using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Common.Configuration;
using MediaBrowser.Model.Globalization;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.Tasks;

namespace Emby.Server.Implementations.ScheduledTasks.Tasks;

/// <summary>
/// Deletes old log files.
/// </summary>
public class DeleteLogFileTask : IScheduledTask, IConfigurableScheduledTask
{
    private readonly IConfigurationManager _configurationManager;
    private readonly IFileSystem _fileSystem;
    private readonly ILocalizationManager _localization;

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

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

    /// <inheritdoc />
    public string Description => string.Format(
        CultureInfo.InvariantCulture,
        _localization.GetLocalizedString("TaskCleanLogsDescription"),
        _configurationManager.CommonConfiguration.LogFileRetentionDays);

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

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

    /// <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.IntervalTrigger,
            IntervalTicks = TimeSpan.FromHours(24).Ticks
        };
    }

    /// <inheritdoc />
    public Task ExecuteAsync(IProgress<double> progress, CancellationToken cancellationToken)
    {
        // Delete log files more than n days old
        var minDateModified = DateTime.UtcNow.AddDays(-_configurationManager.CommonConfiguration.LogFileRetentionDays);

        // Only delete files that serilog doesn't manage (anything that doesn't start with 'log_'
        var filesToDelete = _fileSystem.GetFiles(_configurationManager.CommonApplicationPaths.LogDirectoryPath, true)
            .Where(f => !f.Name.StartsWith("log_", StringComparison.Ordinal)
                        && _fileSystem.GetLastWriteTimeUtc(f) < minDateModified)
            .ToList();

        var index = 0;

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

            progress.Report(100 * percent);

            cancellationToken.ThrowIfCancellationRequested();

            _fileSystem.DeleteFile(file.FullName);

            index++;
        }

        progress.Report(100);

        return Task.CompletedTask;
    }
}