#include <sys/ioctl.h>
#include <stdint.h>
#include <fcntl.h>
#include <unistd.h>
#include <alsa/asoundlib.h>

#include "sound_output.h"

static snd_pcm_t *handle;

uint32_t Audio_Init()
{
	snd_pcm_hw_params_t *params;
	uint32_t val;
	int32_t dir = -1;
	snd_pcm_uframes_t frames;
	
	/* Open PCM device for playback. */
	int32_t rc = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);

	if (rc < 0)
		rc = snd_pcm_open(&handle, "plughw:0,0,0", SND_PCM_STREAM_PLAYBACK, 0);

	if (rc < 0)
		rc = snd_pcm_open(&handle, "plughw:0,0", SND_PCM_STREAM_PLAYBACK, 0);
		
	if (rc < 0)
		rc = snd_pcm_open(&handle, "plughw:1,0,0", SND_PCM_STREAM_PLAYBACK, 0);

	if (rc < 0)
		rc = snd_pcm_open(&handle, "plughw:1,0", SND_PCM_STREAM_PLAYBACK, 0);

	if (rc < 0)
	{
		fprintf(stderr, "unable to open PCM device: %s\n", snd_strerror(rc));
		return 1;
	}

	/* Allocate a hardware parameters object. */
	snd_pcm_hw_params_alloca(&params);

	/* Fill it in with default values. */
	rc = snd_pcm_hw_params_any(handle, params);
	if (rc < 0)
	{
		fprintf(stderr, "Error:snd_pcm_hw_params_any %s\n", snd_strerror(rc));
		return 1;
	}

	/* Set the desired hardware parameters. */

	/* Interleaved mode */
	rc = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
	if (rc < 0)
	{
		fprintf(stderr, "Error:snd_pcm_hw_params_set_access %s\n", snd_strerror(rc));
		return 1;
	}

	/* Signed 16-bit little-endian format */
	rc = snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
	if (rc < 0)
	{
		fprintf(stderr, "Error:snd_pcm_hw_params_set_format %s\n", snd_strerror(rc));
		return 1;
	}

	/* Two channels (stereo) */
	rc = snd_pcm_hw_params_set_channels(handle, params, 2);
	if (rc < 0)
	{
		fprintf(stderr, "Error:snd_pcm_hw_params_set_channels %s\n", snd_strerror(rc));
		return 1;
	}
	
	val = SOUND_OUTPUT_FREQUENCY;
	rc = snd_pcm_hw_params_set_rate_near(handle, params, &val, &dir);
	if (rc < 0)
	{
		fprintf(stderr, "Error:snd_pcm_hw_params_set_rate_near %s\n", snd_strerror(rc));
		return 1;
	}

	/* Set period size to settings.aica.BufferSize frames. */
	frames = SOUND_SAMPLES_SIZE;
	rc = snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir);
	if (rc < 0)
	{
		fprintf(stderr, "Error:snd_pcm_hw_params_set_buffer_size_near %s\n", snd_strerror(rc));
		return 1;
	}
	frames *= 4;
	rc = snd_pcm_hw_params_set_buffer_size_near(handle, params, &frames);
	if (rc < 0)
	{
		fprintf(stderr, "Error:snd_pcm_hw_params_set_buffer_size_near %s\n", snd_strerror(rc));
		return 1;
	}

	/* Write the parameters to the driver */
	rc = snd_pcm_hw_params(handle, params);
	if (rc < 0)
	{
		fprintf(stderr, "Unable to set hw parameters: %s\n", snd_strerror(rc));
		return 1;
	}
	
	return 0;
}

void Audio_Write(int16_t* restrict buffer, uint32_t buffer_size)
{
	uint32_t i;
	long ret, len;

	if (!handle) return;
	
	len = buffer_size;
	
	ret = snd_pcm_writei(handle, buffer, len);
	while(ret != len) 
	{
		if (ret < 0) 
		{
			snd_pcm_prepare( handle );
		}
		else 
		{
			len -= ret;
		}
		ret = snd_pcm_writei(handle, buffer, len);
	}
}

bool Audio_Underrun_Likely() {
	return false;
}

void Audio_Close()
{
	if (handle)
	{
		snd_pcm_drain(handle);
		snd_pcm_close(handle);
	}
}