Convert attachment download events to reactive

app/Desktop/Desktop.csproj

@@ -21,6 +21,7 @@
     <PackageReference Include="Avalonia.Desktop" Version="11.0.6" />
     <PackageReference Include="Avalonia.Diagnostics" Version="11.0.6" Condition=" '$(Configuration)' == 'Debug' " />
     <PackageReference Include="Avalonia.Fonts.Inter" Version="11.0.6" />
+    <PackageReference Include="Avalonia.ReactiveUI" Version="11.0.6" />
     <PackageReference Include="Avalonia.Themes.Fluent" Version="11.0.6" />
   </ItemGroup>
   

app/Desktop/Main/Controls/AttachmentFilterPanelModel.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using DHT.Desktop.Common;
+using DHT.Server;
 using DHT.Server.Data.Filters;
 using DHT.Server.Database;
 using DHT.Utils.Models;
@@ -47,7 +48,7 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 
 	public IEnumerable<Unit> Units => AllUnits;
 
-	private readonly IDatabaseFile db;
+	private readonly State state;
 	private readonly string verb;
 
 	private readonly AsyncValueComputer<long> matchingAttachmentCountComputer;
@@ -55,10 +56,10 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 	private long? totalAttachmentCount;
 
 	[Obsolete("Designer")]
-	public AttachmentFilterPanelModel() : this(DummyDatabaseFile.Instance) {}
+	public AttachmentFilterPanelModel() : this(State.Dummy) {}
 
-	public AttachmentFilterPanelModel(IDatabaseFile db, string verb = "Matches") {
-		this.db = db;
+	public AttachmentFilterPanelModel(State state, string verb = "Matches") {
+		this.state = state;
 		this.verb = verb;
 
 		this.matchingAttachmentCountComputer = AsyncValueComputer<long>.WithResultProcessor(SetAttachmentCounts).Build();
@@ -66,11 +67,11 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 		UpdateFilterStatistics();
 
 		PropertyChanged += OnPropertyChanged;
-		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+		state.Db.Statistics.PropertyChanged += OnDbStatisticsChanged;
 	}
 
 	public void Dispose() {
-		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+		state.Db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
 	}
 
 	private void OnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
@@ -81,7 +82,7 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 
 	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
 		if (e.PropertyName == nameof(DatabaseStatistics.TotalAttachments)) {
-			totalAttachmentCount = db.Statistics.TotalAttachments;
+			totalAttachmentCount = state.Db.Statistics.TotalAttachments;
 			UpdateFilterStatistics();
 		}
 	}
@@ -96,7 +97,7 @@ sealed class AttachmentFilterPanelModel : BaseModel, IDisposable {
 		else {
 			matchingAttachmentCount = null;
 			UpdateFilterStatisticsText();
-			matchingAttachmentCountComputer.Compute(() => db.CountAttachments(filter));
+			matchingAttachmentCountComputer.Compute(() => state.Db.CountAttachments(filter));
 		}
 	}
 

app/Desktop/Main/Controls/MessageFilterPanelModel.cs

@@ -8,6 +8,7 @@ using Avalonia.Controls;
 using DHT.Desktop.Common;
 using DHT.Desktop.Dialogs.CheckBox;
 using DHT.Desktop.Dialogs.Message;
+using DHT.Server;
 using DHT.Server.Data;
 using DHT.Server.Data.Filters;
 using DHT.Server.Database;
@@ -62,7 +63,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 	}
 
 	public HashSet<ulong> IncludedChannels {
-		get => includedChannels ?? db.GetAllChannels().Select(static channel => channel.Id).ToHashSet();
+		get => includedChannels ?? state.Db.GetAllChannels().Select(static channel => channel.Id).ToHashSet();
 		set => Change(ref includedChannels, value);
 	}
 
@@ -72,7 +73,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 	}
 
 	public HashSet<ulong> IncludedUsers {
-		get => includedUsers ?? db.GetAllUsers().Select(static user => user.Id).ToHashSet();
+		get => includedUsers ?? state.Db.GetAllUsers().Select(static user => user.Id).ToHashSet();
 		set => Change(ref includedUsers, value);
 	}
 
@@ -91,7 +92,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 	}
 
 	private readonly Window window;
-	private readonly IDatabaseFile db;
+	private readonly State state;
 	private readonly string verb;
 
 	private readonly AsyncValueComputer<long> exportedMessageCountComputer;
@@ -99,11 +100,11 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 	private long? totalMessageCount;
 
 	[Obsolete("Designer")]
-	public MessageFilterPanelModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public MessageFilterPanelModel() : this(null!, State.Dummy) {}
 
-	public MessageFilterPanelModel(Window window, IDatabaseFile db, string verb = "Matches") {
+	public MessageFilterPanelModel(Window window, State state, string verb = "Matches") {
 		this.window = window;
-		this.db = db;
+		this.state = state;
 		this.verb = verb;
 
 		this.exportedMessageCountComputer = AsyncValueComputer<long>.WithResultProcessor(SetExportedMessageCount).Build();
@@ -113,11 +114,11 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		UpdateUserFilterLabel();
 
 		PropertyChanged += OnPropertyChanged;
-		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+		state.Db.Statistics.PropertyChanged += OnDbStatisticsChanged;
 	}
 
 	public void Dispose() {
-		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+		state.Db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
 	}
 
 	private void OnPropertyChanged(object? sender, PropertyChangedEventArgs e) {
@@ -136,7 +137,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 
 	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
 		if (e.PropertyName == nameof(DatabaseStatistics.TotalMessages)) {
-			totalMessageCount = db.Statistics.TotalMessages;
+			totalMessageCount = state.Db.Statistics.TotalMessages;
 			UpdateFilterStatistics();
 		}
 		else if (e.PropertyName == nameof(DatabaseStatistics.TotalChannels)) {
@@ -157,7 +158,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		else {
 			exportedMessageCount = null;
 			UpdateFilterStatisticsText();
-			exportedMessageCountComputer.Compute(() => db.CountMessages(filter));
+			exportedMessageCountComputer.Compute(() => state.Db.CountMessages(filter));
 		}
 	}
 
@@ -175,11 +176,11 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 	}
 
 	public async void OpenChannelFilterDialog() {
-		var servers = db.GetAllServers().ToDictionary(static server => server.Id);
+		var servers = state.Db.GetAllServers().ToDictionary(static server => server.Id);
 		var items = new List<CheckBoxItem<ulong>>();
 		var included = IncludedChannels;
 
-		foreach (var channel in db.GetAllChannels()) {
+		foreach (var channel in state.Db.GetAllChannels()) {
 			var channelId = channel.Id;
 			var channelName = channel.Name;
 
@@ -223,7 +224,7 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 		var items = new List<CheckBoxItem<ulong>>();
 		var included = IncludedUsers;
 
-		foreach (var user in db.GetAllUsers()) {
+		foreach (var user in state.Db.GetAllUsers()) {
 			var name = user.Name;
 			var discriminator = user.Discriminator;
 
@@ -240,13 +241,13 @@ sealed class MessageFilterPanelModel : BaseModel, IDisposable {
 	}
 
 	private void UpdateChannelFilterLabel() {
-		long total = db.Statistics.TotalChannels;
+		long total = state.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 total = state.Db.Statistics.TotalUsers;
 		long included = FilterByUser ? IncludedUsers.Count : total;
 		UserFilterLabel = "Selected " + included.Format() + " / " + total.Pluralize("user") + ".";
 	}

app/Desktop/Main/Controls/ServerConfigurationPanelModel.cs

@@ -1,14 +1,19 @@
 using System;
+using System.Threading.Tasks;
 using Avalonia.Controls;
+using Avalonia.Threading;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Server;
-using DHT.Server.Database;
+using DHT.Server;
 using DHT.Server.Service;
+using DHT.Utils.Logging;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main.Controls;
 
 sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
+	private static readonly Log Log = Log.ForType<ServerConfigurationPanelModel>();
+	
 	private string inputPort;
 
 	public string InputPort {
@@ -29,7 +34,7 @@ sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
 		}
 	}
 
-	public bool HasMadeChanges => ServerManager.Port.ToString() != InputPort || ServerManager.Token != InputToken;
+	public bool HasMadeChanges => ServerConfiguration.Port.ToString() != InputPort || ServerConfiguration.Token != InputToken;
 
 	private bool isToggleServerButtonEnabled = true;
 
@@ -38,59 +43,69 @@ sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
 		set => Change(ref isToggleServerButtonEnabled, value);
 	}
 
-	public string ToggleServerButtonText => serverManager.IsRunning ? "Stop Server" : "Start Server";
-
-	public event EventHandler<StatusBarModel.Status>? ServerStatusChanged;
+	public string ToggleServerButtonText => server.IsRunning ? "Stop Server" : "Start Server";
 
 	private readonly Window window;
-	private readonly ServerManager serverManager;
+	private readonly ServerManager server;
 
 	[Obsolete("Designer")]
-	public ServerConfigurationPanelModel() : this(null!, new ServerManager(DummyDatabaseFile.Instance)) {}
+	public ServerConfigurationPanelModel() : this(null!, State.Dummy) {}
 
-	public ServerConfigurationPanelModel(Window window, ServerManager serverManager) {
+	public ServerConfigurationPanelModel(Window window, State state) {
 		this.window = window;
-		this.serverManager = serverManager;
-		this.inputPort = ServerManager.Port.ToString();
-		this.inputToken = ServerManager.Token;
-	}
+		this.server = state.Server;
+		this.inputPort = ServerConfiguration.Port.ToString();
+		this.inputToken = ServerConfiguration.Token;
 		
-	public void Initialize() {
-		ServerLauncher.ServerStatusChanged += ServerLauncherOnServerStatusChanged;
+		server.StatusChanged += OnServerStatusChanged;
 	}
 
 	public void Dispose() {
-		ServerLauncher.ServerStatusChanged -= ServerLauncherOnServerStatusChanged;
+		server.StatusChanged -= OnServerStatusChanged;
 	}
 
-	private void ServerLauncherOnServerStatusChanged(object? sender, EventArgs e) {
-		ServerStatusChanged?.Invoke(this, serverManager.IsRunning ? StatusBarModel.Status.Ready : StatusBarModel.Status.Stopped);
+	private void OnServerStatusChanged(object? sender, ServerManager.Status e) {
+		Dispatcher.UIThread.InvokeAsync(UpdateServerStatus);
+	}
+
+	private void UpdateServerStatus() {
 		OnPropertyChanged(nameof(ToggleServerButtonText));
+	}
+
+	private async Task StartServer() {
+		IsToggleServerButtonEnabled = false;
+		
+		try {
+			await server.Start(ServerConfiguration.Port, ServerConfiguration.Token);
+		} catch (Exception e) {
+			Log.Error(e);
+			await Dialog.ShowOk(window, "Internal Server Error", e.Message);
+		}
+		
+		UpdateServerStatus();
 		IsToggleServerButtonEnabled = true;
 	}
 
-	private void BeforeServerStart() {
+	private async Task StopServer() {
 		IsToggleServerButtonEnabled = false;
-		ServerStatusChanged?.Invoke(this, StatusBarModel.Status.Starting);
+		
+		try {
+			await server.Stop();
+		} catch (Exception e) {
+			Log.Error(e);
+			await Dialog.ShowOk(window, "Internal Server Error", e.Message);
 		}
 		
-	private void StartServer() {
-		BeforeServerStart();
-		serverManager.Launch();
+		UpdateServerStatus();
+		IsToggleServerButtonEnabled = true;
 	}
 
-	private void StopServer() {
-		IsToggleServerButtonEnabled = false;
-		ServerStatusChanged?.Invoke(this, StatusBarModel.Status.Stopping);
-		serverManager.Stop();
-	}
-
-	public void OnClickToggleServerButton() {
-		if (serverManager.IsRunning) {
-			StopServer();
+	public async Task OnClickToggleServerButton() {
+		if (server.IsRunning) {
+			await StopServer();
 		}
 		else {
-			StartServer();
+			await StartServer();
 		}
 	}
 
@@ -98,19 +113,21 @@ sealed class ServerConfigurationPanelModel : BaseModel, IDisposable {
 		InputToken = ServerUtils.GenerateRandomToken(20);
 	}
 
-	public async void OnClickApplyChanges() {
+	public async Task OnClickApplyChanges() {
 		if (!ushort.TryParse(InputPort, out ushort port)) {
 			await Dialog.ShowOk(window, "Invalid Port", "Port must be a number between 0 and 65535.");
 			return;
 		}
 
-		BeforeServerStart();
-		serverManager.Relaunch(port, InputToken);
+		ServerConfiguration.Port = port;
+		ServerConfiguration.Token = inputToken;
+		await StartServer();
+		
 		OnPropertyChanged(nameof(HasMadeChanges));
 	}
 
 	public void OnClickCancelChanges() {
-		InputPort = ServerManager.Port.ToString();
-		InputToken = ServerManager.Token;
+		InputPort = ServerConfiguration.Port.ToString();
+		InputToken = ServerConfiguration.Token;
 	}
 }

app/Desktop/Main/Controls/StatusBar.axaml

@@ -40,22 +40,22 @@
     <StackPanel Orientation="Horizontal" Margin="6 3">
         <StackPanel Orientation="Vertical" Width="65">
             <TextBlock Classes="label">Status</TextBlock>
-            <TextBlock FontSize="12" Margin="0 3 0 0" Text="{Binding StatusText}" />
+            <TextBlock FontSize="12" Margin="0 3 0 0" Text="{Binding ServerStatusText}" />
         </StackPanel>
         <Rectangle />
         <StackPanel Orientation="Vertical">
             <TextBlock Classes="label">Servers</TextBlock>
-            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalServers, Converter={StaticResource NumberValueConverter}}" />
+            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalServers, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" />
         </StackPanel>
         <Rectangle />
         <StackPanel Orientation="Vertical">
             <TextBlock Classes="label">Channels</TextBlock>
-            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalChannels, Converter={StaticResource NumberValueConverter}}" />
+            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalChannels, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" />
         </StackPanel>
         <Rectangle />
         <StackPanel Orientation="Vertical">
             <TextBlock Classes="label">Messages</TextBlock>
-            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalMessages, Converter={StaticResource NumberValueConverter}}" />
+            <TextBlock Classes="value" Text="{Binding DatabaseStatistics.TotalMessages, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" />
         </StackPanel>
     </StackPanel>
 

app/Desktop/Main/Controls/StatusBarModel.cs

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

app/Desktop/Main/MainWindow.axaml

@@ -11,7 +11,7 @@
         Width="800" Height="500"
         MinWidth="520" MinHeight="300"
         WindowStartupLocation="CenterScreen"
-        Closed="OnClosed">
+        Closing="OnClosing">
 
     <Design.DataContext>
         <main:MainWindowModel />

app/Desktop/Main/MainWindow.axaml.cs

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

app/Desktop/Main/MainWindowModel.cs

@@ -7,14 +7,17 @@ using Avalonia.Controls;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Screens;
 using DHT.Desktop.Server;
-using DHT.Server.Database;
+using DHT.Server;
+using DHT.Utils.Logging;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main;
 
-sealed class MainWindowModel : BaseModel, IDisposable {
+sealed class MainWindowModel : BaseModel, IAsyncDisposable {
 	private const string DefaultTitle = "Discord History Tracker";
 	
+	private static readonly Log Log = Log.ForType<MainWindowModel>();
+
 	public string Title { get; private set; } = DefaultTitle;
 
 	public UserControl CurrentScreen { get; private set; }
@@ -27,7 +30,7 @@ sealed class MainWindowModel : BaseModel, IDisposable {
 
 	private readonly Window window;
 
-	private IDatabaseFile? db;
+	private State? state;
 
 	[Obsolete("Designer")]
 	public MainWindowModel() : this(null!, Arguments.Empty) {}
@@ -63,11 +66,11 @@ sealed class MainWindowModel : BaseModel, IDisposable {
 		}
 
 		if (args.ServerPort != null) {
-			ServerManager.Port = args.ServerPort.Value;
+			ServerConfiguration.Port = args.ServerPort.Value;
 		}
 
 		if (args.ServerToken != null) {
-			ServerManager.Token = args.ServerToken;
+			ServerConfiguration.Token = args.ServerToken;
 		}
 	}
 
@@ -78,18 +81,29 @@ sealed class MainWindowModel : BaseModel, IDisposable {
 				mainContentScreenModel.Dispose();
 			}
 
-			db?.Dispose();
-			db = welcomeScreenModel.Db;
+			if (state != null) {
+				await state.DisposeAsync();
+			}
 			
-			if (db == null) {
+			if (welcomeScreenModel.Db == null) {
+				state = null;
 				Title = DefaultTitle;
 				mainContentScreenModel = null;
 				mainContentScreen = null;
 				CurrentScreen = welcomeScreen;
 			}
 			else {
-				Title = Path.GetFileName(db.Path) + " - " + DefaultTitle;
-				mainContentScreenModel = new MainContentScreenModel(window, db);
+				state = new State(welcomeScreenModel.Db);
+
+				try {
+					await state.Server.Start(ServerConfiguration.Port, ServerConfiguration.Token);
+				} catch (Exception ex) {
+					Log.Error(ex);
+					await Dialog.ShowOk(window, "Internal Server Error", ex.Message);
+				}
+				
+				Title = Path.GetFileName(state.Db.Path) + " - " + DefaultTitle;
+				mainContentScreenModel = new MainContentScreenModel(window, state);
 				await mainContentScreenModel.Initialize();
 				mainContentScreenModel.DatabaseClosed += MainContentScreenModelOnDatabaseClosed;
 				mainContentScreen = new MainContentScreen { DataContext = mainContentScreenModel };
@@ -107,10 +121,14 @@ sealed class MainWindowModel : BaseModel, IDisposable {
 		welcomeScreenModel.CloseDatabase();
 	}
 
-	public void Dispose() {
-		welcomeScreenModel.Dispose();
+	public async ValueTask DisposeAsync() {
 		mainContentScreenModel?.Dispose();
-		db?.Dispose();
-		db = null;
+
+		if (state != null) {
+			await state.DisposeAsync();
+			state = null;
+		}
+		
+		welcomeScreenModel.Dispose();
 	}
 }

app/Desktop/Main/Pages/AdvancedPageModel.cs

@@ -2,8 +2,7 @@ using System;
 using Avalonia.Controls;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Controls;
-using DHT.Desktop.Server;
-using DHT.Server.Database;
+using DHT.Server;
 using DHT.Utils.Models;
 
 namespace DHT.Desktop.Main.Pages;
@@ -12,20 +11,16 @@ sealed class AdvancedPageModel : BaseModel, IDisposable {
 	public ServerConfigurationPanelModel ServerConfigurationModel { get; }
 
 	private readonly Window window;
-	private readonly IDatabaseFile db;
+	private readonly State state;
 
 	[Obsolete("Designer")]
-	public AdvancedPageModel() : this(null!, DummyDatabaseFile.Instance, new ServerManager(DummyDatabaseFile.Instance)) {}
+	public AdvancedPageModel() : this(null!, State.Dummy) {}
 
-	public AdvancedPageModel(Window window, IDatabaseFile db, ServerManager serverManager) {
+	public AdvancedPageModel(Window window, State state) {
 		this.window = window;
-		this.db = db;
+		this.state = state;
 
-		ServerConfigurationModel = new ServerConfigurationPanelModel(window, serverManager);
-	}
-
-	public void Initialize() {
-		ServerConfigurationModel.Initialize();
+		ServerConfigurationModel = new ServerConfigurationPanelModel(window, state);
 	}
 
 	public void Dispose() {
@@ -33,7 +28,7 @@ sealed class AdvancedPageModel : BaseModel, IDisposable {
 	}
 
 	public async void VacuumDatabase() {
-		db.Vacuum();
+		state.Db.Vacuum();
 		await Dialog.ShowOk(window, "Vacuum Database", "Done.");
 	}
 }

app/Desktop/Main/Pages/AttachmentsPage.axaml

@@ -33,7 +33,7 @@
     <StackPanel Orientation="Vertical" Spacing="20">
         <DockPanel>
             <Button Command="{Binding OnClickToggleDownload}" Content="{Binding ToggleDownloadButtonText}" IsEnabled="{Binding IsToggleDownloadButtonEnabled}" DockPanel.Dock="Left" />
-            <TextBlock Text="{Binding DownloadMessage}" Margin="10 0 0 0" VerticalAlignment="Center" DockPanel.Dock="Left" />
+            <TextBlock Text="{Binding DownloadMessage}" MinWidth="100" Margin="10 0 0 0" VerticalAlignment="Center" TextAlignment="Right" DockPanel.Dock="Left" />
             <ProgressBar Value="{Binding DownloadProgress}" IsVisible="{Binding IsDownloading}" Margin="15 0" VerticalAlignment="Center" DockPanel.Dock="Right" />
         </DockPanel>
         <controls:AttachmentFilterPanel DataContext="{Binding FilterModel}" IsEnabled="{Binding !IsDownloading, RelativeSource={RelativeSource AncestorType=pages:AttachmentsPageModel}}" />
@@ -42,8 +42,8 @@
                 <DataGrid ItemsSource="{Binding StatisticsRows}" AutoGenerateColumns="False" CanUserReorderColumns="False" CanUserResizeColumns="False" CanUserSortColumns="False" IsReadOnly="True">
                     <DataGrid.Columns>
                         <DataGridTextColumn Header="State" Binding="{Binding State}" Width="*" />
-                        <DataGridTextColumn Header="Attachments" Binding="{Binding Items, Converter={StaticResource NumberValueConverter}}" Width="*" CellStyleClasses="right" />
-                        <DataGridTextColumn Header="Size" Binding="{Binding Size, Converter={StaticResource BytesValueConverter}}" Width="*" CellStyleClasses="right" />
+                        <DataGridTextColumn Header="Attachments" Binding="{Binding Items, Mode=OneWay, Converter={StaticResource NumberValueConverter}}" Width="*" CellStyleClasses="right" />
+                        <DataGridTextColumn Header="Size" Binding="{Binding Size, Mode=OneWay, Converter={StaticResource BytesValueConverter}}" Width="*" CellStyleClasses="right" />
                     </DataGrid.Columns>
                 </DataGrid>
             </Expander>

app/Desktop/Main/Pages/AttachmentsPageModel.cs

@@ -1,15 +1,16 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
-using System.Threading;
-using Avalonia.Threading;
+using System.Reactive.Linq;
+using System.Threading.Tasks;
+using Avalonia.ReactiveUI;
 using DHT.Desktop.Common;
 using DHT.Desktop.Main.Controls;
+using DHT.Server;
 using DHT.Server.Data;
 using DHT.Server.Data.Aggregations;
 using DHT.Server.Data.Filters;
 using DHT.Server.Database;
-using DHT.Server.Download;
 using DHT.Utils.Models;
 using DHT.Utils.Tasks;
 
@@ -18,13 +19,14 @@ namespace DHT.Desktop.Main.Pages;
 sealed class AttachmentsPageModel : BaseModel, IDisposable {
 	private static readonly DownloadItemFilter EnqueuedItemFilter = new () {
 		IncludeStatuses = new HashSet<DownloadStatus> {
-			DownloadStatus.Enqueued
+			DownloadStatus.Enqueued,
+			DownloadStatus.Downloading
 		}
 	};
 
 	private bool isThreadDownloadButtonEnabled = true;
 
-	public string ToggleDownloadButtonText => downloadThread == null ? "Start Downloading" : "Stop Downloading";
+	public string ToggleDownloadButtonText => IsDownloading ? "Stop Downloading" : "Start Downloading";
 
 	public bool IsToggleDownloadButtonEnabled {
 		get => isThreadDownloadButtonEnabled;
@@ -32,7 +34,7 @@ sealed class AttachmentsPageModel : BaseModel, IDisposable {
 	}
 
 	public string DownloadMessage { get; set; } = "";
-	public double DownloadProgress => allItemsCount is null or 0 ? 0.0 : 100.0 * doneItemsCount / allItemsCount.Value;
+	public double DownloadProgress => totalItemsToDownloadCount is null or 0 ? 0.0 : 100.0 * doneItemsCount / totalItemsToDownloadCount.Value;
 
 	public AttachmentFilterPanelModel FilterModel { get; }
 
@@ -52,33 +54,34 @@ sealed class AttachmentsPageModel : BaseModel, IDisposable {
 		}
 	}
 
-	public bool IsDownloading => downloadThread != null;
+	public bool IsDownloading => state.Downloader.IsDownloading;
 	public bool HasFailedDownloads => statisticsFailed.Items > 0;
 
-	private readonly IDatabaseFile db;
+	private readonly State state;
 	private readonly AsyncValueComputer<DownloadStatusStatistics>.Single downloadStatisticsComputer;
-	private BackgroundDownloadThread? downloadThread;
 	
+	private IDisposable? finishedItemsSubscription;
 	private int doneItemsCount;
-	private int? allItemsCount;
+	private int initialFinishedCount;
+	private int? totalItemsToDownloadCount;
 
-	public AttachmentsPageModel() : this(DummyDatabaseFile.Instance) {}
+	public AttachmentsPageModel() : this(State.Dummy) {}
 
-	public AttachmentsPageModel(IDatabaseFile db) {
-		this.db = db;
-		this.FilterModel = new AttachmentFilterPanelModel(db);
+	public AttachmentsPageModel(State state) {
+		this.state = state;
 
-		this.downloadStatisticsComputer = AsyncValueComputer<DownloadStatusStatistics>.WithResultProcessor(UpdateStatistics).WithOutdatedResults().BuildWithComputer(db.GetDownloadStatusStatistics);
-		this.downloadStatisticsComputer.Recompute();
+		FilterModel = new AttachmentFilterPanelModel(state);
 
-		db.Statistics.PropertyChanged += OnDbStatisticsChanged;
+		downloadStatisticsComputer = AsyncValueComputer<DownloadStatusStatistics>.WithResultProcessor(UpdateStatistics).WithOutdatedResults().BuildWithComputer(state.Db.GetDownloadStatusStatistics);
+		downloadStatisticsComputer.Recompute();
+
+		state.Db.Statistics.PropertyChanged += OnDbStatisticsChanged;
 	}
 
 	public void Dispose() {
-		db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
-
+		state.Db.Statistics.PropertyChanged -= OnDbStatisticsChanged;
+		finishedItemsSubscription?.Dispose();
 		FilterModel.Dispose();
-		DisposeDownloadThread();
 	}
 
 	private void OnDbStatisticsChanged(object? sender, PropertyChangedEventArgs e) {
@@ -98,7 +101,7 @@ sealed class AttachmentsPageModel : BaseModel, IDisposable {
 	private void EnqueueDownloadItems() {
 		var filter = FilterModel.CreateFilter();
 		filter.DownloadItemRule = AttachmentFilter.DownloadItemRules.OnlyNotPresent;
-		db.EnqueueDownloadItems(filter);
+		state.Db.EnqueueDownloadItems(filter);
 
 		downloadStatisticsComputer.Recompute();
 	}
@@ -124,75 +127,76 @@ sealed class AttachmentsPageModel : BaseModel, IDisposable {
 			OnPropertyChanged(nameof(HasFailedDownloads));
 		}
 
-		allItemsCount = doneItemsCount + statisticsEnqueued.Items;
+		totalItemsToDownloadCount = statisticsEnqueued.Items + statisticsDownloaded.Items + statisticsFailed.Items - initialFinishedCount;
 		UpdateDownloadMessage();
 	}
 
 	private void UpdateDownloadMessage() {
-		DownloadMessage = IsDownloading ? doneItemsCount.Format() + " / " + (allItemsCount?.Format() ?? "?") : "";
+		DownloadMessage = IsDownloading ? doneItemsCount.Format() + " / " + (totalItemsToDownloadCount?.Format() ?? "?") : "";
 
 		OnPropertyChanged(nameof(DownloadMessage));
 		OnPropertyChanged(nameof(DownloadProgress));
 	}
 
-	private void DownloadThreadOnOnItemFinished(object? sender, DownloadItem e) {
-		Interlocked.Increment(ref doneItemsCount);
-
-		Dispatcher.UIThread.Invoke(UpdateDownloadMessage);
+	private void OnItemsFinished(int finishedItemCount) {
+		doneItemsCount += finishedItemCount;
+		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 {
+	public async Task OnClickToggleDownload() {
 		IsToggleDownloadButtonEnabled = false;
-			DisposeDownloadThread();
 		
-			db.RemoveDownloadItems(EnqueuedItemFilter, FilterRemovalMode.RemoveMatching);
+		if (IsDownloading) {
+			await state.Downloader.Stop();
+			
+			finishedItemsSubscription?.Dispose();
+			finishedItemsSubscription = null;
+			
+			downloadStatisticsComputer.Recompute();
+
+			state.Db.RemoveDownloadItems(EnqueuedItemFilter, FilterRemovalMode.RemoveMatching);
 
 			doneItemsCount = 0;
-			allItemsCount = null;
+			initialFinishedCount = 0;
+			totalItemsToDownloadCount = null;
 			UpdateDownloadMessage();
 		}
+		else {
+			var finishedItems = await state.Downloader.Start();
+
+			initialFinishedCount = statisticsDownloaded.Items + statisticsFailed.Items;
+			finishedItemsSubscription = finishedItems.Select(static _ => true)
+			                                         .Buffer(TimeSpan.FromMilliseconds(100))
+			                                         .Select(static items => items.Count)
+			                                         .Where(static items => items > 0)
+			                                         .ObserveOn(AvaloniaScheduler.Instance)
+			                                         .Subscribe(OnItemsFinished);
+			
+			EnqueueDownloadItems();
+		}
 
 		OnPropertyChanged(nameof(ToggleDownloadButtonText));
 		OnPropertyChanged(nameof(IsDownloading));
+		IsToggleDownloadButtonEnabled = true;
 	}
 
 	public void OnClickRetryFailedDownloads() {
 		var allExceptFailedFilter = new DownloadItemFilter {
 			IncludeStatuses = new HashSet<DownloadStatus> {
 				DownloadStatus.Enqueued,
+				DownloadStatus.Downloading,
 				DownloadStatus.Success
 			}
 		};
 
-		db.RemoveDownloadItems(allExceptFailedFilter, FilterRemovalMode.KeepMatching);
+		state.Db.RemoveDownloadItems(allExceptFailedFilter, FilterRemovalMode.KeepMatching);
 
 		if (IsDownloading) {
 			EnqueueDownloadItems();
 		}
 	}
 
-	private void DisposeDownloadThread() {
-		if (downloadThread != null) {
-			downloadThread.OnItemFinished -= DownloadThreadOnOnItemFinished;
-			downloadThread.StopThread();
-		}
-
-		downloadThread = null;
-	}
-
 	public sealed class StatisticsRow {
 		public string State { get; }
 		public int Items { get; set; }

app/Desktop/Main/Pages/DatabasePageModel.cs

@@ -14,6 +14,7 @@ using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Dialogs.Progress;
 using DHT.Desktop.Dialogs.TextBox;
+using DHT.Server;
 using DHT.Server.Data;
 using DHT.Server.Database;
 using DHT.Server.Database.Import;
@@ -33,11 +34,11 @@ sealed class DatabasePageModel : BaseModel {
 	private readonly Window window;
 
 	[Obsolete("Designer")]
-	public DatabasePageModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public DatabasePageModel() : this(null!, State.Dummy) {}
 
-	public DatabasePageModel(Window window, IDatabaseFile db) {
+	public DatabasePageModel(Window window, State state) {
 		this.window = window;
-		this.Db = db;
+		this.Db = state.Db;
 	}
 
 	public async void OpenDatabaseFolder() {

app/Desktop/Main/Pages/DebugPageModel.cs

@@ -6,8 +6,8 @@ using System.Threading.Tasks;
 using Avalonia.Controls;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Dialogs.Progress;
+using DHT.Server;
 using DHT.Server.Data;
-using DHT.Server.Database;
 using DHT.Server.Service;
 using DHT.Utils.Models;
 
@@ -18,14 +18,14 @@ namespace DHT.Desktop.Main.Pages {
 		public string GenerateMessages { get; set; } = "0";
 
 		private readonly Window window;
-		private readonly IDatabaseFile db;
+		private readonly State state;
 
 		[Obsolete("Designer")]
-		public DebugPageModel() : this(null!, DummyDatabaseFile.Instance) {}
+		public DebugPageModel() : this(null!, State.Dummy) {}
 
-		public DebugPageModel(Window window, IDatabaseFile db) {
+		public DebugPageModel(Window window, State state) {
 			this.window = window;
-			this.db = db;
+			this.state = state;
 		}
 
 		public async void OnClickAddRandomDataToDatabase() {
@@ -83,11 +83,11 @@ namespace DHT.Desktop.Main.Pages {
 				Discriminator = rand.Next(0, 9999).ToString(),
 			}).ToArray();
 
-			db.AddServer(server);
-			db.AddUsers(users);
+			state.Db.AddServer(server);
+			state.Db.AddUsers(users);
 
 			foreach (var channel in channels) {
-				db.AddChannel(channel);
+				state.Db.AddChannel(channel);
 			}
 
 			var now = DateTimeOffset.Now;
@@ -117,7 +117,7 @@ namespace DHT.Desktop.Main.Pages {
 					};
 				}).ToArray();
 
-				db.AddMessages(messages);
+				state.Db.AddMessages(messages);
 
 				messageCount -= BatchSize;
 				await callback.Update("Adding messages in batches of " + BatchSize, ++batchIndex, batchCount);

app/Desktop/Main/Pages/TrackingPageModel.cs

@@ -54,7 +54,7 @@ sealed class TrackingPageModel : BaseModel {
 	}
 	
 	public async Task<bool> OnClickCopyTrackingScript() {
-		string url = $"http://127.0.0.1:{ServerManager.Port}/get-tracking-script?token={HttpUtility.UrlEncode(ServerManager.Token)}";
+		string url = $"http://127.0.0.1:{ServerConfiguration.Port}/get-tracking-script?token={HttpUtility.UrlEncode(ServerConfiguration.Token)}";
 		string script = (await Resources.ReadTextAsync("tracker-loader.js")).Trim().Replace("{url}", url);
 
 		var clipboard = window.Clipboard;

app/Desktop/Main/Pages/ViewerPageModel.cs

@@ -13,8 +13,8 @@ using DHT.Desktop.Dialogs.File;
 using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Controls;
 using DHT.Desktop.Server;
+using DHT.Server;
 using DHT.Server.Data.Filters;
-using DHT.Server.Database;
 using DHT.Server.Database.Export;
 using DHT.Server.Database.Export.Strategy;
 using DHT.Utils.Models;
@@ -38,16 +38,16 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 	public MessageFilterPanelModel FilterModel { get; }
 
 	private readonly Window window;
-	private readonly IDatabaseFile db;
+	private readonly State state;
 
 	[Obsolete("Designer")]
-	public ViewerPageModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public ViewerPageModel() : this(null!, State.Dummy) {}
 
-	public ViewerPageModel(Window window, IDatabaseFile db) {
+	public ViewerPageModel(Window window, State state) {
 		this.window = window;
-		this.db = db;
+		this.state = state;
 
-		FilterModel = new MessageFilterPanelModel(window, db, "Will export");
+		FilterModel = new MessageFilterPanelModel(window, state, "Will export");
 		FilterModel.FilterPropertyChanged += OnFilterPropertyChanged;
 	}
 
@@ -66,15 +66,13 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		string viewerTemplate = indexFile.Replace("/*[JS]*/", await Resources.ReadJoinedAsync("Viewer/scripts/", '\n'))
 		                                 .Replace("/*[CSS]*/", await Resources.ReadJoinedAsync("Viewer/styles/", '\n'));
 
-		viewerTemplate = strategy.ProcessViewerTemplate(viewerTemplate);
-
 		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());
+			await ViewerJsonExport.Generate(jsonStream, strategy, state.Db, FilterModel.CreateFilter());
 
 			char[] jsonBuffer = new char[Math.Min(32768, jsonStream.Position)];
 			jsonStream.Position = 0;
@@ -100,7 +98,7 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 
 	public async void OnClickOpenViewer() {
 		string rootPath = Path.Combine(Path.GetTempPath(), "DiscordHistoryTracker");
-		string filenameBase = Path.GetFileNameWithoutExtension(db.Path) + "-" + DateTime.Now.ToString("yyyy-MM-dd");
+		string filenameBase = Path.GetFileNameWithoutExtension(state.Db.Path) + "-" + DateTime.Now.ToString("yyyy-MM-dd");
 		string fullPath = Path.Combine(rootPath, filenameBase + ".html");
 		int counter = 0;
 
@@ -112,7 +110,7 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		TemporaryFiles.Add(fullPath);
 
 		Directory.CreateDirectory(rootPath);
-		await WriteViewerFile(fullPath, new LiveViewerExportStrategy(ServerManager.Port, ServerManager.Token));
+		await WriteViewerFile(fullPath, new LiveViewerExportStrategy(ServerConfiguration.Port, ServerConfiguration.Token));
 
 		Process.Start(new ProcessStartInfo(fullPath) { UseShellExecute = true });
 	}
@@ -125,8 +123,8 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		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)),
+			SuggestedFileName = Path.GetFileNameWithoutExtension(state.Db.Path) + ".html",
+			SuggestedStartLocation = await FileDialogs.GetSuggestedStartLocation(window, Path.GetDirectoryName(state.Db.Path)),
 		});
 
 		if (path != null) {
@@ -138,13 +136,13 @@ sealed class ViewerPageModel : BaseModel, IDisposable {
 		var filter = FilterModel.CreateFilter();
 
 		if (DatabaseToolFilterModeKeep) {
-			if (DialogResult.YesNo.Yes == await Dialog.ShowYesNo(window, "Keep Matching Messages in This Database", db.CountMessages(filter).Pluralize("message") + " will be kept, and the rest will be removed from this database. This action cannot be undone. Proceed?")) {
-				db.RemoveMessages(filter, FilterRemovalMode.KeepMatching);
+			if (DialogResult.YesNo.Yes == await Dialog.ShowYesNo(window, "Keep Matching Messages in This Database", state.Db.CountMessages(filter).Pluralize("message") + " will be kept, and the rest will be removed from this database. This action cannot be undone. Proceed?")) {
+				state.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, FilterRemovalMode.RemoveMatching);
+			if (DialogResult.YesNo.Yes == await Dialog.ShowYesNo(window, "Remove Matching Messages in This Database", state.Db.CountMessages(filter).Pluralize("message") + " will be removed from this database. This action cannot be undone. Proceed?")) {
+				state.Db.RemoveMessages(filter, FilterRemovalMode.RemoveMatching);
 			}
 		}
 	}

app/Desktop/Main/Screens/MainContentScreenModel.cs

@@ -1,12 +1,9 @@
 using System;
 using System.Threading.Tasks;
 using Avalonia.Controls;
-using DHT.Desktop.Dialogs.Message;
 using DHT.Desktop.Main.Controls;
 using DHT.Desktop.Main.Pages;
-using DHT.Desktop.Server;
-using DHT.Server.Database;
-using DHT.Server.Service;
+using DHT.Server;
 using DHT.Utils.Logging;
 
 namespace DHT.Desktop.Main.Screens;
@@ -49,71 +46,43 @@ sealed class MainContentScreenModel : IDisposable {
 		}
 	}
 
-	private readonly Window window;
-	private readonly ServerManager serverManager;
-
 	[Obsolete("Designer")]
-	public MainContentScreenModel() : this(null!, DummyDatabaseFile.Instance) {}
+	public MainContentScreenModel() : this(null!, State.Dummy) {}
 
-	public MainContentScreenModel(Window window, IDatabaseFile db) {
-		this.window = window;
-		this.serverManager = new ServerManager(db);
-
-		ServerLauncher.ServerManagementExceptionCaught += ServerLauncherOnServerManagementExceptionCaught;
-
-		DatabasePageModel = new DatabasePageModel(window, db);
+	public MainContentScreenModel(Window window, State state) {
+		DatabasePageModel = new DatabasePageModel(window, state);
 		DatabasePage = new DatabasePage { DataContext = DatabasePageModel };
 
 		TrackingPageModel = new TrackingPageModel(window);
 		TrackingPage = new TrackingPage { DataContext = TrackingPageModel };
 
-		AttachmentsPageModel = new AttachmentsPageModel(db);
+		AttachmentsPageModel = new AttachmentsPageModel(state);
 		AttachmentsPage = new AttachmentsPage { DataContext = AttachmentsPageModel };
 
-		ViewerPageModel = new ViewerPageModel(window, db);
+		ViewerPageModel = new ViewerPageModel(window, state);
 		ViewerPage = new ViewerPage { DataContext = ViewerPageModel };
 
-		AdvancedPageModel = new AdvancedPageModel(window, db, serverManager);
+		AdvancedPageModel = new AdvancedPageModel(window, state);
 		AdvancedPage = new AdvancedPage { DataContext = AdvancedPageModel };
 
 		#if DEBUG
-		DebugPageModel = new DebugPageModel(window, db);
+		DebugPageModel = new DebugPageModel(window, state);
 		DebugPage = new DebugPage { DataContext = DebugPageModel };
 		#else
 		DebugPage = null;
 		#endif
 
-		StatusBarModel = new StatusBarModel(db.Statistics);
-
-		AdvancedPageModel.ServerConfigurationModel.ServerStatusChanged += OnServerStatusChanged;
-		DatabaseClosed += OnDatabaseClosed;
-
-		StatusBarModel.CurrentStatus = serverManager.IsRunning ? StatusBarModel.Status.Ready : StatusBarModel.Status.Stopped;
+		StatusBarModel = new StatusBarModel(state);
 	}
 
 	public async Task Initialize() {
 		await TrackingPageModel.Initialize();
-		AdvancedPageModel.Initialize();
-		serverManager.Launch();
 	}
 
 	public void Dispose() {
-		ServerLauncher.ServerManagementExceptionCaught -= ServerLauncherOnServerManagementExceptionCaught;
 		AttachmentsPageModel.Dispose();
 		ViewerPageModel.Dispose();
-		serverManager.Dispose();
-	}
-
-	private void OnServerStatusChanged(object? sender, StatusBarModel.Status e) {
-		StatusBarModel.CurrentStatus = e;
-	}
-
-	private void OnDatabaseClosed(object? sender, EventArgs e) {
-		serverManager.Stop();
-	}
-
-	private async void ServerLauncherOnServerManagementExceptionCaught(object? sender, Exception ex) {
-		Log.Error(ex);
-		await Dialog.ShowOk(window, "Internal Server Error", ex.Message);
+		AdvancedPageModel.Dispose();
+		StatusBarModel.Dispose();
 	}
 }

app/Desktop/Server/ServerConfiguration.cs

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

app/Desktop/Server/ServerManager.cs

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

app/Resources/Viewer/index.html

@@ -6,8 +6,6 @@
     
     <script type="text/javascript">
 		window.DHT_EMBEDDED = "/*[ARCHIVE]*/";
-		window.DHT_SERVER_URL = "/*[SERVER_URL]*/";
-    window.DHT_SERVER_TOKEN = "/*[SERVER_TOKEN]*/";
 		/*[JS]*/
     </script>
     <style>

app/Resources/Viewer/scripts/state.js

@@ -182,32 +182,15 @@ const STATE = (function() {
 		return null;
 	};
 	
-	const getMessageList = async function(abortSignal) {
+	const getMessageList = function() {
 		if (!loadedMessages) {
 			return [];
 		}
 		
 		const messages = getMessages(selectedChannel);
 		const startIndex = messagesPerPage * (root.getCurrentPage() - 1);
-		const slicedMessages = loadedMessages.slice(startIndex, !messagesPerPage ? undefined : startIndex + messagesPerPage);
 		
-		let messageTexts = null;
-		
-		if (window.DHT_SERVER_URL !== null) {
-			const messageIds = new Set(slicedMessages);
-			
-			for (const key of slicedMessages) {
-				const message = messages[key];
-				
-				if ("r" in message) {
-					messageIds.add(message.r);
-				}
-			}
-			
-			messageTexts = await getMessageTextsFromServer(messageIds, abortSignal);
-		}
-		
-		return slicedMessages.map(key => {
+		return loadedMessages.slice(startIndex, !messagesPerPage ? undefined : startIndex + messagesPerPage).map(key => {
 			/**
 			 * @type {{}}
 			 * @property {Number} u
@@ -233,9 +216,6 @@ const STATE = (function() {
 			if ("m" in message) {
 				obj["contents"] = message.m;
 			}
-			else if (messageTexts && key in messageTexts) {
-				obj["contents"] = messageTexts[key];
-			}
 			
 			if ("e" in message) {
 				obj["embeds"] = message.e.map(embed => JSON.parse(embed));
@@ -250,16 +230,15 @@ const STATE = (function() {
 			}
 			
 			if ("r" in message) {
-				const replyId = message.r;
-				const replyMessage = getMessageById(replyId);
+				const replyMessage = getMessageById(message.r);
 				const replyUser = replyMessage ? getUser(replyMessage.u) : null;
 				const replyAvatar = replyUser && replyUser.avatar ? { id: getUserId(replyMessage.u), path: replyUser.avatar } : null;
 				
 				obj["reply"] = replyMessage ? {
-					"id": replyId,
+					"id": message.r,
 					"user": replyUser,
 					"avatar": replyAvatar,
-					"contents": messageTexts != null && replyId in messageTexts ? messageTexts[replyId] : replyMessage.m,
+					"contents": replyMessage.m
 				} : null;
 			}
 			
@@ -271,35 +250,9 @@ const STATE = (function() {
 		});
 	};
 	
-	const getMessageTextsFromServer = async function(messageIds, abortSignal) {
-		let idParams = "";
-		
-		for (const messageId of messageIds) {
-			idParams += "id=" + encodeURIComponent(messageId) + "&";
-		}
-		
-		const response = await fetch(DHT_SERVER_URL + "/get-messages?" + idParams + "token=" + encodeURIComponent(DHT_SERVER_TOKEN), {
-			method: "GET",
-			headers: {
-				"Content-Type": "application/json",
-			},
-			credentials: "omit",
-			redirect: "error",
-			signal: abortSignal
-		});
-		
-		if (response.status === 200) {
-			return response.json();
-		}
-		else {
-			throw new Error("Server returned status " + response.status + " " + response.statusText);
-		}
-	};
-	
 	let eventOnUsersRefreshed;
 	let eventOnChannelsRefreshed;
 	let eventOnMessagesRefreshed;
-	let messageLoaderAborter = null;
 	
 	const triggerUsersRefreshed = function() {
 		eventOnUsersRefreshed && eventOnUsersRefreshed(getUserList());
@@ -310,22 +263,7 @@ const STATE = (function() {
 	};
 	
 	const triggerMessagesRefreshed = function() {
-		if (!eventOnMessagesRefreshed) {
-			return;
-		}
-		
-		if (messageLoaderAborter != null) {
-			messageLoaderAborter.abort();
-		}
-		
-		const aborter = new AbortController();
-		messageLoaderAborter = aborter;
-		
-		getMessageList(aborter.signal).then(eventOnMessagesRefreshed).finally(() => {
-			if (messageLoaderAborter === aborter) {
-				messageLoaderAborter = null;
-			}
-		});
+		eventOnMessagesRefreshed && eventOnMessagesRefreshed(getMessageList());
 	};
 	
 	const getFilteredMessageKeys = function(channel) {

app/Server/Data/DownloadStatus.cs

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

app/Server/Database/DummyDatabaseFile.cs

@@ -44,7 +44,7 @@ public sealed class DummyDatabaseFile : IDatabaseFile {
 		return 0;
 	}
 
-	public List<Message> GetMessages(MessageFilter? filter = null, bool includeText = true) {
+	public List<Message> GetMessages(MessageFilter? filter = null) {
 		return new();
 	}
 
@@ -74,7 +74,7 @@ public sealed class DummyDatabaseFile : IDatabaseFile {
 
 	public void EnqueueDownloadItems(AttachmentFilter? filter = null) {}
 
-	public List<DownloadItem> GetEnqueuedDownloadItems(int count) {
+	public List<DownloadItem> PullEnqueuedDownloadItems(int count) {
 		return new();
 	}
 

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

@@ -3,7 +3,5 @@ using DHT.Server.Data;
 namespace DHT.Server.Database.Export.Strategy;
 
 public interface IViewerExportStrategy {
-	bool IncludeMessageText { get; }
-	string ProcessViewerTemplate(string template);
 	string GetAttachmentUrl(Attachment attachment);
 }

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

@@ -12,13 +12,6 @@ public sealed class LiveViewerExportStrategy : IViewerExportStrategy {
 		this.safeToken = WebUtility.UrlEncode(token);
 	}
 
-	public bool IncludeMessageText => false;
-
-	public string ProcessViewerTemplate(string template) {
-		return template.Replace("/*[SERVER_URL]*/", "http://127.0.0.1:" + safePort)
-		               .Replace("/*[SERVER_TOKEN]*/", WebUtility.UrlEncode(safeToken));
-	}
-
 	public string GetAttachmentUrl(Attachment attachment) {
 		return "http://127.0.0.1:" + safePort + "/get-attachment/" + WebUtility.UrlEncode(attachment.NormalizedUrl) + "?token=" + safeToken;
 	}

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

@@ -7,13 +7,6 @@ public sealed class StandaloneViewerExportStrategy : IViewerExportStrategy {
 
 	private StandaloneViewerExportStrategy() {}
 
-	public bool IncludeMessageText => true;
-
-	public string ProcessViewerTemplate(string template) {
-		return template.Replace("\"/*[SERVER_URL]*/\"", "null")
-		               .Replace("\"/*[SERVER_TOKEN]*/\"", "null");
-	}
-
 	public string GetAttachmentUrl(Attachment attachment) {
 		// The normalized URL will not load files from Discord CDN once the time limit is enforced.
 		

app/Server/Database/Export/ViewerJsonExport.cs

@@ -21,7 +21,7 @@ public static class ViewerJsonExport {
 		var includedChannelIds = new HashSet<ulong>();
 		var includedServerIds = new HashSet<ulong>();
 
-		var includedMessages = db.GetMessages(filter, strategy.IncludeMessageText);
+		var includedMessages = db.GetMessages(filter);
 		var includedChannels = new List<Channel>();
 
 		foreach (var message in includedMessages) {

app/Server/Database/IDatabaseFile.cs

@@ -23,7 +23,7 @@ public interface IDatabaseFile : IDisposable {
 
 	void AddMessages(Message[] messages);
 	int CountMessages(MessageFilter? filter = null);
-	List<Message> GetMessages(MessageFilter? filter = null, bool includeText = true);
+	List<Message> GetMessages(MessageFilter? filter = null);
 	HashSet<ulong> GetMessageIds(MessageFilter? filter = null);
 	void RemoveMessages(MessageFilter filter, FilterRemovalMode mode);
 
@@ -35,7 +35,7 @@ public interface IDatabaseFile : IDisposable {
 	DownloadedAttachment? GetDownloadedAttachment(string url);
 
 	void EnqueueDownloadItems(AttachmentFilter? filter = null);
-	List<DownloadItem> GetEnqueuedDownloadItems(int count);
+	List<DownloadItem> PullEnqueuedDownloadItems(int count);
 	void RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode);
 	DownloadStatusStatistics GetDownloadStatusStatistics();
 

app/Server/Database/Sqlite/Schema.cs

@@ -174,8 +174,8 @@ sealed class Schema {
 		int processedUrls = -1;
 
 		await using (var updateCmd = conn.Command("UPDATE attachments SET download_url = url, url = :normalized_url WHERE attachment_id = :attachment_id")) {
-			updateCmd.Parameters.Add(":attachment_id", SqliteType.Integer);
-			updateCmd.Parameters.Add(":normalized_url", SqliteType.Text);
+			updateCmd.Add(":attachment_id", SqliteType.Integer);
+			updateCmd.Add(":normalized_url", SqliteType.Text);
 				
 			foreach (var (attachmentId, normalizedUrl) in normalizedUrls) {
 				if (++processedUrls % 1000 == 0) {
@@ -235,8 +235,8 @@ sealed class Schema {
 		tx = conn.BeginTransaction();
 		
 		await using (var updateCmd = conn.Command("UPDATE downloads SET download_url = :download_url, url = :normalized_url WHERE url = :download_url")) {
-			updateCmd.Parameters.Add(":normalized_url", SqliteType.Text);
-			updateCmd.Parameters.Add(":download_url", SqliteType.Text);
+			updateCmd.Add(":normalized_url", SqliteType.Text);
+			updateCmd.Add(":download_url", SqliteType.Text);
 			
 			foreach (var (normalizedUrl, downloadUrl) in normalizedUrlsToOriginalUrls) {
 				if (++processedUrls % 100 == 0) {

app/Server/Database/Sqlite/SqliteDatabaseFile.cs

@@ -360,7 +360,7 @@ public sealed class SqliteDatabaseFile : IDatabaseFile {
 		return reader.Read() ? reader.GetInt32(0) : 0;
 	}
 
-	public List<Message> GetMessages(MessageFilter? filter = null, bool includeText = true) {
+	public List<Message> GetMessages(MessageFilter? filter = null) {
 		var perf = log.Start();
 		var list = new List<Message>();
 
@@ -370,7 +370,7 @@ public sealed class SqliteDatabaseFile : IDatabaseFile {
 
 		using var conn = pool.Take();
 		using var cmd = conn.Command($"""
-		                              SELECT m.message_id, m.sender_id, m.channel_id, {(includeText ? "m.text" : "NULL")}, m.timestamp, et.edit_timestamp, rt.replied_to_id
+		                              SELECT m.message_id, m.sender_id, m.channel_id, m.text, m.timestamp, et.edit_timestamp, rt.replied_to_id
 		                              FROM messages m
 		                              LEFT JOIN edit_timestamps et ON m.message_id = et.message_id
 		                              LEFT JOIN replied_to rt ON m.message_id = rt.message_id
@@ -385,7 +385,7 @@ public sealed class SqliteDatabaseFile : IDatabaseFile {
 				Id = id,
 				Sender = reader.GetUint64(1),
 				Channel = reader.GetUint64(2),
-				Text = includeText ? reader.GetString(3) : string.Empty,
+				Text = reader.GetString(3),
 				Timestamp = reader.GetInt64(4),
 				EditTimestamp = reader.IsDBNull(5) ? null : reader.GetInt64(5),
 				RepliedToId = reader.IsDBNull(6) ? null : reader.GetUint64(6),
@@ -522,25 +522,42 @@ public sealed class SqliteDatabaseFile : IDatabaseFile {
 		cmd.ExecuteNonQuery();
 	}
 
-	public List<DownloadItem> GetEnqueuedDownloadItems(int count) {
-		var list = new List<DownloadItem>();
+	public List<DownloadItem> PullEnqueuedDownloadItems(int count) {
+		var found = new List<DownloadItem>();
+		var pulled = new List<DownloadItem>();
 
 		using var conn = pool.Take();
-		using var cmd = conn.Command("SELECT normalized_url, download_url, size FROM downloads WHERE status = :enqueued LIMIT :limit");
+		using (var cmd = conn.Command("SELECT normalized_url, download_url, size FROM downloads WHERE status = :enqueued LIMIT :limit")) {
 			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
 			cmd.AddAndSet(":limit", SqliteType.Integer, Math.Max(0, count));
 
 			using var reader = cmd.ExecuteReader();
 
 			while (reader.Read()) {
-			list.Add(new DownloadItem {
+				found.Add(new DownloadItem {
 					NormalizedUrl = reader.GetString(0),
 					DownloadUrl = reader.GetString(1),
 					Size = reader.GetUint64(2),
 				});
 			}
+		}
 
-		return list;
+		if (found.Count != 0) {
+			using var cmd = conn.Command("UPDATE downloads SET status = :downloading WHERE normalized_url = :normalized_url AND status = :enqueued");
+			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
+			cmd.AddAndSet(":downloading", SqliteType.Integer, (int) DownloadStatus.Downloading);
+			cmd.Add(":normalized_url", SqliteType.Text);
+
+			foreach (var item in found) {
+				cmd.Set(":normalized_url", item.NormalizedUrl);
+
+				if (cmd.ExecuteNonQuery() == 1) {
+					pulled.Add(item);
+				}
+			}
+		}
+
+		return pulled;
 	}
 
 	public void RemoveDownloadItems(DownloadItemFilter? filter, FilterRemovalMode mode) {
@@ -562,15 +579,16 @@ public sealed class SqliteDatabaseFile : IDatabaseFile {
 		static void LoadSuccessStatistics(ISqliteConnection conn, DownloadStatusStatistics result) {
 			using var cmd = conn.Command("""
 			                             SELECT
-			                             IFNULL(SUM(CASE WHEN status = :enqueued THEN 1 ELSE 0 END), 0),
-			                             IFNULL(SUM(CASE WHEN status = :enqueued THEN size ELSE 0 END), 0),
+			                             IFNULL(SUM(CASE WHEN status IN (:enqueued, :downloading) THEN 1 ELSE 0 END), 0),
+			                             IFNULL(SUM(CASE WHEN status IN (:enqueued, :downloading) THEN size ELSE 0 END), 0),
 			                             IFNULL(SUM(CASE WHEN status = :success THEN 1 ELSE 0 END), 0),
 			                             IFNULL(SUM(CASE WHEN status = :success THEN size ELSE 0 END), 0),
-			                             IFNULL(SUM(CASE WHEN status != :enqueued AND status != :success THEN 1 ELSE 0 END), 0),
-			                             IFNULL(SUM(CASE WHEN status != :enqueued AND status != :success THEN size ELSE 0 END), 0)
+			                             IFNULL(SUM(CASE WHEN status NOT IN (:enqueued, :downloading) AND status != :success THEN 1 ELSE 0 END), 0),
+			                             IFNULL(SUM(CASE WHEN status NOT IN (:enqueued, :downloading) AND status != :success THEN size ELSE 0 END), 0)
 			                             FROM downloads
 			                             """);
 			cmd.AddAndSet(":enqueued", SqliteType.Integer, (int) DownloadStatus.Enqueued);
+			cmd.AddAndSet(":downloading", SqliteType.Integer, (int) DownloadStatus.Downloading);
 			cmd.AddAndSet(":success", SqliteType.Integer, (int) DownloadStatus.Success);
 
 			using var reader = cmd.ExecuteReader();

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

@@ -62,6 +62,10 @@ static class SqliteExtensions {
 		}
 	}
 
+	public static void Add(this SqliteCommand cmd, string key, SqliteType type) {
+		cmd.Parameters.Add(key, type);
+	}
+
 	public static void AddAndSet(this SqliteCommand cmd, string key, SqliteType type, object? value) {
 		cmd.Parameters.Add(key, type).Value = value ?? DBNull.Value;
 	}

app/Server/Download/BackgroundDownloadThread.cs

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

app/Server/Download/Downloader.cs

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

app/Server/Download/DownloaderTask.cs

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

app/Server/Endpoints/GetMessagesEndpoint.cs

@@ -1,34 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Net;
-using System.Threading.Tasks;
-using DHT.Server.Data.Filters;
-using DHT.Server.Database;
-using DHT.Utils.Http;
-using Microsoft.AspNetCore.Http;
-using GetMessagesJsonContext = DHT.Server.Endpoints.Responses.GetMessagesJsonContext;
-
-namespace DHT.Server.Endpoints;
-
-sealed class GetMessagesEndpoint : BaseEndpoint {
-	public GetMessagesEndpoint(IDatabaseFile db) : base(db) {}
-
-	protected override Task<IHttpOutput> Respond(HttpContext ctx) {
-		HashSet<ulong> messageIdSet;
-		try {
-			var messageIds = ctx.Request.Query["id"];
-			messageIdSet = messageIds.Select(ulong.Parse!).ToHashSet();
-		} catch (Exception) {
-			throw new HttpException(HttpStatusCode.BadRequest, "Invalid message ids.");
-		}
-
-		var messageFilter = new MessageFilter {
-			MessageIds = messageIdSet
-		};
-		
-		var messages = Db.GetMessages(messageFilter).ToDictionary(static message => message.Id, static message => message.Text);
-		var response = new HttpOutput.Json<Dictionary<ulong, string>>(messages, GetMessagesJsonContext.Default.DictionaryUInt64String);
-		return Task.FromResult<IHttpOutput>(response);
-	}
-}

app/Server/Endpoints/Responses/GetMessagesJsonContext.cs

@@ -1,8 +0,0 @@
-using System.Collections.Generic;
-using System.Text.Json.Serialization;
-
-namespace DHT.Server.Endpoints.Responses;
-
-[JsonSourceGenerationOptions(PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase, GenerationMode = JsonSourceGenerationMode.Default)]
-[JsonSerializable(typeof(Dictionary<ulong, string>))]
-sealed partial class GetMessagesJsonContext : JsonSerializerContext {}

app/Server/Server.csproj

@@ -12,6 +12,7 @@
   
   <ItemGroup>
     <PackageReference Include="Microsoft.Data.Sqlite" Version="8.0.0" />
+    <PackageReference Include="System.Reactive" Version="6.0.0" />
   </ItemGroup>
   
   <ItemGroup>

app/Server/Service/ServerLauncher.cs

@@ -1,126 +0,0 @@
-using System;
-using System.Collections.Concurrent;
-using System.Diagnostics.CodeAnalysis;
-using System.Threading;
-using DHT.Server.Database;
-using DHT.Utils.Logging;
-using Microsoft.AspNetCore.Hosting;
-using Microsoft.AspNetCore.Server.Kestrel.Core;
-using Microsoft.Extensions.DependencyInjection;
-
-namespace DHT.Server.Service;
-
-public static class ServerLauncher {
-	private static readonly Log Log = Log.ForType(typeof(ServerLauncher));
-
-	private static IWebHost? Server { get; set; } = null;
-
-	public static bool IsRunning { get; private set; }
-	public static event EventHandler? ServerStatusChanged;
-	public static event EventHandler<Exception>? ServerManagementExceptionCaught;
-
-	private static Thread? ManagementThread { get; set; } = null;
-	private static readonly Mutex ManagementThreadLock = new();
-	private static readonly BlockingCollection<IMessage> Messages = new(new ConcurrentQueue<IMessage>());
-
-	private static void EnqueueMessage(IMessage message) {
-		ManagementThreadLock.WaitOne();
-
-		try {
-			if (ManagementThread == null) {
-				ManagementThread = new Thread(RunManagementThread) {
-					Name = "DHT server management thread",
-					IsBackground = true
-				};
-				ManagementThread.Start();
-			}
-
-			Messages.Add(message);
-		} finally {
-			ManagementThreadLock.ReleaseMutex();
-		}
-	}
-
-	[SuppressMessage("ReSharper", "FunctionNeverReturns")]
-	private static void RunManagementThread() {
-		foreach (IMessage message in Messages.GetConsumingEnumerable()) {
-			try {
-				switch (message) {
-					case IMessage.StartServer start:
-						StopServerFromManagementThread();
-						StartServerFromManagementThread(start.Port, start.Token, start.Db);
-						break;
-					case IMessage.StopServer:
-						StopServerFromManagementThread();
-						break;
-				}
-			} catch (Exception e) {
-				ServerManagementExceptionCaught?.Invoke(null, e);
-			}
-		}
-	}
-
-	private static void StartServerFromManagementThread(ushort port, string token, IDatabaseFile db) {
-		Log.Info("Starting server on port " + port + "...");
-
-		void AddServices(IServiceCollection services) {
-			services.AddSingleton(typeof(IDatabaseFile), db);
-			services.AddSingleton(typeof(ServerParameters), new ServerParameters(port, token));
-		}
-
-		void SetKestrelOptions(KestrelServerOptions options) {
-			options.Limits.MaxRequestBodySize = null;
-			options.Limits.MinResponseDataRate = null;
-			options.ListenLocalhost(port, static listenOptions => listenOptions.Protocols = HttpProtocols.Http1);
-		}
-
-		Server = new WebHostBuilder()
-		         .ConfigureServices(AddServices)
-		         .UseKestrel(SetKestrelOptions)
-		         .UseStartup<Startup>()
-		         .Build();
-
-		Server.Start();
-
-		Log.Info("Server started");
-		IsRunning = true;
-		ServerStatusChanged?.Invoke(null, EventArgs.Empty);
-	}
-
-	private static void StopServerFromManagementThread() {
-		if (Server != null) {
-			Log.Info("Stopping server...");
-			Server.StopAsync().Wait();
-			Server.Dispose();
-			Server = null;
-
-			Log.Info("Server stopped");
-			IsRunning = false;
-			ServerStatusChanged?.Invoke(null, EventArgs.Empty);
-		}
-	}
-
-	public static void Relaunch(ushort port, string token, IDatabaseFile db) {
-		EnqueueMessage(new IMessage.StartServer(port, token, db));
-	}
-
-	public static void Stop() {
-		EnqueueMessage(new IMessage.StopServer());
-	}
-
-	private interface IMessage {
-		public sealed class StartServer : IMessage {
-			public ushort Port { get; }
-			public string Token { get; }
-			public IDatabaseFile Db { get; }
-
-			public StartServer(ushort port, string token, IDatabaseFile db) {
-				this.Port = port;
-				this.Token = token;
-				this.Db = db;
-			}
-		}
-
-		public sealed class StopServer : IMessage {}
-	}
-}

app/Server/Service/ServerManager.cs

@@ -0,0 +1,107 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using DHT.Server.Database;
+using DHT.Utils.Logging;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Server.Kestrel.Core;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace DHT.Server.Service;
+
+public sealed class ServerManager {
+	private static readonly Log Log = Log.ForType(typeof(ServerManager));
+
+	private IWebHost? server;
+	public bool IsRunning => server != null;
+	
+	public event EventHandler<Status>? StatusChanged;
+
+	public enum Status {
+		Starting,
+		Started,
+		Stopping,
+		Stopped
+	}
+
+	private readonly IDatabaseFile db;
+	private readonly SemaphoreSlim semaphore = new (1, 1);
+
+	internal ServerManager(IDatabaseFile db) {
+		this.db = db;
+	}
+
+	public async Task Start(ushort port, string token) {
+		await semaphore.WaitAsync();
+		try {
+			await StartInternal(port, token);
+		} finally {
+			semaphore.Release();
+		}
+	}
+
+	public async Task Stop() {
+		await semaphore.WaitAsync();
+		try {
+			await StopInternal();
+		} finally {
+			semaphore.Release();
+		}
+	}
+
+	private async Task StartInternal(ushort port, string token) {
+		await StopInternal();
+		
+		StatusChanged?.Invoke(this, Status.Starting);
+
+		void AddServices(IServiceCollection services) {
+			services.AddSingleton(typeof(IDatabaseFile), db);
+			services.AddSingleton(typeof(ServerParameters), new ServerParameters(port, token));
+		}
+
+		void SetKestrelOptions(KestrelServerOptions options) {
+			options.Limits.MaxRequestBodySize = null;
+			options.Limits.MinResponseDataRate = null;
+			options.ListenLocalhost(port, static listenOptions => listenOptions.Protocols = HttpProtocols.Http1);
+		}
+
+		var newServer = new WebHostBuilder()
+		                .ConfigureServices(AddServices)
+		                .UseKestrel(SetKestrelOptions)
+		                .UseStartup<Startup>()
+		                .Build();
+
+		Log.Info("Starting server on port " + port + "...");
+		
+		try {
+			await newServer.StartAsync();
+		} catch (Exception) {
+			Log.Error("Server could not start");
+			StatusChanged?.Invoke(this, Status.Stopped);
+			throw;
+		}
+
+		Log.Info("Server started");
+
+		server = newServer;
+		
+		StatusChanged?.Invoke(this, Status.Started);
+	}
+
+	private async Task StopInternal() {
+		if (server == null) {
+			return;
+		}
+
+		StatusChanged?.Invoke(this, Status.Stopping);
+		
+		Log.Info("Stopping server...");
+		await server.StopAsync();
+		Log.Info("Server stopped");
+
+		server.Dispose();
+		server = null;
+		
+		StatusChanged?.Invoke(this, Status.Stopped);
+	}
+}

app/Server/Service/ServerStartup.cs

@@ -16,7 +16,6 @@ sealed class Startup {
 		"https://ptb.discord.com",
 		"https://canary.discord.com",
 		"https://discordapp.com",
-		"null" // For file:// protocol in the Viewer
 	};
 
 	public void ConfigureServices(IServiceCollection services) {
@@ -42,7 +41,6 @@ sealed class Startup {
 		
 		app.UseEndpoints(endpoints => {
 			endpoints.MapGet("/get-tracking-script", new GetTrackingScriptEndpoint(db, parameters).Handle);
-			endpoints.MapGet("/get-messages", new GetMessagesEndpoint(db).Handle);
 			endpoints.MapGet("/get-attachment/{url}", new GetAttachmentEndpoint(db).Handle);
 			endpoints.MapPost("/track-channel", new TrackChannelEndpoint(db).Handle);
 			endpoints.MapPost("/track-users", new TrackUsersEndpoint(db).Handle);

app/Server/State.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Threading.Tasks;
+using DHT.Server.Database;
+using DHT.Server.Download;
+using DHT.Server.Service;
+
+namespace DHT.Server;
+
+public sealed class State : IAsyncDisposable {
+	public static State Dummy { get; } = new (DummyDatabaseFile.Instance);
+	
+	public IDatabaseFile Db { get; }
+	public Downloader Downloader { get; }
+	public ServerManager Server { get; }
+
+	public State(IDatabaseFile db) {
+		Db = db;
+		Downloader = new Downloader(db);
+		Server = new ServerManager(db);
+	}
+
+	public async ValueTask DisposeAsync() {
+		await Downloader.Stop();
+		await Server.Stop();
+		Db.Dispose();
+	}
+}

app/Utils/Http/HttpOutput.cs

@@ -1,5 +1,4 @@
 using System.Text;
-using System.Text.Json.Serialization.Metadata;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 
@@ -26,20 +25,6 @@ public static class HttpOutput {
 		}
 	}
 
-	public sealed class Json<TValue> : IHttpOutput {
-		private readonly TValue value;
-		private readonly JsonTypeInfo<TValue> typeInfo;
-
-		public Json(TValue value, JsonTypeInfo<TValue> typeInfo) {
-			this.value = value;
-			this.typeInfo = typeInfo;
-		}
-
-		public Task WriteTo(HttpResponse response) {
-			return response.WriteAsJsonAsync(value, typeInfo);
-		}
-	}
-
 	public sealed class File : IHttpOutput {
 		private readonly string? contentType;
 		private readonly byte[] bytes;

app/Utils/Tasks/TaskExtensions.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Threading.Tasks;
+
+namespace DHT.Utils.Tasks;
+
+public static class TaskExtensions {
+	public static async Task WaitIgnoringCancellation(this Task task) {
+		try {
+			await task;
+		} catch (OperationCanceledException) {}
+	}
+}