feat: implemented downloader

music_kraken/download/__init__.py

@@ -415,6 +415,31 @@ class Downloader:
         
         return source.page.fetch_object_from_source(source=source, **kwargs)
 
+    # misc function
+
+    def get_existing_genres(self) -> Generator[str, None, None]:
+        """Yields every existing genre, for the user to select from.
+
+        Yields:
+            Generator[str, None, None]: a generator that yields every existing genre.
+        """
+
+        def is_valid_genre(genre: Path) -> bool:
+            """
+            gets the name of all subdirectories of shared.MUSIC_DIR,
+            but filters out all directories, where the name matches with any Patern
+            from shared.NOT_A_GENRE_REGEX.
+            """
+            if not genre.is_dir():
+                return False
+
+            if any(re.match(regex_pattern, genre.name) for regex_pattern in main_settings["not_a_genre_regex"]):
+                return False
+
+            return True
+        
+        for genre in filter(is_valid_genre, main_settings["music_directory"].iterdir()):
+            yield genre.name
 
 class Page:
     REGISTER = True