Add unfollowing remote users

lib/clacks/activitypub.ex

@@ -132,6 +132,19 @@ defmodule Clacks.ActivityPub do
     }
   end
 
+  @spec undo_follow(actor :: String.t(), follow_activity :: map()) :: map()
+  def undo_follow(actor, %{"object" => followee} = follow_activity) do
+    %{
+      "@context" => @context,
+      "type" => "Undo",
+      "id" => activity_id(Ecto.UUID.generate()),
+      "actor" => actor,
+      "object" => follow_activity,
+      "to" => [followee],
+      "cc" => []
+    }
+  end
+
   @spec object_id(id :: String.t()) :: String.t()
   def object_id(id) do
     url = Application.get_env(:clacks, ClacksWeb.Endpoint)[:url]

lib/clacks/activitypub/federator.ex

@@ -67,7 +67,7 @@ defmodule Clacks.ActivityPub.Federator do
       @public in activity["to"] or @public in activity["cc"] ->
         shared_inbox_for(actor)
 
-      actor.data["followers"] in activity["to"] or actor.data["followers"] in activity["cc"] ->
+      actor["followers"] in activity["to"] or actor["followers"] in activity["cc"] ->
         shared_inbox_for(actor)
 
       true ->

lib/clacks/inbox.ex

@@ -73,7 +73,6 @@ defmodule Clacks.Inbox do
         } = activity
       ) do
     followee = Actor.get_by_ap_id(followee_id)
-    follower = Actor.get_by_ap_id(follower_id)
 
     store_activity(activity)
 
@@ -106,6 +105,8 @@ defmodule Clacks.Inbox do
 
   # as a fallback, just store the activity
   def handle(activity) do
+    Logger.debug("Unhandled activity: #{inspect(activity)}")
+
     case store_activity(activity) do
       {:error, changeset} ->
         Logger.error("Could not store activity: #{inspect(changeset)}")

lib/clacks/object.ex

@@ -54,7 +54,7 @@ defmodule Clacks.Object do
   end
 
   @spec fetch(ap_id :: String.t(), synthesize_create :: boolean(), return :: :object | :activity) ::
-          t() | nil
+          t() | Activity.t() | nil
   def fetch(ap_id, synthesize_create \\ true, return \\ :object) do
     case Clacks.ActivityPub.Fetcher.fetch_object(ap_id) do
       nil ->

lib/clacks_web/controllers/frontend_controller.ex

@@ -174,6 +174,40 @@ defmodule ClacksWeb.FrontendController do
     end
   end
 
+  def unfollow(conn, %{"id" => id}) do
+    current_user = conn.assigns[:user] |> Repo.preload(:actor)
+
+    case Repo.get(Actor, id) do
+      nil ->
+        resp(conn, 404, "Not Found")
+
+      followee ->
+        unless current_user.actor.ap_id in followee.followers do
+          redirect(conn, to: ClacksWeb.FrontendView.local_actor_link(followee))
+        else
+          new_followers = List.delete(followee.followers, current_user.actor.ap_id)
+          changeset = Actor.changeset(followee, %{followers: new_followers})
+          {:ok, followee} = Repo.update(changeset)
+
+          follow_activity = follow_activity(current_user.actor, followee)
+
+          changeset =
+            Activity.changeset(follow_activity, %{
+              data: %{follow_activity.data | "state" => "unfollowed"}
+            })
+
+          {:ok, follow_activity} = Repo.update(changeset)
+
+          undo_follow = ActivityPub.undo_follow(current_user.actor.ap_id, follow_activity.data)
+          ActivityPub.Helper.save_and_federate(undo_follow, current_user.actor)
+
+          conn
+          |> put_flash(:info, "Unfollowed")
+          |> redirect(to: ClacksWeb.FrontendView.local_actor_link(followee))
+        end
+    end
+  end
+
   def search(conn, %{"q" => q}) when is_binary(q) do
     current_user = conn.assigns[:user]
 
@@ -258,23 +292,31 @@ defmodule ClacksWeb.FrontendController do
     ActivityPub.note(current_user.actor.ap_id, content)
   end
 
-  @spec following_state(follower :: Actor.t(), followee :: Actor.t()) :: boolean()
-  defp following_state(follower, followee) do
+  @spec follow_activity(follower :: Actor.t(), followee :: Actor.t()) :: map()
+  def follow_activity(follower, followee) do
+    # todo: get latest
     query =
       Activity
       |> where([a], fragment("?->>'type'", a.data) == "Follow")
       |> where([a], fragment("?->>'actor'", a.data) == ^follower.ap_id)
       |> where([a], fragment("?->>'object'", a.data) == ^followee.ap_id)
+      |> order_by(desc: :inserted_at)
+      |> limit(1)
 
-    case Repo.one(query) do
-      nil ->
-        :not_following
+    Repo.one(query)
+  end
 
+  @spec following_state(follower :: Actor.t(), followee :: Actor.t()) :: boolean()
+  defp following_state(follower, followee) do
+    case follow_activity(follower, followee) do
       %Activity{data: %{"state" => "pending"}} ->
         :pending
 
       %Activity{data: %{"state" => "accepted"}} ->
         :following
+
+      _ ->
+        :not_following
     end
   end
 end