minor config stuf

charon_vna/gui.py

@@ -154,8 +154,8 @@ class MainWindow(QMainWindow):
     def __init__(self):
         super().__init__()
 
-        self.config_path = None
+        self.config_path = DEFAULT_CONFIG
-        with open(DEFAULT_CONFIG, "r") as f:
+        with open(self.config_path, "r") as f:
             config = json.load(f)
         self._frequency = config["frequency"]
 
@@ -234,11 +234,12 @@ class MainWindow(QMainWindow):
         dialog.setAcceptMode(QFileDialog.AcceptMode.AcceptSave)
         if dialog.exec():
             config_path = Path(dialog.selectedFiles()[0])
-            print(config_path)
             if config_path.suffix != CONFIG_SUFFIX:
                 raise ValueError(
                     f"{config_path.name} is not a valid configuration file. Must have extension {CONFIG_SUFFIX}"
                 )
+            if config_path == DEFAULT_CONFIG:
+                raise ValueError(f"Cannot overwrite default configuration file at {DEFAULT_CONFIG}")
             self.config_path = config_path
             print(f"Config path is now {self.config_path.resolve()}")
 
@@ -262,7 +263,7 @@ class MainWindow(QMainWindow):
             self.load_config(self.config_path)
 
     def save_config(self) -> None:
-        if self.config_path is None:
+        if self.config_path == DEFAULT_CONFIG:
             self.saveas_config()
         else:
             print(f"Saving config to {self.config_path.resolve()}")