Provide a topic filter for modules

server/book/admin.py

@@ -3,6 +3,20 @@ from django.contrib import admin
 from book.models import Book, Topic, Module
 
 
+class TopicListFilter(admin.SimpleListFilter):
+    title = 'topic modules'
+    parameter_name = 'topic_modules'
+
+    def lookups(self, request, model_admin):
+        return list((topic.slug, topic.title) for topic in Topic.objects.all())
+
+    def queryset(self, request, queryset):
+        filter_value = self.value()
+        topic = Topic.objects.filter(slug=filter_value).first()
+        if topic:
+            return Module.get_topic_modules(topic)
+
+
 @admin.register(Book)
 class BookAdmin(admin.ModelAdmin):
     list_display = ('title', 'slug')
@@ -16,3 +30,4 @@ class TopicAdmin(admin.ModelAdmin):
 @admin.register(Module)
 class ModuleAdmin(admin.ModelAdmin):
     list_display = ('title', 'slug', 'meta_title', 'teaser')
+    list_filter = (TopicListFilter, )