internal invoices resolved internally.

LNbits/__init__.py

@@ -280,8 +280,14 @@ def api_transactions():
         # check balance
         balance = db.fetchone("SELECT balance/1000 FROM balances WHERE wallet = ?", (wallet["id"],))[0]
         if balance < 0:
+            db.execute("DELETE FROM apipayments WHERE payhash = ? AND wallet = ?", (invoice.payment_hash, wallet["id"]))
             return jsonify({"ERROR": "INSUFFICIENT BALANCE"}), 403
 
+        # check if the invoice is an internal one
+        if db.fetchone("SELECT count(*) FROM apipayments WHERE payhash = ?", (invoice.payment_hash,))[0] == 2:
+            # internal. mark both sides as fulfilled.
+            db.execute("UPDATE apipayments SET pending = 0, fee = 0 WHERE payhash = ?", (invoice.payment_hash,))
+        else:
             # actually send the payment
             r = WALLET.pay_invoice(data["payment_request"])
             if not r.ok or r.json().get('error'):