# This extension redefines the default behaviour of acts_as_tree function
# to allow you to override the :dependent option for your trees
# The default value defined in Rails is :destroy, but sometime you might want to use
# a different cascade delete logic, or don't use cascade deleted at all.
# 
# Usage:
# 1. put this file into /lib/active_record_ext/ folder inside your rails application
# 2. add the following string somewhere in the environment.rb file:
#     require 'active_record_ext/tree'
# 
# This fix implements patch submitted to Rails development site, but not yet implemented
# in main trunk of Rails. More info available at this link:
# http://dev.rubyonrails.org/attachment/ticket/1924/allow_override_of_default_dependent_option_in_acts_as_tree.patch
# 
# This extension should work without problems on Rails 1.2x, but of course I can not be held responsible
# for any damage/loss/etc it might cause.
#
# http://macdiggs.com/index.php/2007/09/20/override-destroy-parameter-in-acts_as_tree-in-rails/

module ActiveRecord
  module Acts
    module Tree
      module ClassMethods
        def acts_as_tree(options = {})
          configuration = { :foreign_key => "parent_id", :order => nil, :counter_cache => nil, :dependent => :destroy } 
          configuration.update(options) if options.is_a?(Hash)

          belongs_to :parent, :class_name => name, :foreign_key => configuration[:foreign_key], :counter_cache => configuration[:counter_cache]
          has_many :children, :class_name => name, :foreign_key => configuration[:foreign_key], :order => configuration[:order], :dependent => configuration[:dependent] 

          class_eval <<-EOV
            include ActiveRecord::Acts::Tree::InstanceMethods

            def self.roots
              find(:all, :conditions => "#{configuration[:foreign_key]} IS NULL", :order => #{configuration[:order].nil? ? "nil" : %Q{"#{configuration[:order]}"}})
            end

            def self.root
              find(:first, :conditions => "#{configuration[:foreign_key]} IS NULL", :order => #{configuration[:order].nil? ? "nil" : %Q{"#{configuration[:order]}"}})
            end
          EOV
        end
      end
    end
  end
end