Federate pinned statuses over ActivityPub (#6610)

* Federate pinned statuses over ActivityPub

* Display pinned toots in web UI

Fix #6117

* Fix migration

* Fix tests

* Update outbox_serializer.rb

* Update remove_serializer.rb

* Update add_serializer.rb

* Update fetch_featured_collection_service.rb

3 files changed, 85 insertions, 2 deletions

diff --git a/app/controllers/activitypub/collections_controller.rb b/app/controllers/activitypub/collections_controller.rb
new file mode 100644
index 000000000..081914016
--- /dev/null
+++ b/app/controllers/activitypub/collections_controller.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+class ActivityPub::CollectionsController < Api::BaseController
+  include SignatureVerification
+
+  before_action :set_account
+  before_action :set_size
+  before_action :set_statuses
+
+  def show
+    render json: collection_presenter,
+           serializer: ActivityPub::CollectionSerializer,
+           adapter: ActivityPub::Adapter,
+           content_type: 'application/activity+json',
+           skip_activities: true
+  end
+
+  private
+
+  def set_account
+    @account = Account.find_local!(params[:account_username])
+  end
+
+  def set_statuses
+    @statuses = scope_for_collection.paginate_by_max_id(20, params[:max_id], params[:since_id])
+    @statuses = cache_collection(@statuses, Status)
+  end
+
+  def set_size
+    case params[:id]
+    when 'featured'
+      @account.pinned_statuses.count
+    else
+      raise ActiveRecord::NotFound
+    end
+  end
+
+  def scope_for_collection
+    case params[:id]
+    when 'featured'
+      @account.statuses.permitted_for(@account, signed_request_account).tap do |scope|
+        scope.merge!(@account.pinned_statuses)
+      end
+    else
+      raise ActiveRecord::NotFound
+    end
+  end
+
+  def collection_presenter
+    ActivityPub::CollectionPresenter.new(
+      id: account_collection_url(@account, params[:id]),
+      type: :ordered,
+      size: @size,
+      items: @statuses
+    )
+  end
+end
diff --git a/app/controllers/activitypub/outboxes_controller.rb b/app/controllers/activitypub/outboxes_controller.rb
index a431e3557..9ed700c1e 100644
--- a/app/controllers/activitypub/outboxes_controller.rb
+++ b/app/controllers/activitypub/outboxes_controller.rb
@@ -9,7 +9,7 @@ class ActivityPub::OutboxesController < Api::BaseController
     @statuses = @account.statuses.permitted_for(@account, signed_request_account).paginate_by_max_id(20, params[:max_id], params[:since_id])
     @statuses = cache_collection(@statuses, Status)
 
-    render json: outbox_presenter, serializer: ActivityPub::CollectionSerializer, adapter: ActivityPub::Adapter, content_type: 'application/activity+json'
+    render json: outbox_presenter, serializer: ActivityPub::OutboxSerializer, adapter: ActivityPub::Adapter, content_type: 'application/activity+json'
   end
 
   private
diff --git a/app/controllers/api/v1/statuses/pins_controller.rb b/app/controllers/api/v1/statuses/pins_controller.rb
index 3de1009b8..bba6a6f48 100644
--- a/app/controllers/api/v1/statuses/pins_controller.rb
+++ b/app/controllers/api/v1/statuses/pins_controller.rb
@@ -11,12 +11,18 @@ class Api::V1::Statuses::PinsController < Api::BaseController
 
   def create
     StatusPin.create!(account: current_account, status: @status)
+    distribute_add_activity!
     render json: @status, serializer: REST::StatusSerializer
   end
 
   def destroy
     pin = StatusPin.find_by(account: current_account, status: @status)
-    pin&.destroy!
+
+    if pin
+      pin.destroy!
+      distribute_remove_activity!
+    end
+
     render json: @status, serializer: REST::StatusSerializer
   end
 
@@ -25,4 +31,24 @@ class Api::V1::Statuses::PinsController < Api::BaseController
   def set_status
     @status = Status.find(params[:status_id])
   end
+
+  def distribute_add_activity!
+    json = ActiveModelSerializers::SerializableResource.new(
+      @status,
+      serializer: ActivityPub::AddSerializer,
+      adapter: ActivityPub::Adapter
+    ).as_json
+
+    ActivityPub::RawDistributionWorker.perform_async(Oj.dump(json), current_account)
+  end
+
+  def distribute_remove_activity!
+    json = ActiveModelSerializers::SerializableResource.new(
+      @status,
+      serializer: ActivityPub::RemoveSerializer,
+      adapter: ActivityPub::Adapter
+    ).as_json
+
+    ActivityPub::RawDistributionWorker.perform_async(Oj.dump(json), current_account)
+  end
 end