package org.springblade.modules.signature.util;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springblade.common.utils.HttpClientUtils;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.util.*;

/**
 * sign 生成工具类
 * @author zhongrj
 * @since 2022-03-11
 */
public class SignUtil {

	private static Logger LOGGER = LoggerFactory.getLogger(SignUtil.class);


	/**
	 * 获取签名sign
	 * @param params 参数集合不含appSecret
	 * @param secret 验证接口的appSecret
	 * @return
	 */
	public static String getSign(Map params,String secret)
	{
		String sign="";
		StringBuilder sb = new StringBuilder();
		//1. 先对请求参数排序
		Set<String> keyset=params.keySet();
		TreeSet<String> sortSet=new TreeSet<>();
		sortSet.addAll(keyset);
		Iterator<String> it=sortSet.iterator();
		//2. 把参数的key value链接起来 ,再把appSecret拼接参数字符串的最后面，得到要加密的字符串
		while(it.hasNext())
		{
			String key=it.next();
			String value=params.get(key).toString();
			sb.append(key).append(value);
		}
		sb.append(secret);
		byte[] md5Digest;
		try {
			//3. Md5加密
			md5Digest = getMD5Digest(sb.toString());
			//4.得到sign
			sign = byte2hex(md5Digest);
		} catch (IOException e) {
			LOGGER.error("生成签名错误",e);
		}
		// 5. 返回 sign
		return sign;
	}


	/**
	 * 回调接口验证签名方法
	 * @param request
	 * @return
	 */
	public static Boolean checkSign(HttpServletRequest request,String appSecret){
		Boolean flag= false;
		String sign = request.getParameter("sign");//签名
		if(StringUtils.isEmpty(sign)){
			return false;
		}
		//检查sign是否过期
		Enumeration<?> pNames =  request.getParameterNames();
		Map<String, String> params = new HashMap<>();
		while (pNames.hasMoreElements()) {
			String pName = (String) pNames.nextElement();
			if("sign".equals(pName)) {
				continue;
			}
			String pValue = request.getParameter(pName);
			params.put(pName, pValue);
		}
		if(sign.equals(getSign(params, appSecret))){
			flag = true;
		}
		return flag;
	}

	/**
	 * MD5加密数据方法
	 */
	private static byte[] getMD5Digest(String data) throws IOException {
		byte[] bytes = null;
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			bytes = md.digest(data.getBytes("UTF-8"));
		} catch (GeneralSecurityException gse) {
			throw new IOException(gse);
		}
		return bytes;
	}

	/**
	 * MD5加密数据后的数据处理方法
	 */
	private static String byte2hex(byte[] bytes) {
		StringBuilder sign = new StringBuilder();
		for (int i = 0; i < bytes.length; i++) {
			String hex = Integer.toHexString(bytes[i] & 0xFF);
			if (hex.length() == 1) {
				sign.append("0");
			}
			sign.append(hex.toUpperCase());
		}
		return sign.toString();
	}



	public static String utf8Encoding(String value, String sourceCharsetName) {
		try {
			return new String(value.getBytes(sourceCharsetName), "UTF-8");
		} catch (UnsupportedEncodingException e) {
			throw new IllegalArgumentException(e);
		}
	}

	/**
	 测试方法
	 */
	public static void main(String[] args)
	{
		//参数签名算法测试例子
		HashMap<String, String> signMap = new HashMap<String, String>();
		String appkey = "584561146";
		signMap.put("appKey",appkey);

//		System.out.println("得到签名sign1:"+getSign(signMap,"454sd5fa45dsa5fdaf54"));
		String sign = getSign(signMap, "454sd5fa45dsa5fdaf54");
		signMap.put("sign",sign);
		HttpClientUtils.postParams("http://localhost:81/attendance/AppSave", appkey, signMap);
	}
}