/* This is one of the cipher files for the cipher interface written
** by wart@ugcs.caltech.edu
**
** Please don't steal my code without my permission.
**
*/

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include "term.h"
#include "types.h"
#include "ctypes.h"

#define SPC   '.'
#define SPACE_DIGIT (int) 26

tridigit::tridigit(){
  valid_chars = "1234567890";
  period=0;
  *cipher = (char) NULL;
  key.init(27);
}

int tridigit::execute_option(char option){
  int valid_option = TRUE;

  switch(option){
    case SUBSTITUTE:
      substitute();
      break;
    case UNDO:
      undo();
      break;
    default:
      valid_option = base_exec_option(option);
      break;
  }

  return valid_option;
}

void tridigit::substitute(){
  char letter;
  int number;

  prompt("What is the number? ");
  number = get_char();

  prompt("What is the letter? ");
  letter = get_char();

  if(do_sub(number, letter) == BAD_SUB){
    msgerror("Bad substitution.");
  }
}

int tridigit::do_sub(char number, char letter){
  int state = NEW_SUB;
  int i, count = 0;

  if(!isdigit(number)){
    state = BAD_SUB;
  }
  else if(!isalpha(letter)){
    if(letter != SPC){
      state = BAD_SUB;
    }
    else{
      state = key.alter(number, SPACE_DIGIT);
      for(i = 0; i < 26; i++){
        if(key.val(i) == number){
	  key.clearkey(i);
	}
      }
    }
  }
  else{
    letter |= ' ';
    for(i = 0; i < 26; i++){
      if(key.val(i) == number) count++;
    }
    if(count > 2){
      state = BAD_SUB;
    }
    else{
      state = key.alter(number, key.index(letter));
      if(key.val(SPACE_DIGIT) == number){
        key.clearkey(SPACE_DIGIT);
      }
    }
  }

  return state;
}

void tridigit::show_menu(){
  menu(1, "(S)ubstitute   (U)ndo   (W)rite   (Q)uit");
}

void tridigit::show_cipher(){
  int i, j, x, y;
  char lets[3];

  for(i = 0; i < length; i++){
    x = (i%36)*2;
    y = (i/36 + 1)*4;
    put_char(cipher[i], x,  y);
    get_letters(cipher[i], lets);
    for(j = 0; j < 3; j++){
      put_char(lets[j], x, y-1-j);
    }
  }
}

int tridigit::get_letters(char number, char lets[3]){
  int i, count = 0;

  for(i = 0; i < 3; i++)
    lets[i] = BLANK;

  if(key.val(SPACE_DIGIT) == number){
    lets[0] = SPC;
    count = 1;
  }
  else{
    for(i = 25; i >= 0 && count < 3; i--){
      if(key.val(i) == number){
	lets[count++] = i+'a';
      }
    }
  }

  return count;
}

void tridigit::show_key(){
  int i, j;
  char lets[3];

  for(i = 0; i < 10; i++){
    put_char(i+'0', i*2, 20);
    get_letters(i+'0', lets);
    for(j = 0; j < 3; j++){
      put_char(lets[j], i*2, 19-j);
    }
  }
}

void tridigit::undo(){
  char letter;
  int i;

  prompt("Undo which number/letter? ");
  letter = get_char();

  if(letter == '*'){
    key.clearkey();
  }
  else if(isalpha(letter)){
    letter |= ' ';
    key.clearkey(key.index(letter));
  }
  else if(isdigit(letter)){
    for(i = 0; i < 27; i++){
      if(key.val(i) == letter){
        key.clearkey(i);
      }
    }
  }
  else{
    msgerror("Bad letter.");
  }
}

void tridigit::decipher(char *string){
  char lets[3];
  int i, j;

  *string = (char) NULL;

  for(i = 0; i < length; i++){
    get_letters(cipher[i], lets);
    for(j = 0; j < 3; j++){
      sprintf(string+4*i, "%c%c%c\n", lets[0], lets[1], lets[2]);
    }
  }
  string[4*length] = (char) NULL;
}