pixie

defmodule Pixie.Message.Handshake do
  defstruct channel: nil, version: nil, supported_connection_types: nil, minimum_version: nil, ext: nil, id: nil

  @moduledoc """
  Convert an incomikng handshake message into a struct.

      Request
      MUST include:  * channel
                     * version
                     * supportedConnectionTypes
      MAY include:   * minimumVersion
                     * ext
                     * id

  This struct contains the following keys:

    - `:channel` always `"/meta/disconnect"`.
    - `:version` the Bayeux version the client requires.
    - `:supported_connection_types` the connection types (transports) that the
      client is capable of negotiating.
    - `:minimum_version` the minimum Bayeux version the client requires. Optional.
    - `:ext` an arbitrary map of data the client sent for use in extensions
      (usually authentication information, etc). Optional.
    - `:id` a message ID generated by the client. Optional.
  """

  def init %{}=message do
    %Pixie.Message.Handshake{}
      |> get(message, :channel)
      |> get(message, :version)
      |> get(message, :supported_connection_types)
      |> get(message, :minimum_version)
      |> get(message, :ext)
      |> get(message, :id)
  end

  def get handshake, message, :supported_connection_types=field do
    case Map.get message, field do
      ct when is_list(ct) ->
        Map.put handshake, field, Enum.into(ct, HashSet.new)
      _ ->
        handshake
    end
  end

  def get(h,m,f), do: Pixie.Utils.Message.get(h,m,f)
end