Implement event completion workflow (Task 14)

- Add completeEvent endpoint to backend API
- Create EventCompletionForm component with litter quantity input and photo upload
- Update EventDetailModal to show completion form for organizers
- Add isOrganizer check in EventsPage
- Update event service to support completion
- Display completion data (litter collected, photos) for completed events

server/src/controllers/eventController.ts

@@ -343,4 +343,66 @@ export const eventController = {
       });
     }
   },
+
+  // Complete event
+  async completeEvent(req: AuthRequest, res: Response) {
+    try {
+      const clerkId = req.userId;
+      if (!clerkId) {
+        return res.status(401).json({
+          code: 'UNAUTHORIZED',
+          message: 'User not authenticated',
+          timestamp: new Date().toISOString(),
+        });
+      }
+
+      const userId = await findOrCreateUser(clerkId);
+
+      const { id } = req.params;
+      const event = await eventService.getEventById(id);
+
+      if (!event) {
+        return res.status(404).json({
+          code: 'EVENT_NOT_FOUND',
+          message: 'Event not found',
+          timestamp: new Date().toISOString(),
+        });
+      }
+
+      // Check if user is the organizer
+      if (event.organizerId !== userId) {
+        return res.status(403).json({
+          code: 'FORBIDDEN',
+          message: 'Only the event organizer can complete this event',
+          timestamp: new Date().toISOString(),
+        });
+      }
+
+      const { litterCollected, photos } = req.body;
+
+      // Validation
+      if (litterCollected === undefined || litterCollected === null) {
+        return res.status(400).json({
+          code: 'VALIDATION_ERROR',
+          message: 'litterCollected is required',
+          timestamp: new Date().toISOString(),
+        });
+      }
+
+      const completedEvent = await eventService.completeEvent(id, {
+        litterCollected: parseFloat(litterCollected),
+        photos: photos || [],
+      });
+
+      res.json(completedEvent);
+    } catch (error: any) {
+      console.error('Error completing event:', error);
+      res.status(500).json({
+        code: 'COMPLETE_EVENT_ERROR',
+        message: 'Failed to complete event',
+        details: error.message,
+        timestamp: new Date().toISOString(),
+      });
+    }
+  },
 };

server/src/routes/eventRoutes.ts

@@ -16,5 +16,6 @@ router.delete('/:id', requireAuth, eventController.deleteEvent);
 router.post('/:id/register', requireAuth, eventController.registerForEvent);
 router.delete('/:id/register', requireAuth, eventController.unregisterFromEvent);
 router.get('/:id/registration-status', requireAuth, eventController.getRegistrationStatus);
+router.post('/:id/complete', requireAuth, eventController.completeEvent);
 
 export default router;

server/src/services/eventService.ts

@@ -324,4 +324,40 @@ export const eventService = {
 
     return !!registration;
   },
+
+  async completeEvent(eventId: string, data: { litterCollected: number; photos?: string[] }) {
+    const event = await prisma.event.update({
+      where: { id: eventId },
+      data: {
+        status: 'completed',
+        litterCollected: data.litterCollected,
+        photos: data.photos || [],
+      },
+      include: {
+        _count: {
+          select: {
+            registrations: true,
+          },
+        },
+      },
+    });
+
+    return {
+      id: event.id,
+      organizerId: event.organizerId,
+      title: event.title,
+      description: event.description,
+      latitude: parseFloat(event.latitude.toString()),
+      longitude: parseFloat(event.longitude.toString()),
+      locationName: event.locationName,
+      scheduledDate: event.scheduledDate,
+      duration: event.duration,
+      status: event.status || 'upcoming',
+      participantCount: event._count.registrations,
+      litterCollected: event.litterCollected ? parseFloat(event.litterCollected.toString()) : undefined,
+      photos: event.photos ? (Array.isArray(event.photos) ? event.photos : []) : undefined,
+      createdAt: event.createdAt,
+      updatedAt: event.updatedAt,
+    };
+  },
 };