feat(viewer): persist theme/sort via toggle view; use middleware-provided theme/sort in views and templates

viewer/views.py

@@ -1,19 +1,24 @@
 """Top-level views module.
 
 After refactor this file only keeps the minimal public view entry points and imports
-helpers from the new `directory` and `image` modules.
+helpers from the new `directory` and `image` modules. Also provides the
+`toggle_settings` view used by template buttons to persist theme/sort.
 """
 
 # Django imports.
+from urllib.parse import urlparse
 from django.http import HttpResponseNotFound
 from django.conf import settings
 from django.contrib.auth.decorators import login_required
 from django.shortcuts import redirect
+from django.core.exceptions import MultipleObjectsReturned
 
 # Local helpers split into modules
 from .directory import render_directory
 from .image import render_image
 
+from .models import UserSettings
+
 
 @login_required
 def index(request):
@@ -44,3 +49,51 @@ def gallery_view(request, path=None):
         return render_directory(request, path_text, candidate)
 
     return render_image(request, path_text, candidate)
+
+
+@login_required
+def toggle_settings(request):
+    """Persist theme and/or sort for the current user and redirect back.
+
+    Expected query params:
+    - next: the URL to redirect back to (optional)
+    - theme: optional, 'light' or 'dark'
+    - sort: optional, one of allowed sort keys
+
+    The view will obtain or create the UserSettings row for the user and set
+    any provided values. If multiple UserSettings rows exist (shouldn't
+    normally happen) the first is used.
+    """
+
+    next_url = request.GET.get("next") or "/gallery/"
+
+    # Only allow in-site redirects for safety
+    parsed = urlparse(next_url)
+    if parsed.netloc and parsed.netloc != "":
+        next_url = "/gallery/"
+
+    user = getattr(request, "user", None)
+    if not user or not getattr(user, "is_authenticated", False):
+        return redirect(next_url)
+
+    # Obtain or create the settings row
+    try:
+        settings_obj = UserSettings.objects.get(user=user)
+    except UserSettings.DoesNotExist:
+        settings_obj = UserSettings(user=user)
+    except MultipleObjectsReturned:
+        settings_obj = UserSettings.objects.filter(user=user).first()
+
+    # Apply provided values
+    theme = request.GET.get("theme")
+    sort = request.GET.get("sort")
+
+    if theme in ("light", "dark"):
+        settings_obj.theme = theme
+
+    if sort:
+        settings_obj.sort = sort
+
+    settings_obj.save()
+
+    return redirect(next_url)