/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code 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.

Quake III Arena source code 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 Quake III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "snd_local.h"
#include "snd_codec.h"


#define DEF_COMSOUNDMEGS "16"

static sndBuffer* sndbuffers = NULL;
static sndBuffer* freelist = NULL;
static int sndmem_avail = 0;
static int sndmem_inuse = 0;


void SND_free( sndBuffer* v )
{
	*(sndBuffer **)v = freelist;
	freelist = (sndBuffer*)v;
	sndmem_avail += sizeof(sndBuffer);
}


sndBuffer* SND_malloc()
{
	while (!freelist) {
		if (!S_FreeOldestSound()) {
			// Throw an error instead of running an infinite loop.
			// It would be nicer to have a disconnect/drop type of error here,
			// but sadly that would leave the hunk allocator in a bad state.
			Com_Error (ERR_FATAL,
					   "Not enough memory for audio.\n"
					   "Please increase com_soundMegs accordingly.\n");
		}
	}

	sndmem_avail -= sizeof(sndBuffer);
	sndmem_inuse += sizeof(sndBuffer);

	sndBuffer* v = freelist;
	freelist = *(sndBuffer **)freelist;
	v->next = NULL;
	return v;
}


void SND_setup()
{
	sndBuffer *p, *q;

	// a sndBuffer struct is actually a bit over 2048 bytes,
	// so we're really allocating roughly 2x more than what was asked
	const cvar_t* cv = Cvar_Get( "com_soundMegs", DEF_COMSOUNDMEGS, CVAR_LATCH | CVAR_ARCHIVE );
	Cvar_SetRange( "com_soundMegs", CVART_INTEGER, "1", "64" );
	Cvar_SetHelp( "com_soundMegs", "sound system buffer size [MB]\n"
				 "It allocates from " S_COLOR_CVAR "com_hunkMegs" S_COLOR_HELP "'s pool." );
	const int scs = cv->integer * 1024;

	sndbuffers = (sndBuffer*)Hunk_Alloc( scs * sizeof(sndBuffer), h_high );
	sndmem_avail = scs * sizeof(sndBuffer);

	p = sndbuffers;
	q = p + scs;
	while (--q > p)
		*(sndBuffer **)q = q-1;

	*(sndBuffer **)q = NULL;
	freelist = p + scs - 1;
}


void S_DisplayFreeMemory()
{
	Com_Printf( "%d bytes sound buffer memory in use, %d free \n", sndmem_inuse, sndmem_avail );
}


///////////////////////////////////////////////////////////////


// resample / decimate to the current source rate

static void ResampleSfx( sfx_t *sfx, int inrate, int inwidth, byte *data )
{
	int		outcount;
	int		srcsample;
	float	stepscale;
	int		i;
	int		sample, samplefrac, fracstep;
	int			part;
	sndBuffer	*chunk;

	stepscale = (float)inrate / dma.speed;	// this is usually 0.5, 1, or 2

	outcount = sfx->soundLength / stepscale;
	sfx->soundLength = outcount;

	samplefrac = 0;
	fracstep = stepscale * 256;
	chunk = sfx->soundData;

	for (i=0 ; i<outcount ; i++)
	{
		srcsample = samplefrac >> 8;
		samplefrac += fracstep;
		if( inwidth == 2 ) {
			sample = ( ((short *)data)[srcsample] );
		} else {
			sample = (int)( (unsigned char)(data[srcsample]) - 128) << 8;
		}
		part  = (i&(SND_CHUNK_SIZE-1));
		if (part == 0) {
			sndBuffer* newchunk = SND_malloc();
			if (chunk == NULL) {
				sfx->soundData = newchunk;
			} else {
				chunk->next = newchunk;
			}
			chunk = newchunk;
		}

		chunk->sndChunk[part] = sample;
	}
}


qbool S_LoadSound( sfx_t* sfx )
{
	// player specific sounds are never directly loaded
	if (sfx->soundName[0] == '*') {
		return qfalse;
	}

	snd_info_t info;
	byte* data = S_CodecLoad( sfx->soundName, &info );
	if (!data)
		return qfalse;

	if ( info.width == 1 ) {
		Com_DPrintf( S_COLOR_YELLOW "WARNING: %s is a 8 bit wav file\n", sfx->soundName );
	}

	if ( info.rate != 22050 ) {
		Com_DPrintf( S_COLOR_YELLOW "WARNING: %s is not a 22kHz wav file\n", sfx->soundName );
	}

	sfx->lastTimeUsed = Com_Milliseconds();

	sfx->soundLength = info.samples;
	sfx->soundData = NULL;
	ResampleSfx( sfx, info.rate, info.width, data + info.dataofs );

	Z_Free(data);

	return qtrue;
}