package com.liquidnet.service.sweet.utils;

import org.springframework.beans.factory.annotation.Value;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

/**
 * <p>
 * 微信开发者签名验证
 * </p>
 *
 * @author jiangxiulong
 * @since 2021-07-29 3:19 下午
 */
public class WechatSignUtils {

    // 与接口配置信息中的 Token 要一致
    @Value("${liquidnet.wechat.zhengzai.service.token}")
    private static String token;

    /**
     * 验证签名
     *
     * @param signature
     * @param timestamp
     * @param nonce
     * @return
     */
    public static boolean checkSignature(String signature, String timestamp, String nonce) {
        String[] arr = new String[]{token, timestamp, nonce};
        // 将 token、timestamp、nonce 三个参数进行字典序排序
        Arrays.sort(arr);
        StringBuilder content = new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            content.append(arr[i]);
        }
        MessageDigest md = null;
        String tmpStr = null;

        try {
            md = MessageDigest.getInstance("SHA-1");
            // 将三个参数字符串拼接成一个字符串进行 sha1 加密
            byte[] digest = md.digest(content.toString().getBytes());
            tmpStr = byteToStr(digest);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        content = null;
        // 将 sha1 加密后的字符串可与 signature 对比，标识该请求来源于微信
        return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
    }

    /**
     * 将字节数组转换为十六进制字符串
     *
     * @param byteArray
     * @return
     */
    private static String byteToStr(byte[] byteArray) {
        String strDigest = "";
        for (int i = 0; i < byteArray.length; i++) {
            strDigest += byteToHexStr(byteArray[i]);
        }
        return strDigest;
    }

    /**
     * 将字节转换为十六进制字符串
     *
     * @param mByte
     * @return
     */
    private static String byteToHexStr(byte mByte) {
        char[] Digit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        char[] tempArr = new char[2];
        tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
        tempArr[1] = Digit[mByte & 0X0F];
        String s = new String(tempArr);
        return s;
    }
}