nexus-timer/src/services/AudioService.js

let audioContext;
let tickSoundBuffer; // For short tick
let passTurnSoundBuffer; // For 3s pass turn alert
let isMutedGlobally = false;
let continuousTickInterval = null; // For setInterval based continuous ticking
let passTurnSoundTimeout = null;

function getAudioContext() {
  if (!audioContext && (window.AudioContext || window.webkitAudioContext)) {
    audioContext = new (window.AudioContext || window.webkitAudioContext)();
  }
  return audioContext;
}

function createBeepBuffer(frequency = 440, duration = 0.1, type = 'sine') {
  const ctx = getAudioContext();
  if (!ctx) return null;
  const sampleRate = ctx.sampleRate;
  const numFrames = duration * sampleRate;
  const buffer = ctx.createBuffer(1, numFrames, sampleRate);
  const data = buffer.getChannelData(0);
  const gain = 0.1; // Reduce gain to make beeps softer

  for (let i = 0; i < numFrames; i++) {
    // Simple fade out
    const currentGain = gain * (1 - (i / numFrames)); 
    if (type === 'square') {
        data[i] = (Math.sin(2 * Math.PI * frequency * (i / sampleRate)) >= 0 ? 1 : -1) * currentGain;
    } else { // sine
        data[i] = Math.sin(2 * Math.PI * frequency * (i / sampleRate)) * currentGain;
    }
  }
  return buffer;
}

async function initSounds() {
  const ctx = getAudioContext();
  if (!ctx) return;
  // Tick sound (shorter, slightly different pitch)
  if (!tickSoundBuffer) {
    // Using a square wave for a more 'digital' tick, short duration
    tickSoundBuffer = createBeepBuffer(1000, 0.03, 'square'); 
  }
  // Pass turn alert sound (3 beeps)
  if (!passTurnSoundBuffer) {
    passTurnSoundBuffer = createBeepBuffer(660, 0.08, 'sine'); 
  }
}
initSounds();

function playSoundBuffer(buffer) {
  if (isMutedGlobally || !buffer || !audioContext || audioContext.state === 'suspended') return;
  const source = audioContext.createBufferSource();
  source.buffer = buffer;
  source.connect(audioContext.destination);
  source.start();
}

export const AudioService = {
  setMuted(muted) {
    isMutedGlobally = muted;
    if (muted) {
      this.stopContinuousTick();
      this.cancelPassTurnSound();
    }
  },
  
  // This is the single, short tick sound for "All Timers Running" mode.
  _playSingleTick() { 
    playSoundBuffer(tickSoundBuffer);
  },

  playPassTurnAlert() {
    if (isMutedGlobally || !audioContext || audioContext.state === 'suspended') return;
    this.cancelPassTurnSound(); 
    
    let count = 0;
    const playAndSchedule = () => {
      if (count < 3 && !isMutedGlobally && audioContext.state !== 'suspended') {
        playSoundBuffer(passTurnSoundBuffer);
        count++;
        passTurnSoundTimeout = setTimeout(playAndSchedule, 1000); // Beep every second for 3s
      } else {
        passTurnSoundTimeout = null;
      }
    };
    playAndSchedule();
  },

  cancelPassTurnSound() {
    if (passTurnSoundTimeout) {
      clearTimeout(passTurnSoundTimeout);
      passTurnSoundTimeout = null;
    }
  },

  startContinuousTick() {
    this.stopContinuousTick(); // Clear any existing interval
    if (isMutedGlobally || !audioContext || audioContext.state === 'suspended') return;

    // Play immediately once, then set interval
    this._playSingleTick(); 
    continuousTickInterval = setInterval(() => {
      if (!isMutedGlobally && audioContext.state !== 'suspended') {
        this._playSingleTick();
      } else {
        this.stopContinuousTick(); // Stop if muted or context suspended during interval
      }
    }, 1000); // Tick every second
  },

  stopContinuousTick() {
    if (continuousTickInterval) {
      clearInterval(continuousTickInterval);
      continuousTickInterval = null;
    }
    // Ensure no rogue oscillators are playing.
    // If an oscillator was ever used directly and not disconnected, it could persist.
    // The current implementation relies on BufferSource which stops automatically.
  },

  resumeContext() {
    const ctx = getAudioContext();
    if (ctx && ctx.state === 'suspended') {
      ctx.resume().then(() => {
        console.log("AudioContext resumed successfully.");
        initSounds(); // Re-initialize sounds if context was suspended for long
      }).catch(e => console.error("Error resuming AudioContext:", e));
    } else if (ctx && !tickSoundBuffer) { // If context was fine but sounds not loaded
        initSounds();
    }
  }
};