class SimpleAudioPlayer {
  constructor({
    audioSelector = '#globalAudio',
    playBtnSelector = '.player-button',
    timelineSelector = '.timeline',
    infoSelector = '#timeInfo',
    nowPlayingSelector = '#nowPlayingInfo',
    containerSelector = '#audioPlayerContainer',
    footerSelector = 'footer'
  } = {}) {
    // Elements
    this.audio     = document.querySelector(audioSelector);
    this.playBtn   = document.querySelector(playBtnSelector);
    this.timeline  = document.querySelector(timelineSelector);
    this.timeInfo  = document.querySelector(infoSelector);
    this.nowInfo   = document.querySelector(nowPlayingSelector);
    this.container = document.querySelector(containerSelector);
    this.footer    = document.querySelector(footerSelector);

    // State
    this.isSeeking    = false;
    this.rafId        = null;
    this.abortCtrl    = null;
    this._posInterval = null;

    // Pre-compute icons once
    const fill = getComputedStyle(document.documentElement)
                    .getPropertyValue('--dark-background').trim();
    this.icons = {
      play : this.svg(
        'M10 18a8 8 0 100-16 8 8 0 000 16zM9.555 7.168A1 1 0 008 8v4a1 1 0 001.555.832l3-2a1 1 0 000-1.664l-3-2z',
        fill
      ),
      pause: this.svg(
        'M18 10a8 8 0 11-16 0 8 8 0 0116 0zM7 8a1 1 0 012 0v4a1 1 0 11-2 0V8zm5-1a1 1 0 00-1 1v4a1 1 0 102 0V8a1 1 0 00-1-1z',
        fill
      ),
      sound: this.svg(
        'M9.383 3.076A1 1 0 0110 4v12a1 1 0 01-1.707.707L4.586 13H2a1 1 0 01-1-1V8a1 1 0 011-1h2.586l3.707-3.707a1 1 0 011.09-.217zM14.657 2.929a1 1 0 011.414 0A9.972 9.972 0 0119 10a9.972 9.972 0 01-2.929 7.071 1 1 0 01-1.414-1.414A7.971 7.971 0 0017 10c0-2.21-.894-4.208-2.343-5.657a1 1 0 010-1.414zm-2.829 2.828a1 1 0 011.415 0A5.983 5.983 0 0115 10a5.984 5.984 0 01-1.757 4.243 1 1 0 01-1.415-1.415A3.984 3.984 0 0013 10a3.983 3.983 0 00-1.172-2.828 1 1 0 010-1.415z',
        fill
      )
    };

    // Seeked => refresh timeline if external seek (e.g. Android controls)
    this.audio.addEventListener('seeked', () => this.updateTimeline());

    // Bind UI events
    this._bindEvents();

    // Setup MediaSession handlers + heartbeat
    this._initMediaSession();
  }

  // Minimal SVG helper
  svg(pathD, fill) {
    return `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20" fill="${fill}">
      <path fill-rule="evenodd" d="${pathD}" clip-rule="evenodd"/>
    </svg>`;
  }

  _bindEvents() {
    this.playBtn.addEventListener('click', () => this.togglePlay());

    this.audio.addEventListener('loadedmetadata', () => {
      this.timeline.min   = 0;
      this.timeline.max   = this.audio.duration;
      this.timeline.value = 0;
      this.timeline.style.backgroundSize = '0% 100%';
    });

    this.audio.addEventListener('play',  () => this._updatePlayState());
    this.audio.addEventListener('pause', () => this._updatePlayState());
    this.audio.addEventListener('ended', () => this.playBtn.innerHTML = this.icons.play);

    // Native timeupdate => update timeline
    this.audio.addEventListener('timeupdate', () => this.updateTimeline());

    // Fallback interval for throttled mobile
    this._interval = setInterval(() => {
      if (!this.audio.paused && !this.isSeeking) {
        this.updateTimeline();
      }
    }, 500);

    // Unified seek input
    this.timeline.addEventListener('input', () => {
      this.isSeeking = true;
      this.audio.currentTime = this.timeline.value;

      // immediate Android sync
      if (navigator.mediaSession?.setPositionState && Number.isFinite(this.audio.duration)) {
        navigator.mediaSession.setPositionState({
          duration:     this.audio.duration,
          playbackRate: this.audio.playbackRate,
          position:     this.audio.currentTime
        });
      }

      this.updateTimeline();
      this.isSeeking = false;
    });
  }

  togglePlay() {
    this.audio.paused ? this.audio.play() : this.audio.pause();
  }

  _updatePlayState() {
    this.playBtn.innerHTML = this.audio.paused ? this.icons.play : this.icons.pause;
    if ('mediaSession' in navigator) {
      navigator.mediaSession.playbackState = this.audio.paused ? 'paused' : 'playing';
    }
  }

  _formatTime(sec) {
    const m = Math.floor(sec / 60), s = Math.floor(sec % 60);
    return `${m < 10 ? '0' : ''}${m}:${s < 10 ? '0' : ''}${s}`;
  }

  updateTimeline() {
    if (!this.audio.duration || this.isSeeking) return;

    // 1) Move the thumb
    this.timeline.value = this.audio.currentTime;
    // 2) Resize fill
    const pct = (this.audio.currentTime / this.audio.duration) * 100;
    this.timeline.style.backgroundSize = `${pct}% 100%`;
    // 3) Update text
    this.timeInfo.textContent =
      `${this._formatTime(this.audio.currentTime)} / ${this._formatTime(this.audio.duration)}`;
    // 4) Push to Android widget
    if (navigator.mediaSession?.setPositionState && Number.isFinite(this.audio.duration)) {
      navigator.mediaSession.setPositionState({
        duration:     this.audio.duration,
        playbackRate: this.audio.playbackRate,
        position:     this.audio.currentTime
      });
    }
  }

  async fileDownload() {
    const src   = this.audio.currentSrc || this.audio.src;
    if (!src) return;

    // Build the URL with your download flag + cache‑buster
    const downloadUrl = new URL(src, window.location.href);
    downloadUrl.searchParams.set('download', 'true');
    downloadUrl.searchParams.set('_',       Date.now());

    // Create a “real” link to that URL and click it
    const a = document.createElement('a');
    a.href = downloadUrl.toString();
    // NOTE: do NOT set a.download here – we want the server's Content-Disposition to drive it
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
  }

  async loadTrack(relUrl) {
    this.audio.pause();
    this.container.style.display = 'block';
    this.nowInfo.textContent = 'Loading…';

    this.abortCtrl?.abort();
    this.abortCtrl = new AbortController();

    try {
      const head = await fetch(`/media/${relUrl}`, {
        method: 'HEAD',
        signal: this.abortCtrl.signal
      });
      if (!head.ok) throw new Error(`Status ${head.status}`);

      this.audio.src = `/media/${relUrl}`;
      await this.audio.play();

      // Full breadcrumb
      const parts      = relUrl.split('/');
      const file       = parts.pop();
      const folderPath = parts.join(' › ').replace('Gottesdienste S','S'); // Special case
      this.nowInfo.innerHTML =
        `${folderPath}<br><strong>${file.replace(/\.[^/.]+$/, '')}</strong>`;

      if ('mediaSession' in navigator) {
        navigator.mediaSession.metadata = new MediaMetadata({
          title : file.replace(/\.[^/.]+$/, ''),
          artist: parts.pop(),
          artwork: [{ src:'/icons/logo-192x192.png', sizes:'192x192', type:'image/png' }]
        });
      }
    } catch (err) {
      if (err.name !== 'AbortError') {
        this.nowInfo.textContent = 'Error loading track';
        console.error(err);
      }
    }
  }

  _initMediaSession() {
    if (!('mediaSession' in navigator)) return;

    const wrap = fn => details => {
      fn(details);
      this.updateTimeline();
    };

    // Core controls
    navigator.mediaSession.setActionHandler('play',        wrap(() => this.audio.play()));
    navigator.mediaSession.setActionHandler('pause',       wrap(() => this.audio.pause()));
    navigator.mediaSession.setActionHandler('seekbackward', wrap(({seekOffset=10}) => {
      this.audio.currentTime = Math.max(0, this.audio.currentTime - seekOffset);
    }));
    navigator.mediaSession.setActionHandler('seekforward',  wrap(({seekOffset=10}) => {
      this.audio.currentTime = Math.min(this.audio.duration, this.audio.currentTime + seekOffset);
    }));
    navigator.mediaSession.setActionHandler('seekto',       wrap(({seekTime, fastSeek}) => {
      if (fastSeek && this.audio.fastSeek) this.audio.fastSeek(seekTime);
      else this.audio.currentTime = seekTime;
    }));

    // Prev & Next
    navigator.mediaSession.setActionHandler('previoustrack', wrap(() => {
      if (currentMusicIndex > 0) {
        const prevFile = currentMusicFiles[currentMusicIndex - 1];
        const prevLink = document.querySelector(`.play-file[data-url="${prevFile.path}"]`);
        if (prevLink) {
          prevLink.click();
        }
      }
    }));
    navigator.mediaSession.setActionHandler('nexttrack',     wrap(() => {
      if (currentMusicIndex < currentMusicFiles.length - 1) {
        const nextFile = currentMusicFiles[currentMusicIndex + 1];
        const nextLink = document.querySelector(`.play-file[data-url="${nextFile.path}"]`);
        if (nextLink) {
          nextLink.click();
        }
      }
    }));

    // Heartbeat for widget
    this._posInterval = setInterval(() => {
      if (!this.audio.paused && navigator.mediaSession?.setPositionState && Number.isFinite(this.audio.duration)) {
        navigator.mediaSession.setPositionState({
          duration:     this.audio.duration,
          playbackRate: this.audio.playbackRate,
          position:     this.audio.currentTime
        });
      }
    }, 1000);
  }
}

// Initialize instance
const player = new SimpleAudioPlayer();