using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;

namespace PainoBar_Helper
{
    /// <summary>
    /// Manages the Pianobar process lifecycle and communication
    /// </summary>
    public class PianobarManager : IDisposable
    {
        private Process? _process;
        private StreamWriter? _inputWriter;
        private bool _isConnected;
        private readonly object _lockObject = new object();

        public event EventHandler<SongChangedEventArgs>? SongChanged;
        public event EventHandler<string>? StationChanged;
        public event EventHandler<PianobarEventArgs>? EventOccurred;
        public event EventHandler? Connected;
        public event EventHandler? Disconnected;
        public event EventHandler<string>? OutputReceived;

        public bool IsConnected
        {
            get { lock (_lockObject) return _isConnected; }
            private set
            {
                bool changed = false;
                lock (_lockObject)
                {
                    if (_isConnected != value)
                    {
                        _isConnected = value;
                        changed = true;
                    }
                }
                if (changed)
                {
                    if (value)
                        Connected?.Invoke(this, EventArgs.Empty);
                    else
                        Disconnected?.Invoke(this, EventArgs.Empty);
                }
            }
        }

        public string? CurrentSong { get; private set; }
        public string? CurrentArtist { get; private set; }
        public string? CurrentAlbum { get; private set; }
        public string? CurrentAlbumArtUrl { get; private set; }
        public string? CurrentStation { get; private set; }
        public bool IsPlaying { get; private set; } = true;

        public void Connect(string pianobarPath, string? configPath = null)
        {
            if (IsConnected)
                throw new InvalidOperationException("Already connected to Pianobar.");

            // Check if pianobar is already running
            var existingProcesses = Process.GetProcessesByName("pianobar");
            if (existingProcesses.Length > 0)
            {
                foreach (var proc in existingProcesses)
                    proc.Dispose();
                throw new InvalidOperationException("Pianobar is already running. Please close existing instances.");
            }

            try
            {
                var startInfo = new ProcessStartInfo
                {
                    FileName = pianobarPath,
                    UseShellExecute = false,
                    RedirectStandardInput = true,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    CreateNoWindow = true,
                    StandardOutputEncoding = Encoding.UTF8,
                    StandardErrorEncoding = Encoding.UTF8
                };

                if (!string.IsNullOrEmpty(configPath))
                {
                    startInfo.Arguments = $"-c \"{configPath}\"";
                }

                _process = new Process { StartInfo = startInfo };
                _process.OutputDataReceived += Process_OutputDataReceived;
                _process.ErrorDataReceived += Process_ErrorDataReceived;
                _process.Exited += Process_Exited;
                _process.EnableRaisingEvents = true;

                _process.Start();
                _inputWriter = _process.StandardInput;
                _process.BeginOutputReadLine();
                _process.BeginErrorReadLine();

                IsConnected = true;
                RaiseEvent("Connected to Pianobar");
            }
            catch (Exception ex)
            {
                Cleanup();
                throw new InvalidOperationException($"Failed to start Pianobar: {ex.Message}", ex);
            }
        }

        public void Disconnect()
        {
            if (!IsConnected)
                return;

            Cleanup();
            IsConnected = false;
            RaiseEvent("Disconnected from Pianobar");
        }

        public void SendCommand(char command)
        {
            if (!IsConnected || _inputWriter == null)
                throw new InvalidOperationException("Not connected to Pianobar.");

            try
            {
                _inputWriter.WriteLine(command);
                _inputWriter.Flush();
            }
            catch (Exception ex)
            {
                throw new InvalidOperationException($"Failed to send command: {ex.Message}", ex);
            }
        }

        public void SendCommand(string command)
        {
            if (!IsConnected || _inputWriter == null)
                throw new InvalidOperationException("Not connected to Pianobar.");

            try
            {
                _inputWriter.WriteLine(command);
                _inputWriter.Flush();
            }
            catch (Exception ex)
            {
                throw new InvalidOperationException($"Failed to send command: {ex.Message}", ex);
            }
        }

        public void PlayPause()
        {
            SendCommand('p');
            IsPlaying = !IsPlaying;
            RaiseEvent(IsPlaying ? "Resumed" : "Paused");
        }

        public void Skip()
        {
            SendCommand('n');
            RaiseEvent("Skipped Track");
        }

        public void ShowStations()
        {
            SendCommand('s');
        }

        private void Process_OutputDataReceived(object? sender, DataReceivedEventArgs e)
        {
            if (string.IsNullOrEmpty(e.Data))
                return;

            string line = e.Data;
            OutputReceived?.Invoke(this, line);

            ParseOutput(line);
        }

        private void Process_ErrorDataReceived(object? sender, DataReceivedEventArgs e)
        {
            if (!string.IsNullOrEmpty(e.Data))
                OutputReceived?.Invoke(this, e.Data);
        }

        private void Process_Exited(object? sender, EventArgs e)
        {
            IsConnected = false;
            RaiseEvent("Pianobar process exited");
        }

        private void ParseOutput(string line)
        {
            try
            {
                // Parse song information
                if (line.Contains("|>"))
                {
                    // Song is playing
                    IsPlaying = true;
                    ParseSongLine(line);
                }
                else if (line.Contains("||"))
                {
                    // Song is paused
                    IsPlaying = false;
                }

                // Parse station selection
                var stationMatch = Regex.Match(line, @"\|\s*Station\s+""(.+?)""");
                if (stationMatch.Success)
                {
                    CurrentStation = stationMatch.Groups[1].Value;
                    StationChanged?.Invoke(this, CurrentStation);
                    RaiseEvent("Station Selected");
                }

                // Parse song metadata
                if (line.Contains("Title:"))
                {
                    var match = Regex.Match(line, @"Title:\s*(.+)");
                    if (match.Success)
                        CurrentSong = match.Groups[1].Value.Trim();
                }
                else if (line.Contains("Artist:"))
                {
                    var match = Regex.Match(line, @"Artist:\s*(.+)");
                    if (match.Success)
                        CurrentArtist = match.Groups[1].Value.Trim();
                }
                else if (line.Contains("Album:"))
                {
                    var match = Regex.Match(line, @"Album:\s*(.+)");
                    if (match.Success)
                        CurrentAlbum = match.Groups[1].Value.Trim();
                }
                else if (line.Contains("coverArt"))
                {
                    var match = Regex.Match(line, @"coverArt:\s*(.+)");
                    if (match.Success)
                    {
                        CurrentAlbumArtUrl = match.Groups[1].Value.Trim();
                        TriggerSongChanged();
                    }
                }
            }
            catch
            {
                // Ignore parsing errors
            }
        }

        private void ParseSongLine(string line)
        {
            // Parse format: |>  "Song Title" by "Artist" on "Album"
            var match = Regex.Match(line, @"\|>\s+""(.+?)""\s+by\s+""(.+?)""\s+on\s+""(.+?)""");
            if (match.Success)
            {
                CurrentSong = match.Groups[1].Value;
                CurrentArtist = match.Groups[2].Value;
                CurrentAlbum = match.Groups[3].Value;
                TriggerSongChanged();
            }
        }

        private void TriggerSongChanged()
        {
            if (!string.IsNullOrEmpty(CurrentSong) && !string.IsNullOrEmpty(CurrentArtist))
            {
                SongChanged?.Invoke(this, new SongChangedEventArgs
                {
                    Title = CurrentSong,
                    Artist = CurrentArtist,
                    Album = CurrentAlbum,
                    AlbumArtUrl = CurrentAlbumArtUrl
                });
                RaiseEvent("Song Changed");
            }
        }

        private void RaiseEvent(string eventText)
        {
            EventOccurred?.Invoke(this, new PianobarEventArgs { EventText = eventText });
        }

        private void Cleanup()
        {
            try
            {
                if (_process != null)
                {
                    _process.OutputDataReceived -= Process_OutputDataReceived;
                    _process.ErrorDataReceived -= Process_ErrorDataReceived;
                    _process.Exited -= Process_Exited;

                    _inputWriter?.Close();
                    _inputWriter = null;

                    // Don't kill the process, just detach
                    _process.Close();
                    _process = null;
                }
            }
            catch
            {
                // Ignore cleanup errors
            }
        }

        public void Dispose()
        {
            Disconnect();
        }
    }

    public class SongChangedEventArgs : EventArgs
    {
        public string? Title { get; set; }
        public string? Artist { get; set; }
        public string? Album { get; set; }
        public string? AlbumArtUrl { get; set; }
    }

    public class PianobarEventArgs : EventArgs
    {
        public string EventText { get; set; } = string.Empty;
    }
}