Refactor get walletclass (#1776)

* move `get_wallet_class` to wallets module

* adjust imports, fix type issues

flake8

lnbits/wallets/__init__.py

@@ -1,4 +1,12 @@
+from __future__ import annotations
+
 # flake8: noqa: F401
+import importlib
+from typing import Optional
+
+from lnbits.settings import settings
+from lnbits.wallets.base import Wallet
+
 from .cliche import ClicheWallet
 from .cln import CoreLightningWallet
 from .cln import CoreLightningWallet as CLightningWallet
@@ -12,3 +20,21 @@ from .lntips import LnTipsWallet
 from .opennode import OpenNodeWallet
 from .spark import SparkWallet
 from .void import VoidWallet
+
+
+def set_wallet_class(class_name: Optional[str] = None):
+    backend_wallet_class = class_name or settings.lnbits_backend_wallet_class
+    wallet_class = getattr(wallets_module, backend_wallet_class)
+    global WALLET
+    WALLET = wallet_class()
+
+
+def get_wallet_class() -> Wallet:
+    return WALLET
+
+
+wallets_module = importlib.import_module("lnbits.wallets")
+FAKE_WALLET: Wallet = FakeWallet()
+
+# initialize as fake wallet
+WALLET: Wallet = FAKE_WALLET