/*

	openal.c: audio output on OpenAL

	copyright 1995-2016 by the mpg123 project - free software under the terms of the LGPL 2.1

	see COPYING and AUTHORS files in distribution or http://mpg123.org

	initially written by Taihei Monma

*/

/* Need usleep(). */

#define _DEFAULT_SOURCE

#define _BSD_SOURCE

#include "out123_int.h"

#ifdef OPENAL_SUBDIR_OPENAL

	#include <OpenAL/al.h>

	#include <OpenAL/alc.h>

#elif defined(OPENAL_SUBDIR_AL)

	#include <AL/al.h>

	#include <AL/alc.h>

#else

	#include <al.h>

	#include <alc.h>

#endif

#include <errno.h>

#include <unistd.h>

#include "debug.h"

#define NUM_BUFFERS 16

#ifndef AL_FORMAT_MONO_FLOAT32

#define AL_FORMAT_MONO_FLOAT32 0x10010

#endif

#ifndef AL_FORMAT_STEREO_FLOAT32

#define AL_FORMAT_STEREO_FLOAT32 0x10011

#endif

typedef struct

{

	ALCdevice *device;

	ALCcontext *context;

	ALuint source, buffer;

	ALenum format;

	ALsizei rate;

} mpg123_openal_t;

static int open_openal(out123_handle *ao)

{

	mpg123_openal_t* al = (mpg123_openal_t*)ao->userptr;

	al->device = alcOpenDevice(NULL);

	al->context = alcCreateContext(al->device, NULL);

	alcMakeContextCurrent(al->context);

	alGenSources(1, &al->source);

	al->rate = ao->rate;

	if(ao->format == MPG123_ENC_SIGNED_16 && ao->channels == 2) al->format = AL_FORMAT_STEREO16;

	else if(ao->format == MPG123_ENC_SIGNED_16 && ao->channels == 1) al->format = AL_FORMAT_MONO16;

	else if(ao->format == MPG123_ENC_UNSIGNED_8 && ao->channels == 2) al->format = AL_FORMAT_STEREO8;

	else if(ao->format == MPG123_ENC_UNSIGNED_8 && ao->channels == 1) al->format = AL_FORMAT_MONO8;

	else if(ao->format == MPG123_ENC_FLOAT_32 && ao->channels == 2) al->format = AL_FORMAT_STEREO_FLOAT32;

	else if(ao->format == MPG123_ENC_FLOAT_32 && ao->channels == 1) al->format = AL_FORMAT_MONO_FLOAT32;

	return 0;

}

static int get_formats_openal(out123_handle *ao)

{

	return MPG123_ENC_SIGNED_16|MPG123_ENC_UNSIGNED_8|((alIsExtensionPresent((ALubyte*)"AL_EXT_float32") == AL_TRUE) ? MPG123_ENC_FLOAT_32 : 0);

}

static int write_openal(out123_handle *ao, unsigned char *buf, int len)

{

	ALint state, n;

	mpg123_openal_t* al = (mpg123_openal_t*)ao->userptr;

	alGetSourcei(al->source, AL_BUFFERS_QUEUED, &n);

	if(n < NUM_BUFFERS)

	{

		alGenBuffers(1, &al->buffer);

	}

	else

	{

		alGetSourcei(al->source, AL_SOURCE_STATE, &state);

		if(state != AL_PLAYING)

		{

			alSourcePlay(al->source);

		}

		while(alGetSourcei(al->source, AL_BUFFERS_PROCESSED, &n), n == 0)

		{	

			usleep(10000);

		}

		alSourceUnqueueBuffers(al->source, 1, &al->buffer);

	}

	alBufferData(al->buffer, al->format, buf, len, al->rate);

	alSourceQueueBuffers(al->source, 1, &al->buffer);

	return len;

}

static int close_openal(out123_handle *ao)

{

	ALint state, n;

	mpg123_openal_t* al = (mpg123_openal_t*)ao->userptr;

	if (al)

	{

		/* wait until all buffers are consumed */

		while(alGetSourcei(al->source, AL_SOURCE_STATE, &state), state == AL_PLAYING)

		{

			usleep(10000);

		}

		/* free all processed buffers */

		while(alGetSourcei(al->source, AL_BUFFERS_PROCESSED, &n), n > 0)

		{

			alSourceUnqueueBuffers(al->source, 1, &al->buffer);

			alDeleteBuffers(1, &al->buffer);

		}

		alDeleteSources(1, &al->source);

		alcMakeContextCurrent(NULL);

		alcDestroyContext(al->context);

		alcCloseDevice(al->device);

	}

	return 0;

}

static void flush_openal(out123_handle *ao)

{

	ALint n;

	mpg123_openal_t* al = (mpg123_openal_t*)ao->userptr;

	if (al)

	{

		/* stop playing and flush all buffers */

		alSourceStop(al->source);

		while(alGetSourcei(al->source, AL_BUFFERS_PROCESSED, &n), n > 0)

		{

			alSourceUnqueueBuffers(al->source, 1, &al->buffer);

			alDeleteBuffers(1, &al->buffer);

		}

	}

}

static int deinit_openal(out123_handle* ao)

{

	/* Free up memory */

	if(ao->userptr)

	{

		free( ao->userptr );

		ao->userptr = NULL;

	}

	/* Success */

	return 0;

}

static int init_openal(out123_handle* ao)

{

	if (ao==NULL) return -1;

	/* Set callbacks */

	ao->open = open_openal;

	ao->flush = flush_openal;

	ao->write = write_openal;

	ao->get_formats = get_formats_openal;

	ao->close = close_openal;

	ao->deinit = deinit_openal;

	/* Allocate memory for data structure */

	ao->userptr = malloc( sizeof( mpg123_openal_t ) );

	if(ao->userptr==NULL)

	{

		if(!AOQUIET)

			error("failed to malloc memory for 'mpg123_openal_t'");

		return -1;

	}

	memset( ao->userptr, 0, sizeof(mpg123_openal_t) );

	/* Success */

	return 0;

}

/* 

	Module information data structure

*/

mpg123_module_t mpg123_output_module_info = {

	/* api_version */	MPG123_MODULE_API_VERSION,

	/* name */			"openal",

	/* description */	"Output audio using OpenAL.",

	/* revision */		"$Rev:$",

	/* handle */		NULL,

	/* init_output */	init_openal,

};