/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2007 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

    Stéphan Kochen

    stephan@kochen.nl

    Based on parts of the ALSA and ESounD output drivers.

*/

#include "SDL_config.h"

/* Allow access to an PulseAudio network stream mixing buffer */

#include <sys/types.h>

#include <unistd.h>

#include <signal.h>

#include <errno.h>

#include <pulse/simple.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_pulseaudio.h"

#ifdef SDL_AUDIO_DRIVER_PULSE_DYNAMIC

#include "SDL_name.h"

#include "SDL_loadso.h"

#else

#define SDL_NAME(X)	X

#endif

/* The tag name used by the driver */

#define PULSE_DRIVER_NAME	"pulse"

/* Audio driver functions */

static int PULSE_OpenAudio(_THIS, SDL_AudioSpec *spec);

static void PULSE_WaitAudio(_THIS);

static void PULSE_PlayAudio(_THIS);

static Uint8 *PULSE_GetAudioBuf(_THIS);

static void PULSE_CloseAudio(_THIS);

#ifdef SDL_AUDIO_DRIVER_PULSE_DYNAMIC

static const char *pulse_library = SDL_AUDIO_DRIVER_PULSE_DYNAMIC;

static void *pulse_handle = NULL;

static int pulse_loaded = 0;

static pa_simple* (*SDL_NAME(pa_simple_new))(

	const char *server,

	const char *name,

	pa_stream_direction_t dir,

	const char *dev,

	const char *stream_name,

	const pa_sample_spec *ss,

	const pa_channel_map *map,

	const pa_buffer_attr *attr,

	int *error

);

static void (*SDL_NAME(pa_simple_free))(pa_simple *s);

static int (*SDL_NAME(pa_simple_drain))(pa_simple *s, int *error);

static int (*SDL_NAME(pa_simple_write))(

	pa_simple *s,

	const void *data,

	size_t length,

	int *error 

);

static pa_channel_map* (*SDL_NAME(pa_channel_map_init_auto))(

	pa_channel_map *m,

	unsigned channels,

	pa_channel_map_def_t def

);

static struct {

	const char *name;

	void **func;

} pulse_functions[] = {

	{ "pa_simple_new",

		(void **)&SDL_NAME(pa_simple_new)		},

	{ "pa_simple_free",

		(void **)&SDL_NAME(pa_simple_free)		},

	{ "pa_simple_drain",

		(void **)&SDL_NAME(pa_simple_drain)		},

	{ "pa_simple_write",

		(void **)&SDL_NAME(pa_simple_write)		},

	{ "pa_channel_map_init_auto",

		(void **)&SDL_NAME(pa_channel_map_init_auto)	},

};

static void UnloadPulseLibrary()

{

	if ( pulse_loaded ) {

		SDL_UnloadObject(pulse_handle);

		pulse_handle = NULL;

		pulse_loaded = 0;

	}

}

static int LoadPulseLibrary(void)

{

	int i, retval = -1;

	pulse_handle = SDL_LoadObject(pulse_library);

	if ( pulse_handle ) {

		pulse_loaded = 1;

		retval = 0;

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

			*pulse_functions[i].func = SDL_LoadFunction(pulse_handle, pulse_functions[i].name);

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

				retval = -1;

				UnloadPulseLibrary();

				break;

			}

		}

	}

	return retval;

}

#else

static void UnloadPulseLibrary()

{

	return;

}

static int LoadPulseLibrary(void)

{

	return 0;

}

#endif /* SDL_AUDIO_DRIVER_PULSE_DYNAMIC */

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

	pa_sample_spec paspec;

	pa_simple *connection;

	int available;

	available = 0;

	if ( LoadPulseLibrary() < 0 ) {

		return available;

	}

	/* Connect with a dummy format. */

	paspec.format = PA_SAMPLE_U8;

	paspec.rate = 11025;

	paspec.channels = 1;

	connection = SDL_NAME(pa_simple_new)(

		SDL_getenv("PASERVER"),      /* server */

		"Test stream",               /* application name */

		PA_STREAM_PLAYBACK,          /* playback mode */

		SDL_getenv("PADEVICE"),      /* device on the server */

		"Simple DirectMedia Layer",  /* stream description */

		&paspec,                     /* sample format spec */

		NULL,                        /* channel map */

		NULL,                        /* buffering attributes */

		NULL                         /* error code */

	);

	if ( connection != NULL ) {

		available = 1;

		SDL_NAME(pa_simple_free)(connection);

	}

	UnloadPulseLibrary();

	return(available);

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

	SDL_free(device->hidden);

	SDL_free(device);

	UnloadPulseLibrary();

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

	SDL_AudioDevice *this;

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

	LoadPulseLibrary();

	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));

	/* Set the function pointers */

	this->OpenAudio = PULSE_OpenAudio;

	this->WaitAudio = PULSE_WaitAudio;

	this->PlayAudio = PULSE_PlayAudio;

	this->GetAudioBuf = PULSE_GetAudioBuf;

	this->CloseAudio = PULSE_CloseAudio;

	this->free = Audio_DeleteDevice;

	return this;

}

AudioBootStrap PULSE_bootstrap = {

	PULSE_DRIVER_NAME, "PulseAudio",

	Audio_Available, Audio_CreateDevice

};

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

static void PULSE_WaitAudio(_THIS)

{

	/* 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;

			}

		}

	}

}

static void PULSE_PlayAudio(_THIS)

{

	/* Write the audio data */

	if ( SDL_NAME(pa_simple_write)(stream, mixbuf, mixlen, NULL) != 0 )

	{

		this->enabled = 0;

	}

}

static Uint8 *PULSE_GetAudioBuf(_THIS)

{

	return(mixbuf);

}

static void PULSE_CloseAudio(_THIS)

{

	if ( mixbuf != NULL ) {

		SDL_FreeAudioMem(mixbuf);

		mixbuf = NULL;

	}

	if ( stream != NULL ) {

		SDL_NAME(pa_simple_drain)(stream, NULL);

		SDL_NAME(pa_simple_free)(stream);

		stream = NULL;

	}

}

/* Try to get the name of the program */

static char *get_progname(void)

{

	char *progname = NULL;

#ifdef __LINUX__

	FILE *fp;

	static char temp[BUFSIZ];

	SDL_snprintf(temp, SDL_arraysize(temp), "/proc/%d/cmdline", getpid());

	fp = fopen(temp, "r");

	if ( fp != NULL ) {

		if ( fgets(temp, sizeof(temp)-1, fp) ) {

			progname = SDL_strrchr(temp, '/');

			if ( progname == NULL ) {

				progname = temp;

			} else {

				progname = progname+1;

			}

		}

		fclose(fp);

	}

#endif

	return(progname);

}

static int PULSE_OpenAudio(_THIS, SDL_AudioSpec *spec)

{

	Uint16          test_format;

	pa_sample_spec  paspec;

	pa_buffer_attr  paattr;

	pa_channel_map  pacmap;

	paspec.format = PA_SAMPLE_INVALID;

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

		switch ( test_format ) {

			case AUDIO_U8:

				paspec.format = PA_SAMPLE_U8;

				break;

			case AUDIO_S16LSB:

				paspec.format = PA_SAMPLE_S16LE;

				break;

			case AUDIO_S16MSB:

				paspec.format = PA_SAMPLE_S16BE;

				break;

		}

		if ( paspec.format != PA_SAMPLE_INVALID )

			break;

	}

	if (paspec.format == PA_SAMPLE_INVALID ) {

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

		return(-1);

	}

	spec->format = test_format;

	paspec.channels = spec->channels;

	paspec.rate = spec->freq;

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

	SDL_CalculateAudioSpec(spec);

	/* Allocate mixing buffer */

	mixlen = spec->size;

	mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);

	if ( mixbuf == NULL ) {

		return(-1);

	}

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

	/* Reduced prebuffering compared to the defaults. */

	paattr.tlength = mixlen;

	paattr.minreq = mixlen;

	paattr.fragsize = mixlen;

	paattr.prebuf = mixlen;

	paattr.maxlength = mixlen * 4;

	/* The SDL ALSA output hints us that we use Windows' channel mapping */

	/* http://bugzilla.libsdl.org/show_bug.cgi?id=110 */

	SDL_NAME(pa_channel_map_init_auto)(

		&pacmap, spec->channels, PA_CHANNEL_MAP_WAVEEX);

	/* Connect to the PulseAudio server */

	stream = SDL_NAME(pa_simple_new)(

		SDL_getenv("PASERVER"),      /* server */

		get_progname(),              /* application name */

		PA_STREAM_PLAYBACK,          /* playback mode */

		SDL_getenv("PADEVICE"),      /* device on the server */

		"Simple DirectMedia Layer",  /* stream description */

		&paspec,                     /* sample format spec */

		&pacmap,                     /* channel map */

		&paattr,                     /* buffering attributes */

		NULL                         /* error code */

	);

	if ( stream == NULL ) {

		PULSE_CloseAudio(this);

		SDL_SetError("Could not connect to PulseAudio");

		return(-1);

	}

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

	parent = getpid();

	return(0);

}