"use strict";

const MothershipImpactSound = (function(){

    // Curva de saturación analógica para darle máxima pegada sin romper el audio
    const make_distortion_curve = (amount = 20) => {
        const samples = 44100;
        const curve = new Float32Array(samples);
        const deg = Math.PI / 180;
        for(let i = 0; i < samples; ++i){
            const x = (i * 2) / samples - 1;
            curve[i] = ((3 + amount) * x * 20 * deg) / (Math.PI + amount * Math.abs(x));
        }
        return curve;
    };

    return function(audio_ctx, output_node, volume_multiplier = 1.0){
        const now = audio_ctx.currentTime;
        const duration = 2.4; // Retumbe largo y cavernoso

        // Bus maestro del efecto con booster de presencia
        const master_bus = audio_ctx.createGain();
        master_bus.gain.setValueAtTime(volume_multiplier * 1.35, now);

        // Saturador suave para sonido "aplastante"
        const shaper = audio_ctx.createWaveShaper();
        shaper.curve = make_distortion_curve(18);
        shaper.oversample = "2x";

        // ========================================================
        // CAPA 1: SUB-GRAVE SÍSMICO (Terremoto acústico en cabina)
        // ========================================================
        const sub_osc = audio_ctx.createOscillator();
        const sub_gain = audio_ctx.createGain();

        sub_osc.type = "sine";
        sub_osc.frequency.setValueAtTime(145, now);
        // Caída drástica a frecuencias casi inaudibles pero que mueven aire
        sub_osc.frequency.exponentialRampToValueAtTime(22, now + 0.45);
        sub_osc.frequency.setValueAtTime(20, now + duration);

        sub_gain.gain.setValueAtTime(0.001, now);
        sub_gain.gain.linearRampToValueAtTime(1.0, now + 0.015);
        sub_gain.gain.exponentialRampToValueAtTime(0.001, now + 1.8);

        sub_osc.connect(sub_gain);
        sub_gain.connect(shaper);

        // ========================================================
        // CAPA 2: CRUJIDO DE CASCO Y METRALLA (Ráfaga de ruido blanco)
        // ========================================================
        const buffer_size = Math.floor(audio_ctx.sampleRate * 1.5);
        const noise_buffer = audio_ctx.createBuffer(1, buffer_size, audio_ctx.sampleRate);
        const noise_data = noise_buffer.getChannelData(0);
        for(let i = 0; i < buffer_size; i++){
            noise_data[i] = (Math.random() * 2 - 1);
        }

        const noise_src = audio_ctx.createBufferSource();
        noise_src.buffer = noise_buffer;

        const noise_filter = audio_ctx.createBiquadFilter();
        noise_filter.type = "lowpass";
        noise_filter.frequency.setValueAtTime(4200, now);
        noise_filter.frequency.exponentialRampToValueAtTime(110, now + 1.2);
        noise_filter.Q.setValueAtTime(2.5, now);

        const noise_env = audio_ctx.createGain();
        noise_env.gain.setValueAtTime(0.001, now);
        noise_env.gain.linearRampToValueAtTime(0.9, now + 0.02);
        noise_env.gain.exponentialRampToValueAtTime(0.001, now + 1.4);

        noise_src.connect(noise_filter);
        noise_filter.connect(noise_env);
        noise_env.connect(shaper);

        // ========================================================
        // CAPA 3: DEFORMACIÓN METÁLICA (Resonador desafinado)
        // ========================================================
        const metal_osc_a = audio_ctx.createOscillator();
        const metal_osc_b = audio_ctx.createOscillator();
        const metal_gain = audio_ctx.createGain();

        metal_osc_a.type = "sawtooth";
        metal_osc_b.type = "triangle";

        metal_osc_a.frequency.setValueAtTime(78, now);
        metal_osc_a.frequency.exponentialRampToValueAtTime(32, now + 0.9);

        metal_osc_b.frequency.setValueAtTime(114, now);
        metal_osc_b.frequency.exponentialRampToValueAtTime(38, now + 0.9);

        metal_gain.gain.setValueAtTime(0.001, now);
        metal_gain.gain.linearRampToValueAtTime(0.55, now + 0.04);
        metal_gain.gain.exponentialRampToValueAtTime(0.001, now + 1.1);

        metal_osc_a.connect(metal_gain);
        metal_osc_b.connect(metal_gain);
        metal_gain.connect(shaper);

        // ========================================================
        // CAPA 4: COLA DE REVERBERACIÓN DE LA NAVE (Eco retumbante)
        // ========================================================
        const rumble_delay = audio_ctx.createDelay();
        rumble_delay.delayTime.setValueAtTime(0.075, now);

        const rumble_fb = audio_ctx.createGain();
        rumble_fb.gain.setValueAtTime(0.48, now);

        const rumble_filter = audio_ctx.createBiquadFilter();
        rumble_filter.type = "lowpass";
        rumble_filter.frequency.setValueAtTime(320, now);

        rumble_delay.connect(rumble_filter);
        rumble_filter.connect(rumble_fb);
        rumble_fb.connect(rumble_delay);
        rumble_filter.connect(master_bus);

        // Conexiones de salida
        shaper.connect(master_bus);
        shaper.connect(rumble_delay);
        master_bus.connect(output_node);

        // Disparo coordinado de los generadores
        sub_osc.start(now);
        noise_src.start(now);
        metal_osc_a.start(now);
        metal_osc_b.start(now);

        sub_osc.stop(now + duration);
        noise_src.stop(now + 1.5);
        metal_osc_a.stop(now + 1.2);
        metal_osc_b.stop(now + 1.2);
    };

})();