working dev environment

backend/seed.py

@@ -1,14 +1,18 @@
 """
 Seed script: populates the database with station data.
 
+Idempotent — safe to run multiple times. Uses get-or-create (upsert) for each entity.
+
 Usage:
-    DATABASE_URL=postgresql://... python -m app.seed
-    (or from the repo root:  cd backend && python seed.py)
+    KMTN_DATABASE_URL=... python seed.py
+    (run from the backend/ directory)
 """
 
 import asyncio
 from datetime import date
 
+from sqlalchemy import select
+
 from app.database import async_session
 from app.models import Program, Event, DonationTier
 
@@ -90,29 +94,83 @@ TIERS: list[dict] = [
 ]
 
 
+# ── Helpers ────────────────────────────────────────────────
+
+async def _upsert_program(session, data: dict) -> None:
+    """Get-or-create a program matched on (day_of_week, time)."""
+    existing = await session.execute(
+        select(Program).where(
+            Program.day_of_week == data["day_of_week"],
+            Program.time == data["time"],
+        )
+    )
+    program = existing.scalar_one_or_none()
+    if program:
+        for key, value in data.items():
+            setattr(program, key, value)
+    else:
+        session.add(Program(**data))
+
+
+async def _upsert_event(session, data: dict) -> None:
+    """Get-or-create an event matched on (date, title)."""
+    existing = await session.execute(
+        select(Event).where(
+            Event.date == data["date"],
+            Event.title == data["title"],
+        )
+    )
+    event = existing.scalar_one_or_none()
+    if event:
+        for key, value in data.items():
+            setattr(event, key, value)
+    else:
+        session.add(Event(**data, active=True))
+
+
+async def _upsert_tier(session, data: dict) -> None:
+    """Get-or-create a donation tier matched on name."""
+    existing = await session.execute(
+        select(DonationTier).where(DonationTier.name == data["name"])
+    )
+    tier = existing.scalar_one_or_none()
+    if tier:
+        for key, value in data.items():
+            setattr(tier, key, value)
+    else:
+        session.add(DonationTier(**data))
+
+
 # ── Main ──────────────────────────────────────────────────
 
-async def seed():
+async def seed() -> None:
+    """Populate the database with station data (idempotent)."""
     async with async_session() as session:
-        # Programs
         for data in PROGRAMS:
-            session.add(Program(**data))
+            await _upsert_program(session, data)
         await session.commit()
         print(f"  ✓ Seeded {len(PROGRAMS)} programs")
 
-        # Events
         for data in EVENTS:
-            event = Event(**data, active=True)
-            session.add(event)
+            await _upsert_event(session, data)
         await session.commit()
         print(f"  ✓ Seeded {len(EVENTS)} events")
 
-        # Tiers
         for data in TIERS:
-            session.add(DonationTier(**data))
+            await _upsert_tier(session, data)
         await session.commit()
         print(f"  ✓ Seeded {len(TIERS)} donation tiers")
 
 
+async def truncate_all() -> None:
+    """Remove all seed data from the database."""
+    async with async_session() as session:
+        await session.execute(Program.__table__.delete())
+        await session.execute(Event.__table__.delete())
+        await session.execute(DonationTier.__table__.delete())
+        await session.commit()
+        print("  ✓ Truncated all tables")
+
+
 if __name__ == "__main__":
     asyncio.run(seed())