feat: Adds stripe tap to pay flow for TPoS running on Android PoS/phone devices (#3334)

Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

lnbits/core/views/fiat_api.py

@@ -1,10 +1,11 @@
 from http import HTTPStatus
 
-from fastapi import APIRouter, Depends
+from fastapi import APIRouter, Depends, HTTPException
 
 from lnbits.core.models.misc import SimpleStatus
 from lnbits.core.services.fiat_providers import test_connection
 from lnbits.decorators import check_admin
+from lnbits.fiat import StripeWallet, get_fiat_provider
 
 fiat_router = APIRouter(tags=["Fiat API"], prefix="/api/v1/fiat")
 
@@ -16,3 +17,29 @@ fiat_router = APIRouter(tags=["Fiat API"], prefix="/api/v1/fiat")
 )
 async def api_test_fiat_provider(provider: str) -> SimpleStatus:
     return await test_connection(provider)
+
+
+@fiat_router.post(
+    "/{provider}/connection_token",
+    status_code=HTTPStatus.OK,
+    dependencies=[Depends(check_admin)],
+)
+async def connection_token(provider: str):
+    provider_wallet = await get_fiat_provider(provider)
+    if provider == "stripe":
+        if not isinstance(provider_wallet, StripeWallet):
+            raise HTTPException(
+                status_code=500, detail="Stripe wallet/provider not configured"
+            )
+        try:
+            tok = await provider_wallet.create_terminal_connection_token()
+            secret = tok.get("secret")
+            if not secret:
+                raise HTTPException(
+                    status_code=502, detail="Stripe returned no connection token"
+                )
+            return {"secret": secret}
+        except Exception as e:
+            raise HTTPException(
+                status_code=500, detail="Failed to create connection token"
+            ) from e