/*
	snd_linux_sdl.c

	Sound code taken from Tenebrae to work with Tremor

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program 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 General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to:

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

	$Id: snd_sdl.c,v 1.2 2002/02/09 20:29:38 relnev Exp $
*/
#include "SDL.h"
#include "quakedef.h"

static dma_t the_shm;
static int snd_inited;

extern int desired_speed;
extern int desired_bits;

static void paint_audio(void *unused, Uint8 *stream, int len)
{
	if ( snd_inited ) {
		shm->buffer = stream;
		shm->samplepos += len/(shm->samplebits/4);
		// Check for samplepos overflow?
		S_PaintChannels (shm->samplepos);
	}
}

qboolean SNDDMA_Init(void)
{
	SDL_AudioSpec desired, obtained;
	
	if (SDL_WasInit(SDL_INIT_EVERYTHING) == 0)  {
		if (SDL_Init(SDL_INIT_AUDIO) < 0)  {
			Con_Printf ("Couldn't init SDL audio: %s\n", SDL_GetError ());
			return 0;
		}
	} 
	else if (SDL_WasInit(SDL_INIT_AUDIO) == 0)  {
		if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) {
			Con_Printf ("Couldn't init SDL audio: %s\n", SDL_GetError ());
			return 0;
		}
	}

	snd_inited = 0;

	/* Set up the desired format */
	if (COM_CheckParm("-sndspeed")) //Better sample rate - Eradicator
		desired.freq = Q_atoi(com_argv[COM_CheckParm("-sndspeed")+1]);
        else 
             desired.freq = desired_speed;

	switch (desired_bits) {
		case 8:
			desired.format = AUDIO_U8;
			break;
		case 16:
			if ( SDL_BYTEORDER == SDL_BIG_ENDIAN )
				desired.format = AUDIO_S16MSB;
			else
				desired.format = AUDIO_S16LSB;
			break;
		default:
        		Con_Printf("Unknown number of audio bits: %d\n",
			           desired_bits);
			return 0;
	}

	if (COM_CheckParm("-sndchannels")) //Better sound channels - Eradicator
             shm->channels = Q_atoi(com_argv[COM_CheckParm("-sndchannels")+1]);
        else 
             desired.channels = 2;

	desired.freq = 44100;
	desired.samples = 2048;
	desired.callback = paint_audio;

	/* Open the audio device */
	if ( SDL_OpenAudio(&desired, &obtained) < 0 ) {
        	Con_Printf("Couldn't open SDL audio: %s\n", SDL_GetError());
		return 0;
	}

	/* Make sure we can support the audio format */
	switch (obtained.format) {
		case AUDIO_U8:
			/* Supported */
			break;
		case AUDIO_S16LSB:
		case AUDIO_S16MSB:
			if ( ((obtained.format == AUDIO_S16LSB) &&
			     (SDL_BYTEORDER == SDL_LIL_ENDIAN)) ||
			     ((obtained.format == AUDIO_S16MSB) &&
			     (SDL_BYTEORDER == SDL_BIG_ENDIAN)) ) {
				/* Supported */
				break;
			}
			/* Unsupported, fall through */;
		default:
			/* Not supported -- force SDL to do our bidding */
			SDL_CloseAudio();
			if ( SDL_OpenAudio(&desired, NULL) < 0 ) {
        			Con_Printf("Couldn't open SDL audio: %s\n",
							SDL_GetError());
				return 0;
			}
			memcpy(&obtained, &desired, sizeof(desired));
			break;
	}
	SDL_PauseAudio(0);

	/* Fill the audio DMA information block */
	shm = &the_shm;
	shm->splitbuffer = 0;
	shm->samplebits = (obtained.format & 0xFF);
        shm->speed = obtained.freq;
        shm->channels = obtained.channels;
	shm->samples = obtained.samples*shm->channels;
	shm->samplepos = 0;
	shm->submission_chunk = 1;
	shm->buffer = NULL;

	snd_inited = 1;
	return 1;
}

int SNDDMA_GetDMAPos(void)
{
	return shm->samplepos;
}

void SNDDMA_Shutdown(void)
{
	if (snd_inited)
	{
		SDL_CloseAudio();
		snd_inited = 0;
	}
}

void SNDDMA_Submit (void)
{
//
}