package com.xuekairui.user.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.xuekairui.common.BusinessException;
import com.xuekairui.common.ErrorCode;
import com.xuekairui.user.dto.AdminUserResponse;
import com.xuekairui.user.dto.UpdateRoleRequest;
import com.xuekairui.user.entity.User;
import com.xuekairui.user.enums.UserRole;
import com.xuekairui.user.mapper.UserMapper;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.Objects;

/**
 * 运营用户管理服务
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class AdminUserService {

    private final UserMapper userMapper;

    /**
     * 分页查询用户列表（支持按ID精确/手机号模糊/昵称模糊/角色精确查询）
     * 无删除接口，用户数据不可删除。
     */
    public Page<AdminUserResponse> listUsers(Integer pageNum, Integer pageSize,
                                              Long userId, String phone, String nickname, String role) {
        Page<User> page = new Page<>(pageNum, pageSize);
        LambdaQueryWrapper<User> wrapper = new LambdaQueryWrapper<>();
        if (userId != null) {
            wrapper.eq(User::getId, userId);
        }
        if (phone != null && !phone.isBlank()) {
            wrapper.like(User::getPhone, phone);
        }
        if (nickname != null && !nickname.isBlank()) {
            wrapper.like(User::getNickname, nickname);
        }
        if (role != null && !role.isBlank()) {
            wrapper.eq(User::getRole, UserRole.fromCode(role));
        }
        wrapper.orderByDesc(User::getCreateTime);

        Page<User> userPage = userMapper.selectPage(page, wrapper);
        Page<AdminUserResponse> resultPage = new Page<>(userPage.getCurrent(), userPage.getSize(), userPage.getTotal());
        resultPage.setRecords(userPage.getRecords().stream()
                .map(this::toResponse)
                .toList());
        return resultPage;
    }

    /**
     * 修改用户角色（仅超级管理员可调用）
     */
    @Transactional
    public AdminUserResponse updateUserRole(Long userId, UpdateRoleRequest request, Long operatorId) {
        User user = userMapper.selectById(userId);
        if (user == null) {
            throw new BusinessException(ErrorCode.USER_NOT_FOUND);
        }

        UserRole targetRole = UserRole.fromCode(request.getRole());
        UserRole currentRole = user.getRole() != null ? user.getRole() : UserRole.USER;

        // 禁止取消最后一个超级管理员
        if (currentRole == UserRole.SUPER_ADMIN && targetRole != UserRole.SUPER_ADMIN) {
            long otherSuperAdminCount = userMapper.selectCount(
                    new LambdaQueryWrapper<User>()
                            .eq(User::getRole, UserRole.SUPER_ADMIN)
                            .ne(User::getId, userId));
            if (otherSuperAdminCount == 0) {
                throw new BusinessException(ErrorCode.BUSINESS_ERROR, "系统中至少保留一个超级管理员");
            }
        }

        // 防止操作人取消自己的超级管理员权限后系统无超级管理员
        if (Objects.equals(operatorId, userId)
                && currentRole == UserRole.SUPER_ADMIN
                && targetRole != UserRole.SUPER_ADMIN) {
            throw new BusinessException(ErrorCode.BUSINESS_ERROR, "不能取消自己的超级管理员权限");
        }

        user.setRole(targetRole);
        userMapper.updateById(user);
        log.info("操作人{}修改用户{}角色为{}", operatorId, userId, targetRole.getCode());
        return toResponse(user);
    }

    /**
     * 强制踢出用户（递增 tokenVersion，所有 Token 立即失效）
     */
    public void kickUser(Long userId, Long operatorId) {
        User user = userMapper.selectById(userId);
        if (user == null) {
            throw new BusinessException(ErrorCode.USER_NOT_FOUND);
        }
        long newVersion = (user.getTokenVersion() != null ? user.getTokenVersion() : 0L) + 1;
        user.setTokenVersion(newVersion);
        // 同时清空 Refresh Token，防止旧 Refresh Token 还能刷新
        user.setRefreshTokenHash(null);
        user.setRefreshTokenStatus(null);
        userMapper.updateById(user);
        log.info("管理员{}强制踢出用户{}，新tokenVersion={}", operatorId, userId, newVersion);
    }

    private AdminUserResponse toResponse(User user) {
        return AdminUserResponse.builder()
                .id(user.getId())
                .phone(user.getPhone())
                .nickname(user.getNickname())
                .role(user.getRole() != null ? user.getRole().getCode() : UserRole.USER.getCode())
                .status(user.getStatus())
                .createTime(user.getCreateTime())
                .build();
    }
}