refactor: extract models (#2759)

lnbits/settings.py

@@ -223,14 +223,27 @@ class ThemesSettings(LNbitsSettings):
 
 class OpsSettings(LNbitsSettings):
     lnbits_baseurl: str = Field(default="http://127.0.0.1:5000/")
+    lnbits_hide_api: bool = Field(default=False)
+    lnbits_denomination: str = Field(default="sats")
+
+
+class FeeSettings(LNbitsSettings):
+
     lnbits_reserve_fee_min: int = Field(default=2000)
     lnbits_reserve_fee_percent: float = Field(default=1.0)
     lnbits_service_fee: float = Field(default=0)
     lnbits_service_fee_ignore_internal: bool = Field(default=True)
     lnbits_service_fee_max: int = Field(default=0)
     lnbits_service_fee_wallet: Optional[str] = Field(default=None)
-    lnbits_hide_api: bool = Field(default=False)
-    lnbits_denomination: str = Field(default="sats")
+
+    # WARN: this same value must be used for balance check and passed to
+    # funding_source.pay_invoice(), it may cause a vulnerability if the values differ
+    def fee_reserve(self, amount_msat: int, internal: bool = False) -> int:
+        if internal:
+            return 0
+        reserve_min = self.lnbits_reserve_fee_min
+        reserve_percent = self.lnbits_reserve_fee_percent
+        return max(int(reserve_min), int(amount_msat * reserve_percent / 100.0))
 
 
 class SecuritySettings(LNbitsSettings):
@@ -489,6 +502,7 @@ class EditableSettings(
     ExtensionsSettings,
     ThemesSettings,
     OpsSettings,
+    FeeSettings,
     SecuritySettings,
     FundingSourcesSettings,
     LightningSettings,