defmodule SingleDep do
  
  require Integer
  require Logger
  
  use Reactivity
  
  @moduledoc """

  SingleDep shows how to use Reactivity with a single dependency.

  We initialize the system by creating two source signals. 
  These signals take in:
   - A function that takes one parameter (it's previous value).
   - An initial value.
   - An rate of value generation (ms).
   - A name.
   
  We create temperature and seconds. 

  In the app() function we create a new signal "hot_cold" that will produce a
  pepper emoji or a snowflake emoji based on the temperature.

  Then we apply a new function to that that prints out the current value.

  Finally we create a 

  """  

  def hot_cold(t) do
    if t > 300 do
      :"🌶️"
    else
      :"❄️"
    end
  end

  def app do
    # Create a new signal :hotcold based on the source :temperature.
    source(:temperature)
    |> liftapp(&hot_cold/1)
    |> register(:hotcold)
  

    # Map a print function on the hotcold signal.
    source(:hotcold)
    |> liftapp(fn(x) -> IO.puts x end)
    
    # # Create a new signal :kelvin based on the source :temperature
    source(:temperature)
    |> liftapp(&(&1 + 237.15))
    |> register(:kelvin)
    |> liftapp(&(IO.puts &1))
  end
end