defmodule MTProto.Session.Brain do
  require Logger
  alias MTProto.{Auth, Registry}
  alias MTProto.Session.Handler

  @moduledoc false

  # Process a plain message
  def process(msg, session_id, :plain) do
    name = Map.get(msg, :name)

    case name do
      "resPQ" -> Auth.resPQ(msg, session_id)
      "server_DH_params_ok" -> Auth.server_DH_params_ok(msg, session_id)
      "server_DH_params_fail" -> Auth.server_DH_params_fail(msg, session_id)
      "dh_gen_ok" -> Auth.dh_gen_ok(msg, session_id)
      "dh_gen_fail" -> Auth.dh_gen_fail(msg, session_id)
      "dh_gen_retry" -> Auth.dh_gen_fail(msg, session_id)
      "error" ->
        if Map.get(msg, :code) == -404 do
          session = Registry.get(:session, session_id)
          dc = Registry.get(:dc, session.dc)
          if dc.auth_key == <<0::8*8>> do
            Logger.debug "[Brain] I received a -404 error. I still don't have an auth key
            for this DC (#{dc.id}). Generating authorization key."
            Auth.req_pq(session_id)
          else
            Logger.warn "[Brain] Received error. I don't know what to do !"
          end
        end
      _ ->
        Logger.debug "[Brain] #{session_id} : received an unknow predicate #{name}."
    end
  end

  # Process an encrypted message
  def process(msg, session_id, :encrypted) do
    session = Registry.get :session, session_id
    name = Map.get(msg, :name)

    # Process RPC
    if name == "rpc_result" do
      result = Map.get msg, :result
      name = result |> Map.get(:name)

      case name do
        "auth.sentCode" ->
          hash = Map.get result, :phone_code_hash
          Registry.set :session, session_id, :phone_code_hash, hash
          _ -> :noop
      end

      # ACK
      msg_ids = [Map.get(msg, :msg_id)]
      ack = MTProto.Method.msgs_ack(msg_ids)
      Handler.send_encrypted(ack, session_id)
    end

    # Notify the client
    if session.client != nil do
      send session.client, {:recv, session_id, msg}
    else
      IO.puts "No client for #{session_id}, printing to console."
      IO.inspect {session_id, msg}
    end
  end
end