/*
snd_wav.c - wav format load & save
Copyright (C) 2010 Uncle Mike
Copyright (C) 2023 FTEQW developers

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 3 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.
*/

#include <stddef.h>
#include "nanoquake.h"

static const byte *iff_data;
static const byte *iff_dataPtr;
static const byte *iff_end;
static const byte *iff_lastChunk;
static int iff_chunkLen;

/*
=================
GetLittleShort
=================
*/
static short GetLittleShort( void )
{
	short	val = 0;

	val += (*(iff_dataPtr+0) << 0);
	val += (*(iff_dataPtr+1) << 8);
	iff_dataPtr += 2;

	return val;
}

/*
=================
GetLittleLong
=================
*/
static int GetLittleLong( void )
{
	int	val = 0;

	val += (*(iff_dataPtr+0) << 0);
	val += (*(iff_dataPtr+1) << 8);
	val += (*(iff_dataPtr+2) <<16);
	val += (*(iff_dataPtr+3) <<24);
	iff_dataPtr += 4;

	return val;
}

/*
=================
FindNextChunk
=================
*/
static void FindNextChunk( const char *filename, const char *name )
{
	while( 1 )
	{
		ptrdiff_t remaining = iff_end - iff_lastChunk;

		if( remaining < 8 )
		{
			iff_dataPtr = NULL;
			return;
		}

		iff_dataPtr = iff_lastChunk + 4;
		remaining -= 8;

		iff_chunkLen = GetLittleLong();
		if( iff_chunkLen < 0 )
		{
			iff_dataPtr = NULL;
			return;
		}

		if( iff_chunkLen > remaining )
		{
			Con_DPrintf( "%s: '%s' truncated by %i bytes\n", __func__, filename, iff_chunkLen - remaining );
			iff_chunkLen = remaining;
		}

		remaining -= iff_chunkLen;
		iff_dataPtr -= 8;

		iff_lastChunk = iff_dataPtr + 8 + iff_chunkLen;
		if ((iff_chunkLen&1) && remaining)
			iff_lastChunk++;
		if (!Q_strncmp(iff_dataPtr, name, 4))
			return;
	}
}

/*
=================
FindChunk
=================
*/
static void FindChunk( const char *filename, const char *name )
{
	iff_lastChunk = iff_data;
	FindNextChunk( filename, name );
}

/*
=============
Sound_LoadWAV
=============
*/
qboolean Sound_LoadWAV( const char *name, const byte *buffer, fs_offset_t filesize )
{
	int	samples, fmt;

	if( !buffer || filesize <= 0 )
		return false;

	iff_data = buffer;
	iff_end = buffer + filesize;

	// find "RIFF" chunk
	FindChunk( name, "RIFF" );

	if( !( iff_dataPtr && !Q_strncmp( (const char *)iff_dataPtr + 8, "WAVE", 4 )))
	{
		Con_DPrintf( S_ERROR "Sound_LoadWAV: %s missing 'RIFF/WAVE' chunks\n", name );
		return false;
	}

	// get "fmt " chunk
	iff_data = iff_dataPtr + 12;
	FindChunk( name, "fmt " );

	if( !iff_dataPtr )
	{
		Con_DPrintf( S_ERROR "Sound_LoadWAV: %s missing 'fmt ' chunk\n", name );
		return false;
	}

	iff_dataPtr += 8;
	fmt = GetLittleShort();

	if( fmt != 1 )
	{
		Con_DPrintf( S_ERROR "Sound_LoadWAV: %s not a microsoft PCM format\n", name );
		return false;
	}

	sound.channels = GetLittleShort();
	if( sound.channels != 1 && sound.channels != 2 )
	{
		Con_DPrintf( S_ERROR "Sound_LoadWAV: only mono and stereo WAV files supported (%s)\n", name );
		return false;
	}

	sound.rate = GetLittleLong();
	iff_dataPtr += 6;

	sound.width = GetLittleShort() / 8;

	if( sound.width != 1 && sound.width != 2 )
	{
		Con_DPrintf( S_ERROR "Sound_LoadWAV: only 8 and 16 bit WAV files supported (%s)\n", name );
		return false;
	}

	// get cue chunk
	FindChunk( name, "cue " );

	if( iff_dataPtr )
	{
		iff_dataPtr += 32;
		sound.loopstart = GetLittleLong();
		FindNextChunk( name, "LIST" ); // if the next chunk is a LIST chunk, look for a cue length marker

		if( iff_dataPtr )
		{
			if( !Q_strncmp( (const char *)iff_dataPtr + 28, "mark", 4 ))
			{
				// this is not a proper parse, but it works with CoolEdit...
				iff_dataPtr += 24;
				sound.samples = sound.loopstart + GetLittleLong(); // samples in loop
			}
		}
	}
	else
	{
		sound.loopstart = -1;
		sound.samples = 0;
	}

	// find data chunk
	FindChunk( name, "data" );

	if( !iff_dataPtr )
	{
		Con_DPrintf( S_ERROR "Sound_LoadWAV: %s missing 'data' chunk\n", name );
		return false;
	}

	iff_dataPtr += 4;
	samples = GetLittleLong() / sound.width;

	if( sound.samples )
	{
		if( samples < sound.samples )
		{
			Con_DPrintf( S_ERROR "Sound_LoadWAV: %s has a bad loop length\n", name );
			return false;
		}
	}
	else sound.samples = samples;

	if( sound.samples <= 0 )
	{
		Con_Reportf( S_ERROR "Sound_LoadWAV: file with %i samples (%s)\n", sound.samples, name );
		return false;
	}

	sound.type = WF_PCMDATA;
	sound.samples /= sound.channels;

	// Load the data
	sound.size = sound.samples * sound.width * sound.channels;
	sound.wav = Mem_Malloc( host.soundpool, sound.size );

	memcpy( sound.wav, buffer + (iff_dataPtr - buffer), sound.size );

	// now convert 8-bit sounds to signed
	if( sound.width == 1 )
	{
		int	i, j;
		signed char	*pData = (signed char *)sound.wav;

		for( i = 0; i < sound.samples; i++ )
		{
			for( j = 0; j < sound.channels; j++ )
			{
				*pData = (byte)((int)((byte)*pData) - 128 );
				pData++;
			}
		}
	}

	return true;
}