defmodule NOP.Element.Rule do
  defmacro __using__([]) do
    quote do
      use GenServer
      use NOP.Element.LogicElement

      def start_link(rule_name, fbe_list) do

        #create_element_list needs to be defined!
        element_list = create_element_list(fbe_list)

        # create_instigation_list needs to be defined
        instigation_list = create_instigation_list(fbe_list)

        state = init_state(rule_name, element_list, instigation_list)

        state = init_condition_list(state)

        state = reset_statistics_to_state(state)

        state = set_name(state, rule_name)

        #{:ok, pid} = GenServer.start_link(__MODULE__, state, name: String.to_atom(rule_name))
        {:ok, pid} = GenServer.start_link(__MODULE__, state)

        link_to_elements(element_list, pid, rule_name)

        {:ok, pid}
      end

      def init(state) do
        {:ok, state}
      end

      def handle_cast(:run_manual, state) do
        Logger.debug("Rule #{get_name(state)} launching instigatins manualy")

        run_instigations(state)

        {:noreply, state}
      end

      defp init_state(rule_name, element_list, instigation_list) do

        values = evaluate_elements(rule_name, element_list)

        result = evaluate_rule(rule_name, values)

        %{
          :name => rule_name,
          :element_list => element_list,
          :values => values,
          :result => result,
          :instigation_list => instigation_list
        }
      end

      defp get_instigation_list_from_state(state) do
        Map.get(state, :instigation_list)
      end

      defp evaluate_rule(rule_name, premise_list) do
        premise_aux = Map.to_list(premise_list)

        result = evaluate_rule_int(premise_aux, true)

        Logger.debug(
          "Evaluating rule #{rule_name} with conditions #{inspect(premise_aux)} = #{result}"
        )

        result
      end

      defp evaluate_rule_int(_any, false) do
        #Stop assert on first false
        false
      end

      defp evaluate_rule_int([], result) do
        result
      end

      defp evaluate_rule_int([{_name, assert} | element_list], result) do
        evaluate_rule_int(element_list, result and assert)
      end

      defp run_instigations(state) do
        # Run each instigation in a separated task
        instigation_list = get_instigation_list_from_state(state)

        run_instigations_int(instigation_list)
      end

      defp run_instigations_int([]) do
        # Finished
      end

      defp run_instigations_int([{module, method, args} | instigation_list]) do
        Task.start(module, method, args)

        run_instigations_int(instigation_list)
      end

      defp run_instigations_int([method | instigation_list]) do
        Task.start(method)

        run_instigations_int(instigation_list)
      end

      defp update_my_state(state, name, _element_name, element_values, old_result) do
        result = evaluate_rule(name, element_values)

        if result != old_result and result do
          Logger.debug("Rule #{name} launching instigations after assert true")

          run_instigations(state)
        end

        result
      end
    end
  end

end