# frozen_string_literal: true

require_relative "../../spec_helper"

require_relative "../../../lib/ultravisor/child"
require_relative "../../../lib/ultravisor/error"

class CastCallTest
  def run
  end

  def poke_processor
    process_castcall
  end
end

describe Ultravisor::Child do
  let(:child) { Ultravisor::Child.new(**args) }
  let(:instance) { child.__send__(:new_instance) }

  describe "#cast" do
    context "without enable_castcall" do
      let(:args) do
        {
          id: :cast_child,
          klass: CastCallTest,
          method: :run,
        }
      end

      it "does not accept calls to #cast" do
        expect { child.cast }.to raise_error(NoMethodError)
      end
    end

    context "with enable_castcall" do
      let(:args) do
        {
          id: :cast_child,
          klass: CastCallTest,
          method: :run,
          enable_castcall: true,
        }
      end

      before(:each) do
        # Got to have an instance otherwise all hell breaks loose
        child.instance_variable_set(:@instance, instance)

        # So we can check if and when it's been called
        allow(instance).to receive(:to_s).and_call_original
      end

      it "accepts calls to #cast" do
        expect { child.cast }.to_not raise_error
      end

      it "does not accept cast calls to methods that do not exist on the worker object" do
        expect { child.cast.flibbetygibbets }.to raise_error(NoMethodError)
      end

      it "does not accept cast calls to private methods on the worker object" do
        expect { child.cast.eval }.to raise_error(NoMethodError)
      end

      it "accepts calls to methods that exist on the worker object" do
        expect { child.cast.to_s }.to_not raise_error
      end

      it "calls the instance method only when process_castcall is called" do
        child.cast.to_s
        expect(instance).to_not have_received(:to_s)
        instance.poke_processor
        expect(instance).to have_received(:to_s)
      end

      it "processes all the queued method calls" do
        child.cast.to_s
        child.cast.to_s
        child.cast.to_s
        child.cast.to_s
        child.cast.to_s
        expect(instance).to_not have_received(:to_s)
        instance.poke_processor
        expect(instance).to have_received(:to_s).exactly(5).times
      end

      let(:cc_fd) { instance.__send__(:castcall_fd) }
      it "marks the castcall_fd as readable only after cast is called" do
        expect(IO.select([cc_fd], nil, nil, 0)).to eq(nil)

        child.cast.to_s

        expect(IO.select([cc_fd], nil, nil, 0)).to eq([[cc_fd], [], []])
      end

      it "does not have a readable castcall_fd after process_castcall" do
        child.cast.to_s
        expect(IO.select([cc_fd], nil, nil, 0)).to eq([[cc_fd], [], []])
        instance.poke_processor
        expect(IO.select([cc_fd], nil, nil, 0)).to eq(nil)
      end

      it "does not explode if the instance is dying" do
        instance.instance_variable_get(:@ultravisor_child_castcall_queue).close

        expect { child.cast.to_s }.to_not raise_error
      end
    end
  end
end