/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "common/endian.h"
#include "glk/scott/types.h"
#include "glk/scott/unp64/unp64.h"
#include "glk/scott/unp64/exo_util.h"

namespace Glk {
namespace Scott {

void scnXTC(UnpStr *unp) {
	byte *mem;
	int q = 0, p;
	if (unp->_idFlag)
		return;
	mem = unp->_mem;
	if (unp->_depAdr == 0) {
		if (u16eq(mem + 0x80d, 0xE678) &&
			u32eq(mem + 0x811, 0x1BCE0818) &&
			u32eq(mem + 0x819, 0xC8000099) &&
			u32eq(mem + 0x82c, 0x4CF7D0CA) &&
			mem[0x85c] == 0x99) {
			unp->_retAdr = READ_LE_UINT16(&mem[0x872]); // mem[0x872] | mem[0x873] << 8;
			unp->_depAdr = 0x100;
			unp->_forced = 0x80d; /* the ldy #$00 can be missing, skipped */
			unp->_fEndAf = 0x121;
			unp->_endAdC = 0xffff | EA_USE_Y;
			unp->_strMem = READ_LE_UINT16(&mem[0x85d]); // mem[0x85d] | mem[0x85e] << 8;
			unp->_idFlag = 1;
			return;
		}
	}
	/* XTC packer 1.0 & 2.2/2.4 */
	if (unp->_depAdr == 0) {
		for (p = 0x801; p < 0x80c; p += 0x0a) {
			if (u16eq(mem + p + 0x02, 0xE678) &&
				u32eq(mem + p + 0x07, (unsigned int)(0xce08 | ((p + 0x10) << 16))) &&
				u32eq(mem + p + 0x0e, 0xC8000099) &&
				u32eq(mem + p + 0x23, 0x4CF7D0CA)) {
				/* has variable codebytes so addresses varies */
				for (q = p + 0x37; q < p + 0x60; q += 4) {
					if (mem[q] == 0xc9)
						continue;
					if (mem[q] == 0x99) {
						unp->_depAdr = 0x100;
						break;
					}
					break; /* unexpected byte, get out */
				}
				break;
			}
		}
		if (unp->_depAdr) {
			unp->_retAdr = READ_LE_UINT16(&mem[q + 0x16]); // mem[q + 0x16] | mem[q + 0x17] << 8;
			if (u16noteq(mem + p, 0x00a0))
				unp->_forced = p + 2; /* the ldy #$00 can be missing, skipped */
			else
				unp->_forced = p;

			unp->_fEndAf = READ_LE_UINT16(&mem[q + 0x7]); // mem[q + 0x7] | mem[q + 0x8] << 8;
			unp->_fEndAf--;
			unp->_endAdC = 0xffff | EA_USE_Y;
			unp->_strMem = READ_LE_UINT16(&mem[q + 1]); // mem[q + 1] | mem[q + 2] << 8;
			if (u32eq(mem + q + 0x1f, 0xDDD00285)) {
			} else if (u32eq(mem + q + 0x1f, 0xF620DFD0)) {
				/* rockstar's 2.2+ & shade/light's 2.4 are all the same */
			} else {                                           /* actually found to be Visiomizer 6.2/Zagon */
				unp->_depAdr = READ_LE_UINT16(&mem[p + 0x27]); // mem[p + 0x27] | mem[p + 0x28] << 8;
			}
			unp->_idFlag = 1;
			return;
		}
	}
	/* XTC 2.3 / 6codezipper */
	if (unp->_depAdr == 0) {
		if (u32eq(mem + 0x803, 0xB9018478) &&
			u32eq(mem + 0x80b, 0xF7D0C8FF) &&
			u32eq(mem + 0x81b, 0x00FC9D08) &&
			u32eq(mem + 0x85b, 0xD0D0FFE4)) {
			unp->_depAdr = READ_LE_UINT16(&mem[0x823]); // mem[0x823] | mem[0x824] << 8;
			unp->_forced = 0x803;
			unp->_retAdr = READ_LE_UINT16(&mem[0x865]); // mem[0x865] | mem[0x866] << 8;
			unp->_strMem = READ_LE_UINT16(&mem[0x850]); // mem[0x850] | mem[0x851] << 8;
			unp->_endAdC = 0xffff | EA_USE_Y;
			unp->_fEndAf = 0x128;
			unp->_idFlag = 1;
			return;
		}
	}
	/* XTC 2.3 / G*P, probably by Rockstar */
	if (unp->_depAdr == 0) {
		if ((u32eq(mem + 0x803, 0xB901e678) ||
			 u32eq(mem + 0x803, 0xB9018478)) &&
			u32eq(mem + 0x80b, 0xF7D0C8FF) &&
			u32eq(mem + 0x81b, 0x00F59D08) &&
			u32eq(mem + 0x85b, 0xD0D0F8E4)) {
			unp->_depAdr = READ_LE_UINT16(&mem[0x823]); // mem[0x823] | mem[0x824] << 8;
			unp->_forced = 0x803;
			unp->_retAdr = READ_LE_UINT16(&mem[0x865]); // mem[0x865] | mem[0x866] << 8;
			unp->_strMem = READ_LE_UINT16(&mem[0x850]); // mem[0x850] | mem[0x851] << 8;
			unp->_endAdC = 0xffff | EA_USE_Y;
			unp->_fEndAf = 0x121;
			unp->_idFlag = 1;
			return;
		}
	}
	/* XTC packer 2.x? found in G*P/NEI/Armageddon warez
	just some different byte on copy loop, else is equal to 2.3
	*/
	if (unp->_depAdr == 0) {
		for (p = 0x801; p < 0x80c; p += 0x0a) {
			if (u32eqmasked(mem + p + 0x00, 0xffff0000, 0xE6780000) &&
				u32eqmasked(mem + p + 0x05, 0xffff00ff, 0xB90800CE) &&
				u32eq(mem + p + 0x0b, 0xC8000099) &&
				u32eq(mem + p + 0x1e, 0x4CF7D0CA)) {
				/* has variable codebytes so addresses varies */
				for (q = p + 0x36; q < p + 0x60; q += 4) {
					if (mem[q] == 0xc9)
						continue;
					if (mem[q] == 0x99) {
						unp->_depAdr = 0x100;
						break;
					}
					break; /* unexpected byte, get out */
				}
				break;
			}
		}
		if (unp->_depAdr) {
			unp->_retAdr = READ_LE_UINT16(&mem[q + 0x16]); // mem[q + 0x16] | mem[q + 0x17] << 8;
			unp->_forced = p + 2;
			unp->_fEndAf = READ_LE_UINT16(&mem[q + 0x7]); // mem[q + 0x7] | mem[q + 0x8] << 8;
			unp->_fEndAf--;
			unp->_endAdC = 0xffff | EA_USE_Y;
			unp->_strMem = READ_LE_UINT16(&mem[q + 1]); // mem[q + 1] | mem[q + 2] << 8;
			unp->_idFlag = 1;
			return;
		}
	}
}

} // End of namespace Scott
} // End of namespace Glk