# encoding: utf-8
module Mongoid #:nodoc:

  # This module contains the behaviour for getting the various states a
  # document can transition through.
  module State

    attr_writer :destroyed, :flagged_for_destroy, :new_record

    # Returns true if the +Document+ has not been persisted to the database,
    # false if it has. This is determined by the variable @new_record
    # and NOT if the object has an id.
    #
    # @example Is the document new?
    #   person.new_record?
    #
    # @return [ true, false ] True if new, false if not.
    def new_record?
      @new_record == true
    end
    alias :new? :new_record?

    # Checks if the document has been saved to the database. Returns false
    # if the document has been destroyed.
    #
    # @example Is the document persisted?
    #   person.persisted?
    #
    # @return [ true, false ] True if persisted, false if not.
    def persisted?
      !new_record? && !destroyed?
    end

    # Returns whether or not the document has been flagged for deletion, but
    # not destroyed yet. Used for atomic pulls of child documents.
    #
    # @example Is the document flagged?
    #   document.flagged_for_destroy?
    #
    # @return [ true, false ] If the document is flagged.
    #
    # @since 2.3.2
    def flagged_for_destroy?
      !!@flagged_for_destroy
    end

    # Returns true if the +Document+ has been succesfully destroyed, and false
    # if it hasn't. This is determined by the variable @destroyed and NOT
    # by checking the database.
    #
    # @example Is the document destroyed?
    #   person.destroyed?
    #
    # @return [ true, false ] True if destroyed, false if not.
    def destroyed?
      @destroyed == true
    end
    alias :deleted? :destroyed?

    # Determine if the document can be pushed.
    #
    # @example Is this pushable?
    #   person.pushable?
    #
    # @return [ true, false ] Is the document new and embedded?
    def pushable?
      new? &&
        embedded_many? &&
        _parent.persisted? &&
        !_parent.delayed_atomic_sets[metadata.name.to_s]
    end

    # Determine if the document can be set.
    #
    # @example Is this settable?
    #   person.settable?
    #
    # @return [ true, false ] Is this document a new embeds one?
    #
    # @since 2.1.0
    def settable?
      new? && embedded_one? && _parent.persisted?
    end

    # Is the document updateable?
    #
    # @example Is the document updateable?
    #   person.updateable?
    #
    # @return [ true, false ] If the document is changed and persisted.
    #
    # @since 2.1.0
    def updateable?
      persisted? && changed?
    end
  end
end