mongoid_persistence.rb

require_relative 'base'

module AASM
  module Persistence
    module MongoidPersistence
      # This method:
      #
      # * extends the model with ClassMethods
      # * includes InstanceMethods
      #
      # Adds
      #
      #   before_validation :aasm_ensure_initial_state
      #
      # As a result, it doesn't matter when you define your methods - the following 2 are equivalent
      #
      #   class Foo
      #     include Mongoid::Document
      #     def aasm_write_state(state)
      #       "bar"
      #     end
      #     include AASM
      #   end
      #
      #   class Foo
      #     include Mongoid::Document
      #     include AASM
      #     def aasm_write_state(state)
      #       "bar"
      #     end
      #   end
      #
      def self.included(base)
        base.send(:include, AASM::Persistence::Base)
        base.send(:include, AASM::Persistence::MongoidPersistence::InstanceMethods)

        base.after_initialize :aasm_ensure_initial_state
      end

      module InstanceMethods

        # Writes <tt>state</tt> to the state column and persists it to the database
        # using update_attribute (which bypasses validation)
        #
        #   foo = Foo.find(1)
        #   foo.aasm.current_state # => :opened
        #   foo.close!
        #   foo.aasm.current_state # => :closed
        #   Foo.find(1).aasm.current_state # => :closed
        #
        # NOTE: intended to be called from an event
        def aasm_write_state(state, name=:default)
          old_value = read_attribute(self.class.aasm(name).attribute_name)
          write_attribute(self.class.aasm(name).attribute_name, state.to_s)

          unless self.save(:validate => false)
            write_attribute(self.class.aasm(name).attribute_name, old_value)
            return false
          end

          true
        end

        # Writes <tt>state</tt> to the state column, but does not persist it to the database
        #
        #   foo = Foo.find(1)
        #   foo.aasm.current_state # => :opened
        #   foo.close
        #   foo.aasm.current_state # => :closed
        #   Foo.find(1).aasm.current_state # => :opened
        #   foo.save
        #   foo.aasm.current_state # => :closed
        #   Foo.find(1).aasm.current_state # => :closed
        #
        # NOTE: intended to be called from an event
        def aasm_write_state_without_persistence(state, name=:default)
          write_attribute(self.class.aasm(name).attribute_name, state.to_s)
        end

      private

        # Ensures that if the aasm_state column is nil and the record is new
        # that the initial state gets populated before validation on create
        #
        #   foo = Foo.new
        #   foo.aasm_state # => nil
        #   foo.valid?
        #   foo.aasm_state # => "open" (where :open is the initial state)
        #
        #
        #   foo = Foo.find(:first)
        #   foo.aasm_state # => 1
        #   foo.aasm_state = nil
        #   foo.valid?
        #   foo.aasm_state # => nil
        #
        def aasm_ensure_initial_state
          AASM::StateMachine[self.class].keys.each do |state_machine_name|
            send("#{self.class.aasm(state_machine_name).attribute_name}=", aasm(state_machine_name).enter_initial_state.to_s) if send(self.class.aasm(state_machine_name).attribute_name).blank?
          end
        end
      end # InstanceMethods

      # module NamedScopeMethods
      #   def aasm_state_with_named_scope name, options = {}
      #     aasm_state_without_named_scope name, options
      #     self.named_scope name, :conditions => { "#{table_name}.#{self.aasm.attribute_name}" => name.to_s} unless self.respond_to?(name)
      #   end
      # end
    end
  end # Persistence
end # AASM