package com.lutao.cloud.common.security.util;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class SHAEncrypt{
    /**
     * 传入文本内容，返回 SHA-256 串
     *
     * @param strText
     * @return
     */
    public static String SHA256(final String strText)
   {
        return SHA(strText, "SHA-256");
    }

    /**
     * 传入文本内容，返回 SHA-512 串
     *
     * @param strText
     * @return
     */
    public static String SHA512(final String strText)
   {
        return SHA(strText, "SHA-512");
    }

    /**
     * 字符串 SHA 加密
     *
     * @param strText
     * @param strType
     * @return
     */
    private static String SHA(final String strText, final String strType)
    {
        // 返回值
        String strResult = null;

        // 是否是有效字符串
        if (strText != null && strText.length() > 0)
       {
            try
           {
                // SHA 加密开始
                // 创建加密对象 并傳入加密類型
                MessageDigest messageDigest = MessageDigest.getInstance(strType);
                // 传入要加密的字符串
                messageDigest.update(strText.getBytes(StandardCharsets.UTF_8));
                // 得到 byte 類型结果
                byte[] byteBuffer = messageDigest.digest();

                // 將 byte 轉換爲 string
                StringBuffer strHexString = new StringBuffer();
                // 遍歷 byte buffer
                for (int i = 0; i < byteBuffer.length; i++)
               {
                    String hex = Integer.toHexString(0xff & byteBuffer[i]);
                    if (hex.length() == 1)
                   {
                        strHexString.append('0');
                    }
                    strHexString.append(hex);
                }
                // 得到返回結果
                strResult = strHexString.toString();
            }
            catch (NoSuchAlgorithmException e)
           {
                e.printStackTrace();
            }
        }
        return strResult;
    }

    public static String genPassword(String clientPassword){
        String pwdBySalt = SHA256(String.format("%s%s",clientPassword,"d$d3135ba@ca20e7"));
        return pwdBySalt;
    }

    /**
     * sha256_HMAC加密
     *
     * @param message
     *            消息
     * @param secret
     *            秘钥
     * @return 加密后字符串
     */
    public static String sha256_HMAC(String message, String secret){
        StringBuilder hash = new StringBuilder();
        try{
            Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
            SecretKeySpec secret_key = new SecretKeySpec(secret.getBytes(), "HmacSHA256");
            sha256_HMAC.init(secret_key);
            byte[] bytes = sha256_HMAC.doFinal(message.getBytes());
            for (int i = 0; i < bytes.length; i++)
           {
                String hex = Integer.toHexString(0xff & bytes[i]);
                if (hex.length() == 1)
               {
                    hash.append('0');
                }
                hash.append(hex);
            }

        } catch (Exception e){
            System.out.println("Error HmacSHA256 ===========" + e.getMessage());
        }
        return hash.toString();
    }

}
