FEATURE: per-category default topic list sort order

app/assets/javascripts/discourse/components/edit-category-settings.js.es6

@@ -1,7 +1,25 @@
 import { setting } from 'discourse/lib/computed';
 import { buildCategoryPanel } from 'discourse/components/edit-category-panel';
+import computed from "ember-addons/ember-computed-decorators";
 
 export default buildCategoryPanel('settings', {
   emailInEnabled: setting('email_in'),
   showPositionInput: setting('fixed_category_positions'),
+
+  isDefaultSortOrder: Em.computed.empty('category.sort_order'),
+
+  @computed
+  availableSorts() {
+    return ['likes', 'op_likes', 'views', 'posts', 'activity', 'posters', 'category', 'created']
+      .map(s => ({ name: I18n.t('category.sort_options.' + s), value: s }))
+      .sort((a,b) => { return a.name > b.name; });
+  },
+
+  @computed
+  sortAscendingOptions() {
+    return [
+      {name: I18n.t('category.sort_ascending'),  value: 'true'},
+      {name: I18n.t('category.sort_descending'), value: 'false'}
+    ];
+  }
 });

app/assets/javascripts/discourse/models/category.js.es6

@@ -98,7 +98,9 @@ const Category = RestModel.extend({
         topic_template: this.get('topic_template'),
         suppress_from_homepage: this.get('suppress_from_homepage'),
         allowed_tags: this.get('allowed_tags'),
-        allowed_tag_groups: this.get('allowed_tag_groups')
+        allowed_tag_groups: this.get('allowed_tag_groups'),
+        sort_order: this.get('sort_order'),
+        sort_ascending: this.get('sort_ascending')
       },
       type: id ? 'PUT' : 'POST'
     });

app/assets/javascripts/discourse/templates/components/edit-category-settings.hbs

@@ -19,6 +19,16 @@
   </label>
 </section>
 
+<section class="field">
+  <label>
+    {{i18n "category.sort_order"}}
+    {{combo-box valueAttribute="value" content=availableSorts value=category.sort_order none="category.sort_options.default"}}
+    {{#unless isDefaultSortOrder}}
+      {{combo-box valueAttribute="value" content=sortAscendingOptions value=category.sort_ascending none="category.sort_options.default"}}
+    {{/unless}}
+  </label>
+</section>
+
 {{#if emailInEnabled}}
     <section class='field'>
       <label>

app/controllers/categories_controller.rb

@@ -238,6 +238,8 @@ class CategoriesController < ApplicationController
                         :slug,
                         :allow_badges,
                         :topic_template,
+                        :sort_order,
+                        :sort_ascending,
                         :custom_fields => [params[:custom_fields].try(:keys)],
                         :permissions => [*p.try(:keys)],
                         :allowed_tags => [],

app/models/category.rb

@@ -536,6 +536,8 @@ end
 #  topic_template                :text
 #  suppress_from_homepage        :boolean          default(FALSE)
 #  contains_messages             :boolean
+#  sort_order                    :string
+#  sort_ascending                :boolean
 #
 # Indexes
 #

app/serializers/basic_category_serializer.rb

@@ -19,7 +19,9 @@ class BasicCategorySerializer < ApplicationSerializer
              :notification_level,
              :can_edit,
              :topic_template,
-             :has_children
+             :has_children,
+             :sort_order,
+             :sort_ascending
 
   def include_parent_category_id?
     parent_category_id

config/locales/client.en.yml

@@ -1883,6 +1883,7 @@ en:
       email_in_disabled: "Posting new topics via email is disabled in the Site Settings. To enable posting new topics via email, "
       email_in_disabled_click: 'enable the "email in" setting.'
       suppress_from_homepage: "Suppress this category from the homepage."
+      sort_order: "Default Sort:"
       allow_badges_label: "Allow badges to be awarded in this category"
       edit_permissions: "Edit Permissions"
       add_permission: "Add Permission"
@@ -1908,6 +1909,18 @@ en:
         muted:
           title: "Muted"
           description: "You will never be notified of anything about new topics in these categories, and they will not appear in latest."
+      sort_options:
+        default: "default"
+        likes: "Likes"
+        op_likes: "Original Post Likes"
+        views: "Views"
+        posts: "Posts"
+        activity: "Activity"
+        posters: "Posters"
+        category: "Category"
+        created: "Created"
+      sort_ascending: 'Ascending'
+      sort_descending: 'Descending'
 
     flagging:
       title: 'Thanks for helping to keep our community civil!'

db/migrate/20161031183811_add_sort_fields_to_categories.rb

@@ -0,0 +1,6 @@
+class AddSortFieldsToCategories < ActiveRecord::Migration
+  def change
+    add_column :categories, :sort_order, :string
+    add_column :categories, :sort_ascending, :boolean
+  end
+end

lib/topic_query.rb

@@ -450,6 +450,15 @@ class TopicQuery
           result = result.where('categories.id = :category_id OR (categories.parent_category_id = :category_id AND categories.topic_id <> topics.id)', category_id: category_id)
         end
         result = result.references(:categories)
+
+        if !@options[:order]
+          # category default sort order
+          sort_order, sort_ascending = Category.where(id: category_id).pluck(:sort_order, :sort_ascending).first
+          if sort_order
+            options[:order] = sort_order
+            options[:ascending] = !!sort_ascending ? 'true' : 'false'
+          end
+        end
       end
 
       # ALL TAGS: something like this?

spec/components/topic_query_spec.rb

@@ -379,6 +379,26 @@ describe TopicQuery do
         ).to eq([topic_in_cat2.id, topic_category.id, topic_in_cat1.id])
       end
     end
+
+    describe "category default sort order" do
+      it "can use category's default sort order" do
+        category.update_attributes!(sort_order: 'created', sort_ascending: true)
+        topic_ids = TopicQuery.new(user, category: category.id).list_latest.topics.map(&:id)
+        expect(topic_ids - [topic_category.id]).to eq([topic_in_cat1.id, topic_in_cat2.id])
+      end
+
+      it "ignores invalid order value" do
+        category.update_attributes!(sort_order: 'funny')
+        topic_ids = TopicQuery.new(user, category: category.id).list_latest.topics.map(&:id)
+        expect(topic_ids - [topic_category.id]).to eq([topic_in_cat2.id, topic_in_cat1.id])
+      end
+
+      it "can be overridden" do
+        category.update_attributes!(sort_order: 'created', sort_ascending: true)
+        topic_ids = TopicQuery.new(user, category: category.id, order: 'activity').list_latest.topics.map(&:id)
+        expect(topic_ids - [topic_category.id]).to eq([topic_in_cat2.id, topic_in_cat1.id])
+      end
+    end
   end
 
   context 'unread / read topics' do