using System;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Jellyfin.Plugin.JellyLMS.Models;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using MediaBrowser.Controller.Session;
using MediaBrowser.Model.Session;
using Microsoft.Extensions.Logging;

namespace Jellyfin.Plugin.JellyLMS.Services;

/// <summary>
/// Session controller for LMS player devices.
/// Enables Jellyfin to send playback commands to LMS players via the cast interface.
/// </summary>
public class LmsSessionController : ISessionController, IDisposable
{
    private readonly ILogger _logger;
    private readonly ILmsApiClient _lmsClient;
    private readonly LmsPlayer _player;
    private readonly SessionInfo _session;
    private readonly ISessionManager _sessionManager;
    private readonly ILibraryManager _libraryManager;
    private Timer? _progressTimer;
    private bool _disposed;
    private BaseItem? _currentItem;
    private Guid[] _playlist = [];
    private int _playlistIndex;
    private long _seekOffsetTicks; // Offset from transcoded stream start position

    /// <summary>
    /// Initializes a new instance of the <see cref="LmsSessionController"/> class.
    /// </summary>
    /// <param name="logger">The logger instance.</param>
    /// <param name="lmsClient">The LMS API client.</param>
    /// <param name="player">The LMS player this controller manages.</param>
    /// <param name="session">The Jellyfin session associated with this controller.</param>
    /// <param name="sessionManager">The session manager for reporting playback events.</param>
    /// <param name="libraryManager">The library manager for item lookups.</param>
    public LmsSessionController(
        ILogger logger,
        ILmsApiClient lmsClient,
        LmsPlayer player,
        SessionInfo session,
        ISessionManager sessionManager,
        ILibraryManager libraryManager)
    {
        _logger = logger;
        _lmsClient = lmsClient;
        _player = player;
        _session = session;
        _sessionManager = sessionManager;
        _libraryManager = libraryManager;
    }

    /// <summary>
    /// Gets or sets the currently playing item ID.
    /// </summary>
    public Guid? CurrentItemId { get; set; }

    /// <summary>
    /// Gets or sets a value indicating whether playback is currently active.
    /// </summary>
    public bool IsPlaying { get; set; }

    /// <summary>
    /// Gets or sets a value indicating whether playback is paused.
    /// </summary>
    public bool IsPaused { get; set; }

    /// <inheritdoc />
    public bool IsSessionActive => _player.IsConnected;

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

    /// <summary>
    /// Gets the MAC address of the LMS player.
    /// </summary>
    public string PlayerMac => _player.MacAddress;

    /// <inheritdoc />
    public async Task SendMessage<T>(
        SessionMessageType name,
        Guid messageId,
        T data,
        CancellationToken cancellationToken)
    {
        _logger.LogInformation(
            "LMS Session Controller received message {MessageType} for player {PlayerName} ({Mac}), data type: {DataType}",
            name,
            _player.Name,
            _player.MacAddress,
            data?.GetType().Name ?? "null");

        // Log the data for debugging
        if (data is PlaystateRequest psr)
        {
            _logger.LogInformation(
                "PlaystateRequest: Command={Command}, SeekPositionTicks={Ticks}",
                psr.Command,
                psr.SeekPositionTicks);
        }

        try
        {
            switch (name)
            {
                case SessionMessageType.Play:
                    await HandlePlayCommandAsync(data, cancellationToken).ConfigureAwait(false);
                    break;

                case SessionMessageType.Playstate:
                    await HandlePlaystateCommandAsync(data, cancellationToken).ConfigureAwait(false);
                    break;

                case SessionMessageType.GeneralCommand:
                    await HandleGeneralCommandAsync(data, cancellationToken).ConfigureAwait(false);
                    break;

                default:
                    _logger.LogDebug("Unhandled message type: {MessageType}", name);
                    break;
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error handling message {MessageType} for player {PlayerName}", name, _player.Name);
        }
    }

    private async Task HandlePlayCommandAsync<T>(T data, CancellationToken cancellationToken)
    {
        if (data is not PlayRequest playRequest)
        {
            _logger.LogWarning("Expected PlayRequest but got {Type}", data?.GetType().Name);
            return;
        }

        _logger.LogInformation(
            "Play command received for player {PlayerName}: {ItemCount} items",
            _player.Name,
            playRequest.ItemIds.Length);

        // Power on the player if needed
        if (!_player.IsPoweredOn)
        {
            await _lmsClient.PowerOnAsync(_player.MacAddress).ConfigureAwait(false);
        }

        if (playRequest.ItemIds.Length > 0)
        {
            // Store the full playlist
            _playlist = playRequest.ItemIds;
            _playlistIndex = playRequest.StartIndex ?? 0;

            // Play the item at the start index
            await PlayItemAtIndexAsync(_playlistIndex, playRequest.StartPositionTicks ?? 0).ConfigureAwait(false);
        }
    }

    private async Task PlayItemAtIndexAsync(int index, long startPositionTicks = 0)
    {
        if (index < 0 || index >= _playlist.Length)
        {
            _logger.LogWarning("Invalid playlist index {Index}, playlist has {Count} items", index, _playlist.Length);
            return;
        }

        var itemId = _playlist[index];
        _playlistIndex = index;

        // Look up the item first - we need it for file path if using direct mode
        _currentItem = _libraryManager.GetItemById(itemId);

        // Build stream URL/path with start position
        var (streamUrl, useDirectPath) = BuildPlaybackUrl(itemId, startPositionTicks);
        _logger.LogInformation(
            "Playing item {Index}/{Total} from position {Position}s (direct={Direct}): {Url}",
            index + 1,
            _playlist.Length,
            startPositionTicks / TimeSpan.TicksPerSecond,
            useDirectPath,
            streamUrl);

        await _lmsClient.PlayUrlAsync(_player.MacAddress, streamUrl).ConfigureAwait(false);

        // Track current playback state
        CurrentItemId = itemId;
        IsPlaying = true;
        IsPaused = false;

        // Track the seek offset so we report the correct position
        // When using direct file paths, LMS handles seeking natively so no offset needed
        // When using HTTP streaming with startTimeTicks, the stream starts at 0 but we need to report actual position
        _seekOffsetTicks = useDirectPath ? 0 : startPositionTicks;

        // Report playback start to Jellyfin
        await ReportPlaybackStartAsync(itemId, startPositionTicks).ConfigureAwait(false);

        // Start progress reporting timer (every 2 seconds)
        StartProgressTimer();
    }

    private async Task ReportPlaybackStartAsync(Guid itemId, long positionTicks)
    {
        try
        {
            var startInfo = new PlaybackStartInfo
            {
                ItemId = itemId,
                SessionId = _session.Id,
                PositionTicks = positionTicks,
                PlayMethod = PlayMethod.DirectStream,
                CanSeek = true,
                IsPaused = false,
                IsMuted = false
            };

            _logger.LogInformation(
                "Reporting playback start for item {ItemId}, duration: {Duration}",
                itemId,
                _currentItem?.RunTimeTicks);
            await _sessionManager.OnPlaybackStart(startInfo).ConfigureAwait(false);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to report playback start");
        }
    }

    private void StartProgressTimer()
    {
        // Stop any existing timer
        _progressTimer?.Dispose();

        // Report progress every 2 seconds
        _progressTimer = new Timer(
            async _ => await ReportPlaybackProgressAsync().ConfigureAwait(false),
            null,
            TimeSpan.FromSeconds(2),
            TimeSpan.FromSeconds(2));
    }

    private void StopProgressTimer()
    {
        _progressTimer?.Dispose();
        _progressTimer = null;
    }

    private async Task ReportPlaybackProgressAsync()
    {
        if (!IsPlaying || !CurrentItemId.HasValue)
        {
            return;
        }

        try
        {
            var status = await _lmsClient.GetPlayerStatusAsync(_player.MacAddress).ConfigureAwait(false);
            if (status == null)
            {
                return;
            }

            // LMS reports time relative to the current stream, but after seeking
            // we're playing a transcoded stream that starts at the seek position.
            // Add the seek offset to get the actual track position.
            var positionTicks = (long)(status.Time * TimeSpan.TicksPerSecond) + _seekOffsetTicks;
            var isPaused = status.Mode == "pause";

            // Update our local state from LMS
            IsPaused = isPaused;

            // Check if playback has stopped on LMS side (track ended)
            // Only advance if we're not paused - LMS can briefly report "stop" during transitions
            if (status.Mode == "stop" && !IsPaused)
            {
                // Double-check by getting status again after a brief delay to avoid false positives
                await Task.Delay(500).ConfigureAwait(false);
                var confirmStatus = await _lmsClient.GetPlayerStatusAsync(_player.MacAddress).ConfigureAwait(false);
                if (confirmStatus?.Mode != "stop")
                {
                    _logger.LogDebug("LMS mode changed from stop, ignoring");
                    return;
                }

                _logger.LogInformation("LMS playback stopped, checking if we should advance to next track");

                // Check if there are more tracks in the playlist
                if (_playlistIndex < _playlist.Length - 1)
                {
                    _logger.LogInformation(
                        "Track ended, advancing to next track (index {Index}/{Total})",
                        _playlistIndex + 2,
                        _playlist.Length);
                    await PlayItemAtIndexAsync(_playlistIndex + 1).ConfigureAwait(false);
                }
                else
                {
                    _logger.LogInformation("Playlist finished, reporting playback stopped");
                    await ReportPlaybackStoppedAsync().ConfigureAwait(false);
                }

                return;
            }

            var progressInfo = new PlaybackProgressInfo
            {
                ItemId = CurrentItemId.Value,
                SessionId = _session.Id,
                IsPaused = isPaused,
                PositionTicks = positionTicks,
                PlayMethod = PlayMethod.DirectStream,
                CanSeek = true,
                IsMuted = status.Volume == 0,
                VolumeLevel = status.Volume
            };

            await _sessionManager.OnPlaybackProgress(progressInfo).ConfigureAwait(false);
        }
        catch (Exception ex)
        {
            _logger.LogDebug(ex, "Error reporting playback progress");
        }
    }

    private async Task ReportPlaybackStoppedAsync()
    {
        if (!CurrentItemId.HasValue)
        {
            return;
        }

        try
        {
            StopProgressTimer();

            var stopInfo = new PlaybackStopInfo
            {
                ItemId = CurrentItemId.Value,
                SessionId = _session.Id
            };

            _logger.LogInformation("Reporting playback stopped for item {ItemId}", CurrentItemId.Value);
            await _sessionManager.OnPlaybackStopped(stopInfo).ConfigureAwait(false);

            IsPlaying = false;
            IsPaused = false;
            CurrentItemId = null;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to report playback stopped");
        }
    }

    private async Task HandlePlaystateCommandAsync<T>(T data, CancellationToken cancellationToken)
    {
        if (data is not PlaystateRequest playstateRequest)
        {
            _logger.LogWarning("Expected PlaystateRequest but got {Type}", data?.GetType().Name);
            return;
        }

        _logger.LogInformation(
            "Playstate command {Command} for player {PlayerName} ({Mac})",
            playstateRequest.Command,
            _player.Name,
            _player.MacAddress);

        switch (playstateRequest.Command)
        {
            case PlaystateCommand.Stop:
                var stopResult = await _lmsClient.StopAsync(_player.MacAddress).ConfigureAwait(false);
                _logger.LogInformation("Stop command result: {Result}", stopResult);
                await ReportPlaybackStoppedAsync().ConfigureAwait(false);
                break;

            case PlaystateCommand.Pause:
                var pauseResult = await _lmsClient.PauseAsync(_player.MacAddress).ConfigureAwait(false);
                _logger.LogInformation("Pause command result: {Result}", pauseResult);
                IsPaused = true;
                break;

            case PlaystateCommand.Unpause:
                var playResult = await _lmsClient.PlayAsync(_player.MacAddress).ConfigureAwait(false);
                _logger.LogInformation("Unpause/Play command result: {Result}", playResult);
                IsPaused = false;
                break;

            case PlaystateCommand.PlayPause:
                // Toggle play/pause - check current state first
                var currentState = await _lmsClient.GetPlayerStatusAsync(_player.MacAddress).ConfigureAwait(false);
                if (currentState?.Mode == "play")
                {
                    var togglePauseResult = await _lmsClient.PauseAsync(_player.MacAddress).ConfigureAwait(false);
                    _logger.LogInformation("PlayPause toggle (pause) result: {Result}", togglePauseResult);
                    IsPaused = true;
                }
                else
                {
                    var togglePlayResult = await _lmsClient.PlayAsync(_player.MacAddress).ConfigureAwait(false);
                    _logger.LogInformation("PlayPause toggle (play) result: {Result}", togglePlayResult);
                    IsPaused = false;
                }

                break;

            case PlaystateCommand.Seek:
                _logger.LogInformation(
                    "Seek command received for player {PlayerName}, SeekPositionTicks: {Ticks}, CurrentItemId: {ItemId}, CurrentSeekOffset: {Offset}",
                    _player.Name,
                    playstateRequest.SeekPositionTicks,
                    CurrentItemId,
                    _seekOffsetTicks);
                if (playstateRequest.SeekPositionTicks.HasValue && CurrentItemId.HasValue)
                {
                    var positionTicks = playstateRequest.SeekPositionTicks.Value;
                    var positionSeconds = positionTicks / TimeSpan.TicksPerSecond;

                    // Check if we're using direct file path mode - if so, LMS can seek natively
                    var config = Plugin.Instance?.Configuration;
                    var canSeekNatively = config?.UseDirectFilePath == true
                        && !string.IsNullOrEmpty(config.JellyfinMediaPath)
                        && !string.IsNullOrEmpty(config.LmsMediaPath)
                        && _currentItem?.Path != null
                        && _currentItem.Path.StartsWith(config.JellyfinMediaPath, StringComparison.OrdinalIgnoreCase);

                    if (canSeekNatively)
                    {
                        // Use native LMS seeking - much smoother!
                        _logger.LogInformation("Seeking natively to {Seconds}s using LMS time command", positionSeconds);
                        await _lmsClient.SeekAsync(_player.MacAddress, positionSeconds).ConfigureAwait(false);
                        // No seek offset needed - LMS handles position tracking natively
                        _seekOffsetTicks = 0;
                    }
                    else
                    {
                        // For HTTP streams, LMS can't seek directly - we need to restart with startTimeTicks
                        // Build a new URL with the seek position and restart playback
                        var streamUrl = BuildStreamUrlWithPosition(CurrentItemId.Value, positionTicks);
                        _logger.LogInformation(
                            "Seeking by restarting stream at position {Seconds}s: {Url}",
                            positionSeconds,
                            streamUrl);

                        await _lmsClient.PlayUrlAsync(_player.MacAddress, streamUrl).ConfigureAwait(false);

                        // Track the seek offset so we report the correct position
                        // The transcoded stream starts at 0, but we need to report the actual track position
                        _seekOffsetTicks = positionTicks;
                    }

                    _logger.LogInformation("Seek offset is now {Ticks} ticks ({Seconds}s)", _seekOffsetTicks, _seekOffsetTicks / TimeSpan.TicksPerSecond);
                }
                else
                {
                    _logger.LogWarning("Seek command received but SeekPositionTicks or CurrentItemId is null");
                }

                break;

            case PlaystateCommand.NextTrack:
                if (_playlistIndex < _playlist.Length - 1)
                {
                    _logger.LogInformation("Skipping to next track (index {Index})", _playlistIndex + 1);
                    await PlayItemAtIndexAsync(_playlistIndex + 1).ConfigureAwait(false);
                }
                else
                {
                    _logger.LogInformation("Already at last track, stopping playback");
                    await _lmsClient.StopAsync(_player.MacAddress).ConfigureAwait(false);
                    await ReportPlaybackStoppedAsync().ConfigureAwait(false);
                }

                break;

            case PlaystateCommand.PreviousTrack:
                if (_playlistIndex > 0)
                {
                    _logger.LogInformation("Skipping to previous track (index {Index})", _playlistIndex - 1);
                    await PlayItemAtIndexAsync(_playlistIndex - 1).ConfigureAwait(false);
                }
                else
                {
                    // At first track, restart from beginning
                    _logger.LogInformation("At first track, restarting from beginning");
                    await _lmsClient.SeekAsync(_player.MacAddress, 0).ConfigureAwait(false);
                }

                break;

            default:
                _logger.LogDebug("Unhandled playstate command: {Command}", playstateRequest.Command);
                break;
        }
    }

    private async Task HandleGeneralCommandAsync<T>(T data, CancellationToken cancellationToken)
    {
        if (data is not GeneralCommand command)
        {
            _logger.LogWarning("Expected GeneralCommand but got {Type}", data?.GetType().Name);
            return;
        }

        _logger.LogDebug(
            "General command {CommandName} for player {PlayerName}",
            command.Name,
            _player.Name);

        switch (command.Name)
        {
            case GeneralCommandType.SetVolume:
                if (command.Arguments.TryGetValue("Volume", out var volumeStr) &&
                    int.TryParse(volumeStr, out var volume))
                {
                    await _lmsClient.SetVolumeAsync(_player.MacAddress, volume).ConfigureAwait(false);
                }

                break;

            case GeneralCommandType.VolumeUp:
                var currentStatus = await _lmsClient.GetPlayerStatusAsync(_player.MacAddress).ConfigureAwait(false);
                if (currentStatus != null)
                {
                    var newVolume = Math.Min(100, currentStatus.Volume + 5);
                    await _lmsClient.SetVolumeAsync(_player.MacAddress, newVolume).ConfigureAwait(false);
                }

                break;

            case GeneralCommandType.VolumeDown:
                var status = await _lmsClient.GetPlayerStatusAsync(_player.MacAddress).ConfigureAwait(false);
                if (status != null)
                {
                    var newVolume = Math.Max(0, status.Volume - 5);
                    await _lmsClient.SetVolumeAsync(_player.MacAddress, newVolume).ConfigureAwait(false);
                }

                break;

            case GeneralCommandType.Mute:
                await _lmsClient.SetVolumeAsync(_player.MacAddress, 0).ConfigureAwait(false);
                break;

            case GeneralCommandType.ToggleMute:
                // TODO: Track mute state to toggle properly
                break;

            default:
                _logger.LogDebug("Unhandled general command: {Command}", command.Name);
                break;
        }
    }

    /// <summary>
    /// Builds the playback URL or file path for the given item.
    /// Returns a tuple of (url/path, isDirectFilePath).
    /// </summary>
    private (string Url, bool IsDirectPath) BuildPlaybackUrl(Guid itemId, long startPositionTicks)
    {
        var config = Plugin.Instance?.Configuration;

        // Check if direct file path mode is enabled and configured
        if (config?.UseDirectFilePath == true
            && !string.IsNullOrEmpty(config.JellyfinMediaPath)
            && !string.IsNullOrEmpty(config.LmsMediaPath)
            && _currentItem?.Path != null)
        {
            var directPath = BuildDirectFilePath(_currentItem.Path, config.JellyfinMediaPath, config.LmsMediaPath);
            if (directPath != null)
            {
                _logger.LogDebug(
                    "Using direct file path: {OriginalPath} -> {MappedPath}",
                    _currentItem.Path,
                    directPath);
                return (directPath, true);
            }

            _logger.LogWarning(
                "Direct file path mode enabled but path mapping failed for: {Path}",
                _currentItem.Path);
        }

        // Fall back to HTTP streaming
        return (BuildStreamUrlWithPosition(itemId, startPositionTicks), false);
    }

    /// <summary>
    /// Maps a Jellyfin file path to an LMS file path using the configured path prefixes.
    /// </summary>
    private static string? BuildDirectFilePath(string jellyfinPath, string jellyfinPrefix, string lmsPrefix)
    {
        // Normalize path separators for comparison
        var normalizedPath = jellyfinPath.Replace('\\', '/');
        var normalizedJellyfinPrefix = jellyfinPrefix.TrimEnd('/', '\\').Replace('\\', '/');
        var normalizedLmsPrefix = lmsPrefix.TrimEnd('/', '\\').Replace('\\', '/');

        if (!normalizedPath.StartsWith(normalizedJellyfinPrefix, StringComparison.OrdinalIgnoreCase))
        {
            return null;
        }

        // Replace the prefix
        var relativePath = normalizedPath[normalizedJellyfinPrefix.Length..];
        return normalizedLmsPrefix + relativePath;
    }

    private string BuildStreamUrl(Guid itemId)
    {
        return BuildStreamUrlWithPosition(itemId, 0);
    }

    private string BuildStreamUrlWithPosition(Guid itemId, long startPositionTicks)
    {
        var config = Plugin.Instance?.Configuration;
        var jellyfinUrl = config?.JellyfinServerUrl?.TrimEnd('/') ?? "http://localhost:8096";
        var apiKey = config?.JellyfinApiKey ?? string.Empty;

        string url;

        if (startPositionTicks > 0)
        {
            // For seeking, we need to use transcoding (static=true doesn't support startTimeTicks)
            // Use MP3 transcoding with the start position
            // Add a cache-busting parameter to ensure we get a fresh stream on each seek
            var cacheBuster = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
            url = $"{jellyfinUrl}/Audio/{itemId}/stream.mp3?audioCodec=mp3&audioBitRate=320000&startTimeTicks={startPositionTicks}&_={cacheBuster}";
        }
        else
        {
            // For normal playback from start, use static streaming (better quality, no transcoding)
            url = $"{jellyfinUrl}/Audio/{itemId}/stream.mp3?static=true";
        }

        if (!string.IsNullOrEmpty(apiKey))
        {
            url += $"&api_key={apiKey}";
        }

        return url;
    }

    /// <inheritdoc />
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    /// <summary>
    /// Disposes managed resources.
    /// </summary>
    /// <param name="disposing">Whether to dispose managed resources.</param>
    protected virtual void Dispose(bool disposing)
    {
        if (_disposed)
        {
            return;
        }

        if (disposing)
        {
            StopProgressTimer();
        }

        _disposed = true;
    }
}