#include <stdio.h>
#include <stdint.h>
#include <alsa/asoundlib.h>

#define FORMAT SND_PCM_FORMAT_S16_BE
#define RATE 48000

int main(int argc, char *argv[]) {
	snd_pcm_t *handle;
	snd_pcm_hw_params_t *params;
	snd_pcm_sw_params_t *swparams;
	snd_pcm_uframes_t period_size;
	snd_pcm_uframes_t buffer_size;
	snd_pcm_status_t *status;
	uint8_t *buf;
	int rate;
	int ret;
	ssize_t r;
	int t;

	if ((ret = snd_pcm_open(&handle, argv[1], 
			SND_PCM_STREAM_CAPTURE, 0)) < 0) {
		goto out;
	}

	snd_pcm_hw_params_alloca(&params);
	snd_pcm_sw_params_alloca(&swparams);
	if ((ret = snd_pcm_hw_params_any(handle, params)) < 0) {
		goto out;
	}
	if ((ret = snd_pcm_hw_params_set_access(handle,
			params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
		goto out;
	}
	if ((ret = snd_pcm_hw_params_set_format(handle, params, 
			FORMAT)) < 0) {
		goto out;		
	}
	if ((ret = snd_pcm_hw_params_set_channels(handle,
			params, 2)) < 0) {
		goto out;
	}
	rate = RATE;
	if ((ret = snd_pcm_hw_params_set_rate_near(handle, params,
			&rate, 0) < 0)) {
		goto out;
	}
	period_size = atoi(argv[2]);
	if ((ret = snd_pcm_hw_params_set_period_size_near(handle, params,
			&period_size, 0)) < 0) {
		fprintf(stderr, "failed to set period size.\n");
	}
	t = 1000000;
	if ((ret = snd_pcm_hw_params_set_buffer_time_near(handle, params,
			&t, 0)) < 0) {
		fprintf(stderr, "failed to set buffer time.\n");
	}
	if ((ret = snd_pcm_hw_params(handle, params)) < 0) {
		goto out;
	}
	snd_pcm_hw_params_get_period_size(params, &period_size, 0);
	snd_pcm_hw_params_get_buffer_size(params, &buffer_size);

	snd_pcm_sw_params_current(handle, swparams);
	if ((ret = snd_pcm_sw_params_set_tstamp_mode(handle, swparams,
			 SND_PCM_TSTAMP_MMAP)) < 0) {
		goto out;
	}
	if ((ret = snd_pcm_sw_params(handle, swparams)) < 0) {	
		goto out;
	}
	if ((ret = snd_pcm_prepare(handle)) < 0) {
		goto out;
	}

	buf = malloc(period_size*2*2);

	snd_pcm_status_alloca(&status);
	for (t = 0; t < 1000; t++) {
		r = snd_pcm_readi(handle, buf, period_size);
		if (snd_pcm_status(handle, status) < 0) {
			fprintf(stderr, "snd_pcm_status failed.\n");
		}
		else {
			snd_htimestamp_t tstamp;
			snd_pcm_status_get_htstamp(status, &tstamp);
			printf("time: %d %d\n", tstamp.tv_sec, tstamp.tv_nsec);
		}
	}

	snd_pcm_close(handle);
out:
	return 0;
}