first implementation

backend/routes/counter.py

@@ -0,0 +1,54 @@
+"""Counter routes."""
+from fastapi import APIRouter, Depends
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from auth import require_permission
+from database import get_db
+from models import Counter, User, CounterRecord, Permission
+
+
+router = APIRouter(prefix="/api/counter", tags=["counter"])
+
+
+async def get_or_create_counter(db: AsyncSession) -> Counter:
+    """Get the singleton counter, creating it if it doesn't exist."""
+    result = await db.execute(select(Counter).where(Counter.id == 1))
+    counter = result.scalar_one_or_none()
+    if not counter:
+        counter = Counter(id=1, value=0)
+        db.add(counter)
+        await db.commit()
+        await db.refresh(counter)
+    return counter
+
+
+@router.get("")
+async def get_counter(
+    db: AsyncSession = Depends(get_db),
+    _current_user: User = Depends(require_permission(Permission.VIEW_COUNTER)),
+) -> dict[str, int]:
+    """Get the current counter value."""
+    counter = await get_or_create_counter(db)
+    return {"value": counter.value}
+
+
+@router.post("/increment")
+async def increment_counter(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(require_permission(Permission.INCREMENT_COUNTER)),
+) -> dict[str, int]:
+    """Increment the counter and record the action."""
+    counter = await get_or_create_counter(db)
+    value_before = counter.value
+    counter.value += 1
+
+    record = CounterRecord(
+        user_id=current_user.id,
+        value_before=value_before,
+        value_after=counter.value,
+    )
+    db.add(record)
+    await db.commit()
+    return {"value": counter.value}
+