using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Data.Common;
using System.Diagnostics;
using System.Linq;
using System.Net;
using System.Reflection.Metadata.Ecma335;
using System.Threading;
using System.Threading.Tasks;
using Jellyfin.Data.Enums;
using Jellyfin.Database.Implementations.Entities;
using Jellyfin.Database.Implementations.Entities.Libraries;
using Jellyfin.Plugin.MediaCleaner.Configuration;
using Jellyfin.Plugin.MediaCleaner.Helpers;
using Jellyfin.Plugin.MediaCleaner.Models;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using MediaBrowser.Model.Tasks;
using Microsoft.Extensions.Logging;

namespace Jellyfin.Plugin.MediaCleaner.ScheduledTasks;

/// <summary>
/// A task to scan media for stale files.
/// </summary>
public sealed class StaleMediaTask : IScheduledTask
{
    private readonly ILogger _logger;
    private readonly ILibraryManager _libraryManager;
    private readonly LoggingHelper _loggingHelper;
    private readonly MovieHelper _movieHelper;
    private readonly SeriesHelper _seriesHelper;

    /// <summary>
    /// Initializes a new instance of the <see cref="StaleMediaTask"/> class.
    /// </summary>
    /// <param name="logger">Logger for StaleMediaTask.</param>
    /// <param name="libraryManager">Accesses jellyfin's library manager for media.</param>
    public StaleMediaTask(ILogger<StaleMediaTask> logger, ILibraryManager libraryManager)
    {
        _logger = logger;
        _libraryManager = libraryManager;
        _loggingHelper = new LoggingHelper(_logger);
        _movieHelper = new MovieHelper(_logger);
        _seriesHelper = new SeriesHelper(_logger);
    }

    private static PluginConfiguration Configuration =>
            Plugin.Instance!.Configuration;

    string IScheduledTask.Name => "Scan Stale Media";

    string IScheduledTask.Key => "Stale Media";

    string IScheduledTask.Description => "Scan Stale Media";

    string IScheduledTask.Category => "Media";

    Task IScheduledTask.ExecuteAsync(IProgress<double> progress, CancellationToken cancellationToken)
    {
        _loggingHelper.StartLogging();

        var query = new InternalItemsQuery
        {
            IncludeItemTypes = [BaseItemKind.Movie, BaseItemKind.Series],
            Recursive = true
        };

        List<BaseItem> allItems = [.. _libraryManager.GetItemsResult(query).Items];

        _loggingHelper.PrintItemsInformation(allItems);

        List<BaseItem> series = [.. allItems.Where(item => item.GetBaseItemKind() == BaseItemKind.Series)];
        List<BaseItem> movies = [.. allItems.Where(item => item.GetBaseItemKind() == BaseItemKind.Movie)];

        _loggingHelper.StartScanningSeriesItems();
        List<BaseItem> staleEpisodes = [.. series.SelectMany(GetStaleEpisodes)];

        _loggingHelper.StartScanningMoviesItems();
        List<BaseItem> staleMovies = [.. GetStaleMovies(movies)];

        _loggingHelper.PrintStaleMoviesInformation(staleMovies);
        _loggingHelper.PrintStaleEpisodesInformation(FindSeriesInfoFromEpisodes, staleEpisodes);

        _loggingHelper.EndLogging();

        return Task.CompletedTask;
    }

    private List<BaseItem> GetStaleMovies(List<BaseItem> movies)
    {
        List<BaseItem> staleMovies = [];

        staleMovies.AddRange(movies.Where(_movieHelper.IsMovieStale));

        return staleMovies;
    }


    private List<BaseItem> GetStaleEpisodes(BaseItem item)
    {
        List<BaseItem> staleEpisodes = [];

        // Gets each season in a show
        var seasons = _libraryManager.GetItemList(new InternalItemsQuery
        {
            ParentId = item.Id,
            Recursive = false
        });

        _loggingHelper.PrintDebugDataForSeries(item);

        foreach (var season in seasons)
        {
            // Gets each episode, to access user data.
            var episodes = _libraryManager.GetItemList(new InternalItemsQuery
            {
                ParentId = season.Id,
                Recursive = false
            });

            _loggingHelper.PrintDebugSeasonInfo();

            bool seasonHasUserData = episodes.Any(episode => episode.UserData.Count > 0);
            bool seasonIsStale = seasonHasUserData && _seriesHelper.IsSeasonUserDataStale(episodes);

            if (seasonIsStale)
            {
                if (!seasonHasUserData)
                {
                    _loggingHelper.PrintDebugEpisodeCreationInfo(episodes);
                }

                staleEpisodes.AddRange(episodes);
            }
        }

        _loggingHelper.PrintDebugEndOfScanningForSeries(item);

        return staleEpisodes;
    }

    private List<SeriesInfo> FindSeriesInfoFromEpisodes(IReadOnlyCollection<BaseItem> episodes)
    {
        Guid[] seasonIds = [.. episodes.Select(episode => episode.ParentId).Distinct()];

        var seasons = _libraryManager.GetItemList(new InternalItemsQuery
        {
            ItemIds = seasonIds
        });

        Guid[] seriesIds = [.. seasons.Select(season => season.ParentId).Distinct()];

        var series = _libraryManager.GetItemList(new InternalItemsQuery
        {
            ItemIds = seriesIds
        }).ToList();

        List<string> seriesNames = [.. series.Select(series => series.Name).Distinct()];

        List<SeriesInfo> seriesInfoList = [];

        series.ForEach(series =>
        {
            seriesInfoList.Add(new SeriesInfo
            {
                Id = series.Id,
                SeriesName = series.Name,
                Seasons = [.. seasons.Where(season => season.ParentId == series.Id).Select(season => season.Name)]
            });
        });

        return seriesInfoList;
    }

    IEnumerable<TaskTriggerInfo> IScheduledTask.GetDefaultTriggers()
    {
        // Run this task every 24 hours
        yield return new TaskTriggerInfo
        {
            Type = TaskTriggerInfoType.IntervalTrigger,
            IntervalTicks = TimeSpan.FromHours(24).Ticks
        };
    }
}