/**
 * CHAMPIONS OF LUNERARIA - Ambient Audio Engine
 * Pure Web Audio API Synthesizer (No external sound files, 100% offline & local)
 * Provides an atmospheric fantasy soundscape with gentle bass drone & crystalline pads.
 */

class LuneAudioEngine {
  constructor() {
    this.ctx = null;
    this.isPlaying = false;
    this.masterGain = null;
    this.nodes = [];
    this.intervalId = null;
  }

  init() {
    if (this.ctx) return;
    const AudioContextClass = window.AudioContext || window.webkitAudioContext;
    if (!AudioContextClass) return;
    this.ctx = new AudioContextClass();

    this.masterGain = this.ctx.createGain();
    this.masterGain.gain.setValueAtTime(0, this.ctx.currentTime);
    this.masterGain.connect(this.ctx.destination);
  }

  toggle() {
    this.init();
    if (!this.ctx) return false;

    if (this.ctx.state === 'suspended') {
      this.ctx.resume();
    }

    if (this.isPlaying) {
      this.stop();
      return false;
    } else {
      this.start();
      return true;
    }
  }

  start() {
    if (this.isPlaying) return;
    this.isPlaying = true;
    const now = this.ctx.currentTime;

    // Master fade in
    this.masterGain.gain.cancelScheduledValues(now);
    this.masterGain.gain.linearRampToValueAtTime(0.18, now + 3);

    // 1. Warm Sub Drone (A1: 55Hz)
    const droneOsc = this.ctx.createOscillator();
    droneOsc.type = 'sawtooth';
    droneOsc.frequency.setValueAtTime(55, now);

    const droneFilter = this.ctx.createBiquadFilter();
    droneFilter.type = 'lowpass';
    droneFilter.frequency.setValueAtTime(120, now);

    const droneGain = this.ctx.createGain();
    droneGain.gain.setValueAtTime(0.6, now);

    droneOsc.connect(droneFilter);
    droneFilter.connect(droneGain);
    droneGain.connect(this.masterGain);
    droneOsc.start();
    this.nodes.push(droneOsc);

    // 2. Harmonic Ethereal Pad (A2 / E3 chords)
    const padFrequencies = [110, 164.81, 220, 277.18];
    padFrequencies.forEach((freq, i) => {
      const osc = this.ctx.createOscillator();
      osc.type = 'sine';
      osc.frequency.setValueAtTime(freq, now);

      // Subtle detune for shimmer
      osc.detune.setValueAtTime((i - 1.5) * 4, now);

      const pFilter = this.ctx.createBiquadFilter();
      pFilter.type = 'bandpass';
      pFilter.frequency.setValueAtTime(freq * 1.5, now);
      pFilter.Q.setValueAtTime(2.0, now);

      const pGain = this.ctx.createGain();
      pGain.gain.setValueAtTime(0.25 / padFrequencies.length, now);

      osc.connect(pFilter);
      pFilter.connect(pGain);
      pGain.connect(this.masterGain);
      osc.start();
      this.nodes.push(osc);
    });

    // 3. Periodic Shimmer Bells (Crystalline Moon Chimes)
    this.startShimmerBells();
  }

  startShimmerBells() {
    const bellNotes = [440, 554.37, 659.25, 830.61, 880, 1108.73];
    this.intervalId = setInterval(() => {
      if (!this.isPlaying || !this.ctx) return;
      const note = bellNotes[Math.floor(Math.random() * bellNotes.length)];
      this.playChime(note);
    }, 2800);
  }

  playChime(freq) {
    if (!this.ctx) return;
    const now = this.ctx.currentTime;
    const osc = this.ctx.createOscillator();
    const gain = this.ctx.createGain();

    osc.type = 'triangle';
    osc.frequency.setValueAtTime(freq, now);

    gain.gain.setValueAtTime(0.001, now);
    gain.gain.exponentialRampToValueAtTime(0.04, now + 0.08);
    gain.gain.exponentialRampToValueAtTime(0.0001, now + 2.5);

    osc.connect(gain);
    gain.connect(this.masterGain);

    osc.start(now);
    osc.stop(now + 2.6);
  }

  stop() {
    if (!this.isPlaying) return;
    this.isPlaying = false;
    const now = this.ctx.currentTime;

    // Fade out
    this.masterGain.gain.cancelScheduledValues(now);
    this.masterGain.gain.linearRampToValueAtTime(0.0001, now + 1.5);

    if (this.intervalId) {
      clearInterval(this.intervalId);
      this.intervalId = null;
    }

    setTimeout(() => {
      this.nodes.forEach(n => {
        try { n.stop(); n.disconnect(); } catch (e) {}
      });
      this.nodes = [];
    }, 1600);
  }
}

window.luneAudio = new LuneAudioEngine();