eml_rtmp_session

defmodule RtmpSession.Messages.Amf0Command do
  @moduledoc """

  Message used to denote an amf0 encoded command (or resposne to a command)

  """

  @behaviour RtmpSession.RawMessage
  @type t :: %__MODULE__{}
  
  defstruct command_name: nil,
            transaction_id: nil,
            command_object: nil,
            additional_values: []
  
  def deserialize(data) do
    {:ok, objects} = get_data(data) |> Amf0.deserialize()
    [command_name, transaction_id, command_object | rest] = objects

    %__MODULE__{
      command_name: command_name,
      transaction_id: transaction_id,
      command_object: command_object,
      additional_values: rest
    }
  end
  
  def serialize(message = %__MODULE__{}) do
    objects = [message.command_name, message.transaction_id, message.command_object | message.additional_values]
    
    {:ok, Amf0.serialize(objects)} 
  end
  
  def get_default_chunk_stream_id(%__MODULE__{}),  do: 3

  # For some reason AMF3 commands are just AMF0 encoded commands with a zero in front of it

  # so remove the zero

  defp get_data(<<0::8, rest::binary>>), do: rest
  defp get_data(binary), do: binary
end