BTHLABS-60: Appearance settings

Co-authored-by: Tomek Wójcik <labs@tomekwojcik.pl>
Co-committed-by: Tomek Wójcik <labs@tomekwojcik.pl>

services/backend/hotpocket_backend/apps/ui/context_processors.py

@@ -46,3 +46,33 @@ def version(request: HttpRequest) -> dict:
     return {
         'VERSION': backend_version,
     }
+
+
+def appearance_settings(request: HttpRequest) -> dict:
+    theme = 'hotpocket'
+    result = {
+        'theme': theme,
+        'light_mode': False,
+        'theme_css': 'ui/css/bootstrap-hotpocket.min.css',
+    }
+
+    if request.user.is_anonymous is False:
+        theme = request.user.settings.get('theme', 'hotpocket')
+        result.update({
+            'theme': theme,
+            'light_mode': request.user.settings['light_mode'],
+        })
+
+    match theme:
+        case 'bootstrap':
+            result['theme_css'] = 'ui/css/bootstrap.min.css'
+
+        case 'cosmo':
+            result['theme_css'] = 'ui/css/cosmo.min.css'
+
+        case 'solar':
+            result['theme_css'] = 'ui/css/solar.min.css'
+
+    return {
+        'APPEARANCE_SETTINGS': result,
+    }