Add event counting methods and generic pagination schema

Introduce methods to count user, public, and upcoming events to enhance CRUD functionality for events. Additionally, add a `PaginatedResponse` schema to simplify and standardize paginated API responses. These updates support improved data querying and response handling.

backend/app/crud/event.py

@@ -2,7 +2,7 @@ from datetime import timezone
 from typing import List, Optional, Union, Dict, Any
 from uuid import UUID
 
-from sqlalchemy import desc
+from sqlalchemy import desc, func
 from sqlalchemy.orm import Session
 
 from app.crud.base import CRUDBase
@@ -32,6 +32,21 @@ class CRUDEvent(CRUDBase[Event, EventCreate, EventUpdate]):
 
         return query.order_by(desc(Event.event_date)).offset(skip).limit(limit).all()
 
+    def count_user_events(
+            self,
+            db: Session,
+            *,
+            user_id: UUID,
+            include_inactive: bool = False
+    ) -> int:
+        """Count total events created by a specific user."""
+        query = db.query(func.count(Event.id)).filter(Event.created_by == user_id)
+
+        if not include_inactive:
+            query = query.filter(Event.is_active == True)
+
+        return query.scalar()
+
     def create_with_owner(
             self,
             db: Session,
@@ -83,6 +98,51 @@ class CRUDEvent(CRUDBase[Event, EventCreate, EventUpdate]):
             .all()
         )
 
+    def count_upcoming_events(
+            self,
+            db: Session
+    ) -> int:
+        """Count total upcoming events."""
+        from datetime import datetime
+
+        now = datetime.now(tz=timezone.utc)
+        return (
+            db.query(func.count(Event.id))
+            .filter(Event.is_active == True)
+            .filter(Event.event_date >= now)
+            .scalar()
+        )
+
+    def get_public_events(
+            self,
+            db: Session,
+            *,
+            skip: int = 0,
+            limit: int = 100
+    ) -> List[Event]:
+        """Get public active events."""
+        return (
+            db.query(Event)
+            .filter(Event.is_active == True)
+            .filter(Event.is_public == True)
+            .order_by(Event.event_date)
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+    def count_public_events(
+            self,
+            db: Session
+    ) -> int:
+        """Count total public events."""
+        return (
+            db.query(func.count(Event.id))
+            .filter(Event.is_active == True)
+            .filter(Event.is_public == True)
+            .scalar()
+        )
+
     def get_public_event(
             self,
             db: Session,
@@ -110,4 +170,4 @@ class CRUDEvent(CRUDBase[Event, EventCreate, EventUpdate]):
 
 
 # Create a singleton instance for use across the application
-event = CRUDEvent(Event)
+event = CRUDEvent(Event)