package com.crypto.encrypt;

import java.security.SecureRandom;
import java.io.*;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.Cipher;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import java.lang.reflect.Constructor;
import java.security.spec.KeySpec;
import java.lang.reflect.InvocationTargetException;

public class EncryptData {

  private String keyfile=null;

  public EncryptData() {
  }

  public EncryptData(String keyfile) {
    this.keyfile=keyfile;
  }

  /**
   * 加密文件
   * @param filename String 源路徑
   * @param filenamekey String 加密后的路徑
   */
  public void createEncryptData(String filename,String filenamekey) throws
      IllegalStateException, IllegalBlockSizeException, BadPaddingException,
      NoSuchPaddingException, InvalidKeySpecException, NoSuchAlgorithmException,
      InvalidKeyException, IOException, InstantiationException,
      IllegalAccessException, IllegalArgumentException,
      InvocationTargetException, NoSuchMethodException, SecurityException,
      ClassNotFoundException, IllegalStateException, IllegalBlockSizeException,
      BadPaddingException, NoSuchPaddingException, InvalidKeySpecException,
      NoSuchAlgorithmException, InvalidKeyException, IOException {
    //驗證keyfile
    if(keyfile==null || keyfile.equals(""))
    {
      throw new NullPointerException("無效的key文件路徑");
    }

    encryptData(filename,filenamekey);
  }

  /**
   * 加密類文件
   * @param filename String 原始的類文件
   * @param encryptfile String 加密后的類文件
   * @throws IOException
   * @throws InvalidKeyException
   * @throws NoSuchAlgorithmException
   * @throws InvalidKeySpecException
   * @throws NoSuchPaddingException
   * @throws NoSuchAlgorithmException
   * @throws BadPaddingException
   * @throws IllegalBlockSizeException
   * @throws IllegalStateException
   */
  private void encryptData(String filename,String encryptfile) throws IOException, InvalidKeyException,
      NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException,
      NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException,
      IllegalStateException, ClassNotFoundException, SecurityException,
      NoSuchMethodException, InvocationTargetException,
      IllegalArgumentException, IllegalAccessException, InstantiationException {

    byte data[]=Util.readFile(filename);
    // 執行加密操作
    byte encryptedClassData[] = getencryptData(data);
    // 保存加密后的文件，覆蓋原有的類文件。
    Util.writeFile(encryptedClassData,encryptfile);
  }
  /**
   * 直接獲得加密數據
   * @param bytes byte[]
   * @throws IllegalStateException
   * @throws IllegalBlockSizeException
   * @throws BadPaddingException
   * @throws InvalidKeyException
   * @throws NoSuchPaddingException
   * @throws InvalidKeySpecException
   * @throws NoSuchAlgorithmException
   * @throws InstantiationException
   * @throws IllegalAccessException
   * @throws IllegalArgumentException
   * @throws InvocationTargetException
   * @throws NoSuchMethodException
   * @throws SecurityException
   * @throws ClassNotFoundException
   * @throws IOException
   * @return byte[]
   */
  public byte[] createEncryptData(byte[] bytes) throws IllegalStateException,
      IllegalBlockSizeException, BadPaddingException, InvalidKeyException,
      NoSuchPaddingException, InvalidKeySpecException, NoSuchAlgorithmException,
      InstantiationException, IllegalAccessException, IllegalArgumentException,
      InvocationTargetException, NoSuchMethodException, SecurityException,
      ClassNotFoundException, IOException {
    bytes=getencryptData(bytes);
    return bytes;
  }

  private byte[] getencryptData(byte[] bytes) throws IOException,
      ClassNotFoundException, SecurityException, NoSuchMethodException,
      InvocationTargetException, IllegalArgumentException,
      IllegalAccessException, InstantiationException, NoSuchAlgorithmException,
      InvalidKeySpecException, NoSuchPaddingException, NoSuchAlgorithmException,
      InvalidKeyException, BadPaddingException, IllegalBlockSizeException,
      IllegalStateException {
    // 產生一個可信任的隨機數源
    SecureRandom sr = new SecureRandom();
    //從密鑰文件key Filename中得到密鑰數據
    byte[] rawKeyData = Util.readFile(keyfile);
    // 從原始密鑰數據創建DESKeySpec對象
    Class classkeyspec=Class.forName(Util.getValue("keyspec"));
    Constructor constructor = classkeyspec.getConstructor(new Class[]{byte[].class});
    KeySpec dks = (KeySpec) constructor.newInstance(new Object[]{rawKeyData});
    // 創建一個密鑰工廠，然后用它把DESKeySpec轉換成SecretKey對象
    SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(Util.getAlgorithm());
    SecretKey key = keyFactory.generateSecret(dks);
    // Cipher對象實際完成加密操作
    Cipher cipher = Cipher.getInstance(Util.getAlgorithm());
    // 用密鑰初始化Cipher對象
    cipher.init(Cipher.ENCRYPT_MODE, key, sr);
    // 執行加密操作
    bytes = cipher.doFinal(bytes);
    // 返回字節數組
    return bytes;
  }
  /**
   * 設置key文件路徑
   * @param keyfile String
   */
  public void setKeyFile(String keyfile)
  {
    this.keyfile=keyfile;
  }

}