import React, { useState, useEffect, useCallback } from 'react';
import SongTable from './SongTable';
import NowPlaying from './NowPlaying';
import AddSongPanel from './AddSongPanel';
import { API, getDisplayTitle, PlaylistItem } from '../api/player';

const App: React.FC = () => {
  const [isPlaying, setIsPlaying] = useState(false);
  const [nowPlayingSong, setNowPlayingSong] = useState<string | null>(null);
  const [nowPlayingFileName, setNowPlayingFileName] = useState<string | null>(null);
  const [volume, setVolume] = useState(100);
  const [volumeSettingIsLocked, setVolumeSettingIsLocked] = useState(false);
  const [songs, setSongs] = useState<PlaylistItem[]>([]);
  const [ws, setWs] = useState<WebSocket | null>(null);

  const fetchPlaylist = useCallback(async () => {
    const playlist = await API.getPlaylist();
    setSongs(playlist);
  }, []);

  const fetchNowPlaying = useCallback(async () => {
    const nowPlaying = await API.getNowPlaying();
    setNowPlayingSong(getDisplayTitle(nowPlaying.playingItem));
    setNowPlayingFileName(nowPlaying.playingItem.filename);
    setIsPlaying(!nowPlaying.isPaused);

    if (!volumeSettingIsLocked) {
      setVolume(nowPlaying.volume);
    }
  }, [volumeSettingIsLocked]);

  const handleAddURL = async (url: string) => {
    const urlToAdd = url.trim();
    if (urlToAdd) {
      await API.addToPlaylist(urlToAdd);
      fetchPlaylist();

      if (!isPlaying) {
        await API.play();
      }
    }
  };

  const handleDelete = (index: number) => {
    setSongs(songs.filter((_, i) => i !== index));
    API.removeFromPlaylist(index);
    fetchPlaylist();
    fetchNowPlaying();
  };

  const handleSkipTo = async (index: number) => {
    const song = songs[index];
    if (song.playing) {
      togglePlayPause();
    } else {
      await API.skipTo(index);
      await API.play();
    }

    fetchNowPlaying();
    fetchPlaylist();
  };

  const togglePlayPause = async () => {
    if (isPlaying) {
      await API.pause();
    } else {
      await API.play();
    }

    fetchNowPlaying();
  };

  const handleSkip = async () => {
    await API.skip();
    fetchNowPlaying();
  };

  const handlePrevious = async () => {
    await API.previous();
    fetchNowPlaying();
  };

  const handleVolumeSettingChange = async (volume: number) => {
    setVolume(volume);
    await API.setVolume(volume);
  };

  const handleWebSocketEvent = useCallback((event: any) => {
    switch (event.event) {
      case 'user_modify':
      case 'end-file':
      case 'playback-restart':
      case 'metadata_update':
        fetchPlaylist();
        fetchNowPlaying();
        break;
    }
  }, [fetchPlaylist, fetchNowPlaying]);

  // Initial data fetch
  useEffect(() => {
    fetchPlaylist();
    fetchNowPlaying();
  }, [fetchPlaylist, fetchNowPlaying]);

  // Update WebSocket connection
  useEffect(() => {
    const websocket = API.subscribeToEvents(handleWebSocketEvent);
    setWs(websocket);

    // Handle page visibility changes, so if the user navigates back to this tab, we reconnect the WebSocket
    const handleVisibilityChange = () => {
      if (document.visibilityState === 'visible' && (!ws || ws.readyState === WebSocket.CLOSED)) {
        const newWs = API.subscribeToEvents(handleWebSocketEvent);
        setWs(newWs);
      }
    };

    document.addEventListener('visibilitychange', handleVisibilityChange);

    return () => {
      document.removeEventListener('visibilitychange', handleVisibilityChange);
      if (websocket) {
        websocket.close();
      }
    };
  }, [handleWebSocketEvent]);

  return (
    <div className="flex items-center justify-center h-screen w-screen bg-black md:py-10">
      <div className="bg-violet-900 w-full md:max-w-2xl h-full md:max-h-xl md:border md:rounded-2xl flex flex-col">
        <NowPlaying 
          className="flex flex-row md:rounded-t-2xl" 
          songName={nowPlayingSong || "(Not Playing)"} 
          fileName={nowPlayingFileName || ""} 
          isPlaying={isPlaying} 
          onPlayPause={togglePlayPause} 
          onSkip={handleSkip} 
          onPrevious={handlePrevious} 
          volume={volume}
          onVolumeSettingChange={handleVolumeSettingChange}
          onVolumeWillChange={() => setVolumeSettingIsLocked(true)}
          onVolumeDidChange={() => setVolumeSettingIsLocked(false)}
        />

        {songs.length > 0 ? (
          <SongTable 
            songs={songs}
            isPlaying={isPlaying}
            onDelete={handleDelete} 
            onSkipTo={handleSkipTo} 
          />
        ) : (
          <div className="flex items-center justify-center h-full">
            <div className="text-white text-2xl font-bold">Playlist is empty</div>
          </div>
        )}

        <AddSongPanel onAddURL={handleAddURL} />
      </div>
    </div>
  );
};

export default App;