using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
using Dalamud.Plugin;
using Microsoft.Data.Sqlite;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Pal.Client.Commands;
using Pal.Client.Configuration;
using Pal.Client.Configuration.Legacy;
using Pal.Client.Database;
using Pal.Client.DependencyInjection;
using Pal.Client.Floors;
using Pal.Client.Windows;

namespace Pal.Client;

/// <summary>
/// Takes care of async plugin init - this is mostly everything that requires either the config or the database to
/// be available.
/// </summary>
internal sealed class DependencyContextInitializer
{
    private readonly ILogger<DependencyContextInitializer> _logger;
    private readonly IServiceProvider _serviceProvider;

    public DependencyContextInitializer(ILogger<DependencyContextInitializer> logger,
        IServiceProvider serviceProvider)
    {
        _logger = logger;
        _serviceProvider = serviceProvider;
    }

    public async Task InitializeAsync(CancellationToken cancellationToken)
    {
        using IDisposable? logScope = _logger.BeginScope("AsyncInit");

        _logger.LogInformation("Starting async init");

        await CreateBackup();
        cancellationToken.ThrowIfCancellationRequested();

        await RunMigrations(cancellationToken);
        cancellationToken.ThrowIfCancellationRequested();

        // v1 migration: config migration for import history, json migration for markers
        _serviceProvider.GetRequiredService<ConfigurationManager>().Migrate();
        await _serviceProvider.GetRequiredService<JsonMigration>().MigrateAsync(cancellationToken);
        cancellationToken.ThrowIfCancellationRequested();

        await RunCleanup();
        cancellationToken.ThrowIfCancellationRequested();

        await RemoveOldBackups();
        cancellationToken.ThrowIfCancellationRequested();

        // windows that have logic to open on startup
        _serviceProvider.GetRequiredService<AgreementWindow>();

        // initialize components that are mostly self-contained/self-registered
        _serviceProvider.GetRequiredService<GameHooks>();
        _serviceProvider.GetRequiredService<FrameworkService>();
        _serviceProvider.GetRequiredService<ChatService>();

        // eager load any commands to find errors now, not when running them
        _serviceProvider.GetRequiredService<IEnumerable<ISubCommand>>();

        cancellationToken.ThrowIfCancellationRequested();

        if (_serviceProvider.GetRequiredService<IPalacePalConfiguration>().HasBetaFeature(ObjectTableDebug.FeatureName))
            _serviceProvider.GetRequiredService<ObjectTableDebug>();

        cancellationToken.ThrowIfCancellationRequested();

        _logger.LogInformation("Async init complete");
    }

    private async Task RemoveOldBackups()
    {
        await using var scope = _serviceProvider.CreateAsyncScope();
        var pluginInterface = scope.ServiceProvider.GetRequiredService<IDalamudPluginInterface>();
        var configuration = scope.ServiceProvider.GetRequiredService<IPalacePalConfiguration>();

        var paths = Directory.GetFiles(pluginInterface.GetPluginConfigDirectory(), "backup-*.data.sqlite3",
            new EnumerationOptions
            {
                IgnoreInaccessible = true,
                RecurseSubdirectories = false,
                MatchCasing = MatchCasing.CaseSensitive,
                AttributesToSkip = FileAttributes.ReadOnly | FileAttributes.Hidden | FileAttributes.System,
                ReturnSpecialDirectories = false,
            });
        if (paths.Length == 0)
            return;

        Regex backupRegex = new Regex(@"backup-([\d\-]{10})\.data\.sqlite3", RegexOptions.Compiled);
        List<(DateTime Date, string Path)> backupFiles = new();
        foreach (string path in paths)
        {
            var match = backupRegex.Match(Path.GetFileName(path));
            if (!match.Success)
                continue;

            if (DateTime.TryParseExact(match.Groups[1].Value, "yyyy-MM-dd", CultureInfo.InvariantCulture,
                    DateTimeStyles.AssumeUniversal, out DateTime backupDate))
            {
                backupFiles.Add((backupDate, path));
            }
        }

        var toDelete = backupFiles.OrderByDescending(x => x.Date)
            .Skip(configuration.Backups.MinimumBackupsToKeep)
            .Where(x => (DateTime.Now.ToUniversalTime() - x.Date).Days > configuration.Backups.DaysToDeleteAfter)
            .Select(x => x.Path);
        foreach (var path in toDelete)
        {
            try
            {
                File.Delete(path);
                _logger.LogInformation("Deleted old backup file '{Path}'", path);
            }
            catch (Exception e)
            {
                _logger.LogWarning(e, "Could not delete backup file '{Path}'", path);
            }
        }
    }

    private async Task CreateBackup()
    {
        await using var scope = _serviceProvider.CreateAsyncScope();

        var pluginInterface = scope.ServiceProvider.GetRequiredService<IDalamudPluginInterface>();
        string backupPath = Path.Join(pluginInterface.GetPluginConfigDirectory(),
            $"backup-{DateTime.Now.ToUniversalTime():yyyy-MM-dd}.data.sqlite3");
        string sourcePath = Path.Join(pluginInterface.GetPluginConfigDirectory(),
            DependencyInjectionContext.DatabaseFileName);
        if (File.Exists(sourcePath) && !File.Exists(backupPath))
        {
            try
            {
                if (File.Exists(sourcePath + "-shm") || File.Exists(sourcePath + "-wal"))
                {
                    _logger.LogInformation("Creating database backup '{Path}' (open db)", backupPath);
                    await using var db = scope.ServiceProvider.GetRequiredService<PalClientContext>();
                    await using SqliteConnection source = new(db.Database.GetConnectionString());
                    await source.OpenAsync();
                    await using SqliteConnection backup = new($"Data Source={backupPath}");
                    source.BackupDatabase(backup);
                    SqliteConnection.ClearPool(backup);
                }
                else
                {
                    _logger.LogInformation("Creating database backup '{Path}' (file copy)", backupPath);
                    File.Copy(sourcePath, backupPath);
                }
            }
            catch (Exception e)
            {
                _logger.LogError(e, "Could not create backup");
            }
        }
        else
            _logger.LogInformation("Database backup in '{Path}' already exists", backupPath);
    }

    private async Task RunMigrations(CancellationToken cancellationToken)
    {
        await using var scope = _serviceProvider.CreateAsyncScope();

        _logger.LogInformation("Loading database & running migrations");
        await using var dbContext = scope.ServiceProvider.GetRequiredService<PalClientContext>();

        // takes 2-3 seconds with initializing connections, loading driver etc.
        await dbContext.Database.MigrateAsync(cancellationToken);
        _logger.LogInformation("Completed database migrations");
    }

    private async Task RunCleanup()
    {
        await using var scope = _serviceProvider.CreateAsyncScope();
        await using var dbContext = scope.ServiceProvider.GetRequiredService<PalClientContext>();
        var cleanup = scope.ServiceProvider.GetRequiredService<Cleanup>();

        cleanup.Purge(dbContext);

        await dbContext.SaveChangesAsync();
    }
}