package edu.whut.smilepicturebackend.service.impl;
import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import edu.whut.smilepicturebackend.constant.UserConstant;
import edu.whut.smilepicturebackend.exception.BusinessException;
import edu.whut.smilepicturebackend.exception.ErrorCode;
import edu.whut.smilepicturebackend.model.entity.User;
import edu.whut.smilepicturebackend.model.enums.UserRoleEnum;
import edu.whut.smilepicturebackend.model.vo.LoginUserVO;
import edu.whut.smilepicturebackend.service.UserService;
import edu.whut.smilepicturebackend.mapper.UserMapper;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletRequest;


/**
* @author 张三
* @description 针对表【user(用户)】的数据库操作Service实现
* @createDate 2025-06-05 17:43:52
*/
@Service
@Slf4j
@RequiredArgsConstructor
public class UserServiceImpl extends ServiceImpl<UserMapper, User>
    implements UserService{
    private final BCryptPasswordEncoder passwordEncoder;
    /**
     * 用户注册
     *
     * @param userAccount   用户账户
     * @param userPassword  用户密码
     * @param checkPassword 校验密码
     * @return
     */
    @Override
    public long userRegister(String userAccount, String userPassword, String checkPassword) {
        // 1. 校验参数
        if (StrUtil.hasBlank(userAccount, userPassword, checkPassword)) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "参数为空");
        }
        if (userAccount.length() < 4) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "用户账号过短");
        }
        if (userPassword.length() < 8 || checkPassword.length() < 8) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "用户密码过短");
        }
        if (!userPassword.equals(checkPassword)) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "两次输入的密码不一致");
        }
        // 2. 检查用户账号是否和数据库中已有的重复
        LambdaQueryWrapper<User> lambda = Wrappers.lambdaQuery();
        lambda.eq(User::getUserAccount, userAccount);
        long count = this.baseMapper.selectCount(lambda);
        if (count > 0) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "账号重复");
        }
        // 3. 密码一定要加密
        String encryptPassword = getEncryptPassword(userPassword);
        // 4. 插入数据到数据库中
        User user = new User();
        user.setUserAccount(userAccount);
        user.setUserPassword(encryptPassword);
        user.setUserName("无名");
        user.setUserRole(UserRoleEnum.USER.getValue());
        boolean saveResult = this.save(user);
        if (!saveResult) {
            throw new BusinessException(ErrorCode.SYSTEM_ERROR, "注册失败，数据库错误");
        }
        return user.getId();
    }
    /**
     * 获取加密后的密码
     *
     * @param userPassword 用户密码
     * @return 加密后的密码
     */
    @Override
    public String getEncryptPassword(String userPassword) {
        return passwordEncoder.encode(userPassword);
//        // 加盐，混淆密码
//        final String SALT = "smile12306";
//        return DigestUtils.md5DigestAsHex((SALT + userPassword).getBytes());
    }

    @Override
    public LoginUserVO userLogin(String userAccount, String userPassword, HttpServletRequest request) {
        // 1. 校验
        if (StrUtil.hasBlank(userAccount, userPassword)) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "参数为空");
        }
        if (userAccount.length() < 4) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "用户账号错误");
        }
        if (userPassword.length() < 8) {
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "用户密码错误");
        }
        // 2. 对用户传递的密码进行加密
        String encryptPassword = getEncryptPassword(userPassword);
        // 3. 查询数据库中的用户是否存在
        LambdaQueryWrapper<User> lambda = new LambdaQueryWrapper<>();
        lambda
                .eq(User::getUserAccount, userAccount)
                .eq(User::getUserPassword, encryptPassword);
        User user = this.baseMapper.selectOne(lambda);
        // 不存在，抛异常
        if (user == null) {
            log.info("user login failed, userAccount cannot match userPassword");
            throw new BusinessException(ErrorCode.PARAMS_ERROR, "用户不存在或者密码错误");
        }
        // 4. 保存用户的登录态
        request.getSession().setAttribute(UserConstant.USER_LOGIN_STATE, user);
        return this.getLoginUserVO(user);

    }
    /**
     * 获取脱敏类的用户信息
     *
     * @param user 用户
     * @return 脱敏后的用户信息
     */
    @Override
    public LoginUserVO getLoginUserVO(User user) {
        if (user == null) {
            return null;
        }
        LoginUserVO loginUserVO = new LoginUserVO();
        BeanUtil.copyProperties(user, loginUserVO);
        return loginUserVO;
    }

    @Override
    public User getLoginUser(HttpServletRequest request) {
        // 判断是否已经登录
        Object userObj = request.getSession().getAttribute(UserConstant.USER_LOGIN_STATE);
        User currentUser = (User) userObj;
        if (currentUser == null || currentUser.getId() == null) {
            throw new BusinessException(ErrorCode.NOT_LOGIN_ERROR);
        }
        // 从数据库中查询（追求性能的话可以注释，直接返回上述结果）
        Long userId = currentUser.getId();
        currentUser = this.getById(userId);
        if (currentUser == null) {
            throw new BusinessException(ErrorCode.NOT_LOGIN_ERROR);
        }
        return currentUser;
    }

    /**
     * 退出登录
     *
     * @param request
     * @return
     */
    @Override
    public boolean userLogout(HttpServletRequest request) {
        // 判断是否已经登录
        Object userObj = request.getSession().getAttribute(UserConstant.USER_LOGIN_STATE);
        if (userObj == null) {
            throw new BusinessException(ErrorCode.OPERATION_ERROR, "未登录");
        }
        // 移除登录态
        request.getSession().removeAttribute(UserConstant.USER_LOGIN_STATE);
        return true;
    }
}