/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2002 Xodnizel
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include        <string.h>
#include        <stdlib.h>

#include        "share.h"

typedef struct {
	uint32 mzx, mzy, mzb;
	int zap_readbit;
	int bogo;
	int zappo;
	uint64 zaphit;
} ZAPPER;

static ZAPPER ZD;

static void FP_FASTAPASS(3) ZapperFrapper(uint8 * bg, uint8 * spr, uint32 linets, int final) {
	int xs, xe;
	int zx, zy;

	if (!bg) {	// New line, so reset stuff.
		ZD.zappo = 0;
		return;
	}
	xs = ZD.zappo;
	xe = final;

	zx = ZD.mzx;
	zy = ZD.mzy;

	if (xe > 256) xe = 256;

	if (scanline >= (zy - 4) && scanline <= (zy + 4)) {
		while (xs < xe) {
			uint8 a1, a2;
			uint32 sum;
			if (xs <= (zx + 4) && xs >= (zx - 4)) {
				a1 = bg[xs];
				if (spr) {
					a2 = spr[xs];

					if (!(a2 & 0x80))
						if (!(a2 & 0x40) || (a1 & 64))
							a1 = a2;
				}
				a1 &= 63;

				sum = palo[a1].r + palo[a1].g + palo[a1].b;
				if (sum >= 100 * 3) {
					ZD.zaphit = ((uint64)linets + (xs + 16) * (PAL ? 15 : 16)) / 48 + timestampbase;
					goto endo;
				}
			}
			xs++;
		}
	}
 endo:
	ZD.zappo = final;
}

static INLINE int CheckColor(void) {
	FCEUPPU_LineUpdate();

	if ((ZD.zaphit + 10) >= (timestampbase + timestamp)) return(0);

	return(1);
}


static uint8 FP_FASTAPASS(2) ReadZapper(int w, uint8 ret) {
	if (w) {
		ret &= ~0x18;
		if (ZD.bogo)
			ret |= 0x10;
		if (CheckColor())
			ret |= 0x8;
	} else {
		if (ZD.zap_readbit == 1) {
			ret &= ~2;
			ret |= ZD.mzb & 2;
		}
		ret |= (ret & 1) << 1;
		ZD.zap_readbit++;
	}
	return ret;
}

static void FP_FASTAPASS(2) DrawZapper(uint8 * buf, int arg) {
	if (arg)
		FCEU_DrawGunSight(buf, ZD.mzx, ZD.mzy);
}

static void FP_FASTAPASS(2) UpdateZapper(void *data, int arg) {
	uint32 *ptr = (uint32*)data;

	if (ZD.bogo)
		ZD.bogo--;
	if (ptr[2] & 1 && (!(ZD.mzb & 1)))
		ZD.bogo = 5;

	ZD.mzx = ptr[0];
	ZD.mzy = ptr[1];
	ZD.mzb = ptr[2];
}

static void StrobeShadow(void) {
	ZD.zap_readbit = 0;
}

static INPUTCFC SHADOWC = { ReadZapper, 0, StrobeShadow, UpdateZapper, ZapperFrapper, DrawZapper };

INPUTCFC *FCEU_InitSpaceShadow(void) {
	memset(&ZD, 0, sizeof(ZAPPER));
	return(&SHADOWC);
}