wallpaper: fix when no wall

src/caelestia/subcommands/wallpaper.py

@@ -18,4 +18,4 @@ class Command:
         elif self.args.random:
             set_random(self.args)
         else:
-            print(get_wallpaper())
+            print(get_wallpaper() or "No wallpaper set")

src/caelestia/utils/wallpaper.py

@@ -31,7 +31,10 @@ def check_wall(wall: Path, filter_size: tuple[int, int], threshold: float) -> bo
 
 
 def get_wallpaper() -> str:
+    try:
         return wallpaper_path_path.read_text()
+    except IOError:
+        return None
 
 
 def get_wallpapers(args: Namespace) -> list[Path]:
@@ -71,9 +74,9 @@ def get_thumb(wall: Path, cache: Path) -> Path:
 def get_smart_mode(wall: Path, cache: Path) -> str:
     mode_cache = cache / "mode.txt"
 
-    if mode_cache.exists():
+    try:
         return mode_cache.read_text()
-
+    except IOError:
         with Image.open(get_thumb(wall, cache)) as img:
             img.thumbnail((1, 1), Image.LANCZOS)
             mode = "light" if Hct.from_int(argb_from_rgb(*img.getpixel((0, 0)))).tone > 60 else "dark"