+
+ def follow_changeset(struct, params \\ %{}) do
+ struct
+ |> cast(params, [:following])
+ |> validate_required([:following])
+ end
+
+ def follow(%User{} = follower, %User{} = followed) do
+ ap_followers = User.ap_followers(followed)
+ following = [ap_followers | follower.following]
+ |> Enum.uniq
+
+ follower
+ |> follow_changeset(%{following: following})
+ |> Repo.update
+ end
+
+ def unfollow(%User{} = follower, %User{} = followed) do
+ ap_followers = User.ap_followers(followed)
+ following = follower.following
+ |> List.delete(ap_followers)
+
+ follower
+ |> follow_changeset(%{following: following})
+ |> Repo.update
+ end
+
+ def following?(%User{} = follower, %User{} = followed) do
+ Enum.member?(follower.following, User.ap_followers(followed))
+ end