defmodule Grizzly.ZWave.Commands.UserCodeUsersNumberReport do
  @moduledoc """
  Gets the number of supported user codes

  Params:

    * `supported_users` - the number of supported users (required)
    * `extended_supported_users` - if different, the total amount of supported users (required - v2 and above)

  """

  @behaviour Grizzly.ZWave.Command

  alias Grizzly.ZWave.Command
  alias Grizzly.ZWave.CommandClasses.UserCode

  @type param :: {:supported_users, byte()}

  @impl true
  @spec new([param()]) :: {:ok, Command.t()}
  def new(params) do
    command = %Command{
      name: :user_code_users_number_report,
      command_byte: 0x05,
      command_class: UserCode,
      params: params,
      impl: __MODULE__
    }

    {:ok, command}
  end

  @impl true
  def encode_params(command) do
    extended_supported_users = Command.param(command, :extended_supported_users)

    if extended_supported_users == nil do
      <<Command.param!(command, :supported_users)>>
    else
      # Version 2
      <<Command.param!(command, :supported_users), extended_supported_users::size(16)>>
    end
  end

  @impl true
  # Version 1
  def decode_params(<<supported_users>>) do
    {:ok, [supported_users: supported_users]}
  end

  def decode_params(<<supported_users, extended_supported_users::size(16)>>) do
    {:ok, [supported_users: supported_users, extended_supported_users: extended_supported_users]}
  end
end