#!/usr/bin/tcc -run -I/usr/include/SDL2 -lSDL2
#include <math.h>
#include <stdlib.h>
#include <unistd.h>
#define SDL_DISABLE_IMMINTRIN_H
#include <SDL.h>
#include <SDL_audio.h>

int AMPLITUDE = 28000;
int SAMPLE_RATE = 44100;

void audio_callback(void *user_data, Uint8 *raw_buffer, int bytes)
{
    Sint16 *buffer = (Sint16*)raw_buffer;
    int length = bytes / 2;
    int *sample_nr = (int*)user_data;
    if (sample_nr == NULL)
        return;

    for (int i = 0; i < length; ++i, ++*sample_nr)
    {
        double time = (double)*sample_nr / (double)SAMPLE_RATE;
        buffer[i] = (Sint16)(AMPLITUDE * sin(2.0f * M_PI * 441.0f * time));
    }
}

int main(int argc, char *argv[])
{
    int c;
    while ((c = getopt(argc, argv, "A:S:")) != -1)
    {
        switch (c)
        {
            case 'A': AMPLITUDE = atoi(optarg); break;
            case 'S': SAMPLE_RATE = atoi(optarg); break;
            default: break;
        }
    }

    if (SDL_Init(SDL_INIT_AUDIO) != 0)
        SDL_Log("Failed to initialize SDL: %s", SDL_GetError());

    int sample_nr = 0;

    SDL_AudioSpec want;
    want.freq = SAMPLE_RATE;
    want.format = AUDIO_S16SYS;
    want.channels = 1;
    want.samples = 2048;
    want.callback = audio_callback;
    want.userdata = &sample_nr;

    SDL_AudioSpec have;
    if (SDL_OpenAudio(&want, &have) != 0)
        SDL_LogError(SDL_LOG_CATEGORY_AUDIO, "Failed to open audio: %s", SDL_GetError());
    if (want.format != have.format)
        SDL_LogError(SDL_LOG_CATEGORY_AUDIO, "Failed to get the desired AudioSpec");

    SDL_PauseAudio(0);
    SDL_Delay(1000);
    SDL_PauseAudio(1);

    SDL_CloseAudio();

    return 0;
}