build available theme list dynamically

app/__init__.py

@@ -83,6 +83,18 @@ def create_app():
     app.config['MAX_CONTENT_LENGTH'] = 1000 * 1000
 
     os.makedirs(os.path.dirname(app.config["DB_PATH"]), exist_ok = True)
+
+    css_dir = 'data/static/css/'
+    allowed_themes = []
+    for f in os.listdir(css_dir):
+        if not os.path.isfile(os.path.join(css_dir, f)):
+            continue
+        theme_name = os.path.splitext(os.path.basename(f))[0]
+        allowed_themes.append(theme_name)
+
+    allowed_themes.sort(key=(lambda x: (x != 'style', x)))
+    app.config['allowed_themes'] = allowed_themes
+
     with app.app_context():
         from .schema import create as create_tables
         from .migrations import run_migrations
@@ -179,4 +191,11 @@ def create_app():
     def cachebust(subject):
         return f"{subject}?v={str(int(time.time()))}"
 
+    @app.template_filter('theme_name')
+    def get_theme_name(subject: str):
+        if subject == 'style':
+            return 'Default'
+
+        return f'{subject.removeprefix('theme-').capitalize()} (beta)'
+
     return app