#include <curses.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
 
struct data				// Eine Zeile Speicher
{
struct data* plast;
struct data* pnext;
unsigned char vals[16];
unsigned long zeile;
char len;
};

struct cpos   				// Cursor-Position
{
  char x,y;
}pos;

int mode=1;
WINDOW *stdscr,*woffs,*whex, *wascii, *wtop, *wbot;
const char *topline= " Offset    Hex                                                ASCII          ";
char xoffs[]  = "12345678",*soffs;
char xhex[]   = " 14 15 16 32 32 34 20 54 61 67 65 73 61 6D 74 0D  ",*shex;
char xascii[] = "1234567890123456",*sascii;
int result;
char *ptv="12345678";
FILE *fp;
int ipoint;
data daten,*pdaten,*pfirst, *phelp;

void initvar()
{
 pfirst=&daten;
 (*pfirst).plast=NULL;
 (*pfirst).pnext=NULL;
 (*pfirst).zeile=0;
 (*pfirst).len=0;
 soffs=xoffs;
 shex=xhex;
 sascii=xascii;
}

void miniinit()
{
xoffs  = "        ";
xhex   = "                                                  ";
xascii = "                ";
}

int screeninit()
{
 int retval=0;

 stdscr= initscr();
 if(start_color()) retval=1;
 nonl();
 intrflush(stdscr, FALSE);
 keypad(stdscr, TRUE);

// Zwei Fenster
 woffs =newwin(18,10,3 ,0 );
 whex  =newwin(18,52,3 ,10);
 wascii=newwin(18,18,3 ,62);
 wtop  =newwin(3 ,80,0 ,0 );
 wbot  =newwin(4 ,80,21,0 );

// Scrollen erlauben
 scrollok(woffs,1);
 scrollok(whex,1);
 scrollok(wascii,1);

// Tastatureingabe erlauben
 keypad(stdscr,1);
 keypad(whex,1);
 keypad(wascii,1);

// Echo ausschalten
 noecho();

// Cursor auf Groß setzen
 if(curs_set(2)==ERR) retval=1 ;

// Color-Pairs anlegen (Farbkombinationen)
 if(init_pair(1,COLOR_BLUE,COLOR_BLACK)) retval=1;
 if(init_pair(2,COLOR_CYAN,COLOR_BLACK)) retval=1;

 wattrset(woffs,COLOR_PAIR(1));
 wattrset(whex,COLOR_PAIR(1));
 wattrset(wascii,COLOR_PAIR(1));
 wattrset(wbot,COLOR_PAIR(1));
 wattrset(wtop,COLOR_PAIR(1));

 box(woffs,0,0); 
 box(whex,0,0); 
 box(wascii,0,0); 
 box(wtop,0,0); 
 box(wbot,0,0); 
 
 wattrset(woffs,COLOR_PAIR(2));
 wattrset(whex,COLOR_PAIR(2));
 wattrset(wascii,COLOR_PAIR(2));
 wattrset(wtop,COLOR_PAIR(2)); 
 wattrset(wbot,COLOR_PAIR(2));

 return(retval);
}

char* tonumsysx(int base10,int newbase)
{
 int erg;
 int rest=0;
 int pos=0;
 int i;
 static char swap[9];
 char c[9];
 
 swap="********";
 c[pos]='0'+rest;
 while (base10 > 0)
  {
    erg=base10/newbase;
    rest=base10%newbase;
    if (rest <= 9)
      c[pos]='0'+rest;
    else
      c[pos]='A'+(rest-10);

    base10=erg;
    pos++;
    c[pos]='\0';
  }
 while(pos < 8)
  {
   c[pos]='0';
   pos++;
  }
 pos--;
 for (i=0;i<=pos;i++)
  {
    swap[i]=c[pos-i];
  }

return(swap);


}

unsigned long xto10(char *c, int oldbase)
{
unsigned long base10=0;
unsigned long rest,erg;
int pos=0;
int i;

 while(c[pos++]);
 pos--;
 int len=pos-1;
 while(pos--)
 {
  if(isdigit(c[len-pos]))
  {
   base10 = base10 + (unsigned long)( (double)(c[len-pos]-'0') * ( pow( (double)oldbase,(double)pos ) ) ) ;
  }
  else
  {
   base10 = base10 + (unsigned long)( ((double)(c[len-pos]-'A')+10) * ( pow( (double)oldbase,(double)pos ) ) );
  }
 }
 return(base10);
}

int loadcontents()
{
 int retval=0;
 int x;
 char ch;
 int k=0;
 unsigned long zeile=0;


 pdaten=pfirst;

 ch=fgetc(fp);
 printf("Printing hashmark for every 8 Kbytes.\n");
 while (!(feof(fp)))
 {
 for(x=0;x<16;x++)
   {
    ((*pdaten).vals[x])=ch;
    if (feof(fp)) //(*pdaten).vals[x]==EOF) 
    {
     (*pdaten).vals[x]=0;
     break;     
    }
    (*pdaten).len=x+1;
    ch=fgetc(fp);
   }
 (*pdaten).zeile=zeile++;
 if(!(feof(fp)))
 {
  phelp=pdaten;
  if (!(zeile%500)) {fprintf(stderr,"%c",'#');}
  pdaten=((*pdaten).pnext)=(malloc(sizeof(daten)));
// BUG: Check for Memory-Full does not work.
  if(!pdaten) {abort();}
  (*pdaten).plast=phelp;
  (*pdaten).pnext=NULL;
 }

 }
/* D E B U G   O N L Y

 pdaten=pfirst;

printf("%d\n",zeile);

while (zeile--)
 {
 for(x=0;x<16;x++)
   {
    printf("%c-",(*pdaten).vals[x]);
   }
   pdaten=(*pdaten).pnext;
 } 
getchar();
  --- END DEBUG ---*/
 return (retval);
}

void endscr()
{
 delwin(woffs);
 delwin(whex);
 delwin(wascii);
 delwin(wtop);
 delwin(wbot);
 endwin();
}

void unallocmem()
{
int zv;

/* DEBUG ONLY
 pdaten=pfirst;
int zeile=16;
int x;
printf("%d\n",zeile);

while (zeile--)
 {
 for(x=0;x<16;x++)
   {
    printf("%c-",(*pdaten).vals[x]);
   }
   pdaten=(*pdaten).pnext;
 } 
getchar();
  --- END DEBUG ---*/

pdaten=pfirst;
for(;(*pdaten).pnext;pdaten=(*pdaten).pnext)
 ;
while((*pdaten).plast)
{
phelp=(*pdaten).plast;
free(pdaten);
pdaten=phelp;
}
}


void scrrefresh()
{
 wattrset(woffs,COLOR_PAIR(1));
 wattrset(whex,COLOR_PAIR(1));
 wattrset(wascii,COLOR_PAIR(1));
 wattrset(wbot,COLOR_PAIR(1));
 wattrset(wtop,COLOR_PAIR(1));

 box(woffs,0,0); 
 box(whex,0,0); 
 box(wascii,0,0); 
 box(wtop,0,0); 
 box(wbot,0,0); 
 
 wattrset(woffs,COLOR_PAIR(2));
 wattrset(whex,COLOR_PAIR(2));
 wattrset(wascii,COLOR_PAIR(2));
 wattrset(wtop,COLOR_PAIR(2)); 
 wattrset(wbot,COLOR_PAIR(2));

 !mode?wmove(whex,pos.y,pos.x):wmove(wascii,pos.y,pos.x); 

 wrefresh(woffs);
 wrefresh(wtop);
 wrefresh(wbot);
 // die Reihenfolge wird anhand des Modus bestimmt (das letzte ist aktiv)
 !mode?wrefresh(wascii):wrefresh(whex);
 mode?wrefresh(wascii):wrefresh(whex);
}

void lineout(unsigned long zeile)
{
 int z;

 miniinit();

 ptv = tonumsysx((*pdaten).zeile*16,16);
 for(z=0;z<9;z++)
 {  
  xoffs[z] = *(ptv+z);
 }
 mvwaddstr(woffs,zeile,1,soffs);
 for (z=0;z<(*pdaten).len;z++)
 {
  ptv = tonumsysx((*pdaten).vals[z],16);
  xhex[z*3+1] = *(ptv+6);
  xhex[z*3+2] = *(ptv+7);
 }
 mvwaddstr(whex,zeile,1,shex);
 for (z=0;z<(*pdaten).len;z++)
 {
// BUG: Die Ober- und Untergrenze genau bestimmen.
  xascii[z] = ((((*pdaten).vals[z]) > 31)&&((*pdaten).vals[z] != 127))?((*pdaten).vals[z]):254;
 }
 mvwaddstr(wascii,zeile,1,sascii);
}

void initout()
{
//Initiale Ausgabe (Alle)
int i;
bool schalter=false;
unsigned long zeile=1;
pdaten=pfirst;
 
if ((*pdaten).pnext == NULL) schalter=true;
for(i=0;i<16;i++)
 {
  lineout(i+1);
  if (schalter) break;
  pdaten=(*pdaten).pnext;
  if ((*pdaten).pnext == NULL) schalter=true;
 }
 scrrefresh();

if(i>15) pdaten=(*pdaten).plast;
}

void scrolld()
{
 wscrl(woffs,1);
 wscrl(whex,1);
 wscrl(wascii,1);

 int z;

 miniinit();

 lineout(16);
}

void scrollu()
{
 wscrl(woffs,-1);
 wscrl(whex,-1);
 wscrl(wascii,-1);

 miniinit();

 lineout(1);
}

void switchmode()
{
 if(mode==0)
 {
  mode=1; // modus:Hex->Ascii
  // Umrechnen der Cursorposition
  pos.x=((pos.x+1)/3);
 }
 else
 {
  mode=0; // modue:Ascii->Hex
  // Umrechnen der Cursorposition
  pos.x=((pos.x*3)-1);
 }
}

void moveleft()
{
 if(mode==0)
 {
  if(pos.x > 2)(pos.x%3)?pos.x-=2:pos.x--;
 }
 else
 {
  if(pos.x > 1)pos.x--;
 }
}

void moveright()
{
 if(mode==0)
 {
  if(pos.x < 48)(pos.x%3)?pos.x++:pos.x+=2;
 }
 else
 {
  if(pos.x < 16)pos.x++;
 }
}

void charin(char ch)
{
 int i=0;
 // im Speicher zur Cusrorposition blättern
 while(i<(16-pos.y)&&((*pdaten).plast))
 {
  i++;
  pdaten=(*pdaten).plast;
 }
 // Wert schreiben
  (*pdaten).vals[pos.x-1]=ch;
 // Ausgabe aktualisieren
 lineout(pos.y);
 // wieder zurückblättern
 while(i--)
 {
  pdaten=(*pdaten).pnext;
 }
}

int main(int argc, char *argv[])
{
/*  --- DEBUG ONLY
printf("DEBUG: 5-%u\n",xto10(tonumsysx(5,2),2));
printf("DEBUG: 16-%u\n",xto10(tonumsysx(16,16),16));
printf("DEBUG: 36-%u\n",xto10 (tonumsysx(36,36),36));
printf("DEBUG: 255-%u\n",xto10(tonumsysx(255,16),16));
printf("DEBUG: 255-%u\n",xto10("FF",16));
printf("DEBUG: 125-%u\n",xto10(tonumsysx(125,8),8));
printf("DEBUG: 255-%u\n",xto10(tonumsysx(255,8),8));
getchar();
    --- END DEBUG */
//Variablen
 unsigned int i,z;  			// Allgemeine Zähler
 unsigned long zeile=0;		   	// Zeilennummer 
 bool schalter;          		// Schalter für lesevorlauf
 int inpch;               		// Eingabezeichen

//Vorbereitung
 printf("GHEX Version 0.5\n");
 //Parameter angegeben?
 if(argc < 2)
 {
  fprintf(stderr,"GHEX-MESSAGE:\n\nUSAGE: %s <filename> \n",argv[0]); 
  exit(1);
 }
 //Datei öffnen
 fp=fopen(argv[1],"r");
 if (fp == NULL)
 {
  fprintf(stderr,"GHEX-MESSAGE:\n\nERROR opening file: %s \n",argv[1]); 
  exit(2);
 }
 // pointer setzen
 initvar();
 // sonstige Variableninitialisierung
 pos.x = pos.y = 1;
 //Datei -> Speicher
 if(loadcontents())
 {
  fprintf(stderr,"GHEX-MESSAGE:\n\nERROR reading %s (too less RAM?)\n",argv[1]); 
  exit(3);
 }
 // Terminal initialisieren
 if(screeninit()) 
 {
  endscr(); 
  fprintf(stderr,"!!!Terminal not supported!!! -> Abort \n"); 
  exit(5);
 }
 mvwaddstr(wtop,1,1,topline);
 mvwaddstr(wbot,1,1,argv[1]);


//Hauptprogramm

initout();
scrrefresh();

//Eventschleife
 while(inpch!=KEY_F(10))
 {
  if (mode==0)
  {
   inpch=wgetch(whex);
  }
  else
  {
   inpch=wgetch(wascii);
  }
  switch(inpch)
  {
   case KEY_F(9): switchmode();
                  break;
   case KEY_LEFT: moveleft();
                  break;
   case KEY_RIGHT:moveright();
                  break; 
   case KEY_DOWN: if(pos.y>15)
                  { 
		   if ((*pdaten).pnext != NULL)
                   { pdaten=(*pdaten).pnext;
                   scrolld(); 
                   }
                  }
                  else
                  {
                   pos.y++;
                  }
                  break;
   case KEY_UP:   if(pos.y<2)
                  {
                   z=0;
		   while(((*pdaten).plast != NULL)&&(z < 16))
                   { 
                    pdaten=(*pdaten).plast;
                    z++; 
                   }
                   if(z>15)
                   {
                    z--;
                    scrollu();
                   }
                   while(z--)
                   { 
		    if ((*pdaten).pnext != NULL)
                    { 
                     pdaten=(*pdaten).pnext;
                    }
                   }
                  }
                  else
                  {
                  pos.y--;
                  }
                  break;
   case KEY_NPAGE: 
                  for(i=0;i<16;i++)
                  {
       		   if ((*pdaten).pnext != NULL)
                   { pdaten=(*pdaten).pnext;
                   scrolld(); 
                   }
                  }
                  break;
   case KEY_PPAGE:
                  for(i=0;i<16;i++)
                  { 
                   z=0;
		   while(((*pdaten).plast != NULL)&&(z < 16))
                   { 
                    pdaten=(*pdaten).plast;
                    z++; 
                   }
                   if(z>15)
                   {
                    z--;
                    scrollu();
                   }
                   while(z--)
                   { 
		    if ((*pdaten).pnext != NULL)
                    { 
                     pdaten=(*pdaten).pnext;
                    }
                   }
                  }
                  break;
   case KEY_HOME:
                  initout();
                  break;
   case KEY_END: 
                  while((*pdaten).pnext)
                  {
       		   if ((*pdaten).pnext != NULL)
                   { pdaten=(*pdaten).pnext;
                   scrolld(); 
                   }
                  }
                  break;
   default: 
                  if(mode==0)
                  {
                   if(isdigit(inpch) || (toupper(inpch)>='A' && toupper(inpch)<='F') )
                   {
                    waddch(whex,toupper(inpch));
                    char hch[]="FF";
//  TODO hch korrekt füllen.                  if(pos.x%3) 
                    switchmode();          // um die Koordinaten umzurechnen
                    charin(xto10(hch,16)); // Umrechnen Hex -> Ascii+charin
                    switchmode();          // und wieder zurücksetzen
                    moveright();  
                   }
                  }
                  else
                  {
                   //if((inpch > 31)&&(inpch < 256))
                   if((inpch < 256))
                   {
                    waddch(wascii,inpch);
                    charin(inpch);
                    moveright();
                   }
                  }
  };
 scrrefresh();
 } 
 sleep(1);
 endscr();
 unallocmem();
 return (fclose(fp));
}