/* 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 <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>

#include "fceu-types.h"
#include "x6502.h"
#include "cheat.h"
#include "fceu.h"
#include "general.h"
#include "cart.h"
#include "fceu-memory.h"

static uint8 *CheatRPtrs[64];

void FCEU_CheatResetRAM(void) {
	int x;

	for (x = 0; x < 64; x++)
		CheatRPtrs[x] = 0;
}

void FCEU_CheatAddRAM(int s, uint32 A, uint8 *p) {
	uint32 AB = A >> 10;
	int x;

	for (x = s - 1; x >= 0; x--)
		CheatRPtrs[AB + x] = p - A;
}


struct CHEATF {
	struct CHEATF *next;
	char *name;
	uint16 addr;
	uint8 val;
	int compare;		/* -1 for no compare. */
	int type;			/* 0 for replace, 1 for substitute(GG). */
	int status;
};

typedef struct {
	uint16 addr;
	uint8 val;
	int compare;
	readfunc PrevRead;
} CHEATF_SUBFAST;


static CHEATF_SUBFAST SubCheats[256];
static int numsubcheats = 0;
struct CHEATF *cheats = 0, *cheatsl = 0;


#define CHEATC_NONE     0x8000
#define CHEATC_EXCLUDED 0x4000
#define CHEATC_NOSHOW   0xC000

static uint16 *CheatComp = 0;
static int savecheats;

static DECLFR(SubCheatsRead) {
	CHEATF_SUBFAST *s = SubCheats;
	int x = numsubcheats;

	do {
		if (s->addr == A) {
			if (s->compare >= 0) {
				uint8 pv = s->PrevRead(A);

				if (pv == s->compare)
					return(s->val);
				else
					return(pv);
			} else return(s->val);
		}
		s++;
	} while (--x);
	return(0);	/* We should never get here. */
}

void RebuildSubCheats(void) {
	int x;
	struct CHEATF *c = cheats;

	for (x = 0; x < numsubcheats; x++)
		SetReadHandler(SubCheats[x].addr, SubCheats[x].addr, SubCheats[x].PrevRead);

	numsubcheats = 0;
	while (c) {
		if (c->type == 1 && c->status) {
			if (GetReadHandler(c->addr) == SubCheatsRead) {
				/* Prevent a catastrophe by this check. */
				//FCEU_DispMessage("oops");
			} else {
				SubCheats[numsubcheats].PrevRead = GetReadHandler(c->addr);
				SubCheats[numsubcheats].addr = c->addr;
				SubCheats[numsubcheats].val = c->val;
				SubCheats[numsubcheats].compare = c->compare;
				SetReadHandler(c->addr, c->addr, SubCheatsRead);
				numsubcheats++;
			}
		}
		c = c->next;
	}
}

void FCEU_PowerCheats() {
	numsubcheats = 0;	/* Quick hack to prevent setting of ancient read addresses. */
	RebuildSubCheats();
}

static int AddCheatEntry(char *name, uint32 addr, uint8 val, int compare, int status, int type);
static void CheatMemErr(void) {
	FCEUD_PrintError("Error allocating memory for cheat data.");
}

/* This function doesn't allocate any memory for "name" */
static int AddCheatEntry(char *name, uint32 addr, uint8 val, int compare, int status, int type) {
	struct CHEATF *temp;
	if (!(temp = (struct CHEATF*)malloc(sizeof(struct CHEATF)))) {
		CheatMemErr();
		return(0);
	}
	temp->name = name;
	temp->addr = addr;
	temp->val = val;
	temp->status = status;
	temp->compare = compare;
	temp->type = type;
	temp->next = 0;

	if (cheats) {
		cheatsl->next = temp;
		cheatsl = temp;
	} else
		cheats = cheatsl = temp;

	return(1);
}

void FCEU_LoadGameCheats(FILE *override)
{
   numsubcheats = savecheats = 0;
   RebuildSubCheats();
}

void FCEU_FlushGameCheats(FILE *override, int nosave) {
	if (CheatComp)
   {
		free(CheatComp);
		CheatComp = 0;
	}
	RebuildSubCheats();	/* Remove memory handlers. */
}

void FCEU_ResetCheats(void)
{
	if (CheatComp) {
		free(CheatComp);
		CheatComp = 0;
	}

   if (cheats)
   {
      struct CHEATF *next = cheats;
      for (;; ) {
         struct CHEATF *last = next;
         next = next->next;
         free(last->name);
         free(last);
         if (!next) break;
      }
      cheats = cheatsl = 0;
   }

	RebuildSubCheats();	/* Remove memory handlers. */
}


int FCEUI_AddCheat(const char *name, uint32 addr, uint8 val, int compare, int type) {
	char *t;

	if (!(t = (char*)malloc(strlen(name) + 1))) {
		CheatMemErr();
		return(0);
	}
	strcpy(t, name);
	if (!AddCheatEntry(t, addr, val, compare, 1, type)) {
		free(t);
		return(0);
	}
	savecheats = 1;
	RebuildSubCheats();
	return(1);
}

int FCEUI_DelCheat(uint32 which) {
	struct CHEATF *prev;
	struct CHEATF *cur;
	uint32 x = 0;

	for (prev = 0, cur = cheats;; ) {
		if (x == which) {	// Remove this cheat.
			if (prev) {	// Update pointer to this cheat.
				if (cur->next)	// More cheats.
					prev->next = cur->next;
				else {	// No more.
					prev->next = 0;
					cheatsl = prev;	// Set the previous cheat as the last cheat.
				}
			} else {// This is the first cheat.
				if (cur->next)	// More cheats
					cheats = cur->next;
				else
					cheats = cheatsl = 0;	// No (more) cheats.
			}
			free(cur->name);// Now that all references to this cheat are removed,
			free(cur);	// free the memory.
			break;
		}		// *END REMOVE THIS CHEAT*


		if (!cur->next)	// No more cheats to go through(this shouldn't ever happen...)
			return(0);
		prev = cur;
		cur = prev->next;
		x++;
	}

	savecheats = 1;
	RebuildSubCheats();

	return(1);
}

void FCEU_ApplyPeriodicCheats(void) {
	struct CHEATF *cur = cheats;
	if (!cur) return;

	for (;; ) {
		if (cur->status && !(cur->type))
			if (CheatRPtrs[cur->addr >> 10])
				CheatRPtrs[cur->addr >> 10][cur->addr] = cur->val;
		if (cur->next)
			cur = cur->next;
		else
			break;
	}
}


void FCEUI_ListCheats(int (*callb)(char *name, uint32 a, uint8 v, int compare, int s, int type, void *data), void *data) {
	struct CHEATF *next = cheats;

	while (next) {
		if (!callb(next->name, next->addr, next->val, next->compare, next->status, next->type, data)) break;
		next = next->next;
	}
}

int FCEUI_GetCheat(uint32 which, char **name, uint32 *a, uint8 *v, int *compare, int *s, int *type) {
	struct CHEATF *next = cheats;
	uint32 x = 0;

	while (next) {
		if (x == which) {
			if (name)
				*name = next->name;
			if (a)
				*a = next->addr;
			if (v)
				*v = next->val;
			if (s)
				*s = next->status;
			if (compare)
				*compare = next->compare;
			if (type)
				*type = next->type;
			return(1);
		}
		next = next->next;
		x++;
	}
	return(0);
}

static int GGtobin(char c) {
	static char lets[16] = { 'A', 'P', 'Z', 'L', 'G', 'I', 'T', 'Y', 'E', 'O', 'X', 'U', 'K', 'S', 'V', 'N' };
	int x;

	for (x = 0; x < 16; x++)
		if (lets[x] == toupper(c)) return(x);
	return(0);
}

/* Returns 1 on success, 0 on failure. Sets *a,*v,*c. */
int FCEUI_DecodeGG(const char *str, uint16 *a, uint8 *v, int *c) {
	uint16 A;
	uint8 V, C;
	uint8 t;
	int s;

	A = 0x8000;
	V = 0;
	C = 0;

	s = strlen(str);
	if (s != 6 && s != 8) return(0);

	t = GGtobin(*str++);
	V |= (t & 0x07);
	V |= (t & 0x08) << 4;

	t = GGtobin(*str++);
	V |= (t & 0x07) << 4;
	A |= (t & 0x08) << 4;

	t = GGtobin(*str++);
	A |= (t & 0x07) << 4;
	//if(t&0x08) return(0);  /* 8-character code?! */

	t = GGtobin(*str++);
	A |= (t & 0x07) << 12;
	A |= (t & 0x08);

	t = GGtobin(*str++);
	A |= (t & 0x07);
	A |= (t & 0x08) << 8;

	if (s == 6) {
		t = GGtobin(*str++);
		A |= (t & 0x07) << 8;
		V |= (t & 0x08);

		*a = A;
		*v = V;
		*c = -1;
		return(1);
	} else {
		t = GGtobin(*str++);
		A |= (t & 0x07) << 8;
		C |= (t & 0x08);

		t = GGtobin(*str++);
		C |= (t & 0x07);
		C |= (t & 0x08) << 4;

		t = GGtobin(*str++);
		C |= (t & 0x07) << 4;
		V |= (t & 0x08);
		*a = A;
		*v = V;
		*c = C;
		return(1);
	}
	return(0);
}

int FCEUI_DecodePAR(const char *str, uint16 *a, uint8 *v, int *c, int *type) {
	int boo[4];
	if (strlen(str) != 8) return(0);

	sscanf(str, "%02x%02x%02x%02x", boo, boo + 1, boo + 2, boo + 3);

	*c = -1;

	if (1) {
		*a = (boo[3] << 8) | (boo[2] + 0x7F);
		*v = 0;
	} else {
		*v = boo[3];
		*a = boo[2] | (boo[1] << 8);
	}
	/* Zero-page addressing modes don't go through the normal read/write handlers in FCEU, so
		we must do the old hacky method of RAM cheats.
	*/
	if (*a < 0x0100)
		*type = 0;
	else
		*type = 1;
	return(1);
}

/* name can be NULL if the name isn't going to be changed. */
/* same goes for a, v, and s(except the values of each one must be <0) */

int FCEUI_SetCheat(uint32 which, const char *name, int32 a, int32 v, int compare, int s, int type) {
	struct CHEATF *next = cheats;
	uint32 x = 0;

	while (next) {
		if (x == which) {
			if (name) {
				char *t;

				if ((t = (char*)realloc(next->name, strlen(name + 1)))) {
					next->name = t;
					strcpy(next->name, name);
				} else
					return(0);
			}
			if (a >= 0)
				next->addr = a;
			if (v >= 0)
				next->val = v;
			if (s >= 0)
				next->status = s;
			if (compare >= 0)
				next->compare = compare;
			next->type = type;

			savecheats = 1;
			RebuildSubCheats();

			return(1);
		}
		next = next->next;
		x++;
	}
	return(0);
}

/* Convenience function. */
int FCEUI_ToggleCheat(uint32 which) {
	struct CHEATF *next = cheats;
	uint32 x = 0;

	while (next) {
		if (x == which) {
			next->status = !next->status;
			savecheats = 1;
			RebuildSubCheats();
			return(next->status);
		}
		next = next->next;
		x++;
	}

	return(-1);
}

static int InitCheatComp(void) {
	uint32 x;

	CheatComp = (uint16*)malloc(65536 * sizeof(uint16));
	if (!CheatComp) {
		CheatMemErr();
		return(0);
	}
	for (x = 0; x < 65536; x++)
		CheatComp[x] = CHEATC_NONE;

	return(1);
}

void FCEUI_CheatSearchSetCurrentAsOriginal(void) {
	uint32 x;
	for (x = 0x000; x < 0x10000; x++)
		if (!(CheatComp[x] & CHEATC_NOSHOW)) {
			if (CheatRPtrs[x >> 10])
				CheatComp[x] = CheatRPtrs[x >> 10][x];
			else
				CheatComp[x] |= CHEATC_NONE;
		}
}

void FCEUI_CheatSearchShowExcluded(void) {
	uint32 x;

	for (x = 0x000; x < 0x10000; x++)
		CheatComp[x] &= ~CHEATC_EXCLUDED;
}


int32 FCEUI_CheatSearchGetCount(void) {
	uint32 x, c = 0;

	if (CheatComp) {
		for (x = 0x0000; x < 0x10000; x++)
			if (!(CheatComp[x] & CHEATC_NOSHOW) && CheatRPtrs[x >> 10])
				c++;
	}

	return c;
}
/* This function will give the initial value of the search and the current value at a location. */

void FCEUI_CheatSearchGet(int (*callb)(uint32 a, uint8 last, uint8 current, void *data), void *data) {
	uint32 x;

	if (!CheatComp) {
		if (!InitCheatComp())
			CheatMemErr();
		return;
	}

	for (x = 0; x < 0x10000; x++)
		if (!(CheatComp[x] & CHEATC_NOSHOW) && CheatRPtrs[x >> 10])
			if (!callb(x, CheatComp[x], CheatRPtrs[x >> 10][x], data))
				break;
}

void FCEUI_CheatSearchGetRange(uint32 first, uint32 last, int (*callb)(uint32 a, uint8 last, uint8 current)) {
	uint32 x;
	uint32 in = 0;

	if (!CheatComp) {
		if (!InitCheatComp())
			CheatMemErr();
		return;
	}

	for (x = 0; x < 0x10000; x++)
		if (!(CheatComp[x] & CHEATC_NOSHOW) && CheatRPtrs[x >> 10]) {
			if (in >= first)
				if (!callb(x, CheatComp[x], CheatRPtrs[x >> 10][x]))
					break;
			in++;
			if (in > last) return;
		}
}

void FCEUI_CheatSearchBegin(void) {
	uint32 x;

	if (!CheatComp) {
		if (!InitCheatComp()) {
			CheatMemErr();
			return;
		}
	}
	for (x = 0; x < 0x10000; x++) {
		if (CheatRPtrs[x >> 10])
			CheatComp[x] = CheatRPtrs[x >> 10][x];
		else
			CheatComp[x] = CHEATC_NONE;
	}
}


static int INLINE CAbs(int x) {
	if (x < 0)
		return(0 - x);
	return x;
}

void FCEUI_CheatSearchEnd(int type, uint8 v1, uint8 v2) {
	uint32 x;

	if (!CheatComp) {
		if (!InitCheatComp()) {
			CheatMemErr();
			return;
		}
	}


	if (!type) {// Change to a specific value.
		for (x = 0; x < 0x10000; x++)
			if (!(CheatComp[x] & CHEATC_NOSHOW)) {
				if (CheatComp[x] == v1 && CheatRPtrs[x >> 10][x] == v2) {
				} else
					CheatComp[x] |= CHEATC_EXCLUDED;
			}
	} else if (type == 1) {	// Search for relative change(between values).
		for (x = 0; x < 0x10000; x++)
			if (!(CheatComp[x] & CHEATC_NOSHOW)) {
				if (CheatComp[x] == v1 && CAbs(CheatComp[x] - CheatRPtrs[x >> 10][x]) == v2) {
				} else
					CheatComp[x] |= CHEATC_EXCLUDED;
			}
	} else if (type == 2) {	// Purely relative change.
		for (x = 0x000; x < 0x10000; x++)
			if (!(CheatComp[x] & CHEATC_NOSHOW)) {
				if (CAbs(CheatComp[x] - CheatRPtrs[x >> 10][x]) == v2) {
				} else
					CheatComp[x] |= CHEATC_EXCLUDED;
			}
	} else if (type == 3) {	// Any change.
		for (x = 0; x < 0x10000; x++)
			if (!(CheatComp[x] & CHEATC_NOSHOW)) {
				if (CheatComp[x] != CheatRPtrs[x >> 10][x]) {
				} else
					CheatComp[x] |= CHEATC_EXCLUDED;
			}
	} else if (type == 4) {	// Value decreased.
		for (x = 0; x < 0x10000; x++)
			if (!(CheatComp[x] & CHEATC_NOSHOW)) {
				if (!(CheatRPtrs[x >> 10][x] < CheatComp[x]))
					CheatComp[x] |= CHEATC_EXCLUDED;
			}
	} else if (type == 5) {	// Value increased.
		for (x = 0; x < 0x10000; x++)
			if (!(CheatComp[x] & CHEATC_NOSHOW)) {
				if (!(CheatRPtrs[x >> 10][x] > CheatComp[x]))
					CheatComp[x] |= CHEATC_EXCLUDED;
			}
	}
	if (type > 4)
		FCEUI_CheatSearchSetCurrentAsOriginal();
}