app/api/billing_router.py

"""Author RAG — Billing webhook routes (R-173)."""

import json

from fastapi import APIRouter, Header, HTTPException, Request
from sqlalchemy.ext.asyncio import AsyncSession

from app.config import get_settings
from app.dependencies import get_db
from app.services.billing_service import BillingService, verify_stripe_signature
from fastapi import Depends

router = APIRouter()
cfg = get_settings()


@router.post("/billing/stripe/webhook", tags=["Billing"])
async def stripe_webhook(
    request: Request,
    stripe_signature: str = Header(default="", alias="Stripe-Signature"),
    db: AsyncSession = Depends(get_db),
):
    """Handle Stripe checkout.session.completed events."""
    secret = getattr(cfg, "STRIPE_WEBHOOK_SECRET", None) or ""
    body = await request.body()
    if secret and not verify_stripe_signature(body, stripe_signature, secret):
        raise HTTPException(400, "Invalid webhook signature")

    event = json.loads(body)
    if event.get("type") != "checkout.session.completed":
        return {"received": True, "handled": False}

    session = event.get("data", {}).get("object", {})
    email = (session.get("customer_details") or {}).get("email") or session.get("customer_email")
    plan = (session.get("metadata") or {}).get("plan", "monthly")
    if not email:
        raise HTTPException(400, "Missing customer email")

    result = await BillingService(db).grant_from_checkout(
        customer_email=email,
        plan=plan,
        external_id=session.get("id", ""),
    )
    return {"received": True, "handled": True, **result}