Add states to Spree::Shipment model

shipment_state_decorator.rb

Spree::Shipment.class_eval do

  scope :sent, -> { with_state('sent') }
  scope :confirmed, -> { with_state('confirmed') }

  Spree::Shipment.state_machines[:state] =
  StateMachine::Machine.new(Spree::Shipment, initial: :pending, use_transactions: false) do

    event :ready do
      transition from: :pending, to: :ready, if: lambda { |shipment|
        shipment.determine_state(shipment.order) == 'ready'
      }
    end

    event :pend do
      transition from: :ready, to: :pending
    end

    event :sent do
      transition from: :ready, to: :sent
    end
    after_transition to: :sent, do: :after_sent

    event :confirm do
      transition from: :sent, to: :confirmed
    end
    after_transition to: :confirmed, do: :after_confirmed

    event :ship do
      transition from: :confirmed, to: :shipped
    end
    after_transition to: :shipped, do: :after_ship

    event :cancel do
      transition to: :canceled, from: [:pending, :ready]
    end
    after_transition to: :canceled, do: :after_cancel

    event :resume do
      transition from: :canceled, to: :ready, if: lambda { |shipment|
        shipment.determine_state(shipment.order) == 'ready'
      }
      transition from: :canceled, to: :pending, if: lambda { |shipment|
        shipment.determine_state(shipment.order) == 'ready'
      }
      transition from: :canceled, to: :pending
    end
    after_transition from: :canceled, to: [:pending, :ready], do: :after_resume
    end

    def after_confirmed
      order.update!
    end

    def after_sent
      order.update!
    end

    def to_package
      package = Spree::Stock::Package.new(stock_location, order)
      inventory_units.includes(:variant).each do |inventory_unit|
        package.add inventory_unit.variant, 1, inventory_unit.state
      end
      package
    end

    # Determines the appropriate +state+ according to the following logic:
    #
    # pending    unless order is complete and +order.payment_state+ is +paid+
    # sent       order sent to fulfillment
    # confirmed  order line_items confirmed by fulfilment
    # shipped    if already shipped (ie. does not change the state)
    # ready      all other cases
    def determine_state(order)
      return 'canceled' if order.canceled?
      return 'pending' unless order.can_ship?
      return 'pending' if inventory_units.any? &:backordered?
      return 'shipped' if state == 'shipped'
      return 'sent' if state == 'sent'
      return 'confirmed' if state == 'confirmed'
      order.paid? ? 'ready' : 'pending'
    end
  end