Discord-History-Tracker/app/Desktop/Main/Screens/WelcomeScreenModel.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using Avalonia.Controls;
using CommunityToolkit.Mvvm.ComponentModel;
using DHT.Desktop.Common;
using DHT.Desktop.Dialogs.Message;
using DHT.Desktop.Dialogs.Progress;
using DHT.Server.Data.Settings;
using DHT.Server.Database;
using DHT.Server.Database.Sqlite.Schema;

namespace DHT.Desktop.Main.Screens;

sealed partial class WelcomeScreenModel : ObservableObject {
	public string Version => Program.Version;
	
	[ObservableProperty(Setter = Access.Private)]
	private bool isOpenOrCreateDatabaseButtonEnabled = true;
	
	public event EventHandler<IDatabaseFile>? DatabaseSelected; 
	
	private readonly Window window;

	private string? dbFilePath;

	[Obsolete("Designer")]
	public WelcomeScreenModel() : this(null!) {}

	public WelcomeScreenModel(Window window) {
		this.window = window;
	}

	public async Task OpenOrCreateDatabase() {
		IsOpenOrCreateDatabaseButtonEnabled = false;
		try {
			var path = await DatabaseGui.NewOpenOrCreateDatabaseFileDialog(window, Path.GetDirectoryName(dbFilePath));
			if (path != null) {
				await OpenOrCreateDatabaseFromPath(path);
			}
		} finally {
			IsOpenOrCreateDatabaseButtonEnabled = true;
		}
	}

	public async Task OpenOrCreateDatabaseFromPath(string path) {
		dbFilePath = path;
		
		bool isNew = !File.Exists(path);
		
		var db = await DatabaseGui.TryOpenOrCreateDatabaseFromPath(path, window, new SchemaUpgradeCallbacks(window));
		if (db == null) {
			return;
		}
		
		if (isNew && await Dialog.ShowYesNo(window, "Automatic Downloads", "Do you want to automatically download files hosted on Discord? You can change this later in the Downloads tab.") == DialogResult.YesNo.Yes) {
			await db.Settings.Set(SettingsKey.DownloadsAutoStart, true);
		}
		
		DatabaseSelected?.Invoke(this, db);
	}

	private sealed class SchemaUpgradeCallbacks : ISchemaUpgradeCallbacks {
		private readonly Window window;
		
		public SchemaUpgradeCallbacks(Window window) {
			this.window = window;
		}

		public async Task<bool> CanUpgrade() {
			return DialogResult.YesNo.Yes == await DatabaseGui.ShowCanUpgradeDatabaseDialog(window);
		}

		public async Task Start(int versionSteps, Func<ISchemaUpgradeCallbacks.IProgressReporter, Task> doUpgrade) {
			async Task StartUpgrade(IReadOnlyList<IProgressCallback> callbacks) {
				var reporter = new ProgressReporter(versionSteps, callbacks);
				await reporter.NextVersion();
				await Task.Delay(TimeSpan.FromMilliseconds(800));
				await doUpgrade(reporter);
				await Task.Delay(TimeSpan.FromMilliseconds(600));
			}
			
			await new ProgressDialog { DataContext = new ProgressDialogModel("Upgrading Database", StartUpgrade, progressItems: 3) }.ShowProgressDialog(window);
		}

		private sealed class ProgressReporter : ISchemaUpgradeCallbacks.IProgressReporter {
			private readonly IReadOnlyList<IProgressCallback> callbacks;
			
			private readonly int versionSteps;
			private int versionProgress = 0;
			
			public ProgressReporter(int versionSteps, IReadOnlyList<IProgressCallback> callbacks) {
				this.callbacks = callbacks;
				this.versionSteps = versionSteps;
			}

			public async Task NextVersion() {
				await callbacks[0].Update("Upgrading schema version...", versionProgress++, versionSteps);
				await HideChildren(0);
			}

			public async Task MainWork(string message, int finishedItems, int totalItems) {
				await callbacks[1].Update(message, finishedItems, totalItems);
				await HideChildren(1);
			}

			public async Task SubWork(string message, int finishedItems, int totalItems) {
				await callbacks[2].Update(message, finishedItems, totalItems);
				await HideChildren(2);
			}

			private async Task HideChildren(int parentIndex) {
				for (int i = parentIndex + 1; i < callbacks.Count; i++) {
					await callbacks[i].Hide();
				}
			}
		}
	}

	public async Task ShowAboutDialog() {
		await new AboutWindow { DataContext = new AboutWindowModel() }.ShowDialog(window);
	}

	public void Exit() {
		window.Close();
	}
}