// Music playlist manager
(function() {
  'use strict';
  
  const MUSIC_FOLDER = 'music/';
  const PLAYLIST = [
    'Knights Of The Old Republic II - The Sith Lords — The Temple of Freedon Nadd (www.lightaudio.ru).mp3',
    'Soundtrack — StarWars (www.lightaudio.ru) (1).mp3',
    'Soundtrack — Starwars (www.lightaudio.ru).mp3',
    'StarWars — Across The Stars Love Theme (www.lightaudio.ru).mp3'
  ];
  
  let currentAudio = null;
  let currentTrackIndex = -1;
  let playedTracks = [];
  let volume = 0.5;
  let isPlaying = false;
  let isEnabled = true;
  
  function getRandomTrack() {
    if (playedTracks.length >= PLAYLIST.length) {
      playedTracks = [];
    }
    let available = PLAYLIST.filter((_, i) => !playedTracks.includes(i));
    if (available.length === 0) {
      playedTracks = [];
      available = PLAYLIST;
    }
    const randomIndex = Math.floor(Math.random() * available.length);
    const trackName = available[randomIndex];
    const trackIndex = PLAYLIST.indexOf(trackName);
    playedTracks.push(trackIndex);
    return { trackName, trackIndex };
  }
  
  function loadTrack(trackName) {
    return new Promise((resolve, reject) => {
      const audio = new Audio(MUSIC_FOLDER + trackName);
      audio.volume = volume;
      audio.addEventListener('loadeddata', () => resolve(audio));
      audio.addEventListener('error', (e) => reject(e));
      audio.load();
    });
  }
  
  function playNext() {
    if (!isEnabled) return;
    
    if (currentAudio) {
      currentAudio.pause();
      currentAudio = null;
    }
    
    const { trackName, trackIndex } = getRandomTrack();
    currentTrackIndex = trackIndex;
    
    loadTrack(trackName)
      .then((audio) => {
        currentAudio = audio;
        currentAudio.volume = volume;
        currentAudio.addEventListener('ended', () => {
          playNext();
        });
        currentAudio.addEventListener('error', () => {
          console.warn('Failed to load track:', trackName);
          playNext();
        });
        currentAudio.play().catch((e) => {
          console.warn('Failed to play track:', e);
        });
        isPlaying = true;
        updateUI();
      })
      .catch((e) => {
        console.warn('Failed to load track:', trackName, e);
        playNext();
      });
  }
  
  function stop() {
    if (currentAudio) {
      currentAudio.pause();
      currentAudio = null;
    }
    isPlaying = false;
    updateUI();
  }
  
  function setVolume(newVolume) {
    volume = Math.max(0, Math.min(1, newVolume));
    if (currentAudio) {
      currentAudio.volume = volume;
    }
    localStorage.setItem('musicVolume', volume.toString());
    updateUI();
  }
  
  function toggle() {
    isEnabled = !isEnabled;
    localStorage.setItem('musicEnabled', isEnabled.toString());
    if (isEnabled && !isPlaying) {
      playNext();
    } else if (!isEnabled) {
      stop();
    }
    updateUI();
  }
  
  function updateUI() {
    const volumeSlider = document.getElementById('music-volume-slider');
    const volumeValue = document.getElementById('music-volume-value');
    const musicToggle = document.getElementById('music-toggle');
    
    if (volumeSlider) {
      volumeSlider.value = volume;
    }
    if (volumeValue) {
      volumeValue.textContent = Math.round(volume * 100) + '%';
    }
    if (musicToggle) {
      musicToggle.textContent = isEnabled ? 'Выключить' : 'Включить';
      musicToggle.classList.toggle('active', isEnabled);
    }
  }
  
  function init() {
    const savedVolume = localStorage.getItem('musicVolume');
    if (savedVolume !== null) {
      volume = parseFloat(savedVolume);
    } else {
      volume = 0.5;
    }
    
    const savedEnabled = localStorage.getItem('musicEnabled');
    if (savedEnabled !== null) {
      isEnabled = savedEnabled === 'true';
    } else {
      isEnabled = true;
    }
    
    updateUI();
    
    if (isEnabled) {
      setTimeout(() => {
        playNext();
      }, 500);
    }
  }
  
  window.Music = {
    play: playNext,
    stop: stop,
    setVolume: setVolume,
    toggle: toggle,
    getVolume: () => volume,
    isEnabled: () => isEnabled,
    isPlaying: () => isPlaying,
    init: init
  };
})();