package com.terra.proxy.util;


import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.MessageDigest;
import java.util.Base64;


/**
 * 基础加密组件
 *
 * @author TanBin
 */
public abstract class CoderUtils {
    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
     *
     * @return
     * @throws Exception
     */
    public static String encryptBASE64(byte[] data) {
        return Base64.getEncoder().encodeToString(data);
    }

    /**
     * BASE64解密
     *
     * @param key
     * @return
     * @throws Exception
     */
    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++) {
            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) {

            e.printStackTrace();
        }
    }
}