Use prefetch/select related to optimize. Cleanup.

savepointradio/radio/admin.py

@@ -6,9 +6,10 @@ from inline_actions.admin import (
     InlineActionsMixin, InlineActionsModelAdminMixin
 )
 
+from core.utils import quantify
+from profiles.actions import RequestSongActionMixin, ToggleFavoriteActionsMixin
 from .actions import change_items, publish_items, remove_items
 from .models import Album, Artist, Game, Song, Store
-from profiles.actions import RequestSongActionMixin, ToggleFavoriteActionsMixin
 
 
 class BaseSongInline(RequestSongActionMixin,
@@ -243,7 +244,6 @@ class StoreAdmin(admin.ModelAdmin):
 
 @admin.register(Song)
 class SongAdmin(RequestSongActionMixin,
-                ToggleFavoriteActionsMixin,
                 InlineActionsModelAdminMixin,
                 admin.ModelAdmin):
     formfield_overrides = {
@@ -258,9 +258,10 @@ class SongAdmin(RequestSongActionMixin,
                     '_is_enabled',
                     '_is_published',
                     '_is_requestable')
-    list_select_related = True
+    list_select_related = ('album', 'game')
     search_fields = ['title']
     actions = ['publish_songs',
+               'add_favorites', 'remove_favorites',
                'add_game', 'remove_game',
                'add_album', 'remove_album',
                'add_artists', 'remove_artists']
@@ -300,18 +301,29 @@ class SongAdmin(RequestSongActionMixin,
     )
     inlines = [ArtistInline, StoreInline]
 
+    def get_queryset(self, request):
+        qs = super().get_queryset(request)
+        return qs.prefetch_related('artists', 'stores')
+
     def formfield_for_foreignkey(self, db_field, request, **kwargs):
         if db_field.name == 'active_store':
-            kwargs['queryset'] = Store.objects.filter(
-                song__pk=request.resolver_match.kwargs['object_id']
-            )
+            # New songs won't have an 'object_id' until they are saved for the
+            # first time. So on new songs, force an empty QuerySet.
+            try:
+                kwargs['queryset'] = Store.objects.filter(
+                    song__pk=request.resolver_match.kwargs['object_id']
+                )
+            except KeyError:
+                kwargs['queryset'] = Store.objects.none()
         return super().formfield_for_foreignkey(db_field, request, **kwargs)
 
-    # Admin Actions
-
     def artist_list(self, obj):
         return ', '.join([a.full_name for a in obj.artists.all()])
 
+    # Admin Actions
+
+    ## Metadata CRUD
+
     def add_album(self, request, queryset):
         return change_items(request, queryset, 'album', 'add_album')
     add_album.short_description = "Add album to selected items"
@@ -338,6 +350,28 @@ class SongAdmin(RequestSongActionMixin,
         return remove_items(request, queryset, 'game', 'remove_game')
     remove_game.short_description = "Remove game from selected items"
 
+    ## Allow multiple songs to be favorited by the admin user.
+
+    def add_favorites(self, request, queryset):
+        request.user.profile.favorites.add(*queryset)
+        message = quantify(len(queryset), queryset.model)
+        messages.success(
+            request,
+            '{} successfully added to favorites.'.format(message)
+        )
+    add_favorites.short_description = "Add selected songs to favorites"
+
+    def remove_favorites(self, request, queryset):
+        request.user.profile.favorites.remove(*queryset)
+        message = quantify(len(queryset), queryset.model)
+        messages.success(
+            request,
+            '{} successfully removed from favorites.'.format(message)
+        )
+    remove_favorites.short_description = "Remove selected songs from favorites"
+
+    ## Publish songs if they are sitting unpublished.
+
     def publish_songs(self, request, queryset):
         publish_items(request, queryset)
     publish_songs.short_description = "Publish selected songs"