feat: theme

webui/backend/app/services/settings_service.py

@@ -1,10 +1,15 @@
 from __future__ import annotations
 
+from backend.app.api.errors import AppError
 from backend.app.api.schemas import SettingsResponse, SettingsUpdateRequest
 from backend.app.db.settings_repository import SettingsRepository
 from backend.app.security.path_guard import PathGuard
 
 
+VALID_THEMES = {"default"}
+VALID_COLOR_MODES = {"dark", "light"}
+
+
 class SettingsService:
     def __init__(self, repository: SettingsRepository, path_guard: PathGuard):
         self._repository = repository
@@ -15,10 +20,14 @@ class SettingsService:
         preferred_left = self._as_optional_str(values.get("preferred_startup_path_left"))
         preferred_right = self._as_optional_str(values.get("preferred_startup_path_right"))
         legacy_preferred = self._as_optional_str(values.get("preferred_startup_path"))
+        selected_theme = self._normalize_theme(values.get("selected_theme"))
+        selected_color_mode = self._normalize_color_mode(values.get("selected_color_mode"))
         return SettingsResponse(
             show_thumbnails=self._as_bool(values.get("show_thumbnails"), default=False),
             preferred_startup_path_left=preferred_left or legacy_preferred,
             preferred_startup_path_right=preferred_right,
+            selected_theme=selected_theme,
+            selected_color_mode=selected_color_mode,
         )
 
     def update_settings(self, request: SettingsUpdateRequest) -> SettingsResponse:
@@ -31,6 +40,12 @@ class SettingsService:
         if request.preferred_startup_path_right is not None:
             self._set_directory_setting("preferred_startup_path_right", request.preferred_startup_path_right)
 
+        if request.selected_theme is not None:
+            self._repository.set_setting("selected_theme", self._validate_theme(request.selected_theme))
+
+        if request.selected_color_mode is not None:
+            self._repository.set_setting("selected_color_mode", self._validate_color_mode(request.selected_color_mode))
+
         return self.get_settings()
 
     def _set_directory_setting(self, key: str, value: str) -> None:
@@ -53,3 +68,35 @@ class SettingsService:
             return None
         normalized = value.strip()
         return normalized or None
+
+    @staticmethod
+    def _normalize_theme(value: str | None) -> str:
+        normalized = (value or "").strip()
+        return normalized if normalized in VALID_THEMES else "default"
+
+    @staticmethod
+    def _normalize_color_mode(value: str | None) -> str:
+        normalized = (value or "").strip().lower()
+        return normalized if normalized in VALID_COLOR_MODES else "dark"
+
+    @staticmethod
+    def _validate_theme(value: str) -> str:
+        normalized = value.strip()
+        if normalized not in VALID_THEMES:
+            raise AppError(
+                status_code=400,
+                code="invalid_request",
+                message="Theme must be one of: default",
+            )
+        return normalized
+
+    @staticmethod
+    def _validate_color_mode(value: str) -> str:
+        normalized = value.strip().lower()
+        if normalized not in VALID_COLOR_MODES:
+            raise AppError(
+                status_code=400,
+                code="invalid_request",
+                message="Color mode must be one of: dark, light",
+            )
+        return normalized