defmodule Scopes.CSys do
  alias Scopes.Core.Actor
  alias Scopes.CSys.Environ

  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 notify(msg, scope) do
    Environ.notify(env(scope), msg)
  end

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

  def std_proc({:parent}, scope) do
    env = env(scope)
    syn = synapse(self(), &Function.identity/1)
    new = neuron({[], Environ.get_prog(env, :basic), [syn], env})
    notify({:created, new}, scope)
  end

  def std_proc(msg, scope) do
    unless forward(msg, scope), do: notify(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