defmodule Mobilizon.Service.ActivityPub.Converter.Actor do
  @moduledoc """
  Actor converter.

  This module allows to convert events from ActivityStream format to our own
  internal one, and back.
  """

  alias Mobilizon.Actors.Actor, as: ActorModel
  alias Mobilizon.Service.ActivityPub.{Converter, Convertible}

  @behaviour Converter

  defimpl Convertible, for: ActorModel do
    alias Mobilizon.Service.ActivityPub.Converter.Actor, as: ActorConverter

    defdelegate model_to_as(actor), to: ActorConverter
  end

  @doc """
  Converts an AP object data to our internal data structure.
  """
  @impl Converter
  @spec as_to_model_data(map) :: map
  def as_to_model_data(object) do
    avatar =
      object["icon"]["url"] &&
        %{
          "name" => object["icon"]["name"] || "avatar",
          "url" => object["icon"]["url"]
        }

    banner =
      object["image"]["url"] &&
        %{
          "name" => object["image"]["name"] || "banner",
          "url" => object["image"]["url"]
        }

    %{
      "type" => String.to_existing_atom(object["type"]),
      "preferred_username" => object["preferredUsername"],
      "summary" => object["summary"],
      "url" => object["id"],
      "name" => object["name"],
      "avatar" => avatar,
      "banner" => banner,
      "keys" => object["publicKey"]["publicKeyPem"],
      "manually_approves_followers" => object["manuallyApprovesFollowers"]
    }
  end

  @doc """
  Convert an actor struct to an ActivityStream representation.
  """
  @impl Converter
  @spec model_to_as(ActorModel.t()) :: map
  def model_to_as(%ActorModel{} = actor) do
    %{
      "type" => Atom.to_string(actor.type),
      "to" => ["https://www.w3.org/ns/activitystreams#Public"],
      "preferred_username" => actor.preferred_username,
      "name" => actor.name,
      "summary" => actor.summary,
      "following" => ActorModel.build_url(actor.preferred_username, :following),
      "followers" => ActorModel.build_url(actor.preferred_username, :followers),
      "inbox" => ActorModel.build_url(actor.preferred_username, :inbox),
      "outbox" => ActorModel.build_url(actor.preferred_username, :outbox),
      "id" => ActorModel.build_url(actor.preferred_username, :page),
      "url" => actor.url
    }
  end
end