#include <fcntl.h>
#include <linux/cdrom.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <tinyalsa/pcm.h>
#include <unistd.h>

#define FRAMES 1

#define SIZE CD_FRAMESIZE_RAW
#define PERIOD 1024
#define COUNT 2

struct cdrom_read_audio sr;

void forward(int signum) { sr.addr.lba += 3600; }

void backward(int signum) { sr.addr.lba -= 3600; }

void weite_err(char *s)
{
	char *p;
	p = s;
	while (*p)
		++p;
	write(STDERR_FILENO, s, p - s);
}

int main(int argc, char *argv[])
{
	int fdi, card = 0, device = 0;
	struct pcm *pcm;
	struct pcm_config config;
	char *msg, buff[SIZE * FRAMES];
	struct sigaction f_action, b_action;

	if (argc < 2)
	{
		weite_err("Usage: ");
		weite_err(argv[0]);
		weite_err("cdrom [card=0] [device=0]\n");
		goto err0;
	}

	if ((fdi = open(argv[1], O_RDONLY | O_NONBLOCK)) < 0)
	{
		weite_err("couldn't open input device ");
		weite_err(argv[1]);
		weite_err(" \n");
		goto err0;
	}

	switch (ioctl(fdi, CDROM_DRIVE_STATUS, 0))
	{
	case CDS_NO_DISC:
		weite_err("No disk\n");
		goto err1;
	case CDS_DRIVE_NOT_READY:
		weite_err("Drive not ready\n");
		goto err1;
	case CDS_TRAY_OPEN:
		weite_err("Tray open\n");
		goto err1;
	case -1:
		weite_err("Error\n");
		goto err1;
	}

	switch (argc)
	{
	case 4:
		device = *argv[3] - '0';
	case 3:
		card = *argv[2] - '0';
	}

	/* Prepare signals */
	{
		f_action.sa_handler = forward;
		b_action.sa_handler = backward;

		sigaddset(&f_action.sa_mask, SIGUSR1);
		sigaddset(&b_action.sa_mask, SIGUSR2);
		sigaction(SIGUSR1, &f_action, NULL);
		sigaction(SIGUSR2, &b_action, NULL);
	}

	/* config pcm */
	{
		config.channels = 2;
		config.rate = 44100;
		config.format = PCM_FORMAT_S16_LE;

		config.period_size = PERIOD;
		config.period_count = COUNT;
		config.start_threshold = PERIOD;
		config.silence_threshold = PERIOD * COUNT;
		config.stop_threshold = PERIOD * COUNT;
	}

	/* config sr */
	{
		sr.buf = buff;
		sr.nframes = FRAMES;
		sr.addr_format = CDROM_LBA;
	}

	pcm = pcm_open(card, device, PCM_OUT, &config);

	sr.addr.lba = 0;
	while (ioctl(fdi, CDROMREADAUDIO, &sr) != -1)
	{
		pcm_writei(pcm, buff, SIZE * FRAMES / 4);
		sr.addr.lba += FRAMES;
	}

	pcm_close(pcm);
	close(fdi);
	return 0;
err1:
	close(fdi);
err0:
	return 1;
}