/**
 * Synthesizer for Drone Rotor Hum and Tactical HUD Audio FX
 * Uses Web Audio API without external audio file dependencies
 */
class DroneAudioSystem {
    constructor() {
        this.ctx = null;
        this.enabled = false;
        this.leaderGain = null;
        this.followerGain = null;
        this.leaderOsc1 = null;
        this.leaderOsc2 = null;
        this.followerOsc1 = null;
        this.followerOsc2 = null;
    }

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

            // Master compressor to prevent clipping
            const compressor = this.ctx.createDynamicsCompressor();
            compressor.threshold.setValueAtTime(-18, this.ctx.currentTime);
            compressor.knee.setValueAtTime(30, this.ctx.currentTime);
            compressor.ratio.setValueAtTime(12, this.ctx.currentTime);
            compressor.attack.setValueAtTime(0.003, this.ctx.currentTime);
            compressor.release.setValueAtTime(0.25, this.ctx.currentTime);
            compressor.connect(this.ctx.destination);

            this.masterGain = this.ctx.createGain();
            this.masterGain.gain.setValueAtTime(0.2, this.ctx.currentTime);
            this.masterGain.connect(compressor);

            // Leader Drone sound synthesizer (Dual harmonic oscillator + lowpass filter)
            this.leaderFilter = this.ctx.createBiquadFilter();
            this.leaderFilter.type = "lowpass";
            this.leaderFilter.frequency.setValueAtTime(650, this.ctx.currentTime);

            this.leaderGain = this.ctx.createGain();
            this.leaderGain.gain.setValueAtTime(0.0, this.ctx.currentTime);
            this.leaderGain.connect(this.leaderFilter);
            this.leaderFilter.connect(this.masterGain);

            this.leaderOsc1 = this.ctx.createOscillator();
            this.leaderOsc1.type = "sawtooth";
            this.leaderOsc1.frequency.setValueAtTime(95, this.ctx.currentTime);

            this.leaderOsc2 = this.ctx.createOscillator();
            this.leaderOsc2.type = "triangle";
            this.leaderOsc2.frequency.setValueAtTime(190, this.ctx.currentTime);

            this.leaderOsc1.connect(this.leaderGain);
            this.leaderOsc2.connect(this.leaderGain);
            this.leaderOsc1.start();
            this.leaderOsc2.start();

            // Follower Drone sound synthesizer
            this.followerFilter = this.ctx.createBiquadFilter();
            this.followerFilter.type = "lowpass";
            this.followerFilter.frequency.setValueAtTime(600, this.ctx.currentTime);

            this.followerGain = this.ctx.createGain();
            this.followerGain.gain.setValueAtTime(0.0, this.ctx.currentTime);
            this.followerGain.connect(this.followerFilter);
            this.followerFilter.connect(this.masterGain);

            this.followerOsc1 = this.ctx.createOscillator();
            this.followerOsc1.type = "sawtooth";
            this.followerOsc1.frequency.setValueAtTime(98, this.ctx.currentTime);

            this.followerOsc2 = this.ctx.createOscillator();
            this.followerOsc2.type = "triangle";
            this.followerOsc2.frequency.setValueAtTime(196, this.ctx.currentTime);

            this.followerOsc1.connect(this.followerGain);
            this.followerOsc2.connect(this.followerGain);
            this.followerOsc1.start();
            this.followerOsc2.start();

            this.enabled = true;
        } catch (e) {
            console.warn("Web Audio not supported or blocked", e);
        }
    }

    toggle() {
        if (!this.ctx) {
            this.init();
            return true;
        }
        if (this.ctx.state === 'suspended') {
            this.ctx.resume();
            this.enabled = true;
            return true;
        }
        this.enabled = !this.enabled;
        if (!this.enabled && this.leaderGain && this.followerGain) {
            this.leaderGain.gain.setValueAtTime(0.0, this.ctx.currentTime);
            this.followerGain.gain.setValueAtTime(0.0, this.ctx.currentTime);
        }
        return this.enabled;
    }

    updateMotors(leaderRpm, followerRpm, speedLeader, speedFollower) {
        if (!this.enabled || !this.ctx || this.ctx.state !== 'running') return;

        const now = this.ctx.currentTime;
        // Pitch proportional to RPM and velocity
        const baseFreq1 = 85 + (speedLeader * 2.5) + ((leaderRpm - 4500) * 0.015);
        const baseFreq2 = 88 + (speedFollower * 2.5) + ((followerRpm - 4500) * 0.015);

        this.leaderOsc1.frequency.setTargetAtTime(Math.max(60, Math.min(220, baseFreq1)), now, 0.08);
        this.leaderOsc2.frequency.setTargetAtTime(Math.max(120, Math.min(440, baseFreq1 * 2)), now, 0.08);

        this.followerOsc1.frequency.setTargetAtTime(Math.max(60, Math.min(220, baseFreq2)), now, 0.08);
        this.followerOsc2.frequency.setTargetAtTime(Math.max(120, Math.min(440, baseFreq2 * 2)), now, 0.08);

        this.leaderGain.gain.setTargetAtTime(0.08, now, 0.1);
        this.followerGain.gain.setTargetAtTime(0.08, now, 0.1);
    }

    playBeep(freq = 880, duration = 0.08) {
        if (!this.enabled || !this.ctx) return;
        try {
            const osc = this.ctx.createOscillator();
            const gain = this.ctx.createGain();
            osc.type = "sine";
            osc.frequency.setValueAtTime(freq, this.ctx.currentTime);
            gain.gain.setValueAtTime(0.08, this.ctx.currentTime);
            gain.gain.exponentialRampToValueAtTime(0.001, this.ctx.currentTime + duration);
            osc.connect(gain);
            gain.connect(this.masterGain);
            osc.start();
            osc.stop(this.ctx.currentTime + duration);
        } catch (e) {}
    }
}

window.droneAudio = new DroneAudioSystem();