/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

/* Allow access to a raw mixing buffer */

#ifdef HAVE_SIGNAL_H

#include <signal.h>

#endif

#include <unistd.h>

#include "SDL_timer.h"

#include "SDL_audio.h"

#include "../SDL_audiomem.h"

#include "../SDL_audio_c.h"

#include "../SDL_audiodev_c.h"

#include "SDL_artsaudio.h"

#ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC

#include "SDL_name.h"

#include "SDL_loadso.h"

#else

#define SDL_NAME(X)	X

#endif

/* The tag name used by artsc audio */

#define ARTS_DRIVER_NAME         "arts"

/* Audio driver functions */

static int ARTS_OpenAudio(_THIS, SDL_AudioSpec *spec);

static void ARTS_WaitAudio(_THIS);

static void ARTS_PlayAudio(_THIS);

static Uint8 *ARTS_GetAudioBuf(_THIS);

static void ARTS_CloseAudio(_THIS);

#ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC

static const char *arts_library = SDL_AUDIO_DRIVER_ARTS_DYNAMIC;

static void *arts_handle = NULL;

static int arts_loaded = 0;

static int (*SDL_NAME(arts_init))(void);

static void (*SDL_NAME(arts_free))(void);

static arts_stream_t (*SDL_NAME(arts_play_stream))(int rate, int bits, int channels, const char *name);

static int (*SDL_NAME(arts_stream_set))(arts_stream_t s, arts_parameter_t param, int value);

static int (*SDL_NAME(arts_stream_get))(arts_stream_t s, arts_parameter_t param);

static int (*SDL_NAME(arts_write))(arts_stream_t s, const void *buffer, int count);

static void (*SDL_NAME(arts_close_stream))(arts_stream_t s);

static int (*SDL_NAME(arts_suspended))(void);

static const char *(*SDL_NAME(arts_error_text))(int errorcode);

static struct {

	const char *name;

	void **func;

} arts_functions[] = {

	{ "arts_init",		(void **)&SDL_NAME(arts_init)		},

	{ "arts_free",		(void **)&SDL_NAME(arts_free)		},

	{ "arts_play_stream",	(void **)&SDL_NAME(arts_play_stream)	},

	{ "arts_stream_set",	(void **)&SDL_NAME(arts_stream_set)	},

	{ "arts_stream_get",	(void **)&SDL_NAME(arts_stream_get)	},

	{ "arts_write",		(void **)&SDL_NAME(arts_write)		},

	{ "arts_close_stream",	(void **)&SDL_NAME(arts_close_stream)	},

	{ "arts_suspended",	(void **)&SDL_NAME(arts_suspended)	},

	{ "arts_error_text",	(void **)&SDL_NAME(arts_error_text)	},

};

static void UnloadARTSLibrary()

{

	if ( arts_loaded ) {

		SDL_UnloadObject(arts_handle);

		arts_handle = NULL;

		arts_loaded = 0;

	}

}

static int LoadARTSLibrary(void)

{

	int i, retval = -1;

	arts_handle = SDL_LoadObject(arts_library);

	if ( arts_handle ) {

		arts_loaded = 1;

		retval = 0;

		for ( i=0; i<SDL_arraysize(arts_functions); ++i ) {

			*arts_functions[i].func = SDL_LoadFunction(arts_handle, arts_functions[i].name);

			if ( !*arts_functions[i].func ) {

				retval = -1;

				UnloadARTSLibrary();

				break;

			}

		}

	}

	return retval;

}

#else

static void UnloadARTSLibrary()

{

	return;

}

static int LoadARTSLibrary(void)

{

	return 0;

}

#endif /* SDL_AUDIO_DRIVER_ARTS_DYNAMIC */

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

	int available = 0;

	if ( LoadARTSLibrary() < 0 ) {

		return available;

	}

	if ( SDL_NAME(arts_init)() == 0 ) {

		if ( SDL_NAME(arts_suspended)() ) {

			/* Play a stream so aRts doesn't crash */

			arts_stream_t stream2;

			stream2=SDL_NAME(arts_play_stream)(44100, 16, 2, "SDL");

			SDL_NAME(arts_write)(stream2, "", 0);

			SDL_NAME(arts_close_stream)(stream2);

			available = 1;

		}

		SDL_NAME(arts_free)();

	}

	UnloadARTSLibrary();

	return available;

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

	SDL_free(device->hidden);

	SDL_free(device);

	UnloadARTSLibrary();

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

	SDL_AudioDevice *this;

	/* Initialize all variables that we clean on shutdown */

	LoadARTSLibrary();

	this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));

	if ( this ) {

		SDL_memset(this, 0, (sizeof *this));

		this->hidden = (struct SDL_PrivateAudioData *)

				SDL_malloc((sizeof *this->hidden));

	}

	if ( (this == NULL) || (this->hidden == NULL) ) {

		SDL_OutOfMemory();

		if ( this ) {

			SDL_free(this);

		}

		return(0);

	}

	SDL_memset(this->hidden, 0, (sizeof *this->hidden));

	stream = 0;

	/* Set the function pointers */

	this->OpenAudio = ARTS_OpenAudio;

	this->WaitAudio = ARTS_WaitAudio;

	this->PlayAudio = ARTS_PlayAudio;

	this->GetAudioBuf = ARTS_GetAudioBuf;

	this->CloseAudio = ARTS_CloseAudio;

	this->free = Audio_DeleteDevice;

	return this;

}

AudioBootStrap ARTS_bootstrap = {

	ARTS_DRIVER_NAME, "Analog Realtime Synthesizer",

	Audio_Available, Audio_CreateDevice

};

/* This function waits until it is possible to write a full sound buffer */

static void ARTS_WaitAudio(_THIS)

{

	Sint32 ticks;

	/* Check to see if the thread-parent process is still alive */

	{ static int cnt = 0;

		/* Note that this only works with thread implementations 

		   that use a different process id for each thread.

		*/

		if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */

			if ( kill(parent, 0) < 0 ) {

				this->enabled = 0;

			}

		}

	}

	/* Use timer for general audio synchronization */

	ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS;

	if ( ticks > 0 ) {

		SDL_Delay(ticks);

	}

}

static void ARTS_PlayAudio(_THIS)

{

	int written;

	/* Write the audio data */

	written = SDL_NAME(arts_write)(stream, mixbuf, mixlen);

	/* If timer synchronization is enabled, set the next write frame */

	if ( frame_ticks ) {

		next_frame += frame_ticks;

	}

	/* If we couldn't write, assume fatal error for now */

	if ( written < 0 ) {

		this->enabled = 0;

	}

#ifdef DEBUG_AUDIO

	fprintf(stderr, "Wrote %d bytes of audio data\n", written);

#endif

}

static Uint8 *ARTS_GetAudioBuf(_THIS)

{

	return(mixbuf);

}

static void ARTS_CloseAudio(_THIS)

{

	if ( mixbuf != NULL ) {

		SDL_FreeAudioMem(mixbuf);

		mixbuf = NULL;

	}

	if ( stream ) {

		SDL_NAME(arts_close_stream)(stream);

		stream = 0;

	}

	SDL_NAME(arts_free)();

}

static int ARTS_OpenAudio(_THIS, SDL_AudioSpec *spec)

{

	int bits, frag_spec;

	Uint16 test_format, format;

	int error_code;

	/* Reset the timer synchronization flag */

	frame_ticks = 0.0;

	mixbuf = NULL;

	/* Try for a closest match on audio format */

	format = 0;

	bits = 0;

	for ( test_format = SDL_FirstAudioFormat(spec->format);

						! format && test_format; ) {

#ifdef DEBUG_AUDIO

		fprintf(stderr, "Trying format 0x%4.4x\n", test_format);

#endif

		switch ( test_format ) {

			case AUDIO_U8:

				bits = 8;

				format = 1;

				break;

			case AUDIO_S16LSB:

				bits = 16;

				format = 1;

				break;

			default:

				format = 0;

				break;

		}

		if ( ! format ) {

			test_format = SDL_NextAudioFormat();

		}

	}

	if ( format == 0 ) {

		SDL_SetError("Couldn't find any hardware audio formats");

		return(-1);

	}

	spec->format = test_format;

	error_code = SDL_NAME(arts_init)();

	if ( error_code != 0 ) {

		SDL_SetError("Unable to initialize ARTS: %s", SDL_NAME(arts_error_text)(error_code));

		return(-1);

	}

	if ( ! SDL_NAME(arts_suspended)() ) {

		SDL_SetError("ARTS can not open audio device");

		return(-1);

	}

	stream = SDL_NAME(arts_play_stream)(spec->freq, bits, spec->channels, "SDL");

	/* Calculate the final parameters for this audio specification */

	SDL_CalculateAudioSpec(spec);

	/* Determine the power of two of the fragment size */

	for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );

	if ( (0x01<<frag_spec) != spec->size ) {

		SDL_SetError("Fragment size must be a power of two");

		return(-1);

	}

	frag_spec |= 0x00020000;	/* two fragments, for low latency */

#ifdef ARTS_P_PACKET_SETTINGS

	SDL_NAME(arts_stream_set)(stream, ARTS_P_PACKET_SETTINGS, frag_spec);

#else

	SDL_NAME(arts_stream_set)(stream, ARTS_P_PACKET_SIZE, frag_spec&0xffff);

	SDL_NAME(arts_stream_set)(stream, ARTS_P_PACKET_COUNT, frag_spec>>16);

#endif

	spec->size = SDL_NAME(arts_stream_get)(stream, ARTS_P_PACKET_SIZE);

	/* Allocate mixing buffer */

	mixlen = spec->size;

	mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);

	if ( mixbuf == NULL ) {

		return(-1);

	}

	SDL_memset(mixbuf, spec->silence, spec->size);

	/* Get the parent process id (we're the parent of the audio thread) */

	parent = getpid();

	/* We're ready to rock and roll. :-) */

	return(0);

}