Cancelable jobs for Rails active jobs

module Cancelable
  extend ActiveSupport::Concern

  included do
    around_perform do |job, perform|
      perform.call unless Cancelable.allowed?

      if Cancelable.allowed?
        file_name = "jobs/#{job.class.name.underscore}.rb"
        constant_name = Cancelable.setting_name(job.class)

        setting = Setting.find_or_create_by(name: constant_name) do |new_setting|
          new_setting.value = Cancelable.default_setting_for(constant_name, default: true)
          new_setting.description = "Automatically created in #{file_name}"
        end

        if setting.value
          perform.call
        else
          Rails.logger.info "♦ Job #{job.class} is disabled (#{Rails.application.routes.url_helpers.admin_setting_url(setting)})"
        end
      end
    end
  end

  def self.allowed?
    Rails.env.development?
  end

  def self.setting_name(clazz)
    clazz.name
  end

  def self.default_setting_for(constant_name, default:)
    value = YAML.load_file("config/default_jobs.yml").dig(constant_name)
    value.nil? ? default : value
  end
end

class MyJob < ApplicationJob
  include Cancelable

  def perform
    # do something
  end
end

class CancelableTestJob < ApplicationJob
  def perform = CheckIn.do!("Test", reporting_interval: 5.minutes, grace_period: 3.minutes)
end

describe Cancelable do
  subject(:test_job) { CancelableTestJob.new }

  before { allow(CheckIn).to receive(:do!) }

  context "when cancelable is not active" do
    before { allow(Cancelable).to receive(:allowed?).and_return(false) }

    it "can not be canceled with a default config" do
      allow(Cancelable).to receive(:default_setting_for).with("CancelableTestJob", default: anything).and_return(false)

      test_job.perform_now

      expect(CheckIn).to have_received(:do!)
      expect(Setting).to have(0).settings
    end
  end

  context "when cancelable is active" do
    before { allow(Cancelable).to receive(:allowed?).and_return(true) }

    it "is executed and creates a new setting with a true value" do
      test_job.perform_now

      expect(CheckIn).to have_received(:do!)
      expect(Setting).to have(1).setting
      expect(Setting.first.name).to eq "CancelableTestJob"
      expect(Setting.first.value).to eq true
    end

    it "can be canceled with a default config" do
      allow(Cancelable).to receive(:default_setting_for).with("CancelableTestJob", default: anything).and_return(false)

      test_job.perform_now

      expect(CheckIn).not_to have_received(:do!)
      expect(Setting).to have(1).setting
      expect(Setting.first.name).to eq "CancelableTestJob"
      expect(Setting.first.value).to eq false
    end

    it "can be allowed with a default config" do
      allow(Cancelable).to receive(:default_setting_for).with("CancelableTestJob", default: anything).and_return(true)

      test_job.perform_now

      expect(CheckIn).to have_received(:do!)
      expect(Setting).to have(1).setting
      expect(Setting.first.name).to eq "CancelableTestJob"
      expect(Setting.first.value).to eq true
    end

    describe ".setting_name" do
      it "returns the name of a setting" do
        expect(Cancelable.setting_name(Tesla::DetectPluggedInJob)).to eq "Tesla::DetectPluggedInJob"
      end
    end
  end
end