loop/node-server/assets/script.js

// 1. Sélection des éléments du DOM
const vinyl = document.getElementById('vinyl');
const originalSrc = audio.getAttribute('src');
const audio = document.getElementById('audio');
const progress = document.getElementById('progress');
const currentTimeEl = document.getElementById('currentTime');
const durationEl = document.getElementById('duration');
const backwardBtn = document.getElementById('backward');
const forwardBtn = document.getElementById('forward');
const loopBtn = document.getElementById('loop');

// 2. Variables utiles
let isPlaying = false;
let isLooping = false;
let idleTimeout = null;
let reverseInterval = null;
let reverseAudioLoaded = false;
const reverseSrc = audio.dataset.reverseSrc;


// 3. Variables pour calculer la vitesse de rotation
let lastPosition = null;
let lastTime = null;

// 4. Connexion Socket.io
const socket = io();

socket.on('position', (position) => {
  const now = Date.now();

  if (lastPosition !== null && lastTime !== null) {
    const deltaPos = position - lastPosition;
    const deltaTime = (now - lastTime) / 1000;

    const speed = deltaPos / deltaTime;
    console.log('instant speed:', speed);

    clearTimeout(idleTimeout);

    if (Math.abs(speed) < 15) {
      stopPlayback();
      return;
    }

      const isReverse = speed < 0;

      // Simuler reverse
      if (isReverse) {
        simulateReverse(Math.abs(speed));
      } else {
        stopReverse();
        let playbackSpeed = 1 + speed * 0.0003;
        playbackSpeed = Math.max(0.5, Math.min(1.5, playbackSpeed));
        controlPlayback(playbackSpeed);
      }
    
  }

  lastPosition = position;
  lastTime = now;

  // Détecter l'inactivité : si pas de mise à jour pendant 300ms → stop
  idleTimeout = setTimeout(() => {
    stopPlayback();
  }, 300);
});

// 5. Fonctions

function togglePlay() {
  if (isPlaying) {
    audio.pause();
    vinyl.style.animationPlayState = 'paused';
  } else {
    audio.play();
    vinyl.style.animationPlayState = 'running';
  }
  isPlaying = !isPlaying;
}

function updateProgress() {
  const progressPercent = (audio.currentTime / audio.duration) * 100;
  progress.value = progressPercent;
  currentTimeEl.textContent = formatTime(audio.currentTime);
}

function formatTime(time) {
  const minutes = Math.floor(time / 60);
  const seconds = Math.floor(time % 60);
  return `${minutes}:${seconds < 10 ? '0' : ''}${seconds}`;
}

function setProgress(e) {
  const width = progress.clientWidth;
  const clickX = e.offsetX;
  const duration = audio.duration;
  audio.currentTime = (clickX / width) * duration;
}

// Fonction pour régler la lecture selon la vitesse

function controlPlayback(speed) {
  stopReverse(); // On stoppe le reverse si actif
  if (speed > 0) {
    if (!isPlaying) {
      audio.play();
      vinyl.style.animationPlayState = 'running';
      isPlaying = true;
    }
    audio.playbackRate = speed;
  }
}

function stopPlayback() {
  audio.pause();
  vinyl.style.animationPlayState = 'paused';
  isPlaying = false;
}

function simulateReverse(speed) {
  const reverseSpeed = Math.min(speed * 0.01, 2); // seconds per step

  if (!reverseAudioLoaded && reverseSrc) {
    audio.src = reverseSrc;
    audio.load();
    reverseAudioLoaded = true;
    audio.addEventListener('loadedmetadata', () => {
      audio.currentTime = audio.duration - 0.1; // start from the end
    }, { once: true });
    return; // attend que le fichier soit chargé
  }

  if (!reverseInterval) {
    reverseInterval = setInterval(() => {
      if (audio.currentTime > 0.05) {
        audio.currentTime -= reverseSpeed * 0.1;
        vinyl.style.animationPlayState = 'running';
      } else {
        stopPlayback();
      }
    }, 100);

    if (!isPlaying) {
      isPlaying = true;
    }
  }

  audio.pause(); // on met en pause le vrai son pour éviter conflit
}

function stopReverse() {
  if (reverseInterval) {
    clearInterval(reverseInterval);
    reverseInterval = null;
  }

  if (reverseAudioLoaded) {
    const currentTime = audio.currentTime;
    audio.src = originalSrc;
    audio.load();
    audio.addEventListener('loadedmetadata', () => {
      audio.currentTime = Math.min(currentTime, audio.duration - 0.1);
    }, { once: true });
    reverseAudioLoaded = false;
  }
}



// 6. Événements

vinyl.addEventListener('click', togglePlay);
audio.addEventListener('timeupdate', updateProgress);
audio.addEventListener('loadedmetadata', () => {
  durationEl.textContent = formatTime(audio.duration);
});
progress.addEventListener('click', setProgress);

backwardBtn.addEventListener('click', () => {
  audio.currentTime = Math.max(0, audio.currentTime - 10);
});

forwardBtn.addEventListener('click', () => {
  audio.currentTime = Math.min(audio.duration, audio.currentTime + 10);
});

loopBtn.addEventListener('click', () => {
  isLooping = !isLooping;
  loopBtn.style.backgroundColor = isLooping ? 'white' : 'transparent';
  loopBtn.style.color = isLooping ? '#18344b' : 'white';
});

audio.addEventListener('ended', () => {
  if (isLooping) {
    audio.currentTime = 0;
    audio.play();
  } else {
    vinyl.style.animationPlayState = 'paused';
    isPlaying = false;
  }
});