package my;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2006</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */

import java.util.*;
import java.io.*;
import javax.swing.*;

public class Caeser1 {
  HashMap dic;
  String Text = new String();
  String explain = new String(" ");
  String textPlaint;
  int[] Time = new int[26];
  int numOfword = 0;
  void SetText(String s) {
    this.Text = s;
  }

  void SetExplain(String s) {
    this.explain = s;
  }

  String getout() {
    return textPlaint;
  }

  String getText() {
    return Text;
  }

  String getexplain() {
    return explain;
  }

  private void initialWordClass(String s) {
    dic = new HashMap();
    String temp = "";
    try {
      FileInputStream fis = new FileInputStream(s);
      InputStreamReader isr = new InputStreamReader(fis);
      BufferedReader bfr = new BufferedReader(isr);
      do {
        temp = bfr.readLine();
        if (temp == null)
          break;
        dic.put(temp, temp);
      }
      while (true);
    }
    catch (Exception e) {
      JOptionPane.showMessageDialog(null, "找不到詞庫文件！", "Message Diolog ",
                                    JOptionPane.ERROR_MESSAGE);
    }
  }

  public Caeser1() {
  }

  public int Max(int num, int[] a) {
    int max = a[0];
    int key = 0;
    for (int i = 0; i < 26; i++) {
      if (max < a[i]) {
        max = a[i];
        key = i;
      }
    }
    if (max > (num * 9 / 10)&&num!=0)
      return key;
    else
      if(num==0)
        return key;
      else
        return -1;

  }

  public void Decode1(int key) {
    int L = Text.length();
    int flagOfWord = 0;
    boolean choose;
    StringBuffer out = new StringBuffer();
    StringBuffer tent = new StringBuffer();
    int countOfWord = 0;
    for (int i = 0; i < L; i++) {
      char ch = Text.charAt(i);
      if (ch >= 'A' && ch <= 'Z') {
        ch = (char) ( (ch + 32 - 97 - key + 26) % 26 + 97);
        tent.append(ch);
        out.append(ch);
        countOfWord++;
        flagOfWord = 1;
      }
      else if (ch >= 'a' && ch <= 'z') {
        ch = (char) ( (ch - 97 - key + 26) % 26 + 97);
        tent.append(ch);
        out.append(ch);
        countOfWord++;
        flagOfWord = 1;
      }
      else {
        if (flagOfWord == 1) {
          //  long start = System.currentTimeMillis();
          choose = dic.containsKey(tent.toString());
          // long finish=System.currentTimeMillis();
          //System.out.println("time:: "+(finish-start));

          if (choose == true) {
            //  System.out.println("tent:: "+tent);
            Time[key]++;
            // if(key==0)
            //numOfword++;
          }
          numOfword++;
          tent.delete(0, countOfWord);
          countOfWord = 0;
          flagOfWord = 0;
        }
        out.append(ch);
      }
    }
    textPlaint = out.toString();

  }

  public void C_Decode() {
    //System.out.println("text: " + Text);
    int key;
     long start = System.currentTimeMillis();
    initialWordClass("word.dic");
    for (key = 0; key < 26; key++) {
      //System.out.println("key: " + key);
      numOfword = 0;
      Time[key] = 0;
      Decode1(key);
      if (Time[key] == numOfword && numOfword != 0) {
         long finish=System.currentTimeMillis();
          //System.out.println("time:: "+(finish-start));
        this.SetExplain(" 解密成功！ :)\n  此密文的密鑰是" + key+"\n 耗時："+(finish-start)+"微秒！");
        break;
      }
    }
    int item;
    if (key == 26) {
      item = Max(numOfword, Time);
      if (item == -1) {
        this.SetExplain(" 對不起，無法解密！");
        //explain = explain.toString();
      }
      else {
        this.SetExplain(" 解密成功！ :)\n  此密文的密鑰是" + item);
        //explain = explain.toString();
        Decode1(item);
      }
    }
  }

  //heuristic
  public void C_HDecode(int chance) {
    //相對高的頻率，可能對應于明文字母集合{r,n,I,o,a,s}。
    //最低頻率的字母,很可能包括在集合{w,v,b,k,x,q,j,z}。
     long start1 = System.currentTimeMillis();


    initialWordClass("word.dic");

    int[] Frequent = new int[26];
    char[] Referto =  {
          'e', 't', 'a', 'o', 'i', 'n', 's', 'h', 'r', 'd', 'l',
          'c', 'u', 'm', 'w', 'f', 'g', 'y', 'p', 'b', 'v', 'k', 'j', 'x', 'q',
          'z'};

    int[] Compare = new int[26];
    int key1, key2;

    int Long = Text.length();
    for (int i = 0; i < Long; i++) { //統計26個字母的出現頻率
      char c = Text.charAt(i);
      if (c <= 'z' && c >= 'a')
        Frequent[c - 'a']++;
      else if (c <= 'Z' && c >= 'A')
        Frequent[c - 'A']++;
    }
    //選擇出頻率高的
    if(chance==1)
    {
    int tem = Max(0, Frequent);
    for (int i= 0; i< 26;i++) {
      key1=('a'+tem-Referto[i]+26)%26;
      numOfword = 0;
      Time[key1] = 0;
      Decode1(key1);
      if (Time[key1] == numOfword && numOfword != 0) {
        long finish1=System.currentTimeMillis();
        this.SetExplain("  解密成功！ :)\n  本啟發式函數可以解此密文哦！：P\n  此密文的密鑰是" + key1 +
                        "\n  歡迎再次使用！"+"\n耗時"+(start1-finish1)+"微妙！");
        break;
      }
    //}
    if (i== 25) {
      key2 = Max(numOfword, Time);
      if (key2 == -1) {
        this.SetExplain("Sorry！:< \n 啟發式的啟發函數對此密文不夠解密！\n也許您可以嘗試輸入更長的信息密文！\n鑒于本算法是對字母的信息統計！\n還有待改進啊！\n - -0");
        //explain = explain.toString();
      }
      else {
        this.SetExplain("解密成功！ :)\n  此密文的密鑰是" + key2);
        //explain = explain.toString();
        Decode1(key2);
      }

    }
    }

    }
    else//代入法的程序
    {
      //for (int k = 0; k < 6; k++) {
        int[] tin = Frequent;
        char[] Place = new char[26];
        for (int i = 0; i < 26; i++) {
          int y = Max(0, tin);
          Place[y] = Referto[i];
          tin[y] = -1;

          char c1 = (char) ('a' + y);
          char c2 = (char) ('A' + y);
          Text.replace(c1, Place[y]);
          Text.replace(c2, Place[y]);
        }

        //}
        //System.out.print("place is:"+Place);
        numOfword = 0;
        Time[0] = 0;
        Decode1(0);
        if (Time[0] == numOfword && numOfword != 0 ||
            Time[0] > numOfword * 9 / 10) {
          String temp = "";
          String temp1 = "";
          for (int i = 0; i < 26; i++) {
            temp += Place[i];
            temp += ' ';
            temp1 += (char) ('a' + i);
            temp1 += ' ';
          }
          this.SetExplain("解密成功！ :)\n  此密文的替換表是:\n" + temp1 + "\n" + temp);
        }
        else
          this.SetExplain("Sorry！:< \n 此解密算法不夠解密！");
      //}
    }
  }

}