package top.baogutang.music.service.impl;

import com.baomidou.mybatisplus.extension.conditions.query.LambdaQueryChainWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import top.baogutang.music.dao.entity.UserEntity;
import top.baogutang.music.dao.mapper.UserMapper;
import top.baogutang.music.domain.req.user.UserRegisterAndLoginReq;
import top.baogutang.music.domain.res.user.UserLoginRes;
import top.baogutang.music.enums.UserLevel;
import top.baogutang.music.enums.UserRole;
import top.baogutang.music.exceptions.BusinessException;
import top.baogutang.music.exceptions.LoginException;
import top.baogutang.music.service.IUserService;
import top.baogutang.music.utils.CacheUtil;
import top.baogutang.music.utils.TokenUtil;

import javax.annotation.Resource;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.time.LocalDateTime;
import java.util.Objects;
import java.util.concurrent.TimeUnit;

import static top.baogutang.music.constants.CacheKey.KEY_LOGIN_PREFIX;
import static top.baogutang.music.constants.CacheKey.LOCK_REGISTER_PREFIX;

/**
 *
 * @description:
 *
 * @author: N1KO
 * @date: 2024/12/13 : 16:44
 */
@Slf4j
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, UserEntity> implements IUserService {

    @Resource
    private RedisTemplate<String, Object> redisTemplate;

    @Override
    public void register(UserRegisterAndLoginReq req) {
        // 校验
        UserEntity existsUser = this.validate(req);
        if (Objects.nonNull(existsUser)) {
            throw new BusinessException("当前用户名已被注册");
        }
        // 密码加密
        UserEntity user = new UserEntity();
        user.setUsername(req.getUsername());
        user.setPassword(encryptPassword(req.getPassword()));
        user.setRole(UserRole.NORMAL);
        user.setLevel(UserLevel.NORMAL);
        user.setCreateTime(LocalDateTime.now());
        save(user);
    }

    @Override
    public UserLoginRes login(UserRegisterAndLoginReq req) {
        UserEntity existsUser = this.validate(req);
        if (Objects.isNull(existsUser)) {
            throw new BusinessException("用户不存在");
        }
        boolean checkRes = this.verifyPassword(req.getPassword(), existsUser.getPassword());
        if (!Boolean.TRUE.equals(checkRes)) {
            throw new LoginException("用户名或密码错误");
        }
        UserLoginRes loginRes = new UserLoginRes();
        loginRes.setId(existsUser.getId());
        loginRes.setUsername(existsUser.getUsername());
        loginRes.setLevel(existsUser.getLevel());
        loginRes.setRole(existsUser.getRole());
        // 生成token
        String token = TokenUtil.token(existsUser.getId(), loginRes.getUsername());
        redisTemplate.opsForValue().set(KEY_LOGIN_PREFIX + existsUser.getId(), token, 86400000, TimeUnit.MILLISECONDS);
        loginRes.setToken(token);
        return loginRes;
    }

    @Override
    public void logout(Long id) {
        redisTemplate.delete(KEY_LOGIN_PREFIX + id);
    }

    private UserEntity validate(UserRegisterAndLoginReq req) {
        if (StringUtils.isBlank(req.getUsername())) {
            throw new BusinessException("用户名不能为空");
        }
        if (StringUtils.isBlank(req.getPassword())) {
            throw new BusinessException("密码不能为空");
        }
        if (req.getPassword().length() < 6 || req.getPassword().length() > 16) {
            throw new BusinessException("密码长度不合规");
        }
        if (req.getUsername().length() < 4 || req.getUsername().length() > 12) {
            throw new BusinessException("用户名长度不合规");
        }
        return new LambdaQueryChainWrapper<>(baseMapper)
                .eq(UserEntity::getUsername, req.getUsername())
                .eq(UserEntity::getDeleted, Boolean.FALSE)
                .last(" limit 1")
                .one();
    }

    // 密码加密方法
    public String encryptPassword(String password) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(password.getBytes());
            byte[] digest = md.digest();
            StringBuilder sb = new StringBuilder();
            for (byte b : digest) {
                sb.append(String.format("%02x", b & 0xff));
            }
            return sb.toString();
        } catch (NoSuchAlgorithmException e) {
            throw new BusinessException("请稍后再试");
        }
    }

    // 登录验证方法
    public boolean verifyPassword(String inputPassword, String encryptedPassword) {
        String inputEncryptedPassword = encryptPassword(inputPassword);
        return encryptedPassword.equals(inputEncryptedPassword);
    }
}