Implement various cleanup

- Don't import wallman_systray to see if it exists, use
importlib.util.find_spec() to look for deps instead

- Improve handling if no config file exists.

src/wallman_lib.py

@@ -26,6 +26,8 @@ class _ConfigLib:
         self.config_total_changing_times: int = len(self.config_changing_times)
         self.config_log_level: str = self.config_general.get("loglevel", "INFO").upper()
         self.config_behavior: str = self._set_behavior()
+        # Setup logging
+        self._set_log_level()
         # HACK: Add a function to handle these try/except blocks cleanlier.
         try:
             self.config_notify: bool = self.config_general["notify"]
@@ -38,24 +40,29 @@ class _ConfigLib:
             self.config_systray: bool = True
             logger.warning("'systray' is not set in the dictionary general in the config file, defaulting to 'true'.")
 
-        # Setup logging
-        self._set_log_level()
         # Setup systray.
         if self.config_systray:
-            self._initialize_systray()
+            self._verify_systray_deps()
 
     # Read config. TODO: Add error handling for the config not found case.
     def _initialize_config(self) -> ConfigFile:
         chdir(str(getenv("HOME")) + "/.config/wallman/")
+        try:
             with open("wallman.toml", "rb") as config_file:
                 data: ConfigFile = tomllib.load(config_file) #pyright:ignore
                 return data
+        except FileNotFoundError:
+            raise FileNotFoundError("No config file could be found in ~/.config/wallman/wallman.toml")
+        except tomllib.TOMLDecodeError as e:
+            print("ERROR: Config could not be parsed: Invalid TOML Syntax")
+            raise e
 
-    # HACK on this to avoid double importing of wallman_systray due to variable scope. Idea: Global variable or Variable that is inherited?
-    def _initialize_systray(self):
-        try:
-            import wallman_systray as _
-        except (ImportError, FileNotFoundError):
+    def _verify_systray_deps(self):
+        from importlib import util
+        if util.find_spec("pystray") is None or util.find_spec("pillow") is None:
+            logger.error("systray is enabled, but dependencies for the systray couldn't be found. Are pystray and pillow installed?")
+            logger.info("Setting self.config_systray to false.")
+            print("ERROR: systray is enabled, but dependencies for the systray couldn't be found. Are pystray and pillow installed?")
             self.config_systray = False
 
     def _set_log_level(self):
@@ -313,9 +320,9 @@ class WallpaperLogic(_ConfigLib):
             scheduler.start()
 
         if self.config_systray:
-            # NOTE: The wallman_systray impomrt should be handled differently. See the note in Config_Validity.
             import wallman_systray as systray
             from functools import partial
+
             scheduler: BackgroundScheduler = _schedule_background_wallpapers()
             menu: systray.Menu = systray.Menu (
                 systray.item("Re-Set Wallpaper", partial(systray.set_wallpaper_again, wallpaper_setter=self.set_wallpaper_by_time)),
@@ -325,5 +332,4 @@ class WallpaperLogic(_ConfigLib):
             icon = systray.Icon("wallman_icon", systray.icon_image, "My Tray Icon", menu)
             icon.run()
         else:
-
             _schedule_blocking_wallpapers()