defmodule PotionIngredients.Plugs.AppToken do
  alias Plug.Conn

  def get_user(conn, opts) do
    secret = opts.secret

    signer = Joken.Signer.create("HS256", secret)

    headers = conn.req_headers

    {"app_token", app_token} = Enum.find(headers, fn {key, _header} -> key == "app_token" end)

    app_token
    |> case do
      nil ->
        Conn.resp(conn, :forbidden, Poison.encode!(%{msg: "invalid.token", code: 009}))
        |> Conn.put_resp_content_type("application/json")
        |> Conn.halt()

      token ->
        get_user_from_token(token, signer)
    end
    |> case do
      nil ->
        Conn.resp(conn, :forbidden, Poison.encode!(%{msg: "invalid.token", code: 009}))
        |> Conn.put_resp_content_type("application/json")
        |> Conn.halt()

      app_token ->
        Conn.put_req_header(conn, "app_token", Poison.encode!(app_token))
    end
  end

  defp get_user_from_token(token, signer) do
    PotionIngredients.Utils.Token.verify_and_validate(token, signer)
    |> case do
      {:ok, decoded} -> decoded
      _ -> nil
    end
  end
end