/*
// Created by bruno on 16.2.2025.
*/

#include "audio.h"

AudioData audioData;

void audio_callback(void *userdata, Uint8 *stream, int len) {
    AudioData *audio = (AudioData *) userdata;
    int samples = len / sizeof(float);

    for (int i = 0; i < samples; i++) {
        float mix = 0.0f;
        int activeVoices = 0;

        for (int v = 0; v < NUM_SYNTH_VOICES; v++) {
            SynthVoice *voice = &audio->synthVoices[v];
            if (voice->volume == 0 || voice->frequency == 0) continue;

            float sample = 0.0f;
            float t = (float) voice->phase / 255.0f * 2.0f - 1.0f;

            switch (voice->waveform) {
                default:
                case WAVE_SINE:
                    sample = sinf(voice->phase * 2.0f * M_PI / 256.0f);
                    break;
                case WAVE_SQUARE:
                    sample = (t >= 0.0f) ? 1.0f : -1.0f;
                    break;
                case WAVE_SAWTOOTH:
                    sample = t;
                    break;
                case WAVE_TRIANGLE:
                    sample = (t < 0) ? -t : t;
                    break;
                case WAVE_NOISE:
                    sample = ((float) rand() / RAND_MAX) * 2.0f - 1.0f;
                    break;
            }

            voice->phase += (uint8_t) ((voice->frequency * 256) / SAMPLE_RATE);
            mix += sample * (voice->volume / 255.0f);
            activeVoices++;
        }

        ((float *) stream)[i] = (activeVoices > 0) ? mix / activeVoices : 0.0f;
    }
}