// Copyright 2009 Kwiirk based on negentig.c:
// Copyright 2007,2008  Segher Boessenkool  <segher@kernel.crashing.org>
// Licensed under the terms of the GNU GPL, version 2
// http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt

#include "wiidisc.h"

void aes_set_key(u8 *key);
void aes_decrypt(u8 *iv, u8 *inbuf, u8 *outbuf, unsigned long long len);

static void _decrypt_title_key(u8 *tik, u8 *title_key)
{
	u8 common_key[16]={
                0xeb, 0xe4, 0x2a, 0x22, 0x5e, 0x85, 0x93, 0xe4, 0x48, 0xd9, 0xc5, 0x45,
                0x73, 0x81, 0xaa, 0xf7
        };;
	u8 iv[16];

	wbfs_memset(iv, 0, sizeof iv);
	wbfs_memcpy(iv, tik + 0x01dc, 8);
        aes_set_key(common_key);
	//_aes_cbc_dec(common_key, iv, tik + 0x01bf, 16, title_key);
        aes_decrypt(iv, tik + 0x01bf,title_key,16);
}
static u32 _be32(const u8 *p)
{
	return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
}

static void disc_read(wiidisc_t *d,u32 offset, u8 *data, u32 len)
{
        if(data){
                int ret=0;
                if(len==0)
                        return ;
                ret = d->read(d->fp,offset,len,data);
                if(ret)
                        wbfs_fatal("error reading disc");
        }
        if(d->sector_usage_table)
        {
                u32 blockno = offset>>13;
                do
                {
                        d->sector_usage_table[blockno]=1;
                        blockno+=1;
                        if(len>0x8000)
                                len-=0x8000;
                }while(len>0x8000);
        }
}

static void partition_raw_read(wiidisc_t *d,u32 offset, u8 *data, u32 len)
{
	disc_read(d, d->partition_raw_offset + offset, data, len);
}

static void partition_read_block(wiidisc_t *d,u32 blockno, u8 *block)
{
        u8*raw = d->tmp_buffer;
	u8 iv[16];
	u32 offset;
        if(d->sector_usage_table)
                d->sector_usage_table[d->partition_block+blockno]=1;
        offset = d->partition_data_offset + ((0x8000>>2) * blockno);
        partition_raw_read(d,offset, raw, 0x8000);

        // decrypt data
        memcpy(iv, raw + 0x3d0, 16);
        aes_set_key(d->disc_key);
        aes_decrypt(iv, raw + 0x400,block,0x7c00);
}

static void partition_read(wiidisc_t *d,u32 offset, u8 *data, u32 len,int fake)
{
	u8 *block = d->tmp_buffer2;
	u32 offset_in_block;
	u32 len_in_block;
        if(fake &&  d->sector_usage_table==0)
                return;

	while(len) {
		offset_in_block = offset % (0x7c00>>2);
		len_in_block = 0x7c00 - (offset_in_block<<2);
		if (len_in_block > len)
			len_in_block = len;
                if(!fake){
                        partition_read_block(d,offset / (0x7c00>>2), block);
                        wbfs_memcpy(data, block + (offset_in_block<<2), len_in_block);
                }else
                        d->sector_usage_table[d->partition_block+(offset/(0x7c00>>2))]=1;
		data += len_in_block;
		offset += len_in_block>>2;
		len -= len_in_block;
	}
}


static u32 do_fst(wiidisc_t *d,u8 *fst, const char *names, u32 i)
{
	u32 offset;
	u32 size;
	const char *name;
	u32 j;

	name = names + (_be32(fst + 12*i) & 0x00ffffff);
	size = _be32(fst + 12*i + 8);

	if (i == 0) {
		for (j = 1; j < size && !d->extracted_buffer; ){
			j = do_fst(d,fst, names, j);
                }
		return size;
	}
        //printf("name    %s\n",name);

	if (fst[12*i]) {

		for (j = i + 1; j < size && !d->extracted_buffer; )
			j = do_fst(d,fst, names, j);

		return size;
	} else {
		offset = _be32(fst + 12*i + 4);
                if(d->extract_pathname && strcmp(name, d->extract_pathname)==0)
                {
                        d->extracted_buffer = wbfs_ioalloc(size);
                        partition_read(d,offset, d->extracted_buffer, size,0);
                }else
                        partition_read(d,offset, 0, size,1);
		return i + 1;
	}
}

static void do_files(wiidisc_t*d)
{
	u8 *b = wbfs_ioalloc(0x480); // XXX: determine actual header size
	u32 dol_offset;
	u32 fst_offset;
	u32 fst_size;
	u32 apl_offset;
	u32 apl_size;
	u8 *apl_header = wbfs_ioalloc(0x20);
	u8 *fst;
	u32 n_files;
	partition_read(d,0, b, 0x480,0);

	dol_offset = _be32(b + 0x0420);
	fst_offset = _be32(b + 0x0424);
	fst_size = _be32(b + 0x0428)<<2;

	apl_offset = 0x2440>>2;
	partition_read(d,apl_offset, apl_header, 0x20,0);
	apl_size = 0x20 + _be32(apl_header + 0x14) + _be32(apl_header + 0x18);
        // fake read dol and partition
        partition_read(d,apl_offset, 0, apl_size,1);
        partition_read(d,dol_offset, 0,  (fst_offset - dol_offset)<<2,1);
        

	fst = wbfs_ioalloc(fst_size);
	if (fst == 0)
		wbfs_fatal("malloc fst");
	partition_read(d,fst_offset, fst, fst_size,0);
	n_files = _be32(fst + 8);

	if (n_files > 1)
		do_fst(d,fst, (char *)fst + 12*n_files, 0);
        wbfs_iofree(b);
        wbfs_iofree(apl_header);
	wbfs_iofree(fst);
}

static void do_partition(wiidisc_t*d)
{
	u8 *tik = wbfs_ioalloc(0x2a4);
        u8 *b = wbfs_ioalloc(0x1c);
	u64 tmd_offset;
	u32 tmd_size;
	u8 *tmd;
	u64 cert_offset;
	u32 cert_size;
	u8 *cert;
	u64 h3_offset;

	// read ticket, and read some offsets and sizes
	partition_raw_read(d,0, tik, 0x2a4);
	partition_raw_read(d,0x2a4>>2, b, 0x1c);

	tmd_size = _be32(b);
	tmd_offset = _be32(b + 4);
	cert_size = _be32(b + 8);
	cert_offset = _be32(b + 0x0c);
	h3_offset = _be32(b + 0x10);
	d->partition_data_offset = _be32(b + 0x14);
        d->partition_block = (d->partition_raw_offset+d->partition_data_offset)>>13;
	tmd = wbfs_ioalloc(tmd_size);
	if (tmd == 0)
		wbfs_fatal("malloc tmd");
	partition_raw_read(d,tmd_offset, tmd, tmd_size);

	cert = wbfs_ioalloc(cert_size);
	if (cert == 0)
		wbfs_fatal("malloc cert");
	partition_raw_read(d,cert_offset, cert, cert_size);


	_decrypt_title_key(tik, d->disc_key);

	partition_raw_read(d,h3_offset, 0, 0x18000);
        wbfs_iofree(b);
        wbfs_iofree(tik);
	wbfs_iofree(cert);
	wbfs_iofree(tmd);

	do_files(d);

}
static int test_parition_skip(u32 partition_type,partition_selector_t part_sel)
{
        switch(part_sel)
        {
        case ALL_PARTITIONS:
                return 0;
        case REMOVE_UPDATE_PARTITION:
                return (partition_type==1);
        case ONLY_GAME_PARTITION:
                return (partition_type!=0);
        default:
                return (partition_type!=part_sel);
        }
} 
static void do_disc(wiidisc_t*d)
{
	u8 *b = wbfs_ioalloc(0x100);
	u64 partition_offset[32]; // XXX: don't know the real maximum
	u64 partition_type[32]; // XXX: don't know the real maximum
	u32 n_partitions;
        u32 magic;
	u32 i;
	disc_read(d,0, b, 0x100);
        magic=_be32(b+24);
        if(magic!=0x5D1C9EA3){
                wbfs_error("not a wii disc");
                return ;
        }
	disc_read(d,0x40000>>2, b, 0x100);
	n_partitions = _be32(b);
	disc_read(d,_be32(b + 4), b, 0x100);
	for (i = 0; i < n_partitions; i++){
		partition_offset[i] = _be32(b + 8 * i);
		partition_type[i] = _be32(b + 8 * i+4);
        }
	for (i = 0; i < n_partitions; i++) {
                d->partition_raw_offset = partition_offset[i];
                if(!test_parition_skip(partition_type[i],d->part_sel))
                        do_partition(d);
	}
        wbfs_iofree(b);
}

wiidisc_t *wd_open_disc(read_wiidisc_callback_t read,void*fp)
{
        wiidisc_t *d = wbfs_malloc(sizeof(wiidisc_t));
        if(!d)
                return 0;
        wbfs_memset(d,0,sizeof(wiidisc_t));
        d->read = read;
        d->fp = fp;
        d->part_sel = ALL_PARTITIONS;
        d->tmp_buffer = wbfs_ioalloc(0x8000);
        d->tmp_buffer2 = wbfs_malloc(0x8000);

        return d;
}
void wd_close_disc(wiidisc_t *d)
{
        wbfs_iofree(d->tmp_buffer);
        wbfs_free(d->tmp_buffer2);
        wbfs_free(d);
}
// returns a buffer allocated with wbfs_ioalloc() or NULL if not found of alloc error
// XXX pathname not implemented. files are extracted by their name. 
// first file found with that name is returned.
u8 * wd_extract_file(wiidisc_t *d, partition_selector_t partition_type, char *pathname)
{
        u8 *retval = 0;
        d->extract_pathname = pathname;
        d->extracted_buffer = 0;
        d->part_sel = partition_type;
        do_disc(d);
        d->extract_pathname = 0;
        d->part_sel = ALL_PARTITIONS;
        retval = d->extracted_buffer;
        d->extracted_buffer = 0;
        return retval;
}

void wd_build_disc_usage(wiidisc_t *d, partition_selector_t selector, u8* usage_table)
{
        d->sector_usage_table = usage_table;
        wbfs_memset(usage_table,0,143432*2);
        d->part_sel = selector;
        do_disc(d);
        d->part_sel = ALL_PARTITIONS;
        d->sector_usage_table = 0;
}

void wd_fix_partition_table(wiidisc_t *d, partition_selector_t selector, u8* partition_table)
{
        u8 *b = partition_table;
	u32 partition_offset; 
	u32 partition_type; 
	u32 n_partitions,i,j;
        u32 *b32;
        if(selector == ALL_PARTITIONS)
                return;
	n_partitions = _be32(b);
        if(_be32(b + 4)-(0x40000>>2) >0x50)
                wbfs_fatal("cannot modify this partition table. Please report the bug.");
        
        b += (_be32(b + 4)-(0x40000>>2))*4;
        j=0;
	for (i = 0; i < n_partitions; i++){
		partition_offset = _be32(b + 8 * i);
		partition_type = _be32(b + 8 * i+4);
                if(!test_parition_skip(partition_type,selector))
                {
                        b32 = (u32*)(b + 8 * j);
                        b32[0] = wbfs_htonl(partition_offset);
                        b32[1] = wbfs_htonl(partition_type);
                        j++;
                }
        }
        b32 = (u32*)(partition_table);
        *b32 = wbfs_htonl(j);
}