Send purchase state

hopper/interfaces.py

@@ -1,6 +1,16 @@
-from typing import Protocol
+from typing import Iterable, Optional, Protocol
+
+from hopper.models.product import Product
 
 
 class SendGameDumpInterface(Protocol):
     async def send_game_dump(self) -> None:
         ...
+
+    async def send_product_purchase_message(self, products: Iterable[Product]) -> None:
+        ...
+
+    async def send_product_purchase_done_message(
+        self, product: Optional[Product] = None
+    ) -> None:
+        ...