refactors

backend/schemas/price.py

@@ -0,0 +1,44 @@
+from datetime import datetime
+
+from pydantic import BaseModel
+
+
+class PriceHistoryResponse(BaseModel):
+    """Response model for a price history record."""
+
+    id: int
+    source: str
+    pair: str
+    price: float
+    timestamp: datetime
+    created_at: datetime
+
+
+class ExchangeConfigResponse(BaseModel):
+    """Exchange configuration for the frontend."""
+
+    eur_min: int
+    eur_max: int
+    eur_increment: int
+    premium_percentage: int
+
+
+class PriceResponse(BaseModel):
+    """Current BTC/EUR price for trading.
+
+    Note: The actual agreed price depends on trade direction (buy/sell)
+    and is calculated by the frontend using market_price and premium_percentage.
+    """
+
+    market_price: float  # Raw price from exchange
+    premium_percentage: int
+    timestamp: datetime
+    is_stale: bool
+
+
+class ExchangePriceResponse(BaseModel):
+    """Combined price and configuration response."""
+
+    price: PriceResponse | None  # None if price fetch failed
+    config: ExchangeConfigResponse
+    error: str | None = None