/**

 * $Id$

 *

 * GD-Rom image-file common functions. 

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * 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.

 */

#include <assert.h>

#include <netinet/in.h>

#include "gdrom/gdrom.h"

#include "gdrom/packet.h"

#include "ecc.h"

#include "bootstrap.h"

static void gdrom_image_destroy( gdrom_disc_t disc );

static gdrom_error_t gdrom_image_read_sector( gdrom_disc_t disc, uint32_t lba, int mode, 

					      unsigned char *buf, uint32_t *readlength );

static gdrom_error_t gdrom_image_read_toc( gdrom_disc_t disc, unsigned char *buf );

static gdrom_error_t gdrom_image_read_session( gdrom_disc_t disc, int session, unsigned char *buf );

static gdrom_error_t gdrom_image_read_position( gdrom_disc_t disc, uint32_t lba, unsigned char *buf );

static int gdrom_image_drive_status( gdrom_disc_t disc );

static uint8_t gdrom_default_sync[12] = { 0, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0 };

#define SECTOR_HEADER_SIZE 16

#define SECTOR_SUBHEADER_SIZE 8

/* Data offset (from start of raw sector) by sector mode */

static int gdrom_data_offset[] = { 16, 16, 16, 24, 24, 0, 8, 0, 0 };

struct cdrom_sector_header {

    uint8_t sync[12];

    uint8_t msf[3];

    uint8_t mode;

    uint8_t subhead[8]; // Mode-2 XA sectors only

};

/**

 * Initialize a gdrom_disc structure with the gdrom_image_* methods

 */

void gdrom_image_init( gdrom_disc_t disc )

{

    memset( disc, 0, sizeof(struct gdrom_disc) ); /* safety */

    disc->read_sector = gdrom_image_read_sector;

    disc->read_toc = gdrom_image_read_toc;

    disc->read_session = gdrom_image_read_session;

    disc->read_position = gdrom_image_read_position;

    disc->drive_status = gdrom_image_drive_status;

    disc->play_audio = NULL; /* not supported yet */

    disc->run_time_slice = NULL; /* not needed */

    disc->close = gdrom_image_destroy;

}

gdrom_disc_t gdrom_image_new( const gchar *filename, FILE *f )

{

    gdrom_image_t image = (gdrom_image_t)calloc(sizeof(struct gdrom_image), 1);

    if( image == NULL ) {

	return NULL;

    }

    image->disc_type = IDE_DISC_CDROMXA;

    image->file = f;

    gdrom_disc_t disc = (gdrom_disc_t)image;

    gdrom_image_init(disc);

    if( filename == NULL ) {

	disc->name = NULL;

    } else {

	disc->name = g_strdup(filename);

    }

    return disc;

}

static void gdrom_image_destroy( gdrom_disc_t disc )

{

    int i;

    FILE *lastfile = NULL;

    gdrom_image_t img = (gdrom_image_t)disc;

    if( img->file != NULL ) {

	fclose(img->file);

	img->file = NULL;

    }

    for( i=0; i<img->track_count; i++ ) {

	if( img->track[i].file != NULL && img->track[i].file != lastfile ) {

	    lastfile = img->track[i].file;

	    fclose(lastfile);

	    img->track[i].file = NULL;

	}

    }

    if( disc->name != NULL ) {

	g_free( (gpointer)disc->name );

	disc->name = NULL;

    }

    free( disc );

}

void gdrom_image_destroy_no_close( gdrom_disc_t disc )

{

    int i;

    FILE *lastfile = NULL;

    gdrom_image_t img = (gdrom_image_t)disc;

    if( img->file != NULL ) {

	img->file = NULL;

    }

    for( i=0; i<img->track_count; i++ ) {

	if( img->track[i].file != NULL && img->track[i].file != lastfile ) {

	    lastfile = img->track[i].file;

	    fclose(lastfile);

	    img->track[i].file = NULL;

	}

    }

    if( disc->name != NULL ) {

	g_free( (gpointer)disc->name );

	disc->name = NULL;

    }

    free( disc );

}

static int gdrom_image_get_track_by_lba( gdrom_image_t image, uint32_t lba )

{

    int i;

    for( i=0; i<image->track_count; i++ ) {

	if( image->track[i].lba <= lba && 

	    lba < (image->track[i].lba + image->track[i].sector_count) ) {

	    return i+1;

	}

    }

    return -1;

}

/**

 * Read a block from an image file, handling negative file offsets

 * with 0-fill.

 */

static gboolean gdrom_read_block( unsigned char *buf, int file_offset, int length, FILE *f )

{

    if( file_offset < 0 ) {

	int size = -file_offset;

	if( size >= length ) {

	    memset( buf, 0, length );

	    return;

	} else {

	    memset( buf, 0, size );

	    file_offset = 0;

	    length -= size;

	}

    }

    fseek( f, file_offset, SEEK_SET );

    return fread( buf, length, 1, f ) == 1;

}

static void gdrom_build_sector_header( unsigned char *buf, uint32_t lba, 

				       gdrom_track_mode_t sector_mode )

{

    memcpy( buf, gdrom_default_sync, 12 );

    cd_build_address( buf, sector_mode, lba );

}

/**

 * Return TRUE if the given read mode + track modes are compatible,

 * otherwise FALSE.

 * @param track_mode one of the GDROM_MODE* constants

 * @param read_mode the READ_CD_MODE from the read request

 */

static gboolean gdrom_is_compatible_read_mode( int track_mode, int read_mode )

{

    switch( read_mode ) {

    case READ_CD_MODE_ANY:

	return TRUE;

    case READ_CD_MODE_CDDA:

	return track_mode == GDROM_CDDA;

    case READ_CD_MODE_1:

	return track_mode == GDROM_MODE1 || track_mode == GDROM_MODE2_FORM1;

    case READ_CD_MODE_2_FORM_1:

	return track_mode == GDROM_MODE1 || track_mode == GDROM_MODE2_FORM1;

    case READ_CD_MODE_2_FORM_2:

	return track_mode == GDROM_MODE2_FORM2;

    case READ_CD_MODE_2:

	return track_mode == GDROM_MODE2_FORMLESS;

    default:

	return FALSE;

    }

}

/**

 * Determine the start position in a raw sector, and the amount of data to read

 * in bytes, for a given combination of sector mode and read mode.

 */ 

static void gdrom_get_read_bounds( int sector_mode, int read_mode, int *start, int *size )

{

    if( READ_CD_RAW(read_mode) ) {

	// whole sector

	*start = 0;

	*size = 2352;

    } else {

	*size = 0;

	if( READ_CD_DATA(read_mode) ) {

	    *start = gdrom_data_offset[sector_mode];

	    *size = gdrom_sector_size[sector_mode];

	}

	if( READ_CD_SUBHEAD(read_mode) && 

	    (sector_mode == GDROM_MODE2_FORM1 || sector_mode == GDROM_MODE2_FORM2) ) {

	    *start = SECTOR_HEADER_SIZE;

	    *size += SECTOR_SUBHEADER_SIZE;

	}

	if( READ_CD_HEADER(read_mode) ) {

	    *size += SECTOR_HEADER_SIZE;

	    *start = 0;

	}

    }

}

/**

 * Read a single sector from a disc image. If you thought this would be simple, 

 * I have just one thing to say to you: Bwahahahahahahahah.

 *

 * Once we've decided that there's a real sector at the requested lba, there's 

 * really two things we need to care about:

 *   1. Is the sector mode compatible with the requested read mode

 *   2. Which parts of the sector do we need to return? 

 *      (header/subhead/data/raw sector)

 *

 * Also note that the disc image may supply us with just the data (most common 

 * case), or may have the full raw sector. In the former case we may need to 

 * generate the missing data on the fly, for which we use libedc to compute the

 * data correction codes.

 */

static gdrom_error_t gdrom_image_read_sector( gdrom_disc_t disc, uint32_t lba,

					      int mode, unsigned char *buf, uint32_t *length )

{

    gdrom_image_t image = (gdrom_image_t)disc;

    struct cdrom_sector_header secthead;

    int file_offset, read_len, track_no;

    FILE *f;

    track_no = gdrom_image_get_track_by_lba( image, lba );

    if( track_no == -1 ) {

	return PKT_ERR_BADREAD;

    }

    struct gdrom_track *track = &image->track[track_no-1];

    file_offset = track->offset + track->sector_size * (lba - track->lba);

    read_len = track->sector_size;

    if( track->file != NULL ) {

	f = track->file;

    } else {

	f = image->file;

    }

    /* First figure out what the real sector mode is for raw/semiraw sectors */

    int sector_mode;

    switch( track->mode ) {

    case GDROM_RAW_NONXA:

	gdrom_read_block( (unsigned char *)(&secthead), file_offset, sizeof(secthead), f );

	sector_mode = (secthead.mode == 1) ? GDROM_MODE1 : GDROM_MODE2_FORMLESS;

	break;

    case GDROM_RAW_XA:

	gdrom_read_block( (unsigned char *)(&secthead), file_offset, sizeof(secthead), f );

	if( secthead.mode == 1 ) {

	    sector_mode = GDROM_MODE1;

	} else {

	    sector_mode = ((secthead.subhead[2] & 0x20) == 0 ) ? GDROM_MODE2_FORM1 : GDROM_MODE2_FORM2;

	}

	break;

    case GDROM_SEMIRAW_MODE2:

	gdrom_read_block( secthead.subhead, file_offset, 8, f );

	sector_mode = ((secthead.subhead[2] & 0x20) == 0 ) ? GDROM_MODE2_FORM1 : GDROM_MODE2_FORM2;

	break;

    default:

	/* In the other cases, the track mode completely defines the sector mode */

	sector_mode = track->mode;

	break;

    }

    int mode_restrict = READ_CD_MODE(mode);

    if( !gdrom_is_compatible_read_mode(sector_mode, READ_CD_MODE(mode)) ) {

	return PKT_ERR_BADREADMODE;

    }

    /* Ok, we've got a valid sector, check what parts of the sector we need to

     * return - header | subhead | data | everything

     */

    int channels = READ_CD_CHANNELS(mode);

    if( channels == 0 ) {

	// legal, if weird

	*length = 0;

	return PKT_ERR_OK;

    } else if( channels == 0xA0 && 

	(sector_mode == GDROM_MODE2_FORM1 || sector_mode == GDROM_MODE2_FORM2 )) {

	// caller requested a non-contiguous region

	return PKT_ERR_BADFIELD;

    } else if( READ_CD_RAW(channels) ) {

	channels = 0xF0; // implies everything

    }

    read_len = 0;

    int start, size;

    switch( track->mode ) {

    case GDROM_CDDA:

	// audio is nice and simple (assume perfect reads for now)

	*length = 2352;

	gdrom_read_block( buf, file_offset, track->sector_size, f );

	return PKT_ERR_OK;

    case GDROM_RAW_XA:

    case GDROM_RAW_NONXA:

	gdrom_get_read_bounds( sector_mode, channels, &start, &size );

	gdrom_read_block( buf, file_offset+start, size, f );

	read_len = size;

	break;

    case GDROM_SEMIRAW_MODE2:

	gdrom_get_read_bounds( sector_mode, channels, &start, &size );

	if( READ_CD_HEADER(channels) ) {

	    gdrom_build_sector_header( buf, lba, sector_mode );

	    read_len += SECTOR_HEADER_SIZE;

	    size -= SECTOR_HEADER_SIZE;

	} else {

	    start -= SECTOR_HEADER_SIZE;

	}

	gdrom_read_block( buf + read_len, file_offset+start, size, f );

	read_len += size;

	break;

    default: // Data track w/ data only in file

	if( READ_CD_RAW(channels) ) {

	    gdrom_read_block( buf + gdrom_data_offset[track->mode], file_offset, 

			      track->sector_size, f );

	    do_encode_L2( buf, sector_mode, lba );

	    read_len = 2352;

	} else {

	    if( READ_CD_HEADER(channels) ) {

		gdrom_build_sector_header( buf, lba, sector_mode );

		read_len += SECTOR_HEADER_SIZE;

	    }

	    if( READ_CD_SUBHEAD(channels) && 

		(sector_mode == GDROM_MODE2_FORM1 || sector_mode == GDROM_MODE2_FORM2) ) {

		if( sector_mode == GDROM_MODE2_FORM1 ) {

		    *((uint32_t *)(buf+read_len)) = 0;

		    *((uint32_t *)(buf+read_len+4)) = 0;

		} else {

		    *((uint32_t *)(buf+read_len)) = 0x00200000;

		    *((uint32_t *)(buf+read_len+4)) = 0x00200000;

		}

		read_len += 8;

	    }

	    if( READ_CD_DATA(channels) ) {

		gdrom_read_block( buf+read_len, file_offset, track->sector_size, f );

		read_len += track->sector_size;

	    }

	}

    }

    *length = read_len;

    return PKT_ERR_OK;

}

static gdrom_error_t gdrom_image_read_toc( gdrom_disc_t disc, unsigned char *buf ) 

{

    gdrom_image_t image = (gdrom_image_t)disc;

    struct gdrom_toc *toc = (struct gdrom_toc *)buf;

    int i;

    for( i=0; i<image->track_count; i++ ) {

	toc->track[i] = htonl( image->track[i].lba ) | image->track[i].flags;

    }

    toc->first = 0x0100 | image->track[0].flags;

    toc->last = (image->track_count<<8) | image->track[i-1].flags;

    toc->leadout = htonl(image->track[i-1].lba + image->track[i-1].sector_count) |

	image->track[i-1].flags;

    for( ;i<99; i++ )

	toc->track[i] = 0xFFFFFFFF;

    return PKT_ERR_OK;

}

static gdrom_error_t gdrom_image_read_session( gdrom_disc_t disc, int session, unsigned char *buf )

{

    gdrom_image_t image = (gdrom_image_t)disc;

    struct gdrom_track *last_track = &image->track[image->track_count-1];

    unsigned int end_of_disc = last_track->lba + last_track->sector_count;

    int i;

    buf[0] = 0x01; /* Disc status? */

    buf[1] = 0;

    if( session == 0 ) {

	buf[2] = last_track->session+1; /* last session */

	buf[3] = (end_of_disc >> 16) & 0xFF;

	buf[4] = (end_of_disc >> 8) & 0xFF;

	buf[5] = end_of_disc & 0xFF;

	return PKT_ERR_OK;

    } else {

	session--;

	for( i=0; i<image->track_count; i++ ) {

	    if( image->track[i].session == session ) {

		buf[2] = i+1; /* first track of session */

		buf[3] = (image->track[i].lba >> 16) & 0xFF;

		buf[4] = (image->track[i].lba >> 8) & 0xFF;

		buf[5] = image->track[i].lba & 0xFF;

		return PKT_ERR_OK;

	    }

	}

	return PKT_ERR_BADFIELD; /* No such session */

    }

}

static gdrom_error_t gdrom_image_read_position( gdrom_disc_t disc, uint32_t lba, unsigned char *buf )

{

    gdrom_image_t image = (gdrom_image_t)disc;

    int track_no = gdrom_image_get_track_by_lba( image, lba );

    if( track_no == -1 ) {

	track_no = 1;

	lba = 150;

    }

    struct gdrom_track *track = &image->track[track_no-1];

    uint32_t offset = lba - track->lba;

    buf[4] = track->flags;

    buf[5] = track_no;

    buf[6] = 0x01; /* ?? */

    buf[7] = (offset >> 16) & 0xFF;

    buf[8] = (offset >> 8) & 0xFF;

    buf[9] = offset & 0xFF;

    buf[10] = 0;

    buf[11] = (lba >> 16) & 0xFF;

    buf[12] = (lba >> 8) & 0xFF;

    buf[13] = lba & 0xFF;

    return PKT_ERR_OK;

}

static int gdrom_image_drive_status( gdrom_disc_t disc ) 

{

    gdrom_image_t image = (gdrom_image_t)disc;

    return image->disc_type | IDE_DISC_READY;

}

void gdrom_image_dump_info( gdrom_disc_t d ) {

    gdrom_image_t disc = (gdrom_image_t)d;

    int i;

    int last_session = disc->track[disc->track_count-1].session;

    gboolean is_bootable = FALSE;

    INFO( "Disc ID: %s, %d tracks in %d sessions", disc->mcn, disc->track_count, 

	  disc->track[disc->track_count-1].session + 1 );

    if( last_session > 0 ) {

	/* Boot track is the first data track of the last session, provided that it 

	 * cannot be a single-session disc.

	 */

	int boot_track = -1;

	for( i=disc->track_count-1; i>=0 && disc->track[i].session == last_session; i-- ) {

	    if( disc->track[i].flags & TRACK_DATA ) {

		boot_track = i;

	    }

	}

	if( boot_track != -1 ) {

	    unsigned char boot_sector[MAX_SECTOR_SIZE];

	    uint32_t length = sizeof(boot_sector);

	    if( d->read_sector( d, disc->track[boot_track].lba, 0x28,

				   boot_sector, &length ) == PKT_ERR_OK ) {

		bootstrap_dump(boot_sector, FALSE);

		is_bootable = TRUE;

	    }

	}

    }

    if( !is_bootable ) {

	WARN( "Disc does not appear to be bootable" );

    }

}