using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Jellyfin.Plugin.Jellypod.Models;
using Jellyfin.Plugin.Jellypod.Services;
using MediaBrowser.Controller;
using MediaBrowser.Controller.Channels;
using MediaBrowser.Controller.Providers;
using MediaBrowser.Model.Channels;
using MediaBrowser.Model.Dto;
using MediaBrowser.Model.Entities;
using MediaBrowser.Model.MediaInfo;
using Microsoft.Extensions.Logging;

namespace Jellyfin.Plugin.Jellypod.Channels;

/// <summary>
/// Jellypod channel for browsing and playing podcast episodes.
/// </summary>
public class JellypodChannel : IChannel, IHasCacheKey, IRequiresMediaInfoCallback
{
    private readonly ILogger<JellypodChannel> _logger;
    private readonly IPodcastStorageService _storageService;
    private readonly IRssFeedService _rssFeedService;
    private readonly IPodcastDownloadService _downloadService;
    private readonly IServerApplicationHost _appHost;

    /// <summary>
    /// Initializes a new instance of the <see cref="JellypodChannel"/> class.
    /// </summary>
    /// <param name="loggerFactory">The logger factory.</param>
    /// <param name="storageService">The podcast storage service.</param>
    /// <param name="rssFeedService">The RSS feed service.</param>
    /// <param name="downloadService">The download service.</param>
    /// <param name="appHost">The server application host.</param>
    public JellypodChannel(
        ILoggerFactory loggerFactory,
        IPodcastStorageService storageService,
        IRssFeedService rssFeedService,
        IPodcastDownloadService downloadService,
        IServerApplicationHost appHost)
    {
        _logger = loggerFactory.CreateLogger<JellypodChannel>();
        _storageService = storageService;
        _rssFeedService = rssFeedService;
        _downloadService = downloadService;
        _appHost = appHost;
        _logger.LogDebug("JellypodChannel initialized");
    }

    /// <inheritdoc />
    public string Name => "Podcasts";

    /// <inheritdoc />
    public string Description => "Browse and listen to your podcast subscriptions";

    /// <inheritdoc />
    public string DataVersion => "1.0";

    /// <inheritdoc />
    public string HomePageUrl => string.Empty;

    /// <inheritdoc />
    public ChannelParentalRating ParentalRating => ChannelParentalRating.GeneralAudience;

    /// <inheritdoc />
    public InternalChannelFeatures GetChannelFeatures()
    {
        return new InternalChannelFeatures
        {
            ContentTypes = new List<ChannelMediaContentType>
            {
                ChannelMediaContentType.Podcast
            },
            MediaTypes = new List<ChannelMediaType>
            {
                ChannelMediaType.Audio
            },
            SupportsSortOrderToggle = true,
            DefaultSortFields = new List<ChannelItemSortField>
            {
                ChannelItemSortField.PremiereDate,
                ChannelItemSortField.DateCreated,
                ChannelItemSortField.Name
            },
            AutoRefreshLevels = 1,
            MaxPageSize = 100
        };
    }

    /// <inheritdoc />
    public Task<DynamicImageResponse> GetChannelImage(ImageType type, CancellationToken cancellationToken)
    {
        _logger.LogInformation("GetChannelImage called with type: {Type}", type);

        var assembly = GetType().Assembly;
        var resourceName = "Jellyfin.Plugin.Jellypod.Images.channel-icon.jpg";

        // Log available resources for debugging
        var resourceNames = assembly.GetManifestResourceNames();
        _logger.LogInformation("Available embedded resources: {Resources}", string.Join(", ", resourceNames));

        var stream = assembly.GetManifestResourceStream(resourceName);

        if (stream != null)
        {
            _logger.LogInformation("Found channel icon, stream length: {Length}", stream.Length);
            return Task.FromResult(new DynamicImageResponse
            {
                HasImage = true,
                Stream = stream,
                Format = MediaBrowser.Model.Drawing.ImageFormat.Jpg
            });
        }

        _logger.LogWarning("Channel icon resource not found: {ResourceName}", resourceName);
        return Task.FromResult(new DynamicImageResponse
        {
            HasImage = false
        });
    }

    /// <inheritdoc />
    public IEnumerable<ImageType> GetSupportedChannelImages()
    {
        return new List<ImageType>
        {
            ImageType.Primary,
            ImageType.Thumb
        };
    }

    /// <inheritdoc />
    public async Task<ChannelItemResult> GetChannelItems(InternalChannelItemQuery query, CancellationToken cancellationToken)
    {
        _logger.LogDebug("GetChannelItems called for folder {FolderId}, SortBy: {SortBy}, SortDescending: {SortDescending}", query.FolderId, query.SortBy, query.SortDescending);

        try
        {
            var items = await GetFolderItemsAsync(query.FolderId, query.SortBy, query.SortDescending, cancellationToken).ConfigureAwait(false);
            _logger.LogDebug("Returning {Count} channel items for folder {FolderId}", items.Count, query.FolderId);

            return new ChannelItemResult
            {
                Items = items,
                TotalRecordCount = items.Count
            };
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error getting channel items for folder {FolderId}", query.FolderId);
            return new ChannelItemResult { Items = new List<ChannelItemInfo>(), TotalRecordCount = 0 };
        }
    }

    private async Task<List<ChannelItemInfo>> GetFolderItemsAsync(string? folderId, ChannelItemSortField? sortBy, bool? sortDescending, CancellationToken cancellationToken)
    {
        // Root level - show all subscribed podcasts as folders
        if (string.IsNullOrEmpty(folderId))
        {
            return await GetPodcastFoldersAsync(cancellationToken).ConfigureAwait(false);
        }

        // Podcast folder - show episodes
        if (Guid.TryParse(folderId, out var podcastId))
        {
            return await GetPodcastEpisodesAsync(podcastId, sortBy, sortDescending, cancellationToken).ConfigureAwait(false);
        }

        return new List<ChannelItemInfo>();
    }

    private async Task<List<ChannelItemInfo>> GetPodcastFoldersAsync(CancellationToken cancellationToken)
    {
        var items = new List<ChannelItemInfo>();
        var podcasts = await _storageService.GetAllPodcastsAsync().ConfigureAwait(false);

        foreach (var podcast in podcasts)
        {
            var episodeCount = podcast.Episodes.Count;
            var downloadedCount = podcast.Episodes.Count(e => e.Status == EpisodeStatus.Downloaded);

            items.Add(new ChannelItemInfo
            {
                Id = podcast.Id.ToString("N"),
                Name = podcast.Title,
                Overview = podcast.Description,
                ImageUrl = podcast.ImageUrl,
                Type = ChannelItemType.Folder,
                FolderType = ChannelFolderType.Container,
                DateCreated = podcast.DateAdded,
                DateModified = podcast.LastUpdated
            });

            _logger.LogDebug("Added podcast folder: {Title} ({EpisodeCount} episodes, {DownloadedCount} downloaded)", podcast.Title, episodeCount, downloadedCount);
        }

        _logger.LogInformation("Returning {Count} podcast folders", items.Count);
        return items;
    }

    private async Task<List<ChannelItemInfo>> GetPodcastEpisodesAsync(Guid podcastId, ChannelItemSortField? sortBy, bool? sortDescending, CancellationToken cancellationToken)
    {
        var items = new List<ChannelItemInfo>();
        var podcast = await _storageService.GetPodcastAsync(podcastId).ConfigureAwait(false);

        if (podcast == null)
        {
            _logger.LogWarning("Podcast {PodcastId} not found", podcastId);
            return items;
        }

        // Default to sorting by premiere date descending (newest first)
        var sortField = sortBy ?? ChannelItemSortField.PremiereDate;
        var descending = sortDescending ?? true;

        _logger.LogDebug("Sorting episodes by {SortField}, descending: {Descending}", sortField, descending);

        // Sort episodes based on query parameters
        IEnumerable<Episode> sortedEpisodes = sortField switch
        {
            ChannelItemSortField.Name => descending
                ? podcast.Episodes.OrderByDescending(e => e.Title)
                : podcast.Episodes.OrderBy(e => e.Title),
            ChannelItemSortField.DateCreated or ChannelItemSortField.PremiereDate => descending
                ? podcast.Episodes.OrderByDescending(e => e.PublishedDate)
                : podcast.Episodes.OrderBy(e => e.PublishedDate),
            _ => podcast.Episodes.OrderByDescending(e => e.PublishedDate)
        };

        var episodes = sortedEpisodes.ToList();

        foreach (var episode in episodes)
        {
            // Don't provide MediaSources here - this forces Jellyfin to call GetChannelItemMediaInfo
            // which allows us to download-on-demand and return proper local file paths
            items.Add(new ChannelItemInfo
            {
                Id = episode.Id.ToString("N"),
                Name = episode.Title,
                Overview = episode.Description,
                ImageUrl = episode.ImageUrl ?? podcast.ImageUrl,
                Type = ChannelItemType.Media,
                ContentType = ChannelMediaContentType.Podcast,
                MediaType = ChannelMediaType.Audio,
                DateCreated = episode.PublishedDate,
                PremiereDate = episode.PublishedDate,
                RunTimeTicks = episode.Duration?.Ticks,
                SeriesName = podcast.Title
                // MediaSources intentionally omitted - see GetChannelItemMediaInfo
            });
        }

        _logger.LogInformation("Returning {Count} episodes for podcast {PodcastTitle}", items.Count, podcast.Title);
        return items;
    }

    private MediaSourceInfo CreateMediaSource(Podcast podcast, Episode episode)
    {
        // If episode is downloaded, use local file; otherwise proxy through our endpoint
        var isLocal = episode.Status == EpisodeStatus.Downloaded && !string.IsNullOrEmpty(episode.LocalFilePath);

        string path;
        MediaProtocol protocol;

        if (isLocal)
        {
            path = episode.LocalFilePath!;
            protocol = MediaProtocol.File;
        }
        else
        {
            // Use proxy URL to avoid ffprobe issues with remote URLs
            var encodedUrl = Convert.ToBase64String(Encoding.UTF8.GetBytes(episode.AudioUrl));
            var serverUrl = _appHost.GetSmartApiUrl(string.Empty);
            path = $"{serverUrl}/Jellypod/Stream/{encodedUrl}";
            protocol = MediaProtocol.Http;
        }

        var container = GetContainerFromUrl(episode.AudioUrl);
        var codec = GetCodecFromContainer(container);

        // Create audio stream info - required for Jellyfin to play without probing
        var audioStream = new MediaStream
        {
            Type = MediaStreamType.Audio,
            Index = 0,
            Codec = codec,
            Channels = 2,
            SampleRate = 44100,
            BitRate = 128000,
            IsDefault = true,
            Language = "und"
        };

        return new MediaSourceInfo
        {
            Id = episode.Id.ToString("N"),
            Name = episode.Title,
            Path = path,
            Protocol = protocol,
            Container = container,
            Type = MediaSourceType.Default,
            IsRemote = !isLocal,
            SupportsDirectPlay = true,
            SupportsDirectStream = true,
            SupportsTranscoding = false,
            SupportsProbing = false,
            RequiresOpening = false,
            RequiresClosing = false,
            RunTimeTicks = episode.Duration?.Ticks,
            Size = episode.FileSizeBytes,
            Bitrate = 128000,
            MediaStreams = new List<MediaStream> { audioStream },
            DefaultAudioStreamIndex = 0,
            ReadAtNativeFramerate = false,
            AnalyzeDurationMs = 0,
            IsInfiniteStream = false
        };
    }

    private static string GetCodecFromContainer(string container)
    {
        return container switch
        {
            "mp3" => "mp3",
            "m4a" => "aac",
            "ogg" => "vorbis",
            "opus" => "opus",
            _ => "mp3"
        };
    }

    private static string GetContainerFromUrl(string url)
    {
        try
        {
            var uri = new Uri(url);
            var path = uri.AbsolutePath.ToLowerInvariant();

            if (path.EndsWith(".mp3", StringComparison.Ordinal))
            {
                return "mp3";
            }

            if (path.EndsWith(".m4a", StringComparison.Ordinal))
            {
                return "m4a";
            }

            if (path.EndsWith(".ogg", StringComparison.Ordinal))
            {
                return "ogg";
            }

            if (path.EndsWith(".opus", StringComparison.Ordinal))
            {
                return "opus";
            }
        }
        catch
        {
            // Ignore URL parsing errors
        }

        return "mp3"; // Default to mp3
    }

    /// <inheritdoc />
    public string? GetCacheKey(string? userId)
    {
        // Use 5-minute time buckets for cache key
        var now = DateTime.Now;
        var timeBucket = new DateTime(now.Year, now.Month, now.Day, now.Hour, (now.Minute / 5) * 5, 0);
        return timeBucket.ToString("yyyy-MM-dd-HH-mm", CultureInfo.InvariantCulture);
    }

    /// <inheritdoc />
    public bool IsEnabledFor(string userId)
    {
        return true;
    }

    /// <inheritdoc />
    public async Task<IEnumerable<MediaSourceInfo>> GetChannelItemMediaInfo(string id, CancellationToken cancellationToken)
    {
        _logger.LogDebug("GetChannelItemMediaInfo called for id: {Id}", id);

        // Parse the episode ID
        if (!Guid.TryParse(id, out var episodeId))
        {
            _logger.LogWarning("Invalid episode ID format: {Id}", id);
            return Enumerable.Empty<MediaSourceInfo>();
        }

        // Find the episode across all podcasts
        var podcasts = await _storageService.GetAllPodcastsAsync().ConfigureAwait(false);
        foreach (var podcast in podcasts)
        {
            var episode = podcast.Episodes.FirstOrDefault(e => e.Id == episodeId);
            if (episode != null)
            {
                var currentPodcast = podcast;
                var currentEpisode = episode;

                // Download episode if not already downloaded
                if (currentEpisode.Status != EpisodeStatus.Downloaded || string.IsNullOrEmpty(currentEpisode.LocalFilePath))
                {
                    _logger.LogInformation("Downloading episode on demand: {Title}", currentEpisode.Title);
                    try
                    {
                        await _downloadService.DownloadEpisodeAsync(currentPodcast, currentEpisode, null, cancellationToken).ConfigureAwait(false);
                        // Reload the episode to get updated status
                        var reloadedPodcast = await _storageService.GetPodcastAsync(currentPodcast.Id).ConfigureAwait(false);
                        var reloadedEpisode = reloadedPodcast?.Episodes.FirstOrDefault(e => e.Id == episodeId);
                        if (reloadedEpisode == null)
                        {
                            _logger.LogError("Episode disappeared after download: {Id}", id);
                            return Enumerable.Empty<MediaSourceInfo>();
                        }

                        currentEpisode = reloadedEpisode;
                    }
                    catch (Exception ex)
                    {
                        _logger.LogError(ex, "Failed to download episode: {Title}", currentEpisode.Title);
                        return Enumerable.Empty<MediaSourceInfo>();
                    }
                }

                var mediaSource = CreateMediaSourceForLocalFile(currentEpisode);
                _logger.LogDebug("Returning media source for episode: {Title}, Path: {Path}", currentEpisode.Title, mediaSource.Path);
                return new[] { mediaSource };
            }
        }

        _logger.LogWarning("Episode not found: {Id}", id);
        return Enumerable.Empty<MediaSourceInfo>();
    }

    private MediaSourceInfo CreateMediaSourceForLocalFile(Episode episode)
    {
        // This is for downloaded local files
        var container = GetContainerFromUrl(episode.AudioUrl);
        var codec = GetCodecFromContainer(container);

        // Jellyfin requires MediaStreams with audio info for StreamBuilder.GetOptimalAudioStream
        var audioStream = new MediaStream
        {
            Type = MediaStreamType.Audio,
            Index = 0,
            Codec = codec,
            Channels = 2,
            SampleRate = 44100,
            BitRate = 128000,
            IsDefault = true,
            Language = "und"
        };

        return new MediaSourceInfo
        {
            Id = episode.Id.ToString("N"),
            Name = episode.Title,
            Path = episode.LocalFilePath!,
            Protocol = MediaProtocol.File,
            Container = container,
            Type = MediaSourceType.Default,
            IsRemote = false,
            SupportsDirectPlay = true,
            SupportsDirectStream = true,
            SupportsTranscoding = true,
            SupportsProbing = false,  // Don't probe - we provide stream info
            RequiresOpening = false,
            RequiresClosing = false,
            RunTimeTicks = episode.Duration?.Ticks,
            Size = episode.FileSizeBytes,
            Bitrate = 128000,
            MediaStreams = new List<MediaStream> { audioStream },
            DefaultAudioStreamIndex = 0,
            ReadAtNativeFramerate = false
        };
    }
}