using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Common.Configuration;
using MediaBrowser.Controller.IO;
using MediaBrowser.Model.Globalization;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.Tasks;
using Microsoft.Extensions.Logging;

namespace Emby.Server.Implementations.ScheduledTasks.Tasks;

/// <summary>
/// Deletes all transcoding temp files.
/// </summary>
public class DeleteTranscodeFileTask : IScheduledTask, IConfigurableScheduledTask
{
    private readonly ILogger<DeleteTranscodeFileTask> _logger;
    private readonly IConfigurationManager _configurationManager;
    private readonly IFileSystem _fileSystem;
    private readonly ILocalizationManager _localization;

    /// <summary>
    /// Initializes a new instance of the <see cref="DeleteTranscodeFileTask"/> class.
    /// </summary>
    /// <param name="logger">Instance of the <see cref="ILogger{DeleteTranscodeFileTask}"/> interface.</param>
    /// <param name="fileSystem">Instance of the <see cref="IFileSystem"/> interface.</param>
    /// <param name="configurationManager">Instance of the <see cref="IConfigurationManager"/> interface.</param>
    /// <param name="localization">Instance of the <see cref="ILocalizationManager"/> interface.</param>
    public DeleteTranscodeFileTask(
        ILogger<DeleteTranscodeFileTask> logger,
        IFileSystem fileSystem,
        IConfigurationManager configurationManager,
        ILocalizationManager localization)
    {
        _logger = logger;
        _fileSystem = fileSystem;
        _configurationManager = configurationManager;
        _localization = localization;
    }

    /// <inheritdoc />
    public string Name => _localization.GetLocalizedString("TaskCleanTranscode");

    /// <inheritdoc />
    public string Description => _localization.GetLocalizedString("TaskCleanTranscodeDescription");

    /// <inheritdoc />
    public string Category => _localization.GetLocalizedString("TasksMaintenanceCategory");

    /// <inheritdoc />
    public string Key => "DeleteTranscodeFiles";

    /// <inheritdoc />
    public bool IsHidden => false;

    /// <inheritdoc />
    public bool IsEnabled => true;

    /// <inheritdoc />
    public bool IsLogged => true;

    /// <inheritdoc />
    public IEnumerable<TaskTriggerInfo> GetDefaultTriggers()
    {
        yield return new TaskTriggerInfo
        {
            Type = TaskTriggerInfoType.StartupTrigger
        };

        yield return new TaskTriggerInfo
        {
            Type = TaskTriggerInfoType.IntervalTrigger,
            IntervalTicks = TimeSpan.FromHours(24).Ticks
        };
    }

    /// <inheritdoc />
    public Task ExecuteAsync(IProgress<double> progress, CancellationToken cancellationToken)
    {
        var minDateModified = DateTime.UtcNow.AddDays(-1);
        progress.Report(50);

        DeleteTempFilesFromDirectory(_configurationManager.GetTranscodePath(), minDateModified, progress, cancellationToken);

        return Task.CompletedTask;
    }

    /// <summary>
    /// Deletes the transcoded temp files from directory with a last write time less than a given date.
    /// </summary>
    /// <param name="directory">The directory.</param>
    /// <param name="minDateModified">The min date modified.</param>
    /// <param name="progress">The progress.</param>
    /// <param name="cancellationToken">The task cancellation token.</param>
    private void DeleteTempFilesFromDirectory(string directory, DateTime minDateModified, IProgress<double> progress, CancellationToken cancellationToken)
    {
        var filesToDelete = _fileSystem.GetFiles(directory, true)
            .Where(f => _fileSystem.GetLastWriteTimeUtc(f) < minDateModified)
            .ToList();

        var index = 0;

        foreach (var file in filesToDelete)
        {
            double percent = index;
            percent /= filesToDelete.Count;

            progress.Report(100 * percent);

            cancellationToken.ThrowIfCancellationRequested();

            FileSystemHelper.DeleteFile(_fileSystem, file.FullName, _logger);

            index++;
        }

        FileSystemHelper.DeleteEmptyFolders(_fileSystem, directory, _logger);

        progress.Report(100);
    }
}
