优化目录结构

backend/src/main/java/com/openisle/service/ActivityService.java

@@ -0,0 +1,56 @@
+package com.openisle.service;
+
+import com.openisle.exception.NotFoundException;
+import com.openisle.model.*;
+import com.openisle.repository.ActivityRepository;
+import com.openisle.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+@RequiredArgsConstructor
+public class ActivityService {
+    private final ActivityRepository activityRepository;
+    private final UserRepository userRepository;
+    private final LevelService levelService;
+    private final NotificationService notificationService;
+
+    public List<Activity> list() {
+        return activityRepository.findAll();
+    }
+
+    public Activity getByType(ActivityType type) {
+        Activity a = activityRepository.findByType(type);
+        if (a == null) throw new NotFoundException("Activity not found");
+        return a;
+    }
+
+    public long countLevel1Users() {
+        int threshold = levelService.nextLevelExp(0);
+        return userRepository.countByExperienceGreaterThanEqual(threshold);
+    }
+
+    public void end(Activity activity) {
+        activity.setEnded(true);
+        activityRepository.save(activity);
+    }
+
+    public long countParticipants(Activity activity) {
+        return activity.getParticipants().size();
+    }
+
+    /**
+     * Redeem an activity for the given user.
+     *
+     * @return true if the user redeemed for the first time, false if the
+     *         information was simply updated
+     */
+    public boolean redeem(Activity activity, User user, String contact) {
+        notificationService.createActivityRedeemNotifications(user, contact);
+        boolean added = activity.getParticipants().add(user);
+        activityRepository.save(activity);
+        return added;
+    }
+}