/**

 * $Id$

 *

 * 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 <stdlib.h>

#include <string.h>

#include <ctype.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <netinet/in.h>

#include "gdrom/gddriver.h"

#include "gdrom/packet.h"

#include "ecc.h"

static gboolean gdrom_null_check_status( 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 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 };

gdrom_image_class_t gdrom_image_classes[] = { &cdrom_device_class, 

        &nrg_image_class, 

        &cdi_image_class, 

        &gdi_image_class, 

        NULL };

struct cdrom_sector_header {

    uint8_t sync[12];

    uint8_t msf[3];

    uint8_t mode;

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

};

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

{

    gdrom_disc_t disc = (gdrom_disc_t)g_malloc0(sizeof(struct gdrom_disc));

    if( disc == NULL ) {

        return NULL;

    }

    disc->disc_type = IDE_DISC_NONE;

    disc->file = f;

    if( filename == NULL ) {

        disc->name = NULL;

    } else {

        disc->name = g_strdup(filename);

    }

	disc->check_status = gdrom_null_check_status;

	disc->destroy = gdrom_disc_destroy;

    return disc;

}

void gdrom_disc_destroy( gdrom_disc_t disc, gboolean close_fh )

{

    int i;

    FILE *lastfile = NULL;

    if( disc->file != NULL ) {

    	if( close_fh ) {

        	fclose(disc->file);

    	}

        disc->file = NULL;

    }

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

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

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

            /* Track files (if any) are closed regardless of the value of close_fh */

            fclose(lastfile);

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

        }

    }

    if( disc->name != NULL ) {

        g_free( (gpointer)disc->name );

        disc->name = NULL;

    }

    if( disc->display_name != NULL ) {

    	g_free( (gpointer)disc->name );

    	disc->display_name = NULL;

    }

    free( disc );

}

/**

 * Construct a new gdrom_disc_t and initalize the vtable to the gdrom image

 * default functions.

 */

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

{

	gdrom_disc_t disc = gdrom_disc_new( filename, f );

	if( disc != NULL ) {

	    disc->read_sector = gdrom_image_read_sector;

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

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

	}

}

gdrom_disc_t gdrom_image_open( const gchar *inFilename )

{

    const gchar *filename = inFilename;

    const gchar *ext = strrchr(filename, '.');

    gdrom_disc_t disc = NULL;

    int fd;

    FILE *f;

    int i;

    gdrom_image_class_t extclz = NULL;

    // Check for a url-style filename.

    char *lizard_lips = strstr( filename, "://" );

    if( lizard_lips != NULL ) {

        gchar *path = lizard_lips + 3;

        int method_len = (lizard_lips-filename);

        gchar method[method_len + 1];

        memcpy( method, filename, method_len );

        method[method_len] = '\0';

        if( strcasecmp( method, "file" ) == 0 ) {

            filename = path;

        } else if( strcasecmp( method, "dvd" ) == 0 ||

                strcasecmp( method, "cd" ) == 0 ||

                strcasecmp( method, "cdrom" ) ) {

            return cdrom_open_device( method, path );

        } else {

            ERROR( "Unrecognized URL method '%s' in filename '%s'", method, filename );

            return NULL;

        }

    }

    fd = open( filename, O_RDONLY | O_NONBLOCK );

    if( fd == -1 ) {

        return NULL;

    }

    f = fdopen(fd, "ro");

    /* try extensions */

    if( ext != NULL ) {

        ext++; /* Skip the '.' */

        for( i=0; gdrom_image_classes[i] != NULL; i++ ) {

            if( gdrom_image_classes[i]->extension != NULL &&

                    strcasecmp( gdrom_image_classes[i]->extension, ext ) == 0 ) {

                extclz = gdrom_image_classes[i];

                if( extclz->is_valid_file(f) ) {

                    disc = extclz->open_image_file(filename, f);

                    if( disc != NULL )

                        return disc;

                }

                break;

            }

        }

    }

    /* Okay, fall back to magic */

    gboolean recognized = FALSE;

    for( i=0; gdrom_image_classes[i] != NULL; i++ ) {

        if( gdrom_image_classes[i] != extclz &&

                gdrom_image_classes[i]->is_valid_file(f) ) {

            recognized = TRUE;

            disc = gdrom_image_classes[i]->open_image_file(filename, f);

            if( disc != NULL )

                return disc;

        }

    }

    fclose(f);

    return NULL;

}

/**

 * 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 TRUE;

        } 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;

        }

    }

}

void gdrom_extract_raw_data_sector( char *sector_data, int channels, unsigned char *buf, uint32_t *length )

{

    int sector_mode;

    int start, size;

    struct cdrom_sector_header *secthead = (struct cdrom_sector_header *)sector_data;

    if( secthead->mode == 1 ) {

        sector_mode = GDROM_MODE1;

    } else {

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

    }

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

    memcpy( buf, sector_data+start, size );

    *length = size;

}

/**

 * Default check media status that does nothing and always returns

 * false (unchanged).

 */

static gboolean gdrom_null_check_status( gdrom_disc_t disc )

{

	return FALSE;

}

/**

 * 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 )

{

    struct cdrom_sector_header secthead;

    int file_offset, read_len, track_no;

    FILE *f;

    track_no = gdrom_disc_get_track_by_lba( disc, lba );

    if( track_no == -1 ) {

        return PKT_ERR_BADREAD;

    }

    struct gdrom_track *track = &disc->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 = disc->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;

    }

    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;

}