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modbison/backend/app/routers/payments.py
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3.2 KiB
Python

"""Payments API endpoints for purchasing Credits.
docs/planning/economy.md US-2 (task 575fd14b5360).
"""
from typing import Annotated
from fastapi import APIRouter, Depends, Header, HTTPException, status
from pydantic import BaseModel, Field
from sqlalchemy.ext.asyncio import AsyncSession
from app.database import get_db
from app.dependencies import CurrentUser
from app.models.wallet import TransactionType
from app.services.payment import ALLOWED_CREDIT_PACKS, payment_provider
from app.services.wallet import wallet_service
router = APIRouter()
DbDep = Annotated[AsyncSession, Depends(get_db)]
class PurchaseRequest(BaseModel):
credits: int = Field(..., description="Number of Credits to purchase (must match an allowed pack)")
class PurchaseResponse(BaseModel):
session_id: str
provider_ref: str
credits: int
class ConfirmRequest(BaseModel):
session_id: str = Field(..., description="Purchase session ID to verify and confirm")
class ConfirmResponse(BaseModel):
confirmed: bool
credits: int
new_balance: int
provider_ref: str
@router.post("/purchase", response_model=PurchaseResponse, status_code=status.HTTP_201_CREATED)
async def create_purchase_session(
payload: PurchaseRequest,
current_user: CurrentUser,
idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key")] = None,
):
"""Initiate a Credit purchase session via the payment provider."""
if payload.credits not in ALLOWED_CREDIT_PACKS:
raise HTTPException(
status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
detail=f"Invalid credit pack: {payload.credits}. Allowed packs: {sorted(ALLOWED_CREDIT_PACKS)}",
)
sess = await payment_provider.create_purchase(
user_id=current_user.id,
credits=payload.credits,
idempotency_key=idempotency_key,
)
return PurchaseResponse(
session_id=sess.session_id,
provider_ref=sess.provider_ref,
credits=sess.credits,
)
@router.post("/confirm", response_model=ConfirmResponse)
async def confirm_purchase(
payload: ConfirmRequest,
current_user: CurrentUser,
db: DbDep,
):
"""Verify purchase session with provider and credit the user's wallet.
Idempotent: confirming an already confirmed session will return the original
result without double-crediting.
"""
conf = await payment_provider.confirm(payload.session_id)
if not conf.confirmed or conf.user_id != current_user.id:
raise HTTPException(
status_code=status.HTTP_400_BAD_REQUEST,
detail="Payment confirmation failed, invalid session, or unauthorized.",
)
# Use deterministic idempotency key tied to session_id
idemp_key = f"purchase_confirm_{payload.session_id}"
wallet, tx = await wallet_service.credit(
db,
user_id=current_user.id,
amount=conf.credits,
tx_type=TransactionType.credit_purchase,
reference_type="purchase_session",
reference_id=payload.session_id,
idempotency_key=idemp_key,
metadata={"provider_ref": conf.provider_ref},
)
return ConfirmResponse(
confirmed=True,
credits=conf.credits,
new_balance=wallet.balance,
provider_ref=conf.provider_ref,
)