package org.apereo.cas.web.landtool.utils;


import java.security.MessageDigest;
import java.util.Base64;

import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**  
 * 基础加密组件  
 * @author TanBin    
 */    
public abstract class AbstractCoderUtils {
    public static final String KEY_SHA = "SHA";    
    public static final String KEY_MD5 = "MD5";    
    
    /**  
     * MAC算法可选以下多种算法  
     * <pre>  
     * HmacMD5   
     * HmacSHA1   
     * HmacSHA256   
     * HmacSHA384   
     * HmacSHA512  
     * </pre>  
     */    
    public static final String KEY_MAC = "HmacMD5";    
     
    /**  
     * BASE64加密  
     * @param key  
     * @return  
     * @throws Exception
     *
     * 法1：使用sun.misc套件。1.6之前， 效率不好，新JDK不支持
     * return (new BASE64Encoder()).encodeBuffer(data);
     *
     * 法2：使用Apache Commons Codec。
     * return (new Base64()).encodeToString(data);
     *
     * 法3：使用Java 8的java.util套件。  效率是1的11倍，是2的3倍以上。
     */    
    public static String encryptBase64(byte[] data) {
        //text.getBytes("UTF-8"); new String(decoder.decode(encodedText), "UTF-8")

        return Base64.getEncoder().encodeToString(data);
    }
    
    /**  
     * BASE64解密  
     * @param key  
     * @return  
     * @throws Exception
     *
     * 法1：使用sun.misc套件。 效率不好，新JDK不支持
     * return (new BASE64Decoder()).decodeBuffer(key);
     *
     * 法2：使用Apache Commons Codec。
     * return (new Base64()).decode(key);
     *
     * 法3：使用Java 8的java.util套件。  效率是1的11倍，是2的3倍以上。
     */    
    public static byte[] decryptBase64(String key) {
        return Base64.getDecoder().decode(key);
    }
    
    /**  
     * MD5加密  
     * @param data  
     * @return  
     * @throws Exception  
     */    
    public static byte[] encryptMd5(byte[] data) throws Exception{
        MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);    
        md5.update(data);    
        return md5.digest();
    } 
    
    /**
     * 蓝图的MD5加密算法
     * @param text
     * @return
     * @throws Exception
     */
    public static String lantuEncryptMd5(String text) throws Exception{
    	byte[] b = encryptMd5(text.getBytes("UTF-8"));
    	String key = convertToHexString(b);
    	//转为大写
    	key = key.toUpperCase();
    	//倒序
    	char[] array = key.toCharArray();
    	String reverseKey = "";
    	for (int i = array.length-1; i >= 0; i--) {
    		reverseKey += array[i];
    	}
    	return reverseKey;
    }
    
    /**
     * 字节数组转为32位字符串
     * @param data
     * @return
     */
    private static String convertToHexString(byte[] data) {
    	StringBuffer strBuffer = new StringBuffer();
    	for (int i = 0; i < data.length; i++) {
    		//strBuffer.append(Integer.toHexString(0xff & data[i]));	//30bit
            String haxHex = Integer.toHexString(data[i] & 0xFF);  
            if(haxHex.length() < 2){  
            	strBuffer.append("0");  
            }  
            strBuffer.append(haxHex);
    	}
    	return strBuffer.toString();
    }    
    
    /**  
     * SHA加密  
     * @param data  
     * @return  
     * @throws Exception  
     */    
    public static byte[] encryptSha(byte[] data) throws Exception{
        MessageDigest sha = MessageDigest.getInstance(KEY_SHA);    
        sha.update(data);    
        return sha.digest();    
    }    
    
    /**  
     * 初始化HMAC密钥  
     * @return  
     * @throws Exception  
     */    
    public static String initMacKey() throws Exception{    
        KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_MAC);    
        SecretKey secretKey = keyGenerator.generateKey();    
        return encryptBase64(secretKey.getEncoded());
    }    
	    
    /**  
     * HMAC加密  
     * @param data  
     * @param key  
     * @return  
     * @throws Exception  
     */    
    public static byte[] encryptHmac(byte[] data, String key) throws Exception{
        SecretKey secretKey = new SecretKeySpec(decryptBase64(key), KEY_MAC);
        Mac mac = Mac.getInstance(secretKey.getAlgorithm());    
        mac.init(secretKey);    
        return mac.doFinal(data);    
    }    
    
	public static void main(String[] args) {
        String inputStr = "123456";    
        System.err.println("原文:" + inputStr);    
        try {
			String codeBase64 = encryptBase64(inputStr.getBytes("UTF-8"));
			String codeMd5 = lantuEncryptMd5(inputStr);
			byte[] codeSha = encryptSha(inputStr.getBytes("UTF-8"));
			
			String key = initMacKey();    
			System.err.println("Mac密钥:" + key);
			byte[] codeHmac = encryptHmac(inputStr.getBytes("UTF-8"), key);
			
			System.err.println("\nBASE64:" + codeBase64);
			System.err.println("BASE64解密:" + new String(decryptBase64(codeBase64),"UTF-8"));
			System.err.println("MD5:" + codeMd5);
			System.err.println("SHA:" + codeSha);
			System.err.println("HMAC:" + codeHmac);
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}    
	}
}