1 files changed, 63 insertions, 1 deletions
diff --git a/lib/pleroma/web/activity_pub/builder.ex b/lib/pleroma/web/activity_pub/builder.ex
index 429a510b8..922a444a9 100644
--- a/lib/pleroma/web/activity_pub/builder.ex
+++ b/lib/pleroma/web/activity_pub/builder.ex
@@ -10,8 +10,71 @@ defmodule Pleroma.Web.ActivityPub.Builder do
   alias Pleroma.Web.ActivityPub.Utils
   alias Pleroma.Web.ActivityPub.Visibility
 
+  @spec emoji_react(User.t(), Object.t(), String.t()) :: {:ok, map(), keyword()}
+  def emoji_react(actor, object, emoji) do
+    with {:ok, data, meta} <- object_action(actor, object) do
+      data =
+        data
+        |> Map.put("content", emoji)
+        |> Map.put("type", "EmojiReact")
+
+      {:ok, data, meta}
+    end
+  end
+
+  @spec undo(User.t(), Activity.t()) :: {:ok, map(), keyword()}
+  def undo(actor, object) do
+    {:ok,
+     %{
+       "id" => Utils.generate_activity_id(),
+       "actor" => actor.ap_id,
+       "type" => "Undo",
+       "object" => object.data["id"],
+       "to" => object.data["to"] || [],
+       "cc" => object.data["cc"] || []
+     }, []}
+  end
+
+  @spec delete(User.t(), String.t()) :: {:ok, map(), keyword()}
+  def delete(actor, object_id) do
+    object = Object.normalize(object_id, false)
+
+    user = !object && User.get_cached_by_ap_id(object_id)
+
+    to =
+      case {object, user} do
+        {%Object{}, _} ->
+          # We are deleting an object, address everyone who was originally mentioned
+          (object.data["to"] || []) ++ (object.data["cc"] || [])
+
+        {_, %User{follower_address: follower_address}} ->
+          # We are deleting a user, address the followers of that user
+          [follower_address]
+      end
+
+    {:ok,
+     %{
+       "id" => Utils.generate_activity_id(),
+       "actor" => actor.ap_id,
+       "object" => object_id,
+       "to" => to,
+       "type" => "Delete"
+     }, []}
+  end
+
   @spec like(User.t(), Object.t()) :: {:ok, map(), keyword()}
   def like(actor, object) do
+    with {:ok, data, meta} <- object_action(actor, object) do
+      data =
+        data
+        |> Map.put("type", "Like")
+
+      {:ok, data, meta}
+    end
+  end
+
+  @spec object_action(User.t(), Object.t()) :: {:ok, map(), keyword()}
+  defp object_action(actor, object) do
     object_actor = User.get_cached_by_ap_id(object.data["actor"])
 
     # Address the actor of the object, and our actor's follower collection if the post is public.
@@ -33,7 +96,6 @@ defmodule Pleroma.Web.ActivityPub.Builder do
      %{
        "id" => Utils.generate_activity_id(),
        "actor" => actor.ap_id,
-       "type" => "Like",
        "object" => object.data["id"],
        "to" => to,
        "cc" => cc,