Add featured tags API (mastodon#11778)

* Add featured tags API

* Remove show and update, change scope, fix code style

app/controllers/api/v1/featured_tags/suggestions_controller.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class Api::V1::FeaturedTags::SuggestionsController < Api::BaseController
+  before_action -> { doorkeeper_authorize! :read, :'read:accounts' }, only: :index
+
+  before_action :require_user!
+  before_action :set_most_used_tags, only: :index
+
+  respond_to :json
+
+  def index
+    render json: @most_used_tags, each_serializer: REST::TagSerializer
+  end
+
+  private
+
+  def set_most_used_tags
+    @most_used_tags = Tag.most_used(current_account).where.not(id: current_account.featured_tags).limit(10)
+  end
+end

app/controllers/api/v1/featured_tags_controller.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+class Api::V1::FeaturedTagsController < Api::BaseController
+  before_action -> { doorkeeper_authorize! :read, :'read:accounts' }, only: :index
+  before_action -> { doorkeeper_authorize! :write, :'write:accounts' }, except: :index
+
+  before_action :require_user!
+  before_action :set_featured_tags, only: :index
+  before_action :set_featured_tag, except: [:index, :create]
+
+  def index
+    render json: @featured_tags, each_serializer: REST::FeaturedTagSerializer
+  end
+
+  def create
+    @featured_tag = current_account.featured_tags.new(featured_tag_params)
+    @featured_tag.reset_data
+    @featured_tag.save!
+    render json: @featured_tag, serializer: REST::FeaturedTagSerializer
+  end
+
+  def destroy
+    @featured_tag.destroy!
+    render_empty
+  end
+
+  private
+
+  def set_featured_tag
+    @featured_tag = current_account.featured_tags.find(params[:id])
+  end
+
+  def set_featured_tags
+    @featured_tags = current_account.featured_tags.order(statuses_count: :desc)
+  end
+
+  def featured_tag_params
+    params.permit(:name)
+  end
+end

app/serializers/rest/featured_tag_serializer.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class REST::FeaturedTagSerializer < ActiveModel::Serializer
+  attributes :id, :name, :statuses_count, :last_status_at
+
+  def id
+    object.id.to_s
+  end
+end

config/routes.rb

@@ -380,6 +380,12 @@
         resource :accounts, only: [:show, :create, :destroy], controller: 'lists/accounts'
       end
 
+      namespace :featured_tags do
+        get :suggestions, to: 'suggestions#index'
+      end
+
+      resources :featured_tags, only: [:index, :create, :destroy]
+
       resources :polls, only: [:create, :show] do
         resources :votes, only: :create, controller: 'polls/votes'
       end