defmodule Reactivity.Builtins do
  use GenServer

  alias Reactivity.Signal.Source

  require Logger

  import GenServer

  #######################
  # GenServer Interface #
  #######################

  def start_link([]) do
    start_link(__MODULE__, [], [{:name, __MODULE__}])
  end

  def init([]) do
    Logger.debug "Reactivity: Starting built-in signals.."
    {:ok, _t} = Source.new(fn(_old_value) -> Enum.random(0..500)      end, -1, 2000, :temperature)

    {:ok, _tg} = Source.new(
      fn(_old_value) -> :os.system_time(:second) end, 
     :os.system_time(:second), 
     1000, 
     :seconds)
     
    {:ok, _tg} = Source.new(
      fn(_old_value) -> round(:os.system_time(:seconds) / 60) end, 
      round(:os.system_time(:seconds) / 60), 
      1000 * 60, 
      :minutes)

    {:ok, _tg} = Source.new(
      fn(_old_value) -> :os.system_time(:second) end, 
      round(:os.system_time(:seconds) / (60 * 60)), 
      1000 * 60 * 60, 
      :hours)
    Logger.debug "Done"
    {:ok, %{}}
  end

end