ArchiSteamFarm/ArchiSteamFarm/Core/ASF.cs

//     _                _      _  ____   _                           _____
//    / \    _ __  ___ | |__  (_)/ ___| | |_  ___   __ _  _ __ ___  |  ___|__ _  _ __  _ __ ___
//   / _ \  | '__|/ __|| '_ \ | |\___ \ | __|/ _ \ / _` || '_ ` _ \ | |_  / _` || '__|| '_ ` _ \
//  / ___ \ | |  | (__ | | | || | ___) || |_|  __/| (_| || | | | | ||  _|| (_| || |   | | | | | |
// /_/   \_\|_|   \___||_| |_||_||____/  \__|\___| \__,_||_| |_| |_||_|   \__,_||_|   |_| |_| |_|
// |
// Copyright 2015-2022 Łukasz "JustArchi" Domeradzki
// Contact: JustArchi@JustArchi.net
// |
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// |
// http://www.apache.org/licenses/LICENSE-2.0
// |
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Reflection;
using System.Security.Cryptography;
using System.Threading;
using System.Threading.Tasks;
using ArchiSteamFarm.Helpers;
using ArchiSteamFarm.IPC;
using ArchiSteamFarm.Localization;
using ArchiSteamFarm.NLog;
using ArchiSteamFarm.Plugins;
using ArchiSteamFarm.Steam;
using ArchiSteamFarm.Steam.Integration;
using ArchiSteamFarm.Storage;
using ArchiSteamFarm.Web;
using ArchiSteamFarm.Web.Responses;
using JetBrains.Annotations;
using SteamKit2;
using SteamKit2.Discovery;

namespace ArchiSteamFarm.Core;

public static class ASF {
	// This is based on internal Valve guidelines, we're not using it as a hard limit
	private const byte MaximumRecommendedBotsCount = 10;

	[PublicAPI]
	public static readonly ArchiLogger ArchiLogger = new(SharedInfo.ASF);

	[PublicAPI]
	public static byte LoadBalancingDelay => Math.Max(GlobalConfig?.LoginLimiterDelay ?? 0, GlobalConfig.DefaultLoginLimiterDelay);

	[PublicAPI]
	public static GlobalConfig? GlobalConfig { get; internal set; }

	[PublicAPI]
	public static GlobalDatabase? GlobalDatabase { get; internal set; }

	[PublicAPI]
	public static WebBrowser? WebBrowser { get; private set; }

	internal static readonly SemaphoreSlim OpenConnectionsSemaphore = new(WebBrowser.MaxConnections, WebBrowser.MaxConnections);

	internal static ICrossProcessSemaphore? ConfirmationsSemaphore { get; private set; }
	internal static ICrossProcessSemaphore? GiftsSemaphore { get; private set; }
	internal static ICrossProcessSemaphore? InventorySemaphore { get; private set; }
	internal static ICrossProcessSemaphore? LoginRateLimitingSemaphore { get; private set; }
	internal static ICrossProcessSemaphore? LoginSemaphore { get; private set; }
	internal static ICrossProcessSemaphore? RateLimitingSemaphore { get; private set; }
	internal static ImmutableDictionary<Uri, (ICrossProcessSemaphore RateLimitingSemaphore, SemaphoreSlim OpenConnectionsSemaphore)>? WebLimitingSemaphores { get; private set; }

	private static readonly ImmutableHashSet<string> AssembliesNeededBeforeUpdate = ImmutableHashSet.Create("System.IO.Pipes");
	private static readonly SemaphoreSlim UpdateSemaphore = new(1, 1);

	private static Timer? AutoUpdatesTimer;
	private static FileSystemWatcher? FileSystemWatcher;
	private static ConcurrentDictionary<string, object>? LastWriteEvents;

	[PublicAPI]
	public static bool IsOwner(ulong steamID) {
		if ((steamID == 0) || !new SteamID(steamID).IsIndividualAccount) {
			throw new ArgumentOutOfRangeException(nameof(steamID));
		}

		return (steamID == GlobalConfig?.SteamOwnerID) || (Debugging.IsDebugBuild && (steamID == SharedInfo.ArchiSteamID));
	}

	internal static string GetFilePath(EFileType fileType) {
		if (!Enum.IsDefined(fileType)) {
			throw new InvalidEnumArgumentException(nameof(fileType), (int) fileType, typeof(EFileType));
		}

		return fileType switch {
			EFileType.Config => Path.Combine(SharedInfo.ConfigDirectory, SharedInfo.GlobalConfigFileName),
			EFileType.Database => Path.Combine(SharedInfo.ConfigDirectory, SharedInfo.GlobalDatabaseFileName),
			_ => throw new ArgumentOutOfRangeException(nameof(fileType))
		};
	}

	internal static async Task Init() {
		if (GlobalConfig == null) {
			throw new InvalidOperationException(nameof(GlobalConfig));
		}

		if (!PluginsCore.InitPlugins()) {
			await Task.Delay(SharedInfo.InformationDelay).ConfigureAwait(false);
		}

		WebBrowser = new WebBrowser(ArchiLogger, GlobalConfig.WebProxy, true);

		await UpdateAndRestart().ConfigureAwait(false);

		await PluginsCore.OnASFInitModules(GlobalConfig.AdditionalProperties).ConfigureAwait(false);
		await InitRateLimiters().ConfigureAwait(false);

		StringComparer botsComparer = await PluginsCore.GetBotsComparer().ConfigureAwait(false);
		IMachineInfoProvider? customMachineInfoProvider = await PluginsCore.GetCustomMachineInfoProvider().ConfigureAwait(false);

		Bot.Init(botsComparer, customMachineInfoProvider);

		if (!Program.Service && !GlobalConfig.Headless && !Console.IsInputRedirected) {
			Logging.StartInteractiveConsole();
		}

		if (GlobalConfig.IPC) {
			await ArchiKestrel.Start().ConfigureAwait(false);
		}

		uint changeNumberToStartFrom = await PluginsCore.GetChangeNumberToStartFrom().ConfigureAwait(false);

		SteamPICSChanges.Init(changeNumberToStartFrom);

		await RegisterBots().ConfigureAwait(false);

		if (Program.ConfigWatch) {
			InitConfigWatchEvents();
		}
	}

	internal static bool IsValidBotName(string botName) {
		if (string.IsNullOrEmpty(botName)) {
			throw new ArgumentNullException(nameof(botName));
		}

		if (botName[0] == '.') {
			return false;
		}

		if (botName.Equals(SharedInfo.ASF, StringComparison.OrdinalIgnoreCase)) {
			return false;
		}

		return Path.GetRelativePath(".", botName) == botName;
	}

	internal static async Task RestartOrExit() {
		if (GlobalConfig == null) {
			throw new InvalidOperationException(nameof(GlobalConfig));
		}

		if (Program.RestartAllowed && GlobalConfig.AutoRestart) {
			ArchiLogger.LogGenericInfo(Strings.Restarting);
			await Task.Delay(SharedInfo.ShortInformationDelay).ConfigureAwait(false);
			await Program.Restart().ConfigureAwait(false);
		} else {
			ArchiLogger.LogGenericInfo(Strings.Exiting);
			await Task.Delay(SharedInfo.ShortInformationDelay).ConfigureAwait(false);
			await Program.Exit().ConfigureAwait(false);
		}
	}

	internal static async Task<Version?> Update(bool updateOverride = false) {
		if (GlobalConfig == null) {
			throw new InvalidOperationException(nameof(GlobalConfig));
		}

		if (WebBrowser == null) {
			throw new InvalidOperationException(nameof(WebBrowser));
		}

		if (!SharedInfo.BuildInfo.CanUpdate || (GlobalConfig.UpdateChannel == GlobalConfig.EUpdateChannel.None)) {
			return null;
		}

		await UpdateSemaphore.WaitAsync().ConfigureAwait(false);

		try {
			// If backup directory from previous update exists, it's a good idea to purge it now
			string backupDirectory = Path.Combine(SharedInfo.HomeDirectory, SharedInfo.UpdateDirectory);

			if (Directory.Exists(backupDirectory)) {
				ArchiLogger.LogGenericInfo(Strings.UpdateCleanup);

				// It's entirely possible that old process is still running, wait a short moment for eventual cleanup
				await Task.Delay(5000).ConfigureAwait(false);

				try {
					Directory.Delete(backupDirectory, true);
				} catch (Exception e) {
					ArchiLogger.LogGenericException(e);

					return null;
				}

				ArchiLogger.LogGenericInfo(Strings.Done);
			}

			ArchiLogger.LogGenericInfo(Strings.UpdateCheckingNewVersion);

			GitHub.ReleaseResponse? releaseResponse = await GitHub.GetLatestRelease(GlobalConfig.UpdateChannel == GlobalConfig.EUpdateChannel.Stable).ConfigureAwait(false);

			if (releaseResponse == null) {
				ArchiLogger.LogGenericWarning(Strings.ErrorUpdateCheckFailed);

				return null;
			}

			if (string.IsNullOrEmpty(releaseResponse.Tag)) {
				ArchiLogger.LogGenericWarning(Strings.ErrorUpdateCheckFailed);

				return null;
			}

			Version newVersion = new(releaseResponse.Tag);

			ArchiLogger.LogGenericInfo(string.Format(CultureInfo.CurrentCulture, Strings.UpdateVersionInfo, SharedInfo.Version, newVersion));

			if (SharedInfo.Version >= newVersion) {
				return newVersion;
			}

			if (!updateOverride && (GlobalConfig.UpdatePeriod == 0)) {
				ArchiLogger.LogGenericInfo(Strings.UpdateNewVersionAvailable);
				await Task.Delay(SharedInfo.ShortInformationDelay).ConfigureAwait(false);

				return null;
			}

			// Auto update logic starts here
			if (releaseResponse.Assets.IsEmpty) {
				ArchiLogger.LogGenericWarning(Strings.ErrorUpdateNoAssets);

				return null;
			}

			string targetFile = $"{SharedInfo.ASF}-{SharedInfo.BuildInfo.Variant}.zip";
			GitHub.ReleaseResponse.Asset? binaryAsset = releaseResponse.Assets.FirstOrDefault(asset => !string.IsNullOrEmpty(asset.Name) && asset.Name!.Equals(targetFile, StringComparison.OrdinalIgnoreCase));

			if (binaryAsset == null) {
				ArchiLogger.LogGenericWarning(Strings.ErrorUpdateNoAssetForThisVersion);

				return null;
			}

			if (binaryAsset.DownloadURL == null) {
				ArchiLogger.LogNullError(binaryAsset.DownloadURL);

				return null;
			}

			ArchiLogger.LogGenericInfo(Strings.FetchingChecksumFromRemoteServer);

			string? remoteChecksum = await ArchiNet.FetchBuildChecksum(newVersion, SharedInfo.BuildInfo.Variant).ConfigureAwait(false);

			switch (remoteChecksum) {
				case null:
					// Timeout or error, refuse to update as a security measure
					return null;
				case "":
					// Unknown checksum, release too new or actual malicious build published, no need to scare the user as it's 99.99% the first
					ArchiLogger.LogGenericWarning(Strings.ChecksumMissing);

					return SharedInfo.Version;
			}

			if (!string.IsNullOrEmpty(releaseResponse.ChangelogPlainText)) {
				ArchiLogger.LogGenericInfo(releaseResponse.ChangelogPlainText!);
			}

			ArchiLogger.LogGenericInfo(string.Format(CultureInfo.CurrentCulture, Strings.UpdateDownloadingNewVersion, newVersion, binaryAsset.Size / 1024 / 1024));

			Progress<byte> progressReporter = new();

			progressReporter.ProgressChanged += OnProgressChanged;

			BinaryResponse? response;

			try {
				response = await WebBrowser.UrlGetToBinary(binaryAsset.DownloadURL!, progressReporter: progressReporter).ConfigureAwait(false);
			} finally {
				progressReporter.ProgressChanged -= OnProgressChanged;
			}

			if (response?.Content == null) {
				return null;
			}

			ArchiLogger.LogGenericInfo(Strings.VerifyingChecksumWithRemoteServer);

			byte[] responseBytes = response.Content as byte[] ?? response.Content.ToArray();

			string checksum = Convert.ToHexString(SHA512.HashData(responseBytes));

			if (!checksum.Equals(remoteChecksum, StringComparison.OrdinalIgnoreCase)) {
				ArchiLogger.LogGenericError(Strings.ChecksumWrong);

				return SharedInfo.Version;
			}

			await PluginsCore.OnUpdateProceeding(newVersion).ConfigureAwait(false);

			bool kestrelWasRunning = ArchiKestrel.IsRunning;

			if (kestrelWasRunning) {
				// We disable ArchiKestrel here as the update process moves the core files and might result in IPC crash
				// TODO: It might fail if the update was triggered from the API, this should be something to improve in the future, by changing the structure into request -> return response -> finish update
				try {
					await ArchiKestrel.Stop().ConfigureAwait(false);
				} catch (Exception e) {
					ArchiLogger.LogGenericWarningException(e);
				}
			}

			ArchiLogger.LogGenericInfo(Strings.PatchingFiles);

			MemoryStream ms = new(responseBytes);

			try {
				await using (ms.ConfigureAwait(false)) {
					using ZipArchive zipArchive = new(ms);

					if (!UpdateFromArchive(zipArchive, SharedInfo.HomeDirectory)) {
						ArchiLogger.LogGenericError(Strings.WarningFailed);
					}
				}
			} catch (Exception e) {
				ArchiLogger.LogGenericException(e);

				if (kestrelWasRunning) {
					// We've temporarily disabled ArchiKestrel but the update has failed, let's bring it back up
					// We can't even be sure if it's possible to bring it back up in this state, but it's worth trying anyway
					try {
						await ArchiKestrel.Start().ConfigureAwait(false);
					} catch (Exception ex) {
						ArchiLogger.LogGenericWarningException(ex);
					}
				}

				return null;
			}

			ArchiLogger.LogGenericInfo(Strings.UpdateFinished);

			await PluginsCore.OnUpdateFinished(newVersion).ConfigureAwait(false);

			return newVersion;
		} finally {
			UpdateSemaphore.Release();
		}
	}

	private static async Task<bool> CanHandleWriteEvent(string filePath) {
		if (string.IsNullOrEmpty(filePath)) {
			throw new ArgumentNullException(nameof(filePath));
		}

		if (LastWriteEvents == null) {
			throw new InvalidOperationException(nameof(LastWriteEvents));
		}

		// Save our event in dictionary
		object currentWriteEvent = new();
		LastWriteEvents[filePath] = currentWriteEvent;

		// Wait a second for eventual other events to arrive
		await Task.Delay(1000).ConfigureAwait(false);

		// We're allowed to handle this event if the one that is saved after full second is our event and we succeed in clearing it (we don't care what we're clearing anymore, it doesn't have to be atomic operation)
		return LastWriteEvents.TryGetValue(filePath, out object? savedWriteEvent) && (currentWriteEvent == savedWriteEvent) && LastWriteEvents.TryRemove(filePath, out _);
	}

	private static HashSet<string> GetLoadedAssembliesNames() {
		Assembly[] loadedAssemblies = AppDomain.CurrentDomain.GetAssemblies();

		// ReSharper disable once RedundantSuppressNullableWarningExpression - required for .NET Framework
		return loadedAssemblies.Select(static loadedAssembly => loadedAssembly.FullName).Where(static name => !string.IsNullOrEmpty(name)).ToHashSet(StringComparer.Ordinal)!;
	}

	private static void InitConfigWatchEvents() {
		if ((FileSystemWatcher != null) || (LastWriteEvents != null)) {
			return;
		}

		if (Bot.BotsComparer == null) {
			throw new InvalidOperationException(nameof(Bot.BotsComparer));
		}

		FileSystemWatcher = new FileSystemWatcher(SharedInfo.ConfigDirectory) { NotifyFilter = NotifyFilters.FileName | NotifyFilters.LastWrite };

		FileSystemWatcher.Changed += OnChanged;
		FileSystemWatcher.Created += OnCreated;
		FileSystemWatcher.Deleted += OnDeleted;
		FileSystemWatcher.Renamed += OnRenamed;

		LastWriteEvents = new ConcurrentDictionary<string, object>(Bot.BotsComparer);

		FileSystemWatcher.EnableRaisingEvents = true;
	}

	private static async Task InitRateLimiters() {
		ConfirmationsSemaphore ??= await PluginsCore.GetCrossProcessSemaphore(nameof(ConfirmationsSemaphore)).ConfigureAwait(false);
		GiftsSemaphore ??= await PluginsCore.GetCrossProcessSemaphore(nameof(GiftsSemaphore)).ConfigureAwait(false);
		InventorySemaphore ??= await PluginsCore.GetCrossProcessSemaphore(nameof(InventorySemaphore)).ConfigureAwait(false);
		LoginRateLimitingSemaphore ??= await PluginsCore.GetCrossProcessSemaphore(nameof(LoginRateLimitingSemaphore)).ConfigureAwait(false);
		LoginSemaphore ??= await PluginsCore.GetCrossProcessSemaphore(nameof(LoginSemaphore)).ConfigureAwait(false);
		RateLimitingSemaphore ??= await PluginsCore.GetCrossProcessSemaphore(nameof(RateLimitingSemaphore)).ConfigureAwait(false);

		WebLimitingSemaphores ??= new Dictionary<Uri, (ICrossProcessSemaphore RateLimitingSemaphore, SemaphoreSlim OpenConnectionsSemaphore)>(4) {
			{ ArchiWebHandler.SteamCommunityURL, (await PluginsCore.GetCrossProcessSemaphore($"{nameof(ArchiWebHandler)}-{nameof(ArchiWebHandler.SteamCommunityURL)}").ConfigureAwait(false), new SemaphoreSlim(WebBrowser.MaxConnections, WebBrowser.MaxConnections)) },
			{ ArchiWebHandler.SteamHelpURL, (await PluginsCore.GetCrossProcessSemaphore($"{nameof(ArchiWebHandler)}-{nameof(ArchiWebHandler.SteamHelpURL)}").ConfigureAwait(false), new SemaphoreSlim(WebBrowser.MaxConnections, WebBrowser.MaxConnections)) },
			{ ArchiWebHandler.SteamStoreURL, (await PluginsCore.GetCrossProcessSemaphore($"{nameof(ArchiWebHandler)}-{nameof(ArchiWebHandler.SteamStoreURL)}").ConfigureAwait(false), new SemaphoreSlim(WebBrowser.MaxConnections, WebBrowser.MaxConnections)) },
			{ WebAPI.DefaultBaseAddress, (await PluginsCore.GetCrossProcessSemaphore($"{nameof(ArchiWebHandler)}-{nameof(WebAPI)}").ConfigureAwait(false), new SemaphoreSlim(WebBrowser.MaxConnections, WebBrowser.MaxConnections)) }
		}.ToImmutableDictionary();
	}

	private static void LoadAllAssemblies() {
		HashSet<string> loadedAssembliesNames = GetLoadedAssembliesNames();

		LoadAssembliesRecursively(Assembly.GetExecutingAssembly(), loadedAssembliesNames);
	}

	private static void LoadAssembliesNeededBeforeUpdate() {
		HashSet<string> loadedAssembliesNames = GetLoadedAssembliesNames();

		foreach (string assemblyName in AssembliesNeededBeforeUpdate.Where(loadedAssembliesNames.Add)) {
			Assembly assembly;

			try {
				assembly = Assembly.Load(assemblyName);
			} catch (Exception e) {
				ArchiLogger.LogGenericDebuggingException(e);

				continue;
			}

			LoadAssembliesRecursively(assembly, loadedAssembliesNames);
		}
	}

	[UnconditionalSuppressMessage("AssemblyLoadTrimming", "IL2026:RequiresUnreferencedCode", Justification = "We don't care about trimmed assemblies, as we need it to work only with the known (used) ones")]
	private static void LoadAssembliesRecursively(Assembly assembly, ISet<string> loadedAssembliesNames) {
		ArgumentNullException.ThrowIfNull(assembly);

		if ((loadedAssembliesNames == null) || (loadedAssembliesNames.Count == 0)) {
			throw new ArgumentNullException(nameof(loadedAssembliesNames));
		}

		foreach (AssemblyName assemblyName in assembly.GetReferencedAssemblies().Where(assemblyName => loadedAssembliesNames.Add(assemblyName.FullName))) {
			Assembly loadedAssembly;

			try {
				loadedAssembly = Assembly.Load(assemblyName);
			} catch (Exception e) {
				ArchiLogger.LogGenericDebuggingException(e);

				continue;
			}

			LoadAssembliesRecursively(loadedAssembly, loadedAssembliesNames);
		}
	}

	private static async void OnAutoUpdatesTimer(object? state = null) => await UpdateAndRestart().ConfigureAwait(false);

	private static async void OnChanged(object sender, FileSystemEventArgs e) {
		ArgumentNullException.ThrowIfNull(sender);
		ArgumentNullException.ThrowIfNull(e);

		if (string.IsNullOrEmpty(e.Name)) {
			throw new InvalidOperationException(nameof(e.Name));
		}

		if (string.IsNullOrEmpty(e.FullPath)) {
			throw new InvalidOperationException(nameof(e.FullPath));
		}

		await OnChangedFile(e.Name, e.FullPath).ConfigureAwait(false);
	}

	private static async Task OnChangedConfigFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		await OnCreatedConfigFile(name, fullPath).ConfigureAwait(false);
	}

	private static async Task OnChangedConfigFile(string name) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (!name.Equals(SharedInfo.IPCConfigFile, StringComparison.OrdinalIgnoreCase) || (GlobalConfig?.IPC != true)) {
			return;
		}

		if (!await CanHandleWriteEvent(name).ConfigureAwait(false)) {
			return;
		}

		ArchiLogger.LogGenericInfo(Strings.IPCConfigChanged);
		await ArchiKestrel.Stop().ConfigureAwait(false);
		await ArchiKestrel.Start().ConfigureAwait(false);
	}

	private static async Task OnChangedFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		string extension = Path.GetExtension(name);

		switch (extension) {
			case SharedInfo.JsonConfigExtension:
			case SharedInfo.IPCConfigExtension:
				await OnChangedConfigFile(name, fullPath).ConfigureAwait(false);

				break;
			case SharedInfo.KeysExtension:
				await OnChangedKeysFile(name, fullPath).ConfigureAwait(false);

				break;
		}
	}

	private static async Task OnChangedKeysFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		await OnCreatedKeysFile(name, fullPath).ConfigureAwait(false);
	}

	private static async void OnCreated(object sender, FileSystemEventArgs e) {
		ArgumentNullException.ThrowIfNull(sender);
		ArgumentNullException.ThrowIfNull(e);

		if (string.IsNullOrEmpty(e.Name)) {
			throw new InvalidOperationException(nameof(e.Name));
		}

		if (string.IsNullOrEmpty(e.FullPath)) {
			throw new InvalidOperationException(nameof(e.FullPath));
		}

		await OnCreatedFile(e.Name, e.FullPath).ConfigureAwait(false);
	}

	private static async Task OnCreatedConfigFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		string extension = Path.GetExtension(name);

		switch (extension) {
			case SharedInfo.IPCConfigExtension:
				await OnChangedConfigFile(name).ConfigureAwait(false);

				break;
			case SharedInfo.JsonConfigExtension:
				await OnCreatedJsonFile(name, fullPath).ConfigureAwait(false);

				break;
		}
	}

	private static async Task OnCreatedFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		string extension = Path.GetExtension(name);

		switch (extension) {
			case SharedInfo.JsonConfigExtension:
				await OnCreatedConfigFile(name, fullPath).ConfigureAwait(false);

				break;

			case SharedInfo.KeysExtension:
				await OnCreatedKeysFile(name, fullPath).ConfigureAwait(false);

				break;
		}
	}

	private static async Task OnCreatedJsonFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		if (Bot.Bots == null) {
			throw new InvalidOperationException(nameof(Bot.Bots));
		}

		string botName = Path.GetFileNameWithoutExtension(name);

		if (string.IsNullOrEmpty(botName) || (botName[0] == '.')) {
			return;
		}

		if (!await CanHandleWriteEvent(fullPath).ConfigureAwait(false)) {
			return;
		}

		if (botName.Equals(SharedInfo.ASF, StringComparison.OrdinalIgnoreCase)) {
			ArchiLogger.LogGenericInfo(Strings.GlobalConfigChanged);
			await RestartOrExit().ConfigureAwait(false);

			return;
		}

		if (!IsValidBotName(botName)) {
			return;
		}

		if (Bot.Bots.TryGetValue(botName, out Bot? bot)) {
			await bot.OnConfigChanged(false).ConfigureAwait(false);
		} else {
			await Bot.RegisterBot(botName).ConfigureAwait(false);

			if (Bot.Bots.Count > MaximumRecommendedBotsCount) {
				ArchiLogger.LogGenericWarning(string.Format(CultureInfo.CurrentCulture, Strings.WarningExcessiveBotsCount, MaximumRecommendedBotsCount));
			}
		}
	}

	private static async Task OnCreatedKeysFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		if (Bot.Bots == null) {
			throw new InvalidOperationException(nameof(Bot.Bots));
		}

		string botName = Path.GetFileNameWithoutExtension(name);

		if (string.IsNullOrEmpty(botName) || (botName[0] == '.')) {
			return;
		}

		if (!await CanHandleWriteEvent(fullPath).ConfigureAwait(false)) {
			return;
		}

		if (!Bot.Bots.TryGetValue(botName, out Bot? bot)) {
			return;
		}

		await bot.ImportKeysToRedeem(fullPath).ConfigureAwait(false);
	}

	private static async void OnDeleted(object sender, FileSystemEventArgs e) {
		ArgumentNullException.ThrowIfNull(sender);
		ArgumentNullException.ThrowIfNull(e);

		if (string.IsNullOrEmpty(e.Name)) {
			throw new InvalidOperationException(nameof(e.Name));
		}

		if (string.IsNullOrEmpty(e.FullPath)) {
			throw new InvalidOperationException(nameof(e.FullPath));
		}

		await OnDeletedFile(e.Name, e.FullPath).ConfigureAwait(false);
	}

	private static async Task OnDeletedConfigFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		string extension = Path.GetExtension(name);

		switch (extension) {
			case SharedInfo.IPCConfigExtension:
				await OnChangedConfigFile(name).ConfigureAwait(false);

				break;
			case SharedInfo.JsonConfigExtension:
				await OnDeletedJsonConfigFile(name, fullPath).ConfigureAwait(false);

				break;
		}
	}

	private static async Task OnDeletedFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		string extension = Path.GetExtension(name);

		switch (extension) {
			case SharedInfo.JsonConfigExtension:
			case SharedInfo.IPCConfigExtension:
				await OnDeletedConfigFile(name, fullPath).ConfigureAwait(false);

				break;
		}
	}

	private static async Task OnDeletedJsonConfigFile(string name, string fullPath) {
		if (string.IsNullOrEmpty(name)) {
			throw new ArgumentNullException(nameof(name));
		}

		if (string.IsNullOrEmpty(fullPath)) {
			throw new ArgumentNullException(nameof(fullPath));
		}

		if (Bot.Bots == null) {
			throw new InvalidOperationException(nameof(Bot.Bots));
		}

		string botName = Path.GetFileNameWithoutExtension(name);

		if (string.IsNullOrEmpty(botName)) {
			return;
		}

		if (!await CanHandleWriteEvent(fullPath).ConfigureAwait(false)) {
			return;
		}

		if (botName.Equals(SharedInfo.ASF, StringComparison.OrdinalIgnoreCase)) {
			if (File.Exists(fullPath)) {
				return;
			}

			// Some editors might decide to delete file and re-create it in order to modify it
			// If that's the case, we wait for maximum of 5 seconds before shutting down
			await Task.Delay(5000).ConfigureAwait(false);

			if (File.Exists(fullPath)) {
				return;
			}

			ArchiLogger.LogGenericError(Strings.ErrorGlobalConfigRemoved);
			await Program.Exit(1).ConfigureAwait(false);

			return;
		}

		if (!IsValidBotName(botName)) {
			return;
		}

		if (Bot.Bots.TryGetValue(botName, out Bot? bot)) {
			await bot.OnConfigChanged(true).ConfigureAwait(false);
		}
	}

	private static void OnProgressChanged(object? sender, byte progressPercentage) {
		const byte printEveryPercentage = 10;

		if (progressPercentage % printEveryPercentage != 0) {
			return;
		}

		ArchiLogger.LogGenericDebug($"{progressPercentage}%...");
	}

	private static async void OnRenamed(object sender, RenamedEventArgs e) {
		// This function can be called with a possibility of OldName or (new) Name being null, we have to take it into account
		ArgumentNullException.ThrowIfNull(sender);
		ArgumentNullException.ThrowIfNull(e);

		if (!string.IsNullOrEmpty(e.OldName) && !string.IsNullOrEmpty(e.OldFullPath)) {
			await OnDeletedFile(e.OldName, e.OldFullPath).ConfigureAwait(false);
		}

		if (!string.IsNullOrEmpty(e.Name) && !string.IsNullOrEmpty(e.FullPath)) {
			await OnCreatedFile(e.Name, e.FullPath).ConfigureAwait(false);
		}
	}

	private static async Task RegisterBots() {
		if ((GlobalConfig == null) || (GlobalDatabase == null) || (WebBrowser == null)) {
			throw new InvalidOperationException($"{nameof(GlobalConfig)} || {nameof(GlobalDatabase)} || {nameof(WebBrowser)}");
		}

		// Ensure that we ask for a list of servers if we don't have any saved servers available
		IEnumerable<ServerRecord> servers = await GlobalDatabase.ServerListProvider.FetchServerListAsync().ConfigureAwait(false);

		if (!servers.Any()) {
			ArchiLogger.LogGenericInfo(string.Format(CultureInfo.CurrentCulture, Strings.Initializing, nameof(SteamDirectory)));

			SteamConfiguration steamConfiguration = SteamConfiguration.Create(static builder => builder.WithProtocolTypes(GlobalConfig.SteamProtocols).WithCellID(GlobalDatabase.CellID).WithServerListProvider(GlobalDatabase.ServerListProvider).WithHttpClientFactory(static () => WebBrowser.GenerateDisposableHttpClient()));

			try {
				await SteamDirectory.LoadAsync(steamConfiguration).ConfigureAwait(false);
				ArchiLogger.LogGenericInfo(Strings.Success);
			} catch (Exception e) {
				ArchiLogger.LogGenericWarningException(e);
				ArchiLogger.LogGenericWarning(Strings.BotSteamDirectoryInitializationFailed);
			}
		}

		HashSet<string> botNames;

		try {
			botNames = Directory.EnumerateFiles(SharedInfo.ConfigDirectory, $"*{SharedInfo.JsonConfigExtension}").Select(Path.GetFileNameWithoutExtension).Where(static botName => !string.IsNullOrEmpty(botName) && IsValidBotName(botName)).ToHashSet(Bot.BotsComparer)!;
		} catch (Exception e) {
			ArchiLogger.LogGenericException(e);

			return;
		}

		switch (botNames.Count) {
			case 0:
				ArchiLogger.LogGenericWarning(Strings.ErrorNoBotsDefined);

				return;
			case > MaximumRecommendedBotsCount:
				ArchiLogger.LogGenericWarning(string.Format(CultureInfo.CurrentCulture, Strings.WarningExcessiveBotsCount, MaximumRecommendedBotsCount));
				await Task.Delay(SharedInfo.InformationDelay).ConfigureAwait(false);

				break;
		}

		await Utilities.InParallel(botNames.OrderBy(static botName => botName, Bot.BotsComparer).Select(Bot.RegisterBot)).ConfigureAwait(false);
	}

	private static async Task UpdateAndRestart() {
		if (GlobalConfig == null) {
			throw new InvalidOperationException(nameof(GlobalConfig));
		}

		if (!SharedInfo.BuildInfo.CanUpdate || (GlobalConfig.UpdateChannel == GlobalConfig.EUpdateChannel.None)) {
			return;
		}

		if ((AutoUpdatesTimer == null) && (GlobalConfig.UpdatePeriod > 0)) {
			TimeSpan autoUpdatePeriod = TimeSpan.FromHours(GlobalConfig.UpdatePeriod);

			AutoUpdatesTimer = new Timer(
				OnAutoUpdatesTimer,
				null,
				autoUpdatePeriod, // Delay
				autoUpdatePeriod // Period
			);

			ArchiLogger.LogGenericInfo(string.Format(CultureInfo.CurrentCulture, Strings.AutoUpdateCheckInfo, autoUpdatePeriod.ToHumanReadable()));
		}

		Version? newVersion = await Update().ConfigureAwait(false);

		if (newVersion == null) {
			return;
		}

		if (SharedInfo.Version >= newVersion) {
			if (SharedInfo.Version > newVersion) {
				ArchiLogger.LogGenericWarning(Strings.WarningPreReleaseVersion);
				await Task.Delay(SharedInfo.InformationDelay).ConfigureAwait(false);
			}

			return;
		}

		await RestartOrExit().ConfigureAwait(false);
	}

	private static bool UpdateFromArchive(ZipArchive archive, string targetDirectory) {
		ArgumentNullException.ThrowIfNull(archive);

		if (string.IsNullOrEmpty(targetDirectory)) {
			throw new ArgumentNullException(nameof(targetDirectory));
		}

		if (SharedInfo.HomeDirectory == AppContext.BaseDirectory) {
			// We're running a build that includes our dependencies in ASF's home
			// Before actually moving files in update procedure, let's minimize the risk of some assembly not being loaded that we may need in the process
			LoadAllAssemblies();
		} else {
			// This is a tricky one, for some reason we might need to preload some selected assemblies even in OS-specific builds that normally should be self-contained...
			// It's as if the executable file was directly mapped to memory and moving it out of the original path caused the whole thing to crash
			// TODO: This is a total hack, I wish we could get to the bottom of this hole and find out what is really going on there in regards to the above
			LoadAssembliesNeededBeforeUpdate();
		}

		// Firstly we'll move all our existing files to a backup directory
		string backupDirectory = Path.Combine(targetDirectory, SharedInfo.UpdateDirectory);

		foreach (string file in Directory.EnumerateFiles(targetDirectory, "*", SearchOption.AllDirectories)) {
			string fileName = Path.GetFileName(file);

			if (string.IsNullOrEmpty(fileName)) {
				ArchiLogger.LogNullError(fileName);

				return false;
			}

			string relativeFilePath = Path.GetRelativePath(targetDirectory, file);

			if (string.IsNullOrEmpty(relativeFilePath)) {
				ArchiLogger.LogNullError(relativeFilePath);

				return false;
			}

			string? relativeDirectoryName = Path.GetDirectoryName(relativeFilePath);

			switch (relativeDirectoryName) {
				case null:
					ArchiLogger.LogNullError(relativeDirectoryName);

					return false;
				case "":
					// No directory, root folder
					switch (fileName) {
						case Logging.NLogConfigurationFile:
						case SharedInfo.LogFile:
							// Files with those names in root directory we want to keep
							continue;
					}

					break;
				case SharedInfo.ArchivalLogsDirectory:
				case SharedInfo.ConfigDirectory:
				case SharedInfo.DebugDirectory:
				case SharedInfo.PluginsDirectory:
				case SharedInfo.UpdateDirectory:
					// Files in those directories we want to keep in their current place
					continue;
				default:
					// Files in subdirectories of those directories we want to keep as well
					if (Utilities.RelativeDirectoryStartsWith(relativeDirectoryName, SharedInfo.ArchivalLogsDirectory, SharedInfo.ConfigDirectory, SharedInfo.DebugDirectory, SharedInfo.PluginsDirectory, SharedInfo.UpdateDirectory)) {
						continue;
					}

					break;
			}

			string targetBackupDirectory = relativeDirectoryName.Length > 0 ? Path.Combine(backupDirectory, relativeDirectoryName) : backupDirectory;
			Directory.CreateDirectory(targetBackupDirectory);

			string targetBackupFile = Path.Combine(targetBackupDirectory, fileName);

			File.Move(file, targetBackupFile, true);
		}

		// We can now get rid of directories that are empty
		Utilities.DeleteEmptyDirectoriesRecursively(targetDirectory);

		if (!Directory.Exists(targetDirectory)) {
			Directory.CreateDirectory(targetDirectory);
		}

		// Now enumerate over files in the zip archive, skip directory entries that we're not interested in (we can create them ourselves if needed)
		foreach (ZipArchiveEntry zipFile in archive.Entries.Where(static zipFile => !string.IsNullOrEmpty(zipFile.Name))) {
			string file = Path.GetFullPath(Path.Combine(targetDirectory, zipFile.FullName));

			if (!file.StartsWith(targetDirectory, StringComparison.Ordinal)) {
				throw new InvalidOperationException(nameof(file));
			}

			if (File.Exists(file)) {
				// This is possible only with files that we decided to leave in place during our backup function
				string targetBackupFile = $"{file}.bak";

				File.Move(file, targetBackupFile, true);
			}

			// Check if this file requires its own folder
			if (zipFile.Name != zipFile.FullName) {
				string? directory = Path.GetDirectoryName(file);

				if (string.IsNullOrEmpty(directory)) {
					ArchiLogger.LogNullError(directory);

					return false;
				}

				if (!Directory.Exists(directory)) {
					// ReSharper disable once RedundantSuppressNullableWarningExpression - required for .NET Framework
					Directory.CreateDirectory(directory!);
				}

				// We're not interested in extracting placeholder files (but we still want directories created for them, done above)
				switch (zipFile.Name) {
					case ".gitkeep":
						continue;
				}
			}

			zipFile.ExtractToFile(file);
		}

		return true;
	}

	[PublicAPI]
	public enum EUserInputType : byte {
		None,
		Login,
		Password,
		SteamGuard,
		SteamParentalCode,
		TwoFactorAuthentication,
		Cryptkey
	}

	internal enum EFileType : byte {
		Config,
		Database
	}
}