/* Mednafen - Multi-system 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

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

#include "nes.h"
#include "x6502.h"
#include "cheat.h"
#include "cart.h"
#include "memory.h"

static uint8 *CheatRPtrs[64];

void MDFN_CheatResetRAM(void)
{
 int x;

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

void MDFN_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. */
    //MDFN_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 MDFN_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)
{
 MDFN_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 MDFN_LoadGameCheats(FILE *override)
{
 char linebuf[2048];
 FILE *fp;
 unsigned int addr;
 unsigned int val;
 unsigned int status;
 unsigned int type;
 unsigned int compare;
 unsigned int x;

 char *namebuf;
 int tc=0;

 numsubcheats=savecheats=0;

 if(override)
  fp = override;
 else
 {
  fp=fopen(MDFN_MakeFName(MDFNMKF_CHEAT,0,0).c_str(),"rb");
  if(!fp) return;
 }

 while(fgets(linebuf,2048,fp)>0)
 { 
  char *tbuf=linebuf;
  int doc=0;

  addr=val=compare=status=type=0;

  if(tbuf[0]=='S')
  {
   tbuf++;
   type=1;
  }
  else type=0;

  if(tbuf[0]=='C')
  {
   tbuf++;
   doc=1;
  }

  if(tbuf[0]==':')    
  {
   tbuf++;
   status=0;
  }
  else status=1;

  if(doc)
  {
   char *neo=&tbuf[4+2+2+1+1+1];
   if(sscanf(tbuf,"%04x%*[:]%02x%*[:]%02x",&addr,&val,&compare)!=3)
    continue;
   if(!(namebuf=(char *)malloc(strlen(neo)+1)))
   {
    CheatMemErr();
    break;
   }
   strcpy(namebuf,neo);
  }
  else 
  {
   char *neo=&tbuf[4+2+1+1];
   if(sscanf(tbuf,"%04x%*[:]%02x",&addr,&val)!=2)
    continue;
   if(!(namebuf=(char *)malloc(strlen(neo)+1)))
   {
    CheatMemErr(); 
    break;
   }
   strcpy(namebuf,neo);
  }

  for(x=0;x<strlen(namebuf);x++)
  {
   if(namebuf[x]==10 || namebuf[x]==13)
   {
    namebuf[x]=0;
    break;
   }
   else if(namebuf[x]<0x20) namebuf[x]=' ';
  }

  AddCheatEntry(namebuf,addr,val,doc?compare:~0,status,type);
  tc++;
 }
 RebuildSubCheats();
 if(!override)
  fclose(fp);
}

void MDFN_FlushGameCheats(FILE *override, int nosave)
{
 if(CheatComp)
 {
  free(CheatComp);
  CheatComp=0;
 }
 if((!savecheats || nosave) && !override)	/* Always save cheats if we're being overridden. */
 {
  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;
  }
 }
 else
 {
  std::string fn;

  if(!override)
   fn = MDFN_MakeFName(MDFNMKF_CHEAT,0,0);

  if(cheats)
  {
   struct CHEATF *next=cheats;
   FILE *fp;
   
   if(override)
    fp = override;
   else
    fp=fopen(fn.c_str(),"wb");

   if(fp)
   {
    for(;;)
    {
     struct CHEATF *t;
     if(next->type)
      fputc('S',fp);
     if(next->compare>=0)
      fputc('C',fp);

     if(!next->status)
      fputc(':',fp);

     if(next->compare>=0)
      fprintf(fp,"%04x:%02x:%02x:%s\n",next->addr,next->val,next->compare,next->name);
     else
      fprintf(fp,"%04x:%02x:%s\n",next->addr,next->val,next->name);

     free(next->name);
     t=next;
     next=next->next;
     free(t);
     if(!next) break;
    }
    if(!override)
     fclose(fp);
   }
   else
    MDFND_PrintError(_("Error saving cheats."));
   cheats=cheatsl=0;
  }
  else if(!override)
   remove(fn.c_str());
 }

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

}


int MDFNI_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 MDFNI_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 MDFN_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 MDFNI_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 MDFNI_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 MDFNI_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 MDFNI_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 MDFN, 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 MDFNI_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;
   next->compare=compare;
   next->type=type;

   savecheats=1;
   RebuildSubCheats();

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

/* Convenience function. */
int MDFNI_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 MDFNI_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 MDFNI_CheatSearchShowExcluded(void)
{
 uint32 x;

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


int32 MDFNI_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 MDFNI_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 MDFNI_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 MDFNI_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 MDFNI_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)
  MDFNI_CheatSearchSetCurrentAsOriginal();
}
