/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga

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

    modify it under the terms of the GNU Library General Public

    License as published by the Free Software Foundation; either

    version 2 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

    Library General Public License for more details.

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

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

    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga

    slouken@devolution.com

*/

#ifdef SAVE_RCSID

static char rcsid =

 "@(#) $Id$";

#endif

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

#ifdef ESD_SUPPORT

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <errno.h>

#include <signal.h>

#include <unistd.h>

#include <esd.h>

#include "SDL_audio.h"

#include "SDL_error.h"

#include "SDL_audiomem.h"

#include "SDL_audio_c.h"

#include "SDL_timer.h"

#include "SDL_audiodev_c.h"

#include "SDL_esdaudio.h"

/* The tag name used by ESD audio */

#define ESD_DRIVER_NAME		"esd"

/* Audio driver functions */

static int ESD_OpenAudio(_THIS, SDL_AudioSpec *spec);

static void ESD_WaitAudio(_THIS);

static void ESD_PlayAudio(_THIS);

static Uint8 *ESD_GetAudioBuf(_THIS);

static void ESD_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

	int connection;

	int available;

	available = 0;

	connection = esd_open_sound(NULL);

	if ( connection >= 0 ) {

		available = 1;

		esd_close(connection);

	}

	return(available);

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

	free(device->hidden);

	free(device);

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

	SDL_AudioDevice *this;

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

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

	if ( this ) {

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

		this->hidden = (struct SDL_PrivateAudioData *)

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

	}

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

		SDL_OutOfMemory();

		if ( this ) {

			free(this);

		}

		return(0);

	}

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

	audio_fd = -1;

	/* Set the function pointers */

	this->OpenAudio = ESD_OpenAudio;

	this->WaitAudio = ESD_WaitAudio;

	this->PlayAudio = ESD_PlayAudio;

	this->GetAudioBuf = ESD_GetAudioBuf;

	this->CloseAudio = ESD_CloseAudio;

	this->free = Audio_DeleteDevice;

	return this;

}

AudioBootStrap ESD_bootstrap = {

	ESD_DRIVER_NAME, "Enlightened Sound Daemon",

	Audio_Available, Audio_CreateDevice

};

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

static void ESD_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 ESD_PlayAudio(_THIS)

{

	int written;

	/* Write the audio data, checking for EAGAIN on broken audio drivers */

	do {

		written = write(audio_fd, mixbuf, mixlen);

		if ( (written < 0) && ((errno == 0) || (errno == EAGAIN)) ) {

			SDL_Delay(1);	/* Let a little CPU time go by */

		}

	} while ( (written < 0) && 

	          ((errno == 0) || (errno == EAGAIN) || (errno == EINTR)) );

	/* Set the next write frame */

	next_frame += frame_ticks;

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

	if ( written < 0 ) {

		this->enabled = 0;

	}

}

static Uint8 *ESD_GetAudioBuf(_THIS)

{

	return(mixbuf);

}

static void ESD_CloseAudio(_THIS)

{

	if ( mixbuf != NULL ) {

		SDL_FreeAudioMem(mixbuf);

		mixbuf = NULL;

	}

	if ( audio_fd >= 0 ) {

		close(audio_fd);

		audio_fd = -1;

	}

}

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

static char *get_progname(void)

{

	char *progname = NULL;

#ifdef linux

	FILE *fp;

	static char temp[BUFSIZ];

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

	fp = fopen(temp, "r");

	if ( fp != NULL ) {

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

			progname = strrchr(temp, '/');

			if ( progname == NULL ) {

				progname = temp;

			} else {

				progname = progname+1;

			}

		}

		fclose(fp);

	}

#endif

	return(progname);

}

static int ESD_OpenAudio(_THIS, SDL_AudioSpec *spec)

{

	esd_format_t format;

	/* Convert audio spec to the ESD audio format */

	format = (ESD_STREAM | ESD_PLAY);

	switch ( spec->format & 0xFF ) {

		case 8:

			format |= ESD_BITS8;

			break;

		case 16:

			format |= ESD_BITS16;

			break;

		default:

			SDL_SetError("Unsupported ESD audio format");

			return(-1);

	}

	if ( spec->channels == 1 ) {

		format |= ESD_MONO;

	} else {

		format |= ESD_STEREO;

	}

#if 0

	spec->samples = ESD_BUF_SIZE;	/* Darn, no way to change this yet */

#endif

	/* Open a connection to the ESD audio server */

	audio_fd = esd_play_stream(format, spec->freq, NULL, get_progname());

	if ( audio_fd < 0 ) {

		SDL_SetError("Couldn't open ESD connection");

		return(-1);

	}

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

	SDL_CalculateAudioSpec(spec);

	frame_ticks = (float)(spec->samples*1000)/spec->freq;

	next_frame = SDL_GetTicks()+frame_ticks;

	/* Allocate mixing buffer */

	mixlen = spec->size;

	mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);

	if ( mixbuf == NULL ) {

		return(-1);

	}

	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);

}

#endif /* ESD_SUPPORT */