package cn.edu.whu.boot.common.utils.collection;

import org.apache.commons.codec.digest.DigestUtils;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

/**
 * 加密相关的工具类
 */
public class EncryptUtils {

	/**
	 * 基于File 获取文件的唯一标志码
	 * @param file 文件
	 */
	public static String getMd5ByFile(File file) throws IOException
	{
		FileInputStream fileInputStream = new FileInputStream(file);
		String value = DigestUtils.md2Hex(fileInputStream);
		fileInputStream.close();
		return value;
	}

	/**
	 * @param message     待加密的字符串
	 * @param key         用于加密的Key
	 * @return byte[]     加密后的结果
	 */
	public static byte[] encrypt(String message, String key) throws Exception {
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
		
		DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));

		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
		SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
		IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));
		cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);

		return cipher.doFinal(message.getBytes("UTF-8"));
	}

	/**
	 * 身份证解密算法
	 * @param message     加密后的字符串
	 * @param key         encrypt方法加密的Key
	 * @return            原字符串
	 */
	public static String decrypt(String message, String key) throws Exception {

		byte[] bytesrc = convertHexString(message);
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
		DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
		SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
		IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));

		cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);

		byte[] retByte = cipher.doFinal(bytesrc);
		return new String(retByte);
	}

	/**
	 * 将byte[] 转成String
	 */
	public static String toHexString(byte[] b) {
		StringBuffer hexString = new StringBuffer();
		for (int i = 0; i < b.length; i++) {
			String plainText = Integer.toHexString(0xff & b[i]);
			if (plainText.length() < 2)
				plainText = "0" + plainText;
			hexString.append(plainText);
		}

		return hexString.toString();
	}

	/**
	 * 将String转成byte[]
	 */
	public static byte[] convertHexString(String ss) {
		byte digest[] = new byte[ss.length() / 2];
		for (int i = 0; i < digest.length; i++) {
			String byteString = ss.substring(2 * i, 2 * i + 2);
			int byteValue = Integer.parseInt(byteString, 16);
			digest[i] = (byte) byteValue;
		}
		return digest;
	}
}
