const { google } = require('googleapis');
const youtube = google.youtube('v3');

const YOUTUBE_API_KEY = process.env.YOUTUBE_API_KEY;
const PLAYLIST_ID = "PLmXxqSJJq-yXrCPGIT2gn8b34JjOrl4Xf";

const PLAYLISTS = {
  seventies: 'PLmXxqSJJq-yXrCPGIT2gn8b34JjOrl4Xf',
  eighties: 'PLmXxqSJJq-yUvMWKuZQAB_8yxnjZaOZUp',
  nineties: 'PLmXxqSJJq-yUF3jbzjF_pa--kuBuMlyQQ'
};

const API_KEY = process.env.YOUTUBE_API_KEY;

const cachedSongsByPlaylist = {};

const CACHE_TTL = 3600000; // 1 hour

/**
 * Fetches songs from YouTube playlist and returns them
 */
const fetchPlaylistSongs = async (playlistId = null) => {
  if (!playlistId) {
    console.warn("No playlist ID provided, using default");
    playlistId = PLAYLISTS.seventies; // default fallback
  }

  const now = Date.now();
  if (cachedSongsByPlaylist[playlistId] && 
      cachedSongsByPlaylist[playlistId].songs.length > 0 && 
      (now - cachedSongsByPlaylist[playlistId].timestamp) < CACHE_TTL) {
    console.log(`Using cached songs for playlist ${playlistId}`);
    return cachedSongsByPlaylist[playlistId].songs;
  }
  
  try {
    console.log(`Fetching fresh songs from YouTube API for playlist ${playlistId}...`);
    const playlistUrl = `https://www.googleapis.com/youtube/v3/playlistItems?part=snippet,contentDetails&maxResults=50&playlistId=${playlistId}&key=${YOUTUBE_API_KEY}`;
    const response = await fetch(playlistUrl);
    const data = await response.json();
    
    if (data.error) {
      console.error("YouTube API error:", data.error);
      throw new Error(data.error.message);
    }
    
    if (!data.items || !data.items.length) {
      throw new Error("No songs found in the playlist");
    }

    const songs = data.items.map((item, index) => ({
      id: index + 1,
      youtubeId: item.contentDetails.videoId,
      title: item.snippet.title,
      artist: item.snippet.videoOwnerChannelTitle || "Unknown Artist",
      coverUrl: item.snippet.thumbnails.high?.url || item.snippet.thumbnails.default?.url,
      playlistId: playlistId
    }));

    cachedSongsByPlaylist[playlistId] = {
      songs,
      timestamp: now
    };
    
    return songs;
  } catch (error) {
    console.error(`Error fetching YouTube playlist ${playlistId}:`, error);
    return cachedSongsByPlaylist[playlistId]?.songs || getDefaultSongs();
  }
};

const getAvailableSongIds = async (playlistId) => {
  const songs = await fetchPlaylistSongs(playlistId);
  return songs.map(song => song.id);
};

async function getPlaylistDetails() {
  try {
    const details = {};
    
    for (const [genre, playlistId] of Object.entries(PLAYLISTS)) {
      const response = await youtube.playlists.list({
        key: API_KEY,
        part: 'snippet,contentDetails',
        id: playlistId
      });
      
      const playlist = response.data.items[0];
      details[genre] = {
        id: playlistId,
        title: playlist.snippet.title,
        description: playlist.snippet.description,
        thumbnail: playlist.snippet.thumbnails.maxres || playlist.snippet.thumbnails.high,
        songCount: playlist.contentDetails.itemCount,
        votes: 0
      };
    }
    
    return details;
  } catch (error) {
    console.error('Error fetching playlist details:', error);
    throw error;
  }
}

module.exports = {
  fetchPlaylistSongs,
  getAvailableSongIds,
  PLAYLISTS,
  getPlaylistDetails
};