fix(analytics): recalculate delete side effects asynchronously

Move achievement and summary rebuilds out of the activity delete request path so the UI is not blocked by long-running recalculations.

Signed-off-by: Marcus Fihlon <marcus@fihlon.swiss>

src/main/java/net/javahippie/fitpub/service/ActivityDeleteRecalculationService.java

@@ -0,0 +1,30 @@
+package net.javahippie.fitpub.service;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.event.TransactionPhase;
+import org.springframework.transaction.event.TransactionalEventListener;
+
+/**
+ * Recalculates derived analytics after an activity has been deleted.
+ */
+@Service
+@RequiredArgsConstructor
+@Slf4j
+public class ActivityDeleteRecalculationService {
+
+    private final AchievementService achievementService;
+    private final ActivitySummaryService activitySummaryService;
+
+    @Async
+    @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+    public void handleActivityDeleted(ActivityDeletedEvent event) {
+        achievementService.rebuildAchievementsForUser(event.userId());
+        activitySummaryService.updateWeeklySummary(event.userId(), event.activityDate());
+        activitySummaryService.updateMonthlySummary(event.userId(), event.activityDate());
+        activitySummaryService.updateYearlySummary(event.userId(), event.activityDate());
+        log.info("Recalculated achievements and summaries after deleting activity for user {}", event.userId());
+    }
+}

src/main/java/net/javahippie/fitpub/service/ActivityDeletedEvent.java

@@ -0,0 +1,7 @@
+package net.javahippie.fitpub.service;
+
+import java.time.LocalDate;
+import java.util.UUID;
+
+public record ActivityDeletedEvent(UUID userId, LocalDate activityDate) {
+}

src/main/java/net/javahippie/fitpub/service/FitFileService.java

@@ -18,6 +18,7 @@ import net.javahippie.fitpub.util.FitFileValidator;
 import net.javahippie.fitpub.util.FitParser;
 import net.javahippie.fitpub.util.ParsedActivityData;
 import net.javahippie.fitpub.util.TrackSimplifier;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import org.springframework.web.multipart.MultipartFile;
@@ -52,6 +53,7 @@ public class FitFileService {
     private final ActivitySummaryService activitySummaryService;
     private final WeatherService weatherService;
     private final HeatmapGridService heatmapGridService;
+    private final ApplicationEventPublisher applicationEventPublisher;
 
     /**
      * Processes an uploaded FIT file and creates an activity.
@@ -319,12 +321,10 @@ public class FitFileService {
         return activityRepository.findByIdAndUserId(activityId, userId)
             .map(activity -> {
                 activityRepository.delete(activity);
-                achievementService.rebuildAchievementsForUser(userId);
                 if (activity.getStartedAt() != null) {
-                    java.time.LocalDate activityDate = activity.getStartedAt().toLocalDate();
-                    activitySummaryService.updateWeeklySummary(userId, activityDate);
-                    activitySummaryService.updateMonthlySummary(userId, activityDate);
-                    activitySummaryService.updateYearlySummary(userId, activityDate);
+                    applicationEventPublisher.publishEvent(
+                        new ActivityDeletedEvent(userId, activity.getStartedAt().toLocalDate())
+                    );
                 }
                 log.info("Deleted activity {} for user {}", activityId, userId);
                 return true;

src/test/java/net/javahippie/fitpub/service/ActivityDeleteRecalculationServiceTest.java

@@ -0,0 +1,40 @@
+package net.javahippie.fitpub.service;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.time.LocalDate;
+import java.util.UUID;
+
+import static org.mockito.Mockito.verify;
+
+@ExtendWith(MockitoExtension.class)
+class ActivityDeleteRecalculationServiceTest {
+
+    @Mock
+    private AchievementService achievementService;
+
+    @Mock
+    private ActivitySummaryService activitySummaryService;
+
+    @InjectMocks
+    private ActivityDeleteRecalculationService activityDeleteRecalculationService;
+
+    @Test
+    @DisplayName("Should rebuild achievements and summaries after activity deletion")
+    void shouldRebuildAchievementsAndSummariesAfterActivityDeletion() {
+        UUID userId = UUID.randomUUID();
+        LocalDate activityDate = LocalDate.of(2025, 12, 3);
+
+        activityDeleteRecalculationService.handleActivityDeleted(new ActivityDeletedEvent(userId, activityDate));
+
+        verify(achievementService).rebuildAchievementsForUser(userId);
+        verify(activitySummaryService).updateWeeklySummary(userId, activityDate);
+        verify(activitySummaryService).updateMonthlySummary(userId, activityDate);
+        verify(activitySummaryService).updateYearlySummary(userId, activityDate);
+    }
+}

src/test/java/net/javahippie/fitpub/service/FitFileServiceTest.java

@@ -21,6 +21,7 @@ import net.javahippie.fitpub.util.FitFileValidator;
 import net.javahippie.fitpub.util.FitParser;
 import net.javahippie.fitpub.util.ParsedActivityData;
 import net.javahippie.fitpub.util.TrackSimplifier;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.mock.web.MockMultipartFile;
 
 import java.math.BigDecimal;
@@ -74,6 +75,9 @@ class FitFileServiceTest {
     @Mock
     private HeatmapGridService heatmapGridService;
 
+    @Mock
+    private ApplicationEventPublisher applicationEventPublisher;
+
     @Spy
     private ObjectMapper objectMapper;
 
@@ -240,10 +244,10 @@ class FitFileServiceTest {
         // Assert
         assertTrue(result);
         verify(activityRepository).delete(activity);
-        verify(achievementService).rebuildAchievementsForUser(testUserId);
-        verify(activitySummaryService).updateWeeklySummary(testUserId, startedAt.toLocalDate());
-        verify(activitySummaryService).updateMonthlySummary(testUserId, startedAt.toLocalDate());
-        verify(activitySummaryService).updateYearlySummary(testUserId, startedAt.toLocalDate());
+        ArgumentCaptor<ActivityDeletedEvent> eventCaptor = ArgumentCaptor.forClass(ActivityDeletedEvent.class);
+        verify(applicationEventPublisher).publishEvent(eventCaptor.capture());
+        assertEquals(testUserId, eventCaptor.getValue().userId());
+        assertEquals(startedAt.toLocalDate(), eventCaptor.getValue().activityDate());
     }
 
     @Test
@@ -260,10 +264,7 @@ class FitFileServiceTest {
         // Assert
         assertFalse(result);
         verify(activityRepository, never()).delete(any());
-        verify(achievementService, never()).rebuildAchievementsForUser(any());
-        verify(activitySummaryService, never()).updateWeeklySummary(any(), any());
-        verify(activitySummaryService, never()).updateMonthlySummary(any(), any());
-        verify(activitySummaryService, never()).updateYearlySummary(any(), any());
+        verify(applicationEventPublisher, never()).publishEvent(any());
     }
 
     @Test