defmodule Scopes.CSys do
  alias Scopes.Core.Actor

  def neuron(scope) do
    Actor.create(fn msg -> process(msg, scope) end)
  end

  def synapse(rcvr, op) do
    fn msg -> Actor.send(rcvr, op.(msg)) end
  end

  # predefined neuron processors

  def process(msg, scope) do
    proc(scope).(msg, scope)
  end

  def echo(msg, scope) do
    send(env(scope), msg)
  end

  def forward(msg, scope) do
    Enum.reduce(syns(scope), false, fn s, _acc -> s.(msg) end)
  end

  def std_proc({:parent}, scope) do
    syn = synapse(self(), &Function.identity/1)
    new = neuron({[], [&std_proc/2], [syn], env(scope)})
    # send(env(scope), {:created, new})
    echo({:created, new}, scope)
  end

  def std_proc(msg, scope) do
    unless forward(msg, scope), do: echo(msg, scope)
  end

  # helper functions

  def proc(scope), do: hd(code(scope))

  def state(scope), do: elem(scope, 0)
  def code(scope), do: elem(scope, 1)
  def syns(scope), do: elem(scope, 2)
  def env(scope), do: elem(scope, 3)
end