loop/node-server/assets/script.js

// 1. Sélection des éléments du DOM
const vinyl = document.getElementById('vinyl');
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;

// 3. Variables pour calcul de vitesse
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) < 5) {
      stopPlayback();
      return;
    }

    const isReverse = speed < 0;

    if (isReverse) {
      simulateReverse(Math.abs(speed));
    } else {
      stopReverse();
      controlPlayback(speed);
    }
  }

  lastPosition = position;
  lastTime = now;

  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;
}

// Lecture en avant selon la vitesse
function controlPlayback(speed) {
  stopReverse();

  if (speed > 0) {
    if (!isPlaying) {
      audio.play();
      vinyl.style.animationPlayState = 'running';
      isPlaying = true;
    }

    // Vitesse normalisée
    const normalized = Math.min(speed / 400, 1);
    const minRate = 0.3;
    const maxRate = 1.5;
    const playbackSpeed = minRate + (maxRate - minRate) * Math.pow(normalized, 1.2);

    audio.playbackRate = playbackSpeed;
    vinyl.style.animationDuration = `${1 / playbackSpeed * 2}s`;
    vinyl.style.animationDirection = 'normal';
  }
}

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

function simulateReverse(speed) {
  const reverseSpeed = Math.min(speed * 0.02, 2); // secondes à reculer par tick

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

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

  audio.pause(); // son désactivé pour reverse simulé
}

function stopReverse() {
  if (reverseInterval) {
    clearInterval(reverseInterval);
    reverseInterval = null;
    vinyl.style.animationDirection = 'normal';
  }
}

// 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;
  }
});