Finite

require 'finite'

class Elevator
    include Finite

    def initialize
        @broken = false
    end

    finite initial: :idle do

        before do
            "This is called before every state but has no purpose other than to show its existence in this example."
        end

        before :doors_closing do
            puts 'Doors Closing!'
        end

        before :doors_opening do
            puts 'Doors Opening!'
        end

        event :prepare do
            go from: :idle, to: :doors_closing, if: -> { not @broken }
        end

        event :go_up do
            go from: :doors_closing, to: :elevator_going_up
            after do
                puts 'Going Up!'
            end
        end

        event :go_down do
            go from: :doors_closing, to: :elevator_going_down
            after do
                puts 'Going Down!'
            end
        end

        event :start do
            go from: [:elevator_going_up, :elevator_going_down], to: :moving
        end

        event :approach do
            go from: :moving, to: :stopping
        end

        event :stop do
            go from: :stopping, to: :doors_opening
            before do
                announce_floor
            end
        end

        event :open_doors do
            go from: :doors_opening, to: :at_floor
        end

        event :finish do
            go from: :at_floor, to: :checking_next_dest
        end

        event :make_request do
            go from: :checking_next_dest, to: :doors_closing
        end

        event :make_no_request do
            go from: :checking_next_dest, to: :idle
        end
    end

    def announce_floor
        puts "Arriving on floor #{rand(10)}"
    end
end

elevator = Elevator.new
elevator.current_state          # => :idle
elevator.can_prepare?           # => true
elevator.can_open_doors?        # => false
elevator.open_doors             # => Finite::Error 'Invalid Transition'
elevator.idle?                  # => true
elevator.prepare                # => 'Doors Closing!'
elevator.current_state          # => :doors_closing
elevator.possible_events        # => [:go_up, :go_down]