refactor feature construction

cashu/mint/features.py

@@ -25,6 +25,15 @@
 
 class LedgerFeatures(SupportsBackends):
     def mint_features(self) -> Dict[int, Union[List[Any], Dict[str, Any]]]:
+        mint_features = self.create_mint_features()
+        mint_features = self.add_supported_features(mint_features)
+        mint_features = self.add_mpp_features(mint_features)
+        mint_features = self.add_websocket_features(mint_features)
+        mint_features = self.add_cache_features(mint_features)
+
+        return mint_features
+
+    def create_mint_features(self) -> Dict[int, Union[List[Any], Dict[str, Any]]]:
         mint_method_settings: List[MintMethodSetting] = []
         for method, unit_dict in self.backends.items():
             for unit in unit_dict.keys():
@@ -43,8 +52,6 @@ def mint_features(self) -> Dict[int, Union[List[Any], Dict[str, Any]]]:
                     melt_setting.min_amount = 0
                 melt_method_settings.append(melt_setting)
 
-        supported_dict = dict(supported=True)
-
         mint_features: Dict[int, Union[List[Any], Dict[str, Any]]] = {
             MINT_NUT: dict(
                 methods=mint_method_settings,
@@ -54,15 +61,25 @@ def mint_features(self) -> Dict[int, Union[List[Any], Dict[str, Any]]]:
                 methods=melt_method_settings,
                 disabled=False,
             ),
-            STATE_NUT: supported_dict,
-            FEE_RETURN_NUT: supported_dict,
-            RESTORE_NUT: supported_dict,
-            SCRIPT_NUT: supported_dict,
-            P2PK_NUT: supported_dict,
-            DLEQ_NUT: supported_dict,
-            HTLC_NUT: supported_dict,
         }
+        return mint_features
 
+    def add_supported_features(
+        self, mint_features: Dict[int, Union[List[Any], Dict[str, Any]]]
+    ):
+        supported_dict = dict(supported=True)
+        mint_features[STATE_NUT] = supported_dict
+        mint_features[FEE_RETURN_NUT] = supported_dict
+        mint_features[RESTORE_NUT] = supported_dict
+        mint_features[SCRIPT_NUT] = supported_dict
+        mint_features[P2PK_NUT] = supported_dict
+        mint_features[DLEQ_NUT] = supported_dict
+        mint_features[HTLC_NUT] = supported_dict
+        return mint_features
+
+    def add_mpp_features(
+        self, mint_features: Dict[int, Union[List[Any], Dict[str, Any]]]
+    ):
         # signal which method-unit pairs support MPP
         mpp_features = []
         for method, unit_dict in self.backends.items():
@@ -79,6 +96,11 @@ def mint_features(self) -> Dict[int, Union[List[Any], Dict[str, Any]]]:
         if mpp_features:
             mint_features[MPP_NUT] = dict(methods=mpp_features)
 
+        return mint_features
+
+    def add_websocket_features(
+        self, mint_features: Dict[int, Union[List[Any], Dict[str, Any]]]
+    ):
         # specify which websocket features are supported
         # these two are supported by default
         websocket_features: Dict[str, List[Dict[str, Union[str, List[str]]]]] = {
@@ -106,26 +128,30 @@ def mint_features(self) -> Dict[int, Union[List[Any], Dict[str, Any]]]:
         if websocket_features:
             mint_features[WEBSOCKETS_NUT] = websocket_features
 
+        return mint_features
+
+    def add_cache_features(
+        self, mint_features: Dict[int, Union[List[Any], Dict[str, Any]]]
+    ):
         if settings.mint_redis_cache_enabled:
             cache_features: dict[str, list[dict[str, str]] | int] = {
                 "cached_endpoints": [
                     {
-                        "path": "/v1/mint/bolt11",
                         "method": "POST",
+                        "path": "/v1/mint/bolt11",
                     },
                     {
-                        "path": "/v1/melt/bolt11",
                         "method": "POST",
+                        "path": "/v1/melt/bolt11",
                     },
                     {
-                        "path": "/v1/swap",
                         "method": "POST",
+                        "path": "/v1/swap",
                     },
                 ]
             }
             if settings.mint_redis_cache_ttl:
                 cache_features["ttl"] = settings.mint_redis_cache_ttl
 
             mint_features[CACHE_NUT] = cache_features
-
         return mint_features