/* 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 <ctype.h>
#include "term.h"
#include "types.h"
#include "ctypes.h"

vigenere_base::vigenere_base(){
  period = 0;
  period_set = FALSE;
  length = 0;
}

int vigenere_base::execute_option(char option){
  int valid = TRUE;

  switch(option){
    case CHANGEPERIOD:
      change_period();  
      break;
    case SUBSTITUTE:
      substitute();
      break; 
    case UNDO:
      undo();
      break;
    case ALPHFIT:
      alphfit();
      break;
    default:
      valid = base_exec_option(option);
      break;
  }

  return valid;
}
    
void vigenere_base::change_period(){
  period_set = FALSE;

  set_period();
  clear_to_prompt();
}

void vigenere_base::setup_key(){
  key.init(period);
}

void vigenere_base::substitute(){
  int column;
  char tmp_str[STRINGLENGTH];
  char ct_letter, pt_letter;

  prompt("What column is the letter in? ");
  read_line(tmp_str);

  if(sscanf(tmp_str, "%d", &column) != 1)
    msgerror("Bad input.");
  else if(column < 1 || column > period)
    msgerror("Bad position.");
  else{
    prompt("What is the new letter? (ct,pt) ");
    read_line(tmp_str);
    if(sscanf(tmp_str, "%c,%c", &ct_letter, &pt_letter) != 2){
      msgerror("Bad format.");
    }
    else if(!isalpha(ct_letter) || !isalpha(pt_letter)){
      msgerror("Bad letter.");
    }
    else{
      sub_letter(ct_letter | ' ', pt_letter | ' ', column-1);
    }
  }
}

void vigenere_base::alphfit(){
  char tmp_str[STRINGLENGTH];
  int i, column;

  prompt("Fit which column? (* for all) ");
  read_line(tmp_str);
  if(*tmp_str == '*'){
    for(i = 0; i < period; i++){
      fit_column(i);
    }
  }
  else if(sscanf(tmp_str, "%d", &column) != 1){
    msgerror("Bad column.");
  }
  else if(column < 1 || column > period){
    msgerror("Column out of range.");
  }
  else{
    fit_column(column-1);
  }
}

void vigenere_base::undo(){
  int column, i;

  prompt("Which column? (* for all) ");
  column = get_char();
  if(column == '*'){
    for(i = 0; i < period; i++)
      key.clearkey(i);
  }
  else{
    column -= '1';
    key.clearkey(column);
  }
}

void vigenere_base::show_menu(){
  menu(2, "Options:    (S)ubstitute     (A)pply fit     (U)ndo     (C)hange period");
  menu(1, "            (W)rite          (Q)uit");
}

void vigenere_base::show_cipher(){
  int i, line_length;
  char tmp_str[20];

  line_length = COLS / (period+1);
  i = 0;
  while(i < length){
    strncpy(tmp_str, cipher+i, period);
    tmp_str[period] = (char) NULL;
    msgprint((i*(period+1)/period)%(line_length*(period+1)), (i/(line_length*period))*3 + 1, tmp_str);
    decode(tmp_str);
    msgprint((i*(period+1)/period)%(line_length*(period+1)), (i/(line_length*period))*3 + 0, tmp_str);
    i += period; 
  }
}

void vigenere_base::decode(char *message){
  int i;

  for(i = 0; i < strlen(message); i++){
    if(key.val(i) == BLANK)
      message[i] = BLANK;
    else
      message[i] = get_pt(message[i], key.val(i));
  }
}

void vigenere_base::show_key(){
  int i;

  for(i = 0; i < period; i++){
    if(key.val(i) != BLANK){
      msgprint(3*i+4, 15, "%2d", key.val(i) - 'a');
      put_char(key.val(i), 3*i + 5, 16);
    }
    else{
      msgprint(3*i+4, 15, " .");
      put_char(BLANK, 3*i + 5, 16);
    }
  }
}

void porta::show_key(){
  int i, row_offset;

  for(i = 0; i < period; i++){
    if(key.val(i) != BLANK){
      row_offset = (key.val(i)-'a')%2;
      /* Print the first key letter
      */
      msgprint(3*i+4, 15+row_offset, "%2d", (key.val(i)-'a')/2);
      put_char(key.val(i), 3*i + 5, 16+row_offset);
      /* Print the second key letter
      */
      if(row_offset == 1)
	put_char(key.val(i)-1, 3*i + 5, 16);
      else
	put_char(key.val(i)+1, 3*i + 5, 16+1);
    }
    else{
      msgprint(3*i+4, 15, " .");
      put_char(BLANK, 3*i + 5, 16);
    }
  }
}

void vigenere_base::sub_letter(char ct_letter, char pt_letter, int column){
  char key_letter;

  key_letter = get_key_letter(ct_letter, pt_letter);
  if(key_letter){
    key.alter(key_letter, column);
  }
}

void vigenere_base::fit_column(int column){
  int i, k, fweights[26];
  static int weights[] = { 1863, 954, 1477, 1644, 2114, 1447, 1204, 1544,
   1869, 301, 477, 1544, 1398, 1892, 1869, 1431, 477, 1887, 1799, 1969,
   1431, 1114, 1204, 699, 1279, 0};
  int maxweight=0, maxpos=0;

  for(i = 0; i < 26; i++)
    fweights[i] = 0;

  /* Rotate through the 26 possible keys
  */
  for(k = 0; k < 26; k++){
    /* Rotate each letter in the column
    */
    for(i = column; i < length; i+=period){
      fweights[k] += weights[get_pt(cipher[i], k+'a') - 'a'];
    }
  }

  /* Find the largest weight and make that substitution.
  */

  for(i = 0; i < 26; i++){
    if(maxweight < fweights[i]){
      maxweight = fweights[i];
      maxpos = i;
    }
  }

  sub_letter(get_ct('a', maxpos+'a'), 'a', column);
}

void vigenere_base::decipher(char *string){
  int i=0;

  while(i < length){
    *string++ = get_pt(cipher[i], key.val(i%period));
    i++;
  }
  *string = (char) NULL;
}