real middleman: BTCPay payment gate + webhook + Printful adapter + checkout redirect

backend/app/routers/orders.py

@@ -15,10 +15,11 @@ from fastapi import APIRouter, Depends, HTTPException
 from sqlalchemy.orm import Session
 
 from app.database import get_db
+from app.engines.payments import btcpay
 from app.routers.auth import require_admin
 from app.engines.order_router import route_order
 from app.models import AuditLog, Customer, Order, Product
-from app.schemas import CustomerOrderOut, OrderCreate, OrderOut, TrackingIn
+from app.schemas import CheckoutResponse, CustomerOrderOut, OrderCreate, OrderOut, TrackingIn
 
 router = APIRouter()
 
@@ -36,7 +37,7 @@ def _new_order_number() -> str:
     return f"POL-{datetime.utcnow():%Y%m%d}-{uuid.uuid4().hex[:6].upper()}"
 
 
-@router.post("", response_model=OrderOut)
+@router.post("", response_model=CheckoutResponse)
 def create_order(body: OrderCreate, db: Session = Depends(get_db)):
     email = body.customer_email.strip().lower()
     customer = db.query(Customer).filter(Customer.email == email).first()
@@ -69,14 +70,27 @@ def create_order(body: OrderCreate, db: Session = Depends(get_db)):
         customer_id=customer.id,
         items=items,
         retail_total=retail_total,
-        status="new",
+        status="pending_payment",
     )
     db.add(order)
     db.flush()
 
     result = route_order(db, order)
+    if not result.get("routed"):
+        raise HTTPException(status_code=400, detail="no eligible supplier for this order")
+
+    checkout_url = None
+    try:
+        inv = btcpay.create_invoice(float(order.retail_total), order.order_number)
+        order.btcpay_invoice_id = inv.get("invoice_id")
+        checkout_url = inv.get("checkout_url")
+        db.commit()
+    except Exception as e:
+        db.rollback()
+        raise HTTPException(status_code=502, detail=f"payment provider unavailable: {e}")
+
     db.refresh(order)
-    return order
+    return CheckoutResponse(order=order, checkout_url=checkout_url)
 
 
 @router.get("", response_model=List[OrderOut])