require "mongoid_revisions/version"

module Mongoid
	module Revisions
		extend ActiveSupport::Concern

			included do
				field :revision, :type => Integer, :default => 0
				field :tag, :type => String, :default => "0.0.0"
				field :token, :type => String

				set_callback :create, :before, :create_unique_token
			end

			# BLOCK ACCESS TO REVISION ATTRIBUTE
			def revision=(rev)
				# DOES NOTHING
			end

			def token=(tok)
			end

			# RETURN ALL REVISIONS FOR THIS DOCUMENT
			def revisions
				self.class.where(:token=>self.token).order_by([[:revision,:asc]])
			end 

			# ASSIGN A NEW TAG TO THIS REVISION
			def tag_revision(tag)
				self.tag=tag
				self.save
			end

			# CREATE A NEW REVISION FOR THE DOCUMENT
			def revise
				new_revision = self.class.create self.attributes.except("_id")
				new_revision._token = self.token
				new_revision._revision = (self.revision || 1) + 1
				new_revision.tag = "#{new_revision.revision}.0.0"
				new_revision.save
				self.relations.each do |relation|
          metadata = self.class.reflect_on_association(relation[0])
          metadata.class_name.constantize.where(metadata.foreign_key.to_sym=>self.id).each do |child|
            new_child = metadata.class_name.constantize.create child.attributes.except("_id")
            new_child.revision = child.revision+1
            new_child.tag = "#{new_child.revision}.0.0"
						new_child[metadata.foreign_key.to_sym]=new_revision.id
            new_child.save
          end
        end
	    end

  	  protected

			def _revision=(rev)
				self[:revision]=rev
			end

			def _token=(tok)
				self[:token]=tok
			end

      # CREATE A UNIQUE ID FOR THE DOCUMENT BUT ONLY IF TOKEN IS EMPTY
      def create_unique_token
        self._token=SecureRandom.hex(16) if self.token.nil?
      end
  end
end