#include "play_raw_audio.h"
#include "time_utils.h"
#include <errno.h>
#include <fcntl.h>
#include <pulse/error.h>
#include <pulse/simple.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

// prototypes for static functions
static int play_square_wave(float frequency, float duration);

int play_manual_alarm() {
	int err = 0;

	for (int i = 0; i < 3; i++) {
		for (int i = 0; i < 2; i++) {
			err = play_square_wave(1000.0, 0.2);
			if (err != 0) {
				return err;
			}
			sleep_ms(200);
		}
		sleep_ms(500);
	}
	return 0;
}

// UNUSED
// Playing a raw audio file has the downside of depending on a file.
int play_raw_audio(char file_name[]) {
	int pa_error = 0;
	char content[1024] = "";

	int myfd = open(file_name, O_RDONLY);
	if (myfd == -1) {
		fprintf(stderr, "Failed to open audio file %s: %s.\n", file_name, strerror(errno));
		return 1;
	}

	pa_simple* simple = NULL;
	pa_sample_spec ss;
	ss.format = PA_SAMPLE_S16LE;
	ss.rate = 48000;
	ss.channels = 2;

	simple = pa_simple_new(NULL, "Audio Playback", PA_STREAM_PLAYBACK, NULL, "playback", &ss, NULL, NULL, &pa_error);

	int i = 0;
	while (read(myfd, content, sizeof(content))) {
		// skip the first 1024 bytes to not play the file header
		if (i != 0) {
			pa_simple_write(simple, content, sizeof(content), &pa_error);
		}
		i++;
	}

	pa_simple_drain(simple, NULL);

	pa_simple_free(simple);

	close(myfd);

	return 0;
}

// Output a tone with the audio frequency "frequency"
// for "duration" number of seconds.
// The sound signals are not sine waves but square waves.
static int play_square_wave(float frequency, float duration) {
	const int sample_rate = 44100;
	const int channel_count = 2;
	size_t buffer_size = sample_rate * channel_count * duration;
	short buffer[buffer_size] = {};
	pa_simple *s;

	pa_sample_spec ss = {
		.format = PA_SAMPLE_S16LE,
		.rate = sample_rate,
		.channels = channel_count,
	};

	// number of identical consecutive elements
	// 5 would look like this:
	// [0,0,0,0,0,32768,32768,32768,32768,32768,0,...]
	int array_interval = sample_rate / frequency;

	bool square_peak = false;
	for (int i = 0; i < buffer_size; i++) {
		if (i % array_interval == 0) {
			// toggle the value (0 or the max value for a short)
			square_peak = !square_peak;
		}
		if (square_peak) {
			buffer[i] = SHRT_MAX;
		} else {
			buffer[i] = 0;
		}
	}

	if (!(s = pa_simple_new(NULL, NULL, PA_STREAM_PLAYBACK, NULL, "playback", &ss, NULL, NULL, &errno))) {
		fprintf(stderr, "pa_simple_new() failed: %s\n", pa_strerror(errno));
		return 1;
	}

	if (pa_simple_write(s, buffer, sizeof(buffer), NULL) < 0) {
		fprintf(stderr, "pa_simple_write() failed: %s\n", pa_strerror(errno));
		return 1;
	}

	pa_simple_drain(s, NULL);

	pa_simple_free(s);

	return 0;
}