1 files changed, 69 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..078e97ed4
--- /dev/null
+++ b/app/lib/activitypub/activity/undo.rb
@@ -0,0 +1,69 @@
+# 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)
+    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 ||= @object['object'].is_a?(String) ? @object['object'] : @object['object']['id']
+  end
+end