Merge branch 'origin/master' into sync/upstream

 Conflicts:
	app/javascript/mastodon/components/status_list.js
	app/javascript/mastodon/features/notifications/index.js
	app/javascript/mastodon/features/ui/components/modal_root.js
	app/javascript/mastodon/features/ui/components/onboarding_modal.js
	app/javascript/mastodon/features/ui/index.js
	app/javascript/styles/about.scss
	app/javascript/styles/accounts.scss
	app/javascript/styles/components.scss
	app/presenters/instance_presenter.rb
	app/services/post_status_service.rb
	app/services/reblog_service.rb
	app/views/about/more.html.haml
	app/views/about/show.html.haml
	app/views/accounts/_header.html.haml
	config/webpack/loaders/babel.js
	spec/controllers/api/v1/accounts/credentials_controller_spec.rb

1 files changed, 71 insertions, 0 deletions

diff --git a/app/lib/activitypub/activity/undo.rb b/app/lib/activitypub/activity/undo.rb
new file mode 100644
index 000000000..4b0905de2
--- /dev/null
+++ b/app/lib/activitypub/activity/undo.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+class ActivityPub::Activity::Undo < ActivityPub::Activity
+  def perform
+    case @object['type']
+    when 'Announce'
+      undo_announce
+    when 'Follow'
+      undo_follow
+    when 'Like'
+      undo_like
+    when 'Block'
+      undo_block
+    end
+  end
+
+  private
+
+  def undo_announce
+    status = Status.find_by(uri: object_uri, account: @account)
+
+    if status.nil?
+      delete_later!(object_uri)
+    else
+      RemoveStatusService.new.call(status)
+    end
+  end
+
+  def undo_follow
+    target_account = account_from_uri(target_uri)
+
+    return if target_account.nil? || !target_account.local?
+
+    if @account.following?(target_account)
+      @account.unfollow!(target_account)
+    elsif @account.requested?(target_account)
+      FollowRequest.find_by(account: @account, target_account: target_account)&.destroy
+    else
+      delete_later!(object_uri)
+    end
+  end
+
+  def undo_like
+    status = status_from_uri(target_uri)
+
+    return if status.nil? || !status.account.local?
+
+    if @account.favourited?(status)
+      favourite = status.favourites.where(account: @account).first
+      favourite&.destroy
+    else
+      delete_later!(object_uri)
+    end
+  end
+
+  def undo_block
+    target_account = account_from_uri(target_uri)
+
+    return if target_account.nil? || !target_account.local?
+
+    if @account.blocking?(target_account)
+      UnblockService.new.call(@account, target_account)
+    else
+      delete_later!(object_uri)
+    end
+  end
+
+  def target_uri
+    @target_uri ||= value_or_id(@object['object'])
+  end
+end