package com.hdl.photovoltaic.utils;

import java.io.File;
import java.io.FileInputStream;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Md5Utils {
    /**
     * MD5转字符串
     */
    public static String encodeMD5(String s) {
        try {
            MessageDigest digest = MessageDigest.getInstance("MD5");
            digest.update(s.getBytes(StandardCharsets.UTF_8));
            byte[] messageDigest = digest.digest();
            return toHexString(messageDigest);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }

    private static String toHexString(byte[] keyData) {
        if (keyData == null) {
            return null;
        }
        int expectedStringLen = keyData.length * 2;
        StringBuilder sb = new StringBuilder(expectedStringLen);
        for (byte keyDatum : keyData) {
            String hexStr = Integer.toString(keyDatum & 0x00FF, 16);
            if (hexStr.length() == 1) {
                hexStr = "0" + hexStr;
            }
            sb.append(hexStr);
        }
        return sb.toString();
    }

    /**
     * MD5转字符串
     * 额外值
     */
    public static String encodeMD52(String s) {
        char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
        try {
            byte[] btInput = s.getBytes(StandardCharsets.UTF_8);
            MessageDigest digest = MessageDigest.getInstance("MD5");
            digest.update(btInput);
            byte[] md = digest.digest();
            int j = md.length;
            char[] str = new char[j * 2];
            int k = 0;
            for (byte byte0 : md) {
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * MD5文件转字符串
     */
    public static String encodeMD5(File f) {
        if (!f.isFile()) {
            return null;
        }
        MessageDigest digest;
        byte[] buffer = new byte[1024];
        int len;
        try {
            digest = MessageDigest.getInstance("MD5");
            FileInputStream in = new FileInputStream(f);
            while ((len = in.read(buffer, 0, 1024)) != -1) {
                digest.update(buffer, 0, len);
            }
            in.close();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        BigInteger bigInt = new BigInteger(1, digest.digest());
        return bigInt.toString(16);
    }

    /**
     * MD5文件转字符串
     */
    public static String encodeMD5(byte[] f) {
        MessageDigest digest;
        try {
            digest = MessageDigest.getInstance("MD5");
            digest.update(f);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        BigInteger bigInt = new BigInteger(1, digest.digest());
        return bigInt.toString(16);
    }


}