package cn.efunbox.audio.utils;

import org.apache.commons.lang.StringUtils;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;

/**
 * SecurityUtils
 * Created by xusq on 2018/9/11.
 */
public class SecurityUtils {

    private SecurityUtils(){}

    public static final String MD5 = "MD5";

    public static final String SIGN = "sign";

    public static char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

    public static String createMD5Sign(Map<String, String> paramMap, String signKey) {

        List<String> sortedKeys = new ArrayList<String>();
        for (Map.Entry<String, String> entry : paramMap.entrySet()) {
            if (SIGN.equals(entry.getKey())) {
                continue;
            }

            sortedKeys.add(entry.getKey());
        }

        if (sortedKeys.size() == 0) {
            // 没有参数
            return "";
        }

        Collections.sort(sortedKeys);

        StringBuffer buff = new StringBuffer("");
        for (String key : sortedKeys) {
            String val = paramMap.get(key);
            if (StringUtils.isBlank(val)) {
                continue;
            }

            buff.append(key).append("=").append(val).append("&");
        }

        buff.append("key=").append(signKey);

        try {
            return SecurityUtils.MD5(buff.toString(), null);
        } catch (Exception e) {
            throw new RuntimeException("签名错误");
        }
    }


    /**
     * MD5摘要算法
     *
     * @param content
     *            摘要内容
     * @param charset
     *            字符集，默认为UTF-8
     * @return
     * @throws Exception
     */
    public static String MD5(String content, String charset){
        if (charset == null) {
            charset = "UTF-8";
        }

        MessageDigest digest = null;
        try {
            digest = MessageDigest.getInstance(MD5);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        try {
            digest.update(content.getBytes(charset)); // 使用指定的字节更新摘要
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        byte[] md = digest.digest(); // 获得密文

        return byteToHexString(md);
    }

    // 把密文转换成十六进制的字符串形式
    public static String byteToHexString(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (byte b : bytes) {
            sb.append(byteToHexString(b));
        }

        return sb.toString();
    }

    public static String byteToHexString(byte ib) {
        char[] ob = new char[2];
        ob[0] = hexDigits[(ib >>> 4) & 0X0f];
        ob[1] = hexDigits[ib & 0X0F];
        return new String(ob);
    }

    public static void main(String[] args) {

        Map<String,String> param = new HashMap<>();

        param.put("idChannel","1001");
        param.put("idDevice","10011");
        String test = SecurityUtils.createMD5Sign(param, "IhOTiTyMLDNNLFuP");
        System.out.println(test);


    }
}