package com.yunzhupaas.message.service.impl;

import com.yunzhupaas.base.service.SuperServiceImpl;
import com.yunzhupaas.message.entity.ShortLinkEntity;
import com.yunzhupaas.message.mapper.ShortLInkMapper;
import com.yunzhupaas.message.service.ShortLinkService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;


import com.yunzhupaas.permission.service.AuthorizeService;


import org.springframework.stereotype.Service;
import org.springframework.beans.factory.annotation.Autowired;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;

import com.yunzhupaas.util.*;

import java.security.MessageDigest;
import java.util.*;

/**
 * 消息模板（新）
 * 版本： V3.2.0
 * 版权： 深圳市乐程软件有限公司（http://www.szlecheng.cn）
 * 作者： 云筑产品开发平台组
 * 日期： 2022-08-18
 */
@Service
public class ShortLinkServiceImpl extends SuperServiceImpl<ShortLInkMapper, ShortLinkEntity> implements ShortLinkService {


    @Override
    public ShortLinkEntity getInfoByLink(String link){
        QueryWrapper<ShortLinkEntity> queryWrapper = new QueryWrapper<>();
        queryWrapper.lambda().eq(ShortLinkEntity::getShortLink,link);
        return this.getOne(queryWrapper);
    }


    @Override
    public String shortLink (String link){
        String shortUrl = null;
        if(StringUtil.isNotBlank(link)) {
            String[] aResult = shortUrl(link);//将产生4组6位字符串
            // 打印出结果
            Random random = new Random();
            int j = random.nextInt(4);//产成4以内随机数
            shortUrl = aResult[j];
            if(StringUtil.isNotBlank(shortUrl)) {
                QueryWrapper<ShortLinkEntity> queryWrapper = new QueryWrapper<>();
                if (StringUtil.isNotEmpty(shortUrl)) {
                    queryWrapper.lambda().eq(ShortLinkEntity::getShortLink, shortUrl);
                }
                if (this.list(queryWrapper) != null && this.list(queryWrapper).size() > 0) {
                    shortUrl = shortUrl + j;
                }
            }
        }
        return shortUrl;
    }


    public static String[] shortUrl(String url) {
        // 可以自定义生成 MD5 加密字符传前的混合 KEY
        String key = "test";
        // 要使用生成 URL 的字符
        String[] chars = new String[] { "a", "b", "c", "d", "e", "f", "g", "h",
                "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t",
                "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", "5",
                "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H",
                "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T",
                "U", "V", "W", "X", "Y", "Z"

        };
        // 对传入网址进行 MD5 加密
        String hex = md5ByHex(key + url);

        String[] resUrl = new String[4];
        for (int i = 0; i < 4; i++) {

            // 把加密字符按照 8 位一组 16 进制与 0x3FFFFFFF 进行位与运算
            String sTempSubString = hex.substring(i * 8, i * 8 + 8);

            // 这里需要使用 long 型来转换，因为 Inteper .parseInt() 只能处理 31 位 , 首位为符号位 , 如果不用long ，则会越界
            long lHexLong = 0x3FFFFFFF & Long.parseLong(sTempSubString, 16);
            String outChars = "";
            for (int j = 0; j < 6; j++) {
                // 把得到的值与 0x0000003D 进行位与运算，取得字符数组 chars 索引
                long index = 0x0000003D & lHexLong;
                // 把取得的字符相加
                outChars += chars[(int) index];
                // 每次循环按位右移 5 位
                lHexLong = lHexLong >> 5;
            }
            // 把字符串存入对应索引的输出数组
            resUrl[i] = outChars;
        }
        return resUrl;
    }
    /**
     * MD5加密(32位大写)
     * @param src
     * @return
     */
    public static String md5ByHex(String src) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] b = src.getBytes();
            md.reset();
            md.update(b);
            byte[] hash = md.digest();
            String hs = "";
            String stmp = "";
            for (int i = 0; i < hash.length; i++) {
                stmp = Integer.toHexString(hash[i] & 0xFF);
                if (stmp.length() == 1)
                    hs = hs + "0" + stmp;
                else {
                    hs = hs + stmp;
                }
            }
            return hs.toUpperCase();
        } catch (Exception e) {
            return "";
        }
    }
}

