refactors

backend/repositories/price.py

@@ -0,0 +1,27 @@
+"""Price repository for database queries."""
+
+from sqlalchemy import desc, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from models import PriceHistory
+from price_fetcher import PAIR_BTC_EUR, SOURCE_BITFINEX
+
+
+class PriceRepository:
+    """Repository for price-related database queries."""
+
+    def __init__(self, db: AsyncSession):
+        self.db = db
+
+    async def get_latest(
+        self, source: str = SOURCE_BITFINEX, pair: str = PAIR_BTC_EUR
+    ) -> PriceHistory | None:
+        """Get the most recent price from the database."""
+        query = (
+            select(PriceHistory)
+            .where(PriceHistory.source == source, PriceHistory.pair == pair)
+            .order_by(desc(PriceHistory.timestamp))
+            .limit(1)
+        )
+        result = await self.db.execute(query)
+        return result.scalar_one_or_none()