using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using CompatBot.Commands;
using CompatBot.Commands.Converters;
using CompatBot.Database;
using CompatBot.Database.Providers;
using CompatBot.EventHandlers;
using CompatBot.ThumbScrapper;
using CompatBot.Utils;
using DSharpPlus;
using DSharpPlus.CommandsNext;
using DSharpPlus.Entities;
using DSharpPlus.Interactivity;
using Microsoft.Extensions.Configuration.UserSecrets;
using Microsoft.Extensions.DependencyInjection;

namespace CompatBot
{
    internal static class Program
    {
        private static readonly SemaphoreSlim InstanceCheck = new SemaphoreSlim(0, 1);
        private static readonly SemaphoreSlim ShutdownCheck = new SemaphoreSlim(0, 1);
        // pre-load the assembly so it won't fail after framework update while the process is still running
        private static readonly Assembly diagnosticsAssembly = Assembly.Load(typeof(Process).Assembly.GetName());
        internal const ulong InvalidChannelId = 13;

        internal static async Task Main(string[] args)
        {
            Config.TelemetryClient?.TrackEvent("startup");

            Console.WriteLine("Confinement: " + SandboxDetector.Detect());
            if (args.Length > 0 && args[0] == "--dry-run")
            {
                Console.WriteLine("Database path: " + Path.GetDirectoryName(Path.GetFullPath(DbImporter.GetDbPath("fake.db", Environment.SpecialFolder.ApplicationData))));
                if (Assembly.GetEntryAssembly().GetCustomAttribute<UserSecretsIdAttribute>() != null)
                    Console.WriteLine("Bot config path: " + Path.GetDirectoryName(Path.GetFullPath(Config.GoogleApiConfigPath)));
                return;
            }

            if (Process.GetCurrentProcess().Id == 0)
                Config.Log.Info("Well, this was unexpected");
            var singleInstanceCheckThread = new Thread(() =>
            {
                using var instanceLock = new Mutex(false, @"Global\RPCS3 Compatibility Bot");
                if (instanceLock.WaitOne(1000))
                    try
                    {
                        InstanceCheck.Release();
                        ShutdownCheck.Wait();
                    }
                    finally
                    {
                        instanceLock.ReleaseMutex();
                    }
            });
            try
            {
                singleInstanceCheckThread.Start();
                if (!await InstanceCheck.WaitAsync(1000).ConfigureAwait(false))
                {
                    Config.Log.Fatal("Another instance is already running.");
                    return;
                }

                if (string.IsNullOrEmpty(Config.Token) || Config.Token.Length < 16)
                {
                    Config.Log.Fatal("No token was specified.");
                    return;
                }

                if (SandboxDetector.Detect() == SandboxType.Docker)
                {
                    Config.Log.Info("Checking for updates...");
                    try
                    {
                        var (updated, stdout) = await Sudo.Bot.UpdateAsync().ConfigureAwait(false);
                        if (!string.IsNullOrEmpty(stdout) && updated)
                            Config.Log.Debug(stdout);
                        if (updated)
                        {
                            Sudo.Bot.Restart(InvalidChannelId, "Restarted due to new bot updates not present in this Docker image");
                            return;
                        }
                    }
                    catch (Exception e)
                    {
                        Config.Log.Error(e, "Failed to check for updates");
                    }
                }

                using (var db = new BotDb())
                    if (!await DbImporter.UpgradeAsync(db, Config.Cts.Token))
                        return;

                using (var db = new ThumbnailDb())
                    if (!await DbImporter.UpgradeAsync(db, Config.Cts.Token))
                        return;

                await SqlConfiguration.RestoreAsync().ConfigureAwait(false);
                Config.Log.Debug("Restored configuration variables from persistent storage");

                await StatsStorage.RestoreAsync().ConfigureAwait(false);
                Config.Log.Debug("Restored stats from persistent storage");

                var backgroundTasks = Task.WhenAll(
                    AmdDriverVersionProvider.RefreshAsync(),
#if !DEBUG
                    new PsnScraper().RunAsync(Config.Cts.Token),
                    GameTdbScraper.RunAsync(Config.Cts.Token),
#endif
                    StatsStorage.BackgroundSaveAsync(),
                    MediaScreenshotMonitor.ProcessWorkQueue(),
                    CompatList.ImportCompatListAsync()
                );

                try
                {
                    if (!Directory.Exists(Config.IrdCachePath))
                        Directory.CreateDirectory(Config.IrdCachePath);
                }
                catch (Exception e)
                {
                    Config.Log.Warn(e, $"Failed to create new folder {Config.IrdCachePath}: {e.Message}");
                }

                var config = new DiscordConfiguration
                {
                    Token = Config.Token,
                    TokenType = TokenType.Bot,
                    MessageCacheSize = Config.MessageCacheSize,
                    LoggerFactory = Config.LoggerFactory,
                };
                using var client = new DiscordClient(config);
                var commands = client.UseCommandsNext(new CommandsNextConfiguration
                {
                    StringPrefixes = new[] {Config.CommandPrefix, Config.AutoRemoveCommandPrefix},
                    Services = new ServiceCollection().BuildServiceProvider(),
                });
                commands.RegisterConverter(new TextOnlyDiscordChannelConverter());
                commands.RegisterCommands<Misc>();
                commands.RegisterCommands<CompatList>();
                commands.RegisterCommands<Sudo>();
                commands.RegisterCommands<CommandsManagement>();
                commands.RegisterCommands<ContentFilters>();
                commands.RegisterCommands<Warnings>();
                commands.RegisterCommands<Explain>();
                commands.RegisterCommands<Psn>();
                commands.RegisterCommands<Invites>();
                commands.RegisterCommands<Moderation>();
                commands.RegisterCommands<Ird>();
                commands.RegisterCommands<BotMath>();
                commands.RegisterCommands<Pr>();
                commands.RegisterCommands<Events>();
                commands.RegisterCommands<E3>();
                commands.RegisterCommands<Cyberpunk2077>();
                commands.RegisterCommands<Rpcs3Ama>();
                commands.RegisterCommands<BotStats>();
                commands.RegisterCommands<Syscall>();
                commands.RegisterCommands<ForcedNicknames>();
                commands.RegisterCommands<Minesweeper>();

                if (!string.IsNullOrEmpty(Config.AzureComputerVisionKey))
                    commands.RegisterCommands<Vision>();

                commands.CommandErrored += UnknownCommandHandler.OnError;

                client.UseInteractivity(new InteractivityConfiguration());

                client.Ready += async r =>
                                {
                                    var admin = await r.Client.GetUserAsync(Config.BotAdminId).ConfigureAwait(false);
                                    Config.Log.Info("Bot is ready to serve!");
                                    Config.Log.Info("");
                                    Config.Log.Info($"Bot user id : {r.Client.CurrentUser.Id} ({r.Client.CurrentUser.Username})");
                                    Config.Log.Info($"Bot admin id : {Config.BotAdminId} ({admin.Username ?? "???"}#{admin.Discriminator ?? "????"})");
                                    Config.Log.Info("");
                                };
                client.GuildAvailable += async gaArgs =>
                {
                    await BotStatusMonitor.RefreshAsync(gaArgs.Client).ConfigureAwait(false);
                    Watchdog.DisconnectTimestamps.Clear();
                    Watchdog.TimeSinceLastIncomingMessage.Restart();
                    if (gaArgs.Guild.Id != Config.BotGuildId)
                    {
#if DEBUG
                        Config.Log.Warn($"Unknown discord server {gaArgs.Guild.Id} ({gaArgs.Guild.Name})");
#else
                         Config.Log.Warn($"Unknown discord server {gaArgs.Guild.Id} ({gaArgs.Guild.Name}), leaving...");
                         await gaArgs.Guild.LeaveAsync().ConfigureAwait(false);
#endif
                        return;
                    }

                    Config.Log.Info($"Server {gaArgs.Guild.Name} is available now");
                    Config.Log.Info($"Checking moderation backlogs in {gaArgs.Guild.Name}...");
                    try
                    {
                        await Task.WhenAll(
                            Starbucks.CheckBacklogAsync(gaArgs.Client, gaArgs.Guild).ContinueWith(_ => Config.Log.Info($"Starbucks backlog checked in {gaArgs.Guild.Name}."), TaskScheduler.Default),
                            DiscordInviteFilter.CheckBacklogAsync(gaArgs.Client, gaArgs.Guild).ContinueWith(_ => Config.Log.Info($"Discord invites backlog checked in {gaArgs.Guild.Name}."), TaskScheduler.Default)
                        ).ConfigureAwait(false);
                    }
                    catch (Exception e)
                    {
                        Config.Log.Warn(e, "Error running backlog tasks");
                    }
                    Config.Log.Info($"All moderation backlogs checked in {gaArgs.Guild.Name}.");
                };
                client.GuildAvailable += gaArgs => UsernameValidationMonitor.MonitorAsync(gaArgs.Client, true);
                client.GuildUnavailable += guArgs =>
                {
                    Config.Log.Warn($"{guArgs.Guild.Name} is unavailable");
                    return Task.CompletedTask;
                };
#if !DEBUG
/*
                client.GuildDownloadCompleted += async gdcArgs =>
                                                 {
                                                     foreach (var guild in gdcArgs.Guilds)
                                                         await ModProvider.SyncRolesAsync(guild.Value).ConfigureAwait(false);
                                                 };
*/
#endif
                client.MessageReactionAdded += Starbucks.Handler;
                client.MessageReactionAdded += ContentFilterMonitor.OnReaction;

                client.MessageCreated += _ => { Watchdog.TimeSinceLastIncomingMessage.Restart(); return Task.CompletedTask;};
                client.MessageCreated += ContentFilterMonitor.OnMessageCreated; // should be first
                if (!string.IsNullOrEmpty(Config.AzureComputerVisionKey))
                    client.MessageCreated += MediaScreenshotMonitor.OnMessageCreated;
                client.MessageCreated += ProductCodeLookup.OnMessageCreated;
                client.MessageCreated += LogParsingHandler.OnMessageCreated;
                client.MessageCreated += LogAsTextMonitor.OnMessageCreated;
                client.MessageCreated += DiscordInviteFilter.OnMessageCreated;
                client.MessageCreated += PostLogHelpHandler.OnMessageCreated;
                client.MessageCreated += BotReactionsHandler.OnMessageCreated;
                client.MessageCreated += GithubLinksHandler.OnMessageCreated;
                client.MessageCreated += NewBuildsMonitor.OnMessageCreated;
                client.MessageCreated += TableFlipMonitor.OnMessageCreated;
                client.MessageCreated += IsTheGamePlayableHandler.OnMessageCreated;
                client.MessageCreated += EmpathySimulationHandler.OnMessageCreated;

                client.MessageUpdated += ContentFilterMonitor.OnMessageUpdated;
                client.MessageUpdated += DiscordInviteFilter.OnMessageUpdated;
                client.MessageUpdated += EmpathySimulationHandler.OnMessageUpdated;

                if (Config.DeletedMessagesLogChannelId > 0)
                    client.MessageDeleted += DeletedMessagesMonitor.OnMessageDeleted;
                client.MessageDeleted += ThumbnailCacheMonitor.OnMessageDeleted;
                client.MessageDeleted += EmpathySimulationHandler.OnMessageDeleted;

                client.UserUpdated += UsernameSpoofMonitor.OnUserUpdated;
                client.UserUpdated += UsernameZalgoMonitor.OnUserUpdated;

                client.GuildMemberAdded += Greeter.OnMemberAdded;
                client.GuildMemberAdded += UsernameSpoofMonitor.OnMemberAdded;
                client.GuildMemberAdded += UsernameZalgoMonitor.OnMemberAdded;
                client.GuildMemberAdded += UsernameValidationMonitor.OnMemberAdded;

                client.GuildMemberUpdated += UsernameSpoofMonitor.OnMemberUpdated;
                client.GuildMemberUpdated += UsernameZalgoMonitor.OnMemberUpdated;
                client.GuildMemberUpdated += UsernameValidationMonitor.OnMemberUpdated;

                Watchdog.DisconnectTimestamps.Enqueue(DateTime.UtcNow);

                try
                {
                    await client.ConnectAsync().ConfigureAwait(false);
                }
                catch (Exception e)
                {
                    Config.Log.Error(e, "Failed to connect to Discord: " + e.Message);
                    throw;
                }

                ulong? channelId = null;
                string restartMsg = null;
                using (var db = new BotDb())
                {
                    var chState = db.BotState.FirstOrDefault(k => k.Key == "bot-restart-channel");
                    if (chState != null)
                    {
                        if (ulong.TryParse(chState.Value, out var ch))
                            channelId = ch;
                        db.BotState.Remove(chState);
                    }
                    var msgState = db.BotState.FirstOrDefault(i => i.Key == "bot-restart-msg");
                    if (msgState != null)
                    {
                        restartMsg = msgState.Value;
                        db.BotState.Remove(msgState);
                    }
                    db.SaveChanges();
                }
                if (string.IsNullOrEmpty(restartMsg))
                    restartMsg = null;

                if (channelId.HasValue)
                {
                    Config.Log.Info($"Found channelId {channelId}");
                    DiscordChannel channel;
                    if (channelId == InvalidChannelId)
                    {
                        channel = await client.GetChannelAsync(Config.ThumbnailSpamId).ConfigureAwait(false);
                        await channel.SendMessageAsync(restartMsg ?? "Bot has suffered some catastrophic failure and was restarted").ConfigureAwait(false);
                    }
                    else
                    {
                        channel = await client.GetChannelAsync(channelId.Value).ConfigureAwait(false);
                        await channel.SendMessageAsync("Bot is up and running").ConfigureAwait(false);
                    }
                }
                else
                {
                    Config.Log.Debug($"Args count: {args.Length}");
                    var pArgs = args.Select(a => a == Config.Token ? "<Token>" : $"[{a}]");
                    Config.Log.Debug("Args: " + string.Join(" ", pArgs));
                }

                Config.Log.Debug("Running RPCS3 update check thread");
                backgroundTasks = Task.WhenAll(
                    backgroundTasks,
                    NewBuildsMonitor.MonitorAsync(client),
                    Watchdog.Watch(client),
                    InviteWhitelistProvider.CleanupAsync(client),
                    UsernameValidationMonitor.MonitorAsync(client),
                    Psn.Check.MonitorFwUpdates(client, Config.Cts.Token),
                    Watchdog.SendMetrics(client),
                    Watchdog.CheckGCStats()
                );

                while (!Config.Cts.IsCancellationRequested)
                {
                    if (client.Ping > 1000)
                        Config.Log.Warn($"High ping detected: {client.Ping}");
                    await Task.Delay(TimeSpan.FromMinutes(1), Config.Cts.Token).ContinueWith(dt => {/* in case it was cancelled */}, TaskScheduler.Default).ConfigureAwait(false);
                }
                await backgroundTasks.ConfigureAwait(false);
            }
            catch (Exception e)
            {
                if (!Config.inMemorySettings.ContainsKey("shutdown"))
                    Config.Log.Fatal(e, "Experienced catastrophic failure, attempting to restart...");
            }
            finally
            {
                Config.TelemetryClient?.Flush();
                ShutdownCheck.Release();
                if (singleInstanceCheckThread.IsAlive)
                    singleInstanceCheckThread.Join(100);
            }
            if (!Config.inMemorySettings.ContainsKey("shutdown"))
                Sudo.Bot.Restart(InvalidChannelId, null);
        }
    }
}