src/main/java/com/pt/service/UserService.java

package com.pt.service;

import com.pt.entity.User;
import com.pt.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    public User findByUsername(String username) {
        return userRepository.findByUsername(username);
    }

    public User findByEmail(String email) {
        return userRepository.findByEmail(email);
    }

    public User findByUsernameAndPassword(String username, String password) {
        return userRepository.findByUsernameAndPassword(username, password);
    }

    public User findByEmailAndPassword(String email, String password) {
        return userRepository.findByEmailAndPassword(email, password);
    }

    public User save(User user) {
        return userRepository.save(user);
    }

    public User findById(String uid) {
        return userRepository.findById(uid).orElse(null);
    }

    public void deleteById(String uid) {
        userRepository.deleteById(uid);
    }

    public List<User> listAll() {
        return userRepository.findAll();
    }

    /**
     * 根据用户的统计数据（上传量、下载量、积分）更新其等级。
     * 该方法包含等级提升的规则，且只升不降。
     * @param userId 要更新等级的用户的ID
     */
    public void updateUserLevel(String userId) {
        User user = userRepository.findById(userId).orElse(null);
        if (user == null) {
            // 在实际应用中，这里可能需要记录日志或抛出异常
            return;
        }

        long uploaded = user.getUploaded();
        long downloaded = user.getDownloaded();
        int points = user.getPoints();

        // 定义数据大小常量
        final long GB = 1024L * 1024L * 1024L;
        final long TB = 1024L * GB;

        // 计算分享率。如果下载量为0，分享率视为无限大（只要有上传）
        double shareRatio = (downloaded == 0 && uploaded > 0) ? Double.MAX_VALUE :
                            (downloaded == 0 && uploaded == 0) ? 0 : (double) uploaded / downloaded;

        int newLevel = 1; // 默认为1级

        // 等级规则（从高到低判断）
        // 规则5: 大佬级
        if (uploaded > 5 * TB && shareRatio > 2.0 && points > 10000) {
            newLevel = 5;
        }
        // 规则4: 专家级
        else if (uploaded > 1 * TB && shareRatio > 1.5 && points > 2000) {
            newLevel = 4;
        }
        // 规则3: 熟练级
        else if (uploaded > 200 * GB && shareRatio > 1.0 && points > 500) {
            newLevel = 3;
        }
        // 规则2: 入门级 (获得发布权限)
        else if (uploaded > 50 * GB && shareRatio > 0.5 && points > 100) {
            newLevel = 2;
        }

        // 如果计算出的新等级高于当前等级，则更新用户等级
        if (newLevel > user.getLevel()) {
            user.setLevel(newLevel);
            userRepository.save(user);
        }
    }

    /**
     * 批量更新所有用户的等级。
     * 适合用于定时任务，定期刷新所有用户的等级。
     */
    public void updateAllUsersLevel() {
        List<User> allUsers = userRepository.findAll();
        for (User user : allUsers) {
            updateUserLevel(user.getUid());
        }
    }
}