first commit

app/services/wallet_service.py

@@ -0,0 +1,60 @@
+import uuid
+from decimal import Decimal
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models import User, Transaction
+from app.core.exceptions import BadRequestError
+
+# MVP: hardcoded redeem codes → amount mapping
+REDEEM_CODES = {
+    "SUPERDREAM10": Decimal("10"),
+    "SUPERDREAM50": Decimal("50"),
+    "SUPERDREAM100": Decimal("100"),
+}
+
+
+class WalletService:
+
+    @staticmethod
+    async def get_balance(db: AsyncSession, user_id: str) -> Decimal:
+        user = await db.get(User, user_id)
+        return user.balance
+
+    @staticmethod
+    async def redeem_code(db: AsyncSession, user_id: str, code: str) -> Transaction:
+        amount = REDEEM_CODES.get(code.upper())
+        if not amount:
+            raise BadRequestError("无效的兑换码")
+
+        user = await db.get(User, user_id)
+        user.balance += amount
+        new_balance = user.balance
+
+        txn = Transaction(
+            id=str(uuid.uuid4()),
+            user_id=user_id,
+            type="topup",
+            amount=amount,
+            balance_after=new_balance,
+            reference_id=f"redeem:{code.upper()}",
+        )
+        db.add(txn)
+        await db.commit()
+        await db.refresh(txn)
+        return txn
+
+    @staticmethod
+    async def list_transactions(
+        db: AsyncSession, user_id: str, page: int = 1, size: int = 20
+    ) -> list:
+        offset = (page - 1) * size
+        result = await db.execute(
+            select(Transaction)
+            .where(Transaction.user_id == user_id)
+            .order_by(Transaction.created_at.desc())
+            .offset(offset)
+            .limit(size)
+        )
+        return result.scalars().all()