizationContext.Current;
+				SynchronizationContext.SetSynchronizationContext(new AvaloniaSynchronizationContext());
+				Dictionary<DHT.Server.Data.Server, ulong>? result = await Dispatcher.UIThread.InvokeAsync(() => AskForServerIds(dialog, servers));
+				SynchronizationContext.SetSynchronizationContext(prevSyncContext);
+				return result;
+			});
+		});
+	}
+
+	private static async Task<Dictionary<DHT.Server.Data.Server, ulong>?> AskForServerIds(Window window, DHT.Server.Data.Server[] servers) {
+		static bool IsValidSnowflake(string value) {
+			return string.IsNullOrEmpty(value) || ulong.TryParse(value, out _);
+		}
+			
+		var items = new List<TextBoxItem<DHT.Server.Data.Server>>();
+
+		foreach (var server in servers.OrderBy(static server => server.Type).ThenBy(static server => server.Name)) {
+			items.Add(new TextBoxItem<DHT.Server.Data.Server>(server) {
+				Title = server.Name + " (" + ServerTypes.ToNiceString(server.Type) + ")",
+				ValidityCheck = IsValidSnowflake
+			});
+		}
+
+		var model = new TextBoxDialogModel<DHT.Server.Data.Server>(items) {
+			Title = "Imported Server IDs",
+			Description = "Please fill in the IDs of servers and direct messages. First enable Developer Mode in Discord, then right-click each server or direct message, click 'Copy ID', and paste it into the input field. If a server no longer exists, leave its input field empty to use a random ID."
+		};
+
+		var dialog = new TextBoxDialog { DataContext = model };
+		var result = await dialog.ShowDialog<DialogResult.OkCancel>(window);
+
+		if (result != DialogResult.OkCancel.Ok) {
+			return null;
+		}
+
+		return model.ValidItems
+		            .Where(static item => !string.IsNullOrEmpty(item.Value))
+		            .ToDictionary(static item => item.Item, static item => ulong.Parse(item.Value));
+	}
+
+	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();
 
 		int successful = 0;
 		int finished = 0;
@@ -102,56 +194,52 @@ namespace DHT.Desktop.Main.Pages {
 			++finished;
 
 			if (!File.Exists(path)) {
-					await Dialog.ShowOk(dialog, "Database Error", "Database '" + Path.GetFileName(path) + "' no longer exists.");
-					continue;
-				}
-
-				IDatabaseFile? db = await DatabaseGui.TryOpenOrCreateDatabaseFromPath(path, dialog, CheckCanUpgradeDatabase);
-				if (db == null) {
+				await Dialog.ShowOk(dialog, errorDialogTitle, "File '" + Path.GetFileName(path) + "' no longer exists.");
 				continue;
 			}
 
 			try {
-					target.AddFrom(db);
+				if (await performImport(path)) {
+					++successful;
+				}
 			} catch (Exception ex) {
 				Log.Error(ex);
-					await Dialog.ShowOk(dialog, "Database Error", "Database '" + Path.GetFileName(path) + "' could not be merged: " + ex.Message);
-					continue;
-				} finally {
-					db.Dispose();
+				await Dialog.ShowOk(dialog, errorDialogTitle, "File '" + Path.GetFileName(path) + "' could not be imported: " + ex.Message);
 			}
-
-				++successful;
 		}
 
 		await callback.Update("Done", finished, total);
 
 		if (successful == 0) {
-				await Dialog.ShowOk(dialog, "Database Merge", "Nothing was merged.");
+			await Dialog.ShowOk(dialog, neutralDialogTitle, "Nothing was imported.");
 			return;
 		}
 
-			var newStatistics = target.Statistics;
+		await Dialog.ShowOk(dialog, neutralDialogTitle, GetImportDialogMessage(oldStatistics, target.SnapshotStatistics(), successful, total, itemName));
+	}
+
+	private static string GetImportDialogMessage(DatabaseStatisticsSnapshot oldStatistics, DatabaseStatisticsSnapshot newStatistics, int successfulItems, int totalItems, string itemName) {
 		long newServers = newStatistics.TotalServers - oldStatistics.TotalServers;
 		long newChannels = newStatistics.TotalChannels - oldStatistics.TotalChannels;
-			long newMessages = target.CountMessages() - oldMessageCount;
+		long newUsers = newStatistics.TotalUsers - oldStatistics.TotalUsers;
+		long newMessages = newStatistics.TotalMessages - oldStatistics.TotalMessages;
 
 		StringBuilder message = new StringBuilder();
 		message.Append("Processed ");
 
-			if (successful == total) {
-				message.Append(successful.Pluralize("database file"));
+		if (successfulItems == totalItems) {
+			message.Append(successfulItems.Pluralize(itemName));
 		}
 		else {
-				message.Append(successful.Format()).Append(" out of ").Append(total.Pluralize("database file"));
+			message.Append(successfulItems.Format()).Append(" out of ").Append(totalItems.Pluralize(itemName));
 		}
 
 		message.Append(" and added:\n\n  \u2022 ");
 		message.Append(newServers.Pluralize("server")).Append("\n  \u2022 ");
 		message.Append(newChannels.Pluralize("channel")).Append("\n  \u2022 ");
+		message.Append(newUsers.Pluralize("user")).Append("\n  \u2022 ");
 		message.Append(newMessages.Pluralize("message"));
 
-			await Dialog.ShowOk(dialog, "Database Merge", message.ToString());
-		}
+		return message.ToString();
 	}
 }

app/Desktop/Main/Pages/DebugPage.axaml.cs

@@ -1,16 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Pages {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class DebugPage : UserControl {
+namespace DHT.Desktop.Main.Pages;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class DebugPage : UserControl {
 	public DebugPage() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-	}
 }

app/Desktop/Main/Pages/DebugPageModel.cs

@@ -63,7 +63,7 @@ namespace DHT.Desktop.Main.Pages {
 			var server = new DHT.Server.Data.Server {
 				Id = RandomId(rand),
 				Name = RandomName("s"),
-				Type = ServerType.Server
+				Type = ServerType.Server,
 			};
 
 			var channels = Enumerable.Range(0, channelCount).Select(i => new Channel {
@@ -73,14 +73,14 @@ namespace DHT.Desktop.Main.Pages {
 				ParentId = null,
 				Position = i,
 				Topic = RandomText(rand, 10),
-				Nsfw = rand.Next(4) == 0
+				Nsfw = rand.Next(4) == 0,
 			}).ToArray();
 
 			var users = Enumerable.Range(0, userCount).Select(_ => new User {
 				Id = RandomId(rand),
 				Name = RandomName("u"),
 				AvatarUrl = null,
-				Discriminator = rand.Next(0, 9999).ToString()
+				Discriminator = rand.Next(0, 9999).ToString(),
 			}).ToArray();
 
 			db.AddServer(server);
@@ -97,7 +97,7 @@ namespace DHT.Desktop.Main.Pages {
 				int hourOffset = batchIndex;
 
 				var messages = Enumerable.Range(0, Math.Min(messageCount, BatchSize)).Select(i => {
-					DateTimeOffset time = now.AddHours(hourOffset).AddMinutes((i * 60.0) / BatchSize);
+					DateTimeOffset time = now.AddHours(hourOffset).AddMinutes(i * 60.0 / BatchSize);
 					DateTimeOffset? edit = rand.Next(100) == 0 ? time.AddSeconds(rand.Next(1, 60)) : null;
 
 					var timeMillis = time.ToUnixTimeMilliseconds();
@@ -113,7 +113,7 @@ namespace DHT.Desktop.Main.Pages {
 						RepliedToId = null,
 						Attachments = ImmutableArray<Attachment>.Empty,
 						Embeds = ImmutableArray<Embed>.Empty,
-						Reactions = ImmutableArray<Reaction>.Empty
+						Reactions = ImmutableArray<Reaction>.Empty,
 					};
 				}).ToArray();
 
@@ -161,7 +161,7 @@ namespace DHT.Desktop.Main.Pages {
 			"vanilla",
 			"watercress", "watermelon",
 			"yam",
-			"zucchini"
+			"zucchini",
 		};
 
 		private static string RandomText(Random rand, int maxWords) {

app/Desktop/Main/Pages/TrackingPage.axaml.cs

@@ -3,36 +3,30 @@ using System.Diagnostics.CodeAnalysis;
 using System.Threading.Tasks;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Pages {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class TrackingPage : UserControl {
+namespace DHT.Desktop.Main.Pages;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class TrackingPage : UserControl {
 	private bool isCopyingScript;
 
 	public TrackingPage() {
 		InitializeComponent();
 	}
 
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-
 	public async void CopyTrackingScriptButton_OnClick(object? sender, RoutedEventArgs e) {
 		if (DataContext is TrackingPageModel model) {
-				var button = this.FindControl<Button>("CopyTrackingScript");
-				var originalText = button.Content;
-				button.MinWidth = button.Bounds.Width;
+			var originalText = CopyTrackingScript.Content;
+			CopyTrackingScript.MinWidth = CopyTrackingScript.Bounds.Width;
 
 			if (await model.OnClickCopyTrackingScript() && !isCopyingScript) {
 				isCopyingScript = true;
-					button.Content = "Script Copied!";
+				CopyTrackingScript.Content = "Script Copied!";
 
 				await Task.Delay(TimeSpan.FromSeconds(2));
-					button.Content = originalText;
+				CopyTrackingScript.Content = originalText;
 				isCopyingScript = false;
 			}
 		}
 	}
-	}
 }

app/Desktop/Main/Pages/TrackingPageModel.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Threading.Tasks;
 using System.Web;
-using Avalonia;
 using Avalonia.Controls;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Discord;
@@ -9,8 +8,9 @@ using DHT.Desktop.Server;
 using DHT.Utils.Models;
 using static DHT.Desktop.Program;
 
-namespace DHT.Desktop.Main.Pages {
-	sealed class TrackingPageModel : BaseModel {
+namespace DHT.Desktop.Main.Pages;
+
+sealed class TrackingPageModel : BaseModel {
 	private bool areDevToolsEnabled;
 
 	private bool AreDevToolsEnabled {
@@ -61,7 +61,7 @@ namespace DHT.Desktop.Main.Pages {
 		                         .Replace("/*[CSS-CONTROLLER]*/", await Resources.ReadTextAsync("Tracker/styles/controller.css"))
 		                         .Replace("/*[CSS-SETTINGS]*/", await Resources.ReadTextAsync("Tracker/styles/settings.css"));
 
-			var clipboard = Application.Current?.Clipboard;
+		var clipboard = window.Clipboard;
 		if (clipboard == null) {
 			await Dialog.ShowOk(window, "Copy Tracking Script", "Clipboard is not available on this system.");
 			return false;
@@ -113,5 +113,4 @@ namespace DHT.Desktop.Main.Pages {
 				throw new ArgumentOutOfRangeException();
 		}
 	}
-	}
 }

app/Desktop/Main/Pages/ViewerPage.axaml

@@ -5,9 +5,7 @@
              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"
-             AttachedToVisualTree="OnAttachedToVisualTree"
-             DetachedFromVisualTree="OnDetachedFromVisualTree">
+             x:Class="DHT.Desktop.Main.Pages.ViewerPage">
 
     <Design.DataContext>
         <pages:ViewerPageModel />
@@ -15,17 +13,16 @@
 
     <UserControl.Styles>
         <Style Selector="Expander">
-            <Setter Property="Margin" Value="0 25 0 0" />
+            <Setter Property="Margin" Value="0 5 0 0" />
         </Style>
     </UserControl.Styles>
 
-    <StackPanel Orientation="Vertical">
+    <StackPanel Orientation="Vertical" Spacing="20">
         <StackPanel Orientation="Horizontal" VerticalAlignment="Top">
             <Button Command="{Binding OnClickOpenViewer}" Margin="0 0 5 0">Open Viewer</Button>
             <Button Command="{Binding OnClickSaveViewer}" Margin="5 0 0 0">Save Viewer</Button>
         </StackPanel>
-        <TextBlock Text="{Binding ExportedMessageText}" Margin="0 20 0 0" />
-        <controls:FilterPanel DataContext="{Binding FilterModel}" />
+        <controls:MessageFilterPanel DataContext="{Binding FilterModel}" />
         <Expander Header="Database Tools">
             <StackPanel Orientation="Vertical" Spacing="10">
                 <StackPanel Orientation="Vertical" Spacing="4">

app/Desktop/Main/Pages/ViewerPage.axaml.cs

@@ -1,29 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
-using Avalonia;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Pages {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class ViewerPage : UserControl {
+namespace DHT.Desktop.Main.Pages;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class ViewerPage : UserControl {
 	public ViewerPage() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-
-		public void OnAttachedToVisualTree(object? sender, VisualTreeAttachmentEventArgs e) {
-			if (DataContext is ViewerPageModel model) {
-				model.SetPageVisible(true);
-			}
-		}
-
-		public void OnDetachedFromVisualTree(object? sender, VisualTreeAttachmentEventArgs e) {
-			if (DataContext is ViewerPageModel model) {
-				model.SetPageVisible(false);
-			}
-		}
-	}
 }

app/Desktop/Main/Pages/ViewerPageModel.cs

@@ -1,23 +1,29 @@
 using System;
-using System.Collections.Generic;
+using System.Collections.Concurrent;
 using System.ComponentModel;
 using System.Diagnostics;
 using System.IO;
+using System.Text;
 using System.Threading.Tasks;
 using System.Web;
 using Avalonia.Controls;
+using Avalonia.Platform.Storage;
 using DHT.Desktop.Common;
+using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Controls;
+using DHT.Desktop.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;
 using static DHT.Desktop.Program;
 
-namespace DHT.Desktop.Main.Pages {
-	sealed class ViewerPageModel : BaseModel, IDisposable {
-		public string ExportedMessageText { get; private set; } = "";
+namespace DHT.Desktop.Main.Pages;
+
+sealed class ViewerPageModel : BaseModel, IDisposable {
+	public static readonly ConcurrentBag<string> TemporaryFiles = new ();
 
 	public bool DatabaseToolFilterModeKeep { get; set; } = true;
 	public bool DatabaseToolFilterModeRemove { get; set; } = false;
@@ -29,13 +35,11 @@ namespace DHT.Desktop.Main.Pages {
 		set => Change(ref hasFilters, value);
 	}
 
-		private FilterPanelModel FilterModel { get; }
+	private MessageFilterPanelModel FilterModel { get; }
 
 	private readonly Window window;
 	private readonly IDatabaseFile db;
 
-		private bool isPageVisible = false;
-
 	[Obsolete("Designer")]
 	public ViewerPageModel() : this(null!, DummyDatabaseFile.Instance) {}
 
@@ -43,51 +47,53 @@ namespace DHT.Desktop.Main.Pages {
 		this.window = window;
 		this.db = db;
 
-			FilterModel = new FilterPanelModel(window, db);
+		FilterModel = new MessageFilterPanelModel(window, db, "Will export");
 		FilterModel.FilterPropertyChanged += OnFilterPropertyChanged;
-			db.Statistics.PropertyChanged += OnDbStatisticsChanged;
 	}
 
 	public void Dispose() {
-			db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
 		FilterModel.Dispose();
 	}
 
-		public void SetPageVisible(bool isPageVisible) {
-			this.isPageVisible = isPageVisible;
-			if (isPageVisible) {
-				UpdateStatistics();
-			}
-		}
-
 	private void OnFilterPropertyChanged(object? sender, PropertyChangedEventArgs e) {
-			UpdateStatistics();
 		HasFilters = FilterModel.HasAnyFilters;
 	}
 
-		private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
-			if (isPageVisible && e.PropertyName == nameof(DatabaseStatistics.TotalMessages)) {
-				UpdateStatistics();
+	private async Task WriteViewerFile(string path, IViewerExportStrategy strategy) {
+		const string ArchiveTag = "/*[ARCHIVE]*/";
+
+		string indexFile = await Resources.ReadTextAsync("Viewer/index.html");
+		string viewerTemplate = indexFile.Replace("/*[JS]*/", await Resources.ReadJoinedAsync("Viewer/scripts/", '\n'))
+		                                 .Replace("/*[CSS]*/", await Resources.ReadJoinedAsync("Viewer/styles/", '\n'));
+
+		int viewerArchiveTagStart = viewerTemplate.IndexOf(ArchiveTag);
+		int viewerArchiveTagEnd = viewerArchiveTagStart + ArchiveTag.Length;
+
+		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());
+
+			char[] jsonBuffer = new char[Math.Min(32768, jsonStream.Position)];
+			jsonStream.Position = 0;
+
+			await using (var outputStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.Read))
+			await using (var outputWriter = new StreamWriter(outputStream, Encoding.UTF8)) {
+				await outputWriter.WriteAsync(viewerTemplate[..viewerArchiveTagStart]);
+
+				using (var jsonReader = new StreamReader(jsonStream, Encoding.UTF8)) {
+					int readBytes;
+					while ((readBytes = await jsonReader.ReadAsync(jsonBuffer, 0, jsonBuffer.Length)) > 0) {
+						string jsonChunk = new string(jsonBuffer, 0, readBytes);
+						await outputWriter.WriteAsync(HttpUtility.JavaScriptStringEncode(jsonChunk));
 					}
 				}
 
-		private void UpdateStatistics() {
-			var filter = FilterModel.CreateFilter();
-			var allMessagesCount = db.Statistics.TotalMessages?.Format() ?? "?";
-			var filteredMessagesCount = filter.IsEmpty ? allMessagesCount : db.CountMessages(filter).Format();
-
-			ExportedMessageText = "Will export " + filteredMessagesCount + " out of " + allMessagesCount + " message(s).";
-			OnPropertyChanged(nameof(ExportedMessageText));
+				await outputWriter.WriteAsync(viewerTemplate[viewerArchiveTagEnd..]);
+			}
 		}
 
-		private async Task<string> GenerateViewerContents() {
-			string json = ViewerJsonExport.Generate(db, FilterModel.CreateFilter());
-
-			string index = await Resources.ReadTextAsync("Viewer/index.html");
-			string viewer = index.Replace("/*[JS]*/", await Resources.ReadJoinedAsync("Viewer/scripts/", '\n'))
-			                     .Replace("/*[CSS]*/", await Resources.ReadJoinedAsync("Viewer/styles/", '\n'))
-			                     .Replace("/*[ARCHIVE]*/", HttpUtility.JavaScriptStringEncode(json));
-			return viewer;
+		File.Delete(jsonTempFile);
 	}
 
 	public async void OnClickOpenViewer() {
@@ -101,28 +107,28 @@ namespace DHT.Desktop.Main.Pages {
 			fullPath = Path.Combine(rootPath, filenameBase + "-" + counter + ".html");
 		}
 
+		TemporaryFiles.Add(fullPath);
+
 		Directory.CreateDirectory(rootPath);
-			await File.WriteAllTextAsync(fullPath, await GenerateViewerContents());
+		await WriteViewerFile(fullPath, new LiveViewerExportStrategy(ServerManager.Port, ServerManager.Token));
 
 		Process.Start(new ProcessStartInfo(fullPath) { UseShellExecute = true });
 	}
 
-		public async void OnClickSaveViewer() {
-			var dialog = new SaveFileDialog {
-				Title = "Save Viewer",
-				InitialFileName = "archive.html",
-				Directory = Path.GetDirectoryName(db.Path),
-				Filters = new List<FileDialogFilter> {
-					new() {
-						Name = "Discord History Viewer",
-						Extensions = { "html" }
-					}
-				}
-			}.ShowAsync(window);
+	private static readonly FilePickerFileType[] ViewerFileTypes = {
+		FileDialogs.CreateFilter("Discord History Viewer", new string[] { "html" }),
+	};
 	
-			string? path = await dialog;
-			if (!string.IsNullOrEmpty(path)) {
-				await File.WriteAllTextAsync(path, await GenerateViewerContents());
+	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);
 		}
 	}
 
@@ -131,13 +137,12 @@ namespace DHT.Desktop.Main.Pages {
 
 		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, MessageFilterRemovalMode.KeepMatching);
+				db.RemoveMessages(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, MessageFilterRemovalMode.RemoveMatching);
-				}
+				db.RemoveMessages(filter, FilterRemovalMode.RemoveMatching);
 			}
 		}
 	}

app/Desktop/Main/Screens/MainContentScreen.axaml

@@ -73,14 +73,14 @@
     <DockPanel>
         <Border Classes="statusBar" DockPanel.Dock="Bottom">
             <DockPanel>
-                <TextBlock Classes="invisibleTabItem" DockPanel.Dock="Left">Advanced</TextBlock>
+                <TextBlock Classes="invisibleTabItem" DockPanel.Dock="Left">Attachments</TextBlock>
                 <controls:StatusBar DataContext="{Binding StatusBarModel}" DockPanel.Dock="Right" />
             </DockPanel>
         </Border>
         <TabControl x:Name="TabControl" TabStripPlacement="Left" DockPanel.Dock="Top">
             <TabControl.ItemsPanel>
                 <ItemsPanelTemplate>
-                    <Grid ColumnDefinitions="Auto" RowDefinitions="Auto,Auto,Auto,*,Auto,Auto" />
+                    <Grid ColumnDefinitions="Auto" RowDefinitions="Auto,Auto,Auto,Auto,*,Auto,Auto" />
                 </ItemsPanelTemplate>
             </TabControl.ItemsPanel>
             <TabItem x:Name="TabDatabase" Header="Database" Classes="first" Grid.Row="0">
@@ -93,17 +93,22 @@
                     <ContentPresenter Content="{Binding TrackingPage}" Classes="page" />
                 </ScrollViewer>
             </TabItem>
-            <TabItem x:Name="TabViewer" Header="Viewer" Grid.Row="2">
+            <TabItem x:Name="TabAttachments" Header="Attachments" Grid.Row="2">
+                <ScrollViewer>
+                    <ContentPresenter Content="{Binding AttachmentsPage}" Classes="page" />
+                </ScrollViewer>
+            </TabItem>
+            <TabItem x:Name="TabViewer" Header="Viewer" Grid.Row="3">
                 <ScrollViewer>
                     <ContentPresenter Content="{Binding ViewerPage}" Classes="page" />
                 </ScrollViewer>
             </TabItem>
-            <TabItem x:Name="TabAdvanced" Header="Advanced" Grid.Row="4">
+            <TabItem x:Name="TabAdvanced" Header="Advanced" Grid.Row="5">
                 <ScrollViewer>
                     <ContentPresenter Content="{Binding AdvancedPage}" Classes="page" />
                 </ScrollViewer>
             </TabItem>
-            <TabItem x:Name="TabDebug" Header="Debug" Grid.Row="5" IsVisible="{Binding HasDebugPage}">
+            <TabItem x:Name="TabDebug" Header="Debug" Grid.Row="6" IsVisible="{Binding HasDebugPage}">
                 <ScrollViewer>
                     <ContentPresenter Content="{Binding DebugPage}" Classes="page" />
                 </ScrollViewer>

app/Desktop/Main/Screens/MainContentScreen.axaml.cs

@@ -1,16 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Screens {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class MainContentScreen : UserControl {
+namespace DHT.Desktop.Main.Screens;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class MainContentScreen : UserControl {
 	public MainContentScreen() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-	}
 }

app/Desktop/Main/Screens/MainContentScreenModel.cs

@@ -9,8 +9,9 @@ using DHT.Server.Database;
 using DHT.Server.Service;
 using DHT.Utils.Logging;
 
-namespace DHT.Desktop.Main.Screens {
-	sealed class MainContentScreenModel : IDisposable {
+namespace DHT.Desktop.Main.Screens;
+
+sealed class MainContentScreenModel : IDisposable {
 	private static readonly Log Log = Log.ForType<MainContentScreenModel>();
 
 	public DatabasePage DatabasePage { get; }
@@ -19,6 +20,9 @@ namespace DHT.Desktop.Main.Screens {
 	public TrackingPage TrackingPage { get; }
 	private TrackingPageModel TrackingPageModel { get; }
 
+	public AttachmentsPage AttachmentsPage { get; }
+	private AttachmentsPageModel AttachmentsPageModel { get; }
+
 	public ViewerPage ViewerPage { get; }
 	private ViewerPageModel ViewerPageModel { get; }
 
@@ -63,6 +67,9 @@ namespace DHT.Desktop.Main.Screens {
 		TrackingPageModel = new TrackingPageModel(window);
 		TrackingPage = new TrackingPage { DataContext = TrackingPageModel };
 
+		AttachmentsPageModel = new AttachmentsPageModel(db);
+		AttachmentsPage = new AttachmentsPage { DataContext = AttachmentsPageModel };
+
 		ViewerPageModel = new ViewerPageModel(window, db);
 		ViewerPage = new ViewerPage { DataContext = ViewerPageModel };
 
@@ -92,6 +99,7 @@ namespace DHT.Desktop.Main.Screens {
 
 	public void Dispose() {
 		ServerLauncher.ServerManagementExceptionCaught -= ServerLauncherOnServerManagementExceptionCaught;
+		AttachmentsPageModel.Dispose();
 		ViewerPageModel.Dispose();
 		serverManager.Dispose();
 	}
@@ -108,5 +116,4 @@ namespace DHT.Desktop.Main.Screens {
 		Log.Error(ex);
 		await Dialog.ShowOk(window, "Internal Server Error", ex.Message);
 	}
-	}
 }

app/Desktop/Main/Screens/WelcomeScreen.axaml.cs

@@ -1,16 +1,11 @@
 using System.Diagnostics.CodeAnalysis;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
 
-namespace DHT.Desktop.Main.Screens {
-	[SuppressMessage("ReSharper", "MemberCanBeInternal")]
-	public sealed class WelcomeScreen : UserControl {
+namespace DHT.Desktop.Main.Screens;
+
+[SuppressMessage("ReSharper", "MemberCanBeInternal")]
+public sealed partial class WelcomeScreen : UserControl {
 	public WelcomeScreen() {
 		InitializeComponent();
 	}
-
-		private void InitializeComponent() {
-			AvaloniaXamlLoader.Load(this);
-		}
-	}
 }

app/Desktop/Main/Screens/WelcomeScreenModel.cs

@@ -7,8 +7,9 @@ using DHT.Desktop.Dialogs.Message;
 using DHT.Server.Database;
 using DHT.Utils.Models;
 
-namespace DHT.Desktop.Main.Screens {
-	sealed class WelcomeScreenModel : BaseModel, IDisposable {
+namespace DHT.Desktop.Main.Screens;
+
+sealed class WelcomeScreenModel : BaseModel, IDisposable {
 	public string Version => Program.Version;
 
 	public IDatabaseFile? Db { get; private set; }
@@ -26,11 +27,8 @@ namespace DHT.Desktop.Main.Screens {
 	}
 
 	public async void OpenOrCreateDatabase() {
-			var dialog = DatabaseGui.NewOpenOrCreateDatabaseFileDialog();
-			dialog.Directory = Path.GetDirectoryName(dbFilePath);
-
-			string? path = await dialog.ShowAsync(window);
-			if (!string.IsNullOrWhiteSpace(path)) {
+		var path = await DatabaseGui.NewOpenOrCreateDatabaseFileDialog(window, Path.GetDirectoryName(dbFilePath));
+		if (path != null) {
 			await OpenOrCreateDatabaseFromPath(path);
 		}
 	}
@@ -69,5 +67,4 @@ namespace DHT.Desktop.Main.Screens {
 		Db?.Dispose();
 		Db = null;
 	}
-	}
 }

app/Desktop/Program.cs

@@ -3,8 +3,9 @@ using System.Reflection;
 using Avalonia;
 using DHT.Utils.Resources;
 
-namespace DHT.Desktop {
-	static class Program {
+namespace DHT.Desktop;
+
+static class Program {
 	public static string Version { get; }
 	public static CultureInfo Culture { get; }
 	public static ResourceLoader Resources { get; }
@@ -33,7 +34,7 @@ namespace DHT.Desktop {
 	private static AppBuilder BuildAvaloniaApp() {
 		return AppBuilder.Configure<App>()
 		                 .UsePlatformDetect()
+		                 .WithInterFont()
 		                 .LogToTrace();
 	}
-	}
 }

app/Desktop/Server/ServerManager.cs

@@ -2,8 +2,9 @@ using System;
 using DHT.Server.Database;
 using DHT.Server.Service;
 
-namespace DHT.Desktop.Server {
-	sealed class ServerManager : IDisposable {
+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);
 
@@ -46,5 +47,4 @@ namespace DHT.Desktop.Server {
 			instance = null;
 		}
 	}
-	}
 }

app/Directory.build.props

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

app/Resources/Tracker/scripts/discord.js

@@ -9,7 +9,7 @@ class DISCORD {
 	}
 	
 	static getMessageElements() {
-		return this.getMessageOuterElement().querySelectorAll("[class*='message-']");
+		return this.getMessageOuterElement().querySelectorAll("[class*='message_']");
 	}
 	
 	static hasMoreMessages() {
@@ -91,13 +91,15 @@ class DISCORD {
 	static getMessageElementProps(ele) {
 		const props = DOM.getReactProps(ele);
 		
-		if (props.children && props.children.length >= 4) {
-			const childProps = props.children[3].props;
+		if (props.children && props.children.length) {
+			for (let i = 3; i < props.children.length; i++) {
+				const childProps = props.children[i].props;
 				
-			if ("message" in childProps && "channel" in childProps) {
+				if (childProps && "message" in childProps && "channel" in childProps) {
 					return childProps;
 				}
 			}
+		}
 		
 		return null;
 	}
@@ -110,16 +112,20 @@ class DISCORD {
 			const messages = [];
 			
 			for (const ele of this.getMessageElements()) {
+				try {
 					const props = this.getMessageElementProps(ele);
 					
 					if (props != null) {
 						messages.push(props.message);
 					}
+				} catch (e) {
+					console.error("[DHT] Error extracing message data, skipping it.", e, ele, DOM.tryGetReactProps(ele));
+				}
 			}
 			
 			return messages;
 		} catch (e) {
-			console.error(e);
+			console.error("[DHT] Error retrieving messages.", e);
 			return [];
 		}
 	}
@@ -162,7 +168,7 @@ class DISCORD {
 			if (dms) {
 				let name;
 				
-				for (const ele of dms.querySelectorAll("[class*='channel-'] [class*='selected-'] [class^='name-'] *, [class*='channel-'][class*='selected-'] [class^='name-'] *")) {
+				for (const ele of dms.querySelectorAll("[class*='channel_'] [class*='selected_'] [class^='name_'] *")) {
 					const node = Array.prototype.find.call(ele.childNodes, node => node.nodeType === Node.TEXT_NODE);
 					
 					if (node) {
@@ -191,9 +197,22 @@ class DISCORD {
 				return { server, channel };
 			}
 			else if (obj.guild_id) {
+				let guild;
+				
+				for (const child of DOM.getReactProps(document.querySelector("nav header [class*='headerContent_']")).children) {
+					if (child && child.props && child.props.guild) {
+						guild = child.props.guild;
+						break;
+					}
+				}
+				
+				if (!guild || typeof guild.name !== "string" || obj.guild_id !== guild.id) {
+					return null;
+				}
+				
 				const server = {
-					"id": obj.guild_id,
-					"name": document.querySelector("nav header h1[class*='name-']").innerText,
+					"id": guild.id,
+					"name": guild.name,
 					"type": "SERVER"
 				};
 				
@@ -232,10 +251,10 @@ class DISCORD {
 		
 		if (dms) {
 			const currentChannel = DOM.queryReactClass("selected", dms);
-			const currentChannelContainer = currentChannel && currentChannel.closest("[class*='channel-']");
+			const currentChannelContainer = currentChannel && currentChannel.closest("[class*='channel_']");
 			const nextChannel = currentChannelContainer && currentChannelContainer.nextElementSibling;
 			
-			if (!nextChannel || !nextChannel.getAttribute("class").includes("channel-")) {
+			if (!nextChannel || !nextChannel.getAttribute("class").includes("channel_")) {
 				return false;
 			}
 			
@@ -262,7 +281,7 @@ class DISCORD {
 			let nextChannel = null;
 			
 			for (let index = 0; index < allTextChannels.length - 1; index++) {
-				if (allTextChannels[index].className.includes("selected-")) {
+				if (allTextChannels[index].className.includes("selected_")) {
 					nextChannel = allTextChannels[index + 1];
 					break;
 				}

app/Resources/Tracker/scripts/dom.js

@@ -11,7 +11,7 @@ class DOM {
 	 * Returns the first child element containing the specified obfuscated class. Parent defaults to the entire document.
 	 */
 	static queryReactClass(cls, parent) {
-		return (parent || document).querySelector(`[class*="${cls}-"]`);
+		return (parent || document).querySelector(`[class*="${cls}_"]`);
 	}
 	
 	/**
@@ -71,4 +71,15 @@ class DOM {
 		key = keys.find(key => key.startsWith("__reactProps$"));
 		return key ? ele[key] : null;
 	}
+	
+	/**
+	 * Returns internal React state object of an element, or null if the retrieval throws.
+	 */
+	static tryGetReactProps(ele) {
+		try {
+			return this.getReactProps(ele);
+		} catch (e) {
+			return null;
+		}
+	}
 }

app/Resources/Tracker/scripts/state.js

@@ -251,6 +251,11 @@ const STATE = (function() {
 							mapped.type = attachment.content_type;
 						}
 						
+						if (attachment.width && attachment.height) {
+							mapped.width = attachment.width;
+							mapped.height = attachment.height;
+						}
+						
 						return mapped;
 					});
 				}

app/Resources/Tracker/styles/controller.css

@@ -1,5 +1,5 @@
-#app-mount div[class*="app-"] {
-  margin-bottom: 48px !important;
+#app-mount {
+  height: calc(100% - 48px) !important;
 }
 
 #dht-ctrl {

app/Resources/Viewer/scripts/discord.js

@@ -1,7 +1,7 @@
 const DISCORD = (function() {
 	const regex = {
 		formatBold: /\*\*([\s\S]+?)\*\*(?!\*)/g,
-		formatItalic: /(.)?\*([\s\S]+?)\*(?!\*)/g,
+		formatItalic: /(.)?([_*])([\s\S]+?)\2(?!\2)/g,
 		formatUnderline: /__([\s\S]+?)__(?!_)/g,
 		formatStrike: /~~([\s\S]+?)~~(?!~)/g,
 		formatCodeInline: /(`+)\s*([\s\S]*?[^`])\s*\1(?!`)/g,
@@ -9,7 +9,7 @@ const DISCORD = (function() {
 		formatUrl: /(\b(?:https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig,
 		formatUrlNoEmbed: /<(\b(?:https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])>/ig,
 		specialEscapedBacktick: /\\`/g,
-		specialEscapedSingle: /\\([*\\])/g,
+		specialEscapedSingle: /\\([*_\\])/g,
 		specialEscapedDouble: /\\__|_\\_|\\_\\_|\\~~|~\\~|\\~\\~/g,
 		specialUnescaped: /([*_~\\])/g,
 		mentionRole: /&lt;@&(\d+?)&gt;/g,
@@ -26,6 +26,7 @@ const DISCORD = (function() {
 	let templateUserAvatar;
 	let templateAttachmentDownload;
 	let templateEmbedImage;
+	let templateEmbedImageWithSize;
 	let templateEmbedRich;
 	let templateEmbedRichNoDescription;
 	let templateEmbedUrl;
@@ -46,8 +47,8 @@ const DISCORD = (function() {
 				.replace(regex.specialEscapedSingle, escapeHtmlMatch)
 				.replace(regex.specialEscapedDouble, full => full.replace(/\\/g, "").replace(/(.)/g, escapeHtmlMatch))
 				.replace(regex.formatBold, "<b>$1</b>")
-				.replace(regex.formatItalic, (full, pre, match) => pre === "\\" ? full : (pre || "") + "<i>" + match + "</i>")
 				.replace(regex.formatUnderline, "<u>$1</u>")
+				.replace(regex.formatItalic, (full, pre, char, match) => pre === "\\" ? full : (pre || "") + "<i>" + match + "</i>")
 				.replace(regex.formatStrike, "<s>$1</s>");
 		}
 		
@@ -64,6 +65,25 @@ const DISCORD = (function() {
 		return "<p>" + processed + "</p>";
 	};
 	
+	const getImageEmbed = function(url, image) {
+		if (!SETTINGS.enableImagePreviews) {
+			return "";
+		}
+		
+		if (image.width && image.height) {
+			return templateEmbedImageWithSize.apply({ url, src: image.url, width: image.width, height: image.height });
+		}
+		else {
+			return templateEmbedImage.apply({ url, src: image.url });
+		}
+	};
+	
+	const isImageUrl = function(url) {
+		const dot = url.pathname.lastIndexOf(".");
+		const ext = dot === -1 ? "" : url.pathname.substring(dot).toLowerCase();
+		return ext === ".png" || ext === ".gif" || ext === ".jpg" || ext === ".jpeg";
+	};
+	
 	return {
 		setup() {
 			templateChannelServer = new TEMPLATE([
@@ -109,12 +129,17 @@ const DISCORD = (function() {
 			
 			// noinspection HtmlUnknownTarget
 			templateAttachmentDownload = new TEMPLATE([
-				"<a href='{url}' class='embed download'>Download {filename}</a>"
+				"<a href='{url}' class='embed download'>Download {name}</a>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
 			templateEmbedImage = new TEMPLATE([
-				"<a href='{url}' class='embed thumbnail'><img src='{src}' alt='(image attachment not found)'></a><br>"
+				"<a href='{url}' class='embed thumbnail loading'><img src='{src}' alt='' onload='DISCORD.handleImageLoad(this)' onerror='DISCORD.handleImageLoadError(this)'></a><br>"
+			].join(""));
+			
+			// noinspection HtmlUnknownTarget
+			templateEmbedImageWithSize = new TEMPLATE([
+				"<a href='{url}' class='embed thumbnail loading'><img src='{src}' width='{width}' height='{height}' alt='' onload='DISCORD.handleImageLoad(this)' onerror='DISCORD.handleImageLoadError(this)'></a><br>"
 			].join(""));
 			
 			// noinspection HtmlUnknownTarget
@@ -145,10 +170,20 @@ const DISCORD = (function() {
 			].join(""));
 		},
 		
+		handleImageLoad(ele) {
+			ele.parentElement.classList.remove("loading");
+		},
+		
+		handleImageLoadError(ele) {
+			// noinspection JSUnusedGlobalSymbols
+			ele.onerror = null;
+			ele.parentElement.classList.remove("loading");
+			ele.setAttribute("alt", "(image attachment not found)");
+		},
+		
 		isImageAttachment(attachment) {
-			const dot = attachment.url.lastIndexOf(".");
-			const ext = dot === -1 ? "" : attachment.url.substring(dot).toLowerCase();
-			return ext === ".png" || ext === ".gif" || ext === ".jpg" || ext === ".jpeg";
+			const url = DOM.tryParseUrl(attachment.url);
+			return url != null && isImageUrl(url);
 		},
 		
 		getChannelHTML(channel) { // noinspection FunctionWithInconsistentReturnsJS
@@ -183,10 +218,10 @@ const DISCORD = (function() {
 							return templateEmbedUnsupported.apply(embed);
 						}
 						else if ("image" in embed && embed.image.url) {
-							return SETTINGS.enableImagePreviews ? templateEmbedImage.apply({ url: embed.url, src: embed.image.url }) : "";
+							return getImageEmbed(embed.url, embed.image);
 						}
 						else if ("thumbnail" in embed && embed.thumbnail.url) {
-							return SETTINGS.enableImagePreviews ? templateEmbedImage.apply({ url: embed.url, src: embed.thumbnail.url }) : "";
+							return getImageEmbed(embed.url, embed.thumbnail);
 						}
 						else if ("title" in embed && "description" in embed) {
 							return templateEmbedRich.apply(embed);
@@ -205,16 +240,14 @@ const DISCORD = (function() {
 					}
 					
 					return value.map(attachment => {
-						if (this.isImageAttachment(attachment) && SETTINGS.enableImagePreviews) {
-							return templateEmbedImage.apply({ url: attachment.url, src: attachment.url });
+						if (!DISCORD.isImageAttachment(attachment) || !SETTINGS.enableImagePreviews) {
+							return templateAttachmentDownload.apply(attachment);
+						}
+						else if ("width" in attachment && "height" in attachment) {
+							return templateEmbedImageWithSize.apply({ url: attachment.url, src: attachment.url, width: attachment.width, height: attachment.height });
 						}
 						else {
-							const sliced = attachment.url.split("/");
-							
-							return templateAttachmentDownload.apply({
-								"url": attachment.url,
-								"filename": sliced[sliced.length - 1]
-							});
+							return templateEmbedImage.apply({ url: attachment.url, src: attachment.url });
 						}
 					}).join("");
 				}

app/Resources/Viewer/scripts/dom.js

@@ -51,4 +51,15 @@ class DOM {
 		const date = new Date(timestamp);
 		return date.toLocaleDateString() + ", " + date.toLocaleTimeString();
 	};
+	
+	/**
+	 * Parses a url string into a URL object and returns it. If the parsing fails, returns null.
+	 */
+	static tryParseUrl(url) {
+		try {
+			return new URL(url);
+		} catch (ignore) {
+			return null;
+		}
+	}
 }

app/Resources/Viewer/styles/messages.css

@@ -107,11 +107,25 @@
 }
 
 .message .thumbnail {
+  position: relative;
   max-width: calc(100% - 20px);
   max-height: 320px;
 }
 
+.message .thumbnail.loading::after {
+  content: "";
+  background: rgba(0, 0, 0, 0.75)
+              url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 300 300' preserveAspectRatio='xMidYMid'%3E %3Ccircle cx='150' cy='150' fill='none' stroke='%237983f5' stroke-width='8' r='42' stroke-dasharray='198 68'%3E %3CanimateTransform attributeName='transform' type='rotate' repeatCount='indefinite' dur='1.25s' values='0 150 150;360 150 150' keyTimes='0;1' /%3E %3C/circle%3E %3C/svg%3E")
+              no-repeat center center;
+  position: absolute;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+}
+
 .message .thumbnail img {
+  width: auto;
   max-width: 100%;
   max-height: 320px;
   border-radius: 3px;

app/Server/Data/Aggregations/DownloadStatusStatistics.cs

@@ -0,0 +1,15 @@
+namespace DHT.Server.Data.Aggregations;
+
+public sealed class DownloadStatusStatistics {
+	public int EnqueuedCount { get; internal set; }
+	public ulong EnqueuedSize { get; internal set; }
+
+	public int SuccessfulCount { get; internal set; }
+	public ulong SuccessfulSize { get; internal set; }
+
+	public int FailedCount { get; internal set; }
+	public ulong FailedSize { get; internal set; }
+
+	public int SkippedCount { get; internal set; }
+	public ulong SkippedSize { get; internal set; }
+}

app/Server/Data/Attachment.cs

@@ -1,9 +1,11 @@
-namespace DHT.Server.Data {
-	public readonly struct Attachment {
+namespace DHT.Server.Data;
+
+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 ulong Size { get; internal init; }
-	}
+	public int? Width { get; internal init; }
+	public int? Height { get; internal init; }
 }

app/Server/Data/Channel.cs

@@ -1,5 +1,6 @@
-namespace DHT.Server.Data {
-	public readonly struct Channel {
+namespace DHT.Server.Data;
+
+public readonly struct Channel {
 	public ulong Id { get; init; }
 	public ulong Server { get; init; }
 	public string Name { get; init; }
@@ -7,5 +8,4 @@ namespace DHT.Server.Data {
 	public int? Position { get; init; }
 	public string? Topic { get; init; }
 	public bool? Nsfw { get; init; }
-	}
 }

app/Server/Data/Download.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Net;
+
+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 NewFailure(string url, HttpStatusCode? statusCode, ulong size) {
+		return new Download(url, statusCode.HasValue ? (DownloadStatus) (int) statusCode : DownloadStatus.GenericError, size);
+	}
+
+	public string Url { 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;
+		Status = status;
+		Size = size;
+		Data = data;
+	}
+
+	internal Download WithData(byte[] data) {
+		return new Download(Url, Status, Size, data);
+	}
+}

app/Server/Data/DownloadStatus.cs

@@ -0,0 +1,12 @@
+using System.Net;
+
+namespace DHT.Server.Data;
+
+/// <summary>
+/// Extends <see cref="HttpStatusCode"/> with custom status codes in the range 0-99.
+/// </summary>
+public enum DownloadStatus {
+	Enqueued = 0,
+	GenericError = 1,
+	Success = HttpStatusCode.OK
+}

app/Server/Data/DownloadedAttachment.cs

@@ -0,0 +1,6 @@
+namespace DHT.Server.Data;
+
+public readonly struct DownloadedAttachment {
+	public string? Type { get; internal init; }
+	public byte[] Data { get; internal init; }
+}

app/Server/Data/Embed.cs

@@ -1,5 +1,5 @@
-namespace DHT.Server.Data {
-	public readonly struct Embed {
+namespace DHT.Server.Data;
+
+public readonly struct Embed {
 	public string Json { get; internal init; }
-	}
 }

app/Server/Data/EmojiFlags.cs

@@ -1,9 +1,9 @@
 using System;
 
-namespace DHT.Server.Data {
-	[Flags]
-	public enum EmojiFlags : ushort {
+namespace DHT.Server.Data;
+
+[Flags]
+public enum EmojiFlags : ushort {
 	None = 0,
 	Animated = 0b1
-	}
 }

app/Server/Data/Filters/AttachmentFilter.cs

@@ -0,0 +1,15 @@
+namespace DHT.Server.Data.Filters;
+
+public sealed class AttachmentFilter {
+	public ulong? MaxBytes { get; set; } = null;
+
+	public DownloadItemRules? DownloadItemRule { get; set; } = null;
+
+	public bool IsEmpty => MaxBytes == null &&
+	                       DownloadItemRule == null;
+
+	public enum DownloadItemRules {
+		OnlyNotPresent,
+		OnlyPresent
+	}
+}

app/Server/Data/Filters/DownloadItemFilter.cs

@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace DHT.Server.Data.Filters;
+
+public sealed class DownloadItemFilter {
+	public HashSet<DownloadStatus>? IncludeStatuses { get; init; } = null;
+	public HashSet<DownloadStatus>? ExcludeStatuses { get; init; } = null;
+
+	public bool IsEmpty => IncludeStatuses == null && ExcludeStatuses == null;
+}

app/Server/Data/Filters/FilterRemovalMode.cs

@@ -0,0 +1,6 @@
+namespace DHT.Server.Data.Filters;
+
+public enum FilterRemovalMode {
+	KeepMatching,
+	RemoveMatching
+}

app/Server/Data/Filters/MessageFilter.cs

@@ -1,8 +1,9 @@
 using System;
 using System.Collections.Generic;
 
-namespace DHT.Server.Data.Filters {
-	public sealed class MessageFilter {
+namespace DHT.Server.Data.Filters;
+
+public sealed class MessageFilter {
 	public DateTime? StartDate { get; set; } = null;
 	public DateTime? EndDate { get; set; } = null;
 
@@ -15,5 +16,4 @@ namespace DHT.Server.Data.Filters {
 	                       ChannelIds == null &&
 	                       UserIds == null &&
 	                       MessageIds == null;
-	}
 }

app/Server/Data/Filters/MessageFilterRemovalMode.cs

@@ -1,6 +0,0 @@
-namespace DHT.Server.Data.Filters {
-	public enum MessageFilterRemovalMode {
-		KeepMatching,
-		RemoveMatching
-	}
-}

app/Server/Data/Message.cs

@@ -1,7 +1,8 @@
 using System.Collections.Immutable;
 
-namespace DHT.Server.Data {
-	public readonly struct Message {
+namespace DHT.Server.Data;
+
+public readonly struct Message {
 	public ulong Id { get; init; }
 	public ulong Sender { get; init; }
 	public ulong Channel { get; init; }
@@ -12,5 +13,4 @@ namespace DHT.Server.Data {
 	public ImmutableArray<Attachment> Attachments { get; init; }
 	public ImmutableArray<Embed> Embeds { get; init; }
 	public ImmutableArray<Reaction> Reactions { get; init; }
-	}
 }

app/Server/Data/Reaction.cs

@@ -1,8 +1,8 @@
-namespace DHT.Server.Data {
-	public readonly struct Reaction {
+namespace DHT.Server.Data;
+
+public readonly struct Reaction {
 	public ulong? EmojiId { get; internal init; }
 	public string? EmojiName { get; internal init; }
 	public EmojiFlags EmojiFlags { get; internal init; }
 	public int Count { get; internal init; }
-	}
 }

app/Server/Data/Server.cs

@@ -1,7 +1,7 @@
-namespace DHT.Server.Data {
-	public readonly struct Server {
+namespace DHT.Server.Data;
+
+public readonly struct Server {
 	public ulong Id { get; init; }
 	public string Name { get; init; }
 	public ServerType? Type { get; init; }
-	}
 }

app/Server/Data/ServerType.cs

@@ -1,11 +1,12 @@
-namespace DHT.Server.Data {
-	public enum ServerType {
+namespace DHT.Server.Data;
+
+public enum ServerType {
 	Server,
 	Group,
 	DirectMessage
-	}
+}
 
-	public static class ServerTypes {
+public static class ServerTypes {
 	public static ServerType? FromString(string? str) {
 		return str switch {
 			"SERVER" => ServerType.Server,
@@ -24,6 +25,15 @@ namespace DHT.Server.Data {
 		};
 	}
 
+	public static string ToNiceString(ServerType? type) {
+		return type switch {
+			ServerType.Server        => "Server",
+			ServerType.Group         => "Group",
+			ServerType.DirectMessage => "DM",
+			_                        => "Unknown"
+		};
+	}
+
 	internal static string ToJsonViewerString(ServerType? type) {
 		return type switch {
 			ServerType.Server        => "server",
@@ -32,5 +42,4 @@ namespace DHT.Server.Data {
 			_                        => "unknown"
 		};
 	}
-	}
 }

app/Server/Data/User.cs

@@ -1,8 +1,8 @@
-namespace DHT.Server.Data {
-	public readonly struct User {
+namespace DHT.Server.Data;
+
+public readonly struct User {
 	public ulong Id { get; init; }
 	public string Name { get; init; }
 	public string? AvatarUrl { get; init; }
 	public string? Discriminator { get; init; }
-	}
 }

app/Server/Database/DatabaseExtensions.cs

@@ -1,16 +1,29 @@
-namespace DHT.Server.Database {
-	public static class DatabaseExtensions {
+using System.Collections.Generic;
+using DHT.Server.Data;
+
+namespace DHT.Server.Database;
+
+public static class DatabaseExtensions {
 	public static void AddFrom(this IDatabaseFile target, IDatabaseFile source) {
-			foreach (var server in source.GetAllServers()) {
-				target.AddServer(server);
-			}
-
-			foreach (var channel in source.GetAllChannels()) {
-				target.AddChannel(channel);
-			}
-
+		target.AddServers(source.GetAllServers());
+		target.AddChannels(source.GetAllChannels());
 		target.AddUsers(source.GetAllUsers().ToArray());
 		target.AddMessages(source.GetMessages().ToArray());
+
+		foreach (var download in source.GetDownloadsWithoutData()) {
+			target.AddDownload(download.Status == DownloadStatus.Success ? source.GetDownloadWithData(download) : download);
+		}
+	}
+
+	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);
 		}
 	}
 }

app/Server/Database/DatabaseStatistics.cs

@@ -1,11 +1,18 @@
 using DHT.Utils.Models;
 
-namespace DHT.Server.Database {
-	public sealed class DatabaseStatistics : BaseModel {
+namespace DHT.Server.Database;
+
+/// <summary>
+/// A live view of database statistics.
+/// Some of the totals are computed asynchronously and may not reflect the most recent version of the database, or may not be available at all until computed for the first time.
+/// </summary>
+public sealed class DatabaseStatistics : BaseModel {
 	private long totalServers;
 	private long totalChannels;
 	private long totalUsers;
 	private long? totalMessages;
+	private long? totalAttachments;
+	private long? totalDownloads;
 
 	public long TotalServers {
 		get => totalServers;
@@ -27,13 +34,13 @@ namespace DHT.Server.Database {
 		internal set => Change(ref totalMessages, value);
 	}
 
-		public DatabaseStatistics Clone() {
-			return new DatabaseStatistics {
-				totalServers = totalServers,
-				totalChannels = totalChannels,
-				totalUsers = TotalUsers,
-				totalMessages = totalMessages
-			};
+	public long? TotalAttachments {
+		get => totalAttachments;
+		internal set => Change(ref totalAttachments, value);
 	}
+
+	public long? TotalDownloads {
+		get => totalDownloads;
+		internal set => Change(ref totalDownloads, value);
 	}
 }

app/Server/Database/DatabaseStatisticsSnapshot.cs

@@ -0,0 +1,11 @@
+namespace DHT.Server.Database;
+
+/// <summary>
+/// A complete snapshot of database statistics at a particular point in time.
+/// </summary>
+public readonly struct DatabaseStatisticsSnapshot {
+	public long TotalServers { get; internal init; }
+	public long TotalChannels { get; internal init; }
+	public long TotalUsers { get; internal init; }
+	public long TotalMessages { get; internal init; }
+}