/*
 * This file is part of libextractor.
 * (C) 2006, 2007 Toni Ruottu
 *
 * libextractor 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, or (at your
 * option) any later version.
 *
 * libextractor 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 libextractor; see the file COPYING.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 */

#include "platform.h"
#include "extractor.h"
#include "convert.h"


#define SID1_HEADER_SIZE 0x76
#define SID2_HEADER_SIZE 0x7c

/* flags */

#define MUSPLAYER_FLAG   0x01
#define PLAYSID_FLAG     0x02
#define PAL_FLAG         0x04
#define NTSC_FLAG        0x08
#define MOS6581_FLAG     0x10
#define MOS8580_FLAG     0x20

typedef char sidwrd[ 2 ];
typedef char sidlongwrd[ 4 ];

struct header
{
	char magicid[ 4 ];
	sidwrd sidversion;
	sidwrd dataoffset;
	sidwrd loadaddr;
	sidwrd initaddr;
	sidwrd playaddr;
	sidwrd songs;
	sidwrd firstsong;
	sidlongwrd speed;
	char title[ 32 ];
	char artist[ 32 ];
	char copyright[ 32 ];
	sidwrd flags; /* version 2 specific fields start */
	char startpage;
	char pagelength;
	sidwrd reserved;
};

int sidword( sidwrd data  )
{
	int value =
		( unsigned char ) data[ 0 ] * 0x100 +
		( unsigned char ) data[ 1 ];

	return( value );

}

static struct EXTRACTOR_Keywords * addkword
(
	EXTRACTOR_KeywordList *oldhead,
	const char * phrase,
	EXTRACTOR_KeywordType type
)
{
	EXTRACTOR_KeywordList * keyword;

	keyword = malloc( sizeof( EXTRACTOR_KeywordList ) );
	keyword->next = oldhead;
	keyword->keyword = strdup( phrase );
	keyword->keywordType = type;
	return( keyword );
}


/* "extract" keyword from a SID file
 *
 *  This plugin is based on the nsf extractor
 *
 */
struct EXTRACTOR_Keywords * libextractor_sid_extract
(
	const char * filename,
	char * data,
	size_t size,
	struct EXTRACTOR_Keywords * prev
)
{
	unsigned int flags;
	int version;
	char album[ 33 ];
	char artist[ 33 ];
	char copyright[ 33 ];
	char songs[ 32 ];
	char startingsong[ 32 ];
	char sidversion[ 32 ];
	struct header *head;

	/* Check header size */

	if( size < SID1_HEADER_SIZE )
	{
		return( prev );
	}

	head = ( struct header * ) data;

	/* Check "magic" id bytes */

	if
	(
		memcmp( head->magicid, "PSID", 4 ) &&
		memcmp( head->magicid, "RSID", 4 )
	)
	{
		return( prev );
	}


	/* Mime-type */

	prev = addkword( prev, "audio/prs.sid", EXTRACTOR_MIMETYPE );


	/* Version of SID format */

	version = sidword( head->sidversion );
	sprintf( sidversion, "%d", version );
	prev = addkword( prev, sidversion, EXTRACTOR_FORMAT_VERSION );


	/* Get song count */

	sprintf( songs, "%d", sidword( head->songs ) );
	prev = addkword( prev, songs, EXTRACTOR_SONG_COUNT );


	/* Get number of the first song to be played */

	sprintf( startingsong, "%d", sidword( head->firstsong ) );
	prev = addkword( prev, startingsong, EXTRACTOR_STARTING_SONG );


	/* name, artist, copyright fields */

	memcpy( &album, head->title, 32 );
	memcpy( &artist, head->artist, 32 );
	memcpy( &copyright, head->copyright, 32 );

	album[ 32 ] = '\0';
	artist[ 32 ] = '\0';
	copyright[ 32 ] = '\0';

	prev = addkword( prev, album, EXTRACTOR_ALBUM );
	prev = addkword( prev, artist, EXTRACTOR_ARTIST );
	prev = addkword( prev, copyright, EXTRACTOR_COPYRIGHT );


	if( version < 2 || size < SID2_HEADER_SIZE )
	{
		return( prev );
	}

	/* Version 2 specific options follow
	 *
	 * Note: Had some troubles understanding specification
	 * on the flags in version 2. I hope this is correct.
	 *
	 */

	flags = sidword( head->flags );


	/* MUS data */

	if( flags & MUSPLAYER_FLAG )
	{
		prev = addkword( prev, "Compute!'s Sidplayer", EXTRACTOR_DEPENDENCY );
	}

	/* PlaySID data */

	if( flags & PLAYSID_FLAG )
	{
		prev = addkword( prev, "PlaySID", EXTRACTOR_DEPENDENCY );
	}


	/* PAL or NTSC */

	if( flags & PAL_FLAG )
	{
		if( flags & NTSC_FLAG )
		{
			prev = addkword( prev, "PAL/NTSC", EXTRACTOR_TELEVISION_SYSTEM );
		}
		else
		{
			prev = addkword( prev, "PAL", EXTRACTOR_TELEVISION_SYSTEM );
		}
	}
	else
	{
		if( flags & NTSC_FLAG )
		{
			prev = addkword( prev, "NTSC", EXTRACTOR_TELEVISION_SYSTEM );
		}
	}

	/* Detect SID Chips suitable for play the files */

	if( flags & MOS6581_FLAG )
	{
		if( flags & MOS8580_FLAG )
		{
			prev = addkword( prev, "MOS6581/MOS8580", EXTRACTOR_HARDWARE_DEPENDENCY );
		}
		else
		{
			prev = addkword( prev, "MOS6581", EXTRACTOR_HARDWARE_DEPENDENCY );
		}
	}
	else
	{
		if( flags & MOS8580_FLAG )
		{
			prev = addkword( prev, "MOS8580", EXTRACTOR_HARDWARE_DEPENDENCY );
		}
	}

	return( prev );
}