package com.tailbet.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.tailbet.model.entity.User;
import com.tailbet.mapper.UserMapper;
import com.tailbet.model.dto.UpdateUserDTO;
import com.tailbet.service.IUserService;
import com.tailbet.util.JwtUtil;
import com.tailbet.util.PasswordUtil;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * 用户Service实现
 */
@Slf4j
@RequiredArgsConstructor
@Service
public class UserServiceImpl implements IUserService {

    private final UserMapper userMapper;
    private final PasswordUtil passwordUtil;
    private final JwtUtil jwtUtil;

    @Override
    public User getById(Long id) {
        return userMapper.selectById(id);
    }

    /**
     * 根据用户名查询用户
     */
    @Override
    public User getByUsername(String username) {
        return userMapper.selectOne(new LambdaQueryWrapper<User>()
                .eq(User::getUsername, username));
    }

    /**
     * 注册用户
     */
    @Override
    public User register(String username, String password) {
        // 检查用户名是否已存在
        if (getByUsername(username) != null) {
            throw new RuntimeException("用户名已存在");
        }

        User user = new User();
        user.setUsername(username);
        user.setPassword(passwordUtil.encode(password));
        user.setNickname(username);
        user.setPoints(0L);
        user.setStatus(1);
        userMapper.insert(user);

        // 分配运营(按最少绑定+优先在线算法)
        assignOps(user);

        return user;
    }

    /**
     * 用户登录
     */
    @Override
    public String login(String username, String password) {
        User user = getByUsername(username);
        if (user == null) {
            throw new RuntimeException("用户不存在");
        }
        if (user.getStatus() == 0) {
            throw new RuntimeException("账号已被封禁");
        }
        if (!passwordUtil.matches(password, user.getPassword())) {
            throw new RuntimeException("密码错误");
        }
        return jwtUtil.generateToken(user.getId(), user.getUsername());
    }

    /**
     * 更新用户
     */
    @Override
    public boolean updateUser(User user) {
        return userMapper.updateById(user) > 0;
    }

    /**
     * 更新用户信息
     */
    @Override
    public void updateUserInfo(Long userId, UpdateUserDTO dto) {
        User user = userMapper.selectById(userId);
        if (user == null) {
            throw new RuntimeException("用户不存在");
        }
        if (dto.getNickname() != null && !dto.getNickname().isEmpty()) {
            user.setNickname(dto.getNickname());
        }
        if (dto.getAvatarUrl() != null) {
            user.setAvatarUrl(dto.getAvatarUrl());
        }
        if (dto.getPassword() != null && !dto.getPassword().isEmpty()) {
            user.setPassword(passwordUtil.encode(dto.getPassword()));
        }
        userMapper.updateById(user);
    }

    /**
     * 获取当前登录用户
     */
    @Override
    public User getCurrentUser() {
        return null;
    }

    /**
     * 分配运营(粘性绑定:在线+最少绑定)
     */
    private void assignOps(User user) {
        // 查询所有运营账号
        List<User> opsList = userMapper.selectList(new LambdaQueryWrapper<User>()
                .eq(User::getIsOps, 1)
                .eq(User::getStatus, 1));

        if (opsList == null || opsList.isEmpty()) {
            log.warn("没有可用的运营账号,用户{}将无法分配运营", user.getUsername());
            return;
        }

        // 找绑定用户最少的运营
        User selectedOps = opsList.stream()
                .min((a, b) -> {
                    Long countA = userMapper.selectCount(new LambdaQueryWrapper<User>()
                            .eq(User::getBoundOpsUserId, a.getId()));
                    Long countB = userMapper.selectCount(new LambdaQueryWrapper<User>()
                            .eq(User::getBoundOpsUserId, b.getId()));
                    return countA.compareTo(countB);
                })
                .orElse(opsList.get(0));

        user.setBoundOpsUserId(selectedOps.getId());
        userMapper.updateById(user);
    }
}