package cn.timer.api.callback.esign.service;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.Base64.Encoder;

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



/***
 *
 * @Description: 摘要加密算法辅助类
 * @Team: 公有云技术支持小组
 * @Author: 天云小生
 * @Date: 2018年01月14日
 */
public class DigestHelper {
   
    /***
     * 获取请求签名值
     *
     * @param data
     *            加密前数据
     * @param key
     *            密钥
     * @param algorithm
     *            HmacMD5 HmacSHA1 HmacSHA256 HmacSHA384 HmacSHA512
     * @param encoding
     *            编码格式
     * @return HMAC加密后16进制字符串
     * @throws Exception
     */
    public static String getSignature(String data, String key, String algorithm, String encoding) {
        Mac mac = null;
        try {
            mac = Mac.getInstance(algorithm);
            SecretKeySpec secretKey = new SecretKeySpec(key.getBytes(encoding), algorithm);
            mac.init(secretKey);
            mac.update(data.getBytes(encoding));
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            System.out.println("获取Signature签名信息异常：" + e.getMessage());
            return null;
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            System.out.println("获取Signature签名信息异常：" + e.getMessage());
            return null;
        } catch (InvalidKeyException e) {
            e.printStackTrace();
            System.out.println("获取Signature签名信息异常：" + e.getMessage());
            return null;
        }
        return byte2hex(mac.doFinal());
    }

    /***
     * 计算文件的Content-MD5
     *
     * @param filePath
     * @return
     */
    public static String getContentMD5(String filePath) {
    	 Encoder encoder = Base64.getEncoder();
    	// 获取文件MD5的二进制数组（128位）
        byte[] bytes = getFileMD5Bytes128(filePath);
        // 对文件MD5的二进制数组进行base64编码（而不是对32位的16进制字符串进行编码）
        return  encoder.encodeToString(bytes);
       
    }

    /***
     * 获取文件MD5-二进制数组（128位）
     *
     * @param filePath
     * @return
     * @throws IOException
     */
    public static byte[] getFileMD5Bytes128(String filePath) {
        FileInputStream fis = null;
        byte[] md5Bytes = null;
        try {
            File file = new File(filePath);
            fis = new FileInputStream(file);
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            byte[] buffer = new byte[1024];
            int length = -1;
            while ((length = fis.read(buffer, 0, 1024)) != -1) {
                md5.update(buffer, 0, length);
            }
            md5Bytes = md5.digest();
            fis.close();
        } catch (FileNotFoundException e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
        return md5Bytes;
    }

    /***
     * 获取文件SHA256-十六进制字符串(原文SHA256摘要)
     *
     * @param filePath
     * @return
     * @throws IOException
     */
    public static String getFileSHA256(String filePath) {
        FileInputStream fis = null;
        byte[] md5Bytes = null;
        String hashSHA256 = null;
        try {
            File file = new File(filePath);
            fis = new FileInputStream(file);
            MessageDigest md5 = MessageDigest.getInstance("SHA-256");
            byte[] buffer = new byte[1024];
            int length = -1;
            while ((length = fis.read(buffer, 0, 1024)) != -1) {
                md5.update(buffer, 0, length);
            }
            md5Bytes = md5.digest();
            fis.close();
            hashSHA256 = byte2hex(md5Bytes);

        } catch (FileNotFoundException e) {
            e.printStackTrace();
            System.out.println(e.getMessage());
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            System.out.println(e.getMessage());
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println(e.getMessage());
        }
        return hashSHA256;
    }

    /***
     * 获取字符串的SHA256-十六进制字符串
     *
     * @param str
     * @return
     * @throws IOException
     */
    public static String getStringSHA256(String str) {
        byte[] md5Bytes = null;
        try {
            md5Bytes = str.getBytes("UTF-8");
            // 拿到一个SHA256转换器
            MessageDigest messageDigest;
            messageDigest = MessageDigest.getInstance("SHA-256");
            // 输入的字符串转换成字节数组
            byte[] inputByteArray = str.getBytes();
            // inputByteArray是输入字符串转换得到的字节数组
            messageDigest.update(inputByteArray);
            // 转换并返回结果，也是字节数组，包含16个元素
            md5Bytes = messageDigest.digest();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return byte2hex(md5Bytes);
    }

    /***
     * 将byte[]转成16进制字符串
     *
     * @param data
     *
     * @return 16进制字符串
     */
    public static String byte2hex(byte[] data) {
        StringBuilder hash = new StringBuilder();
        String stmp;
        for (int n = 0; data != null && n < data.length; n++) {
            stmp = Integer.toHexString(data[n] & 0XFF);
            if (stmp.length() == 1)
                hash.append('0');
            hash.append(stmp);
        }
        return hash.toString();
    }
}