Chris@909: module CollectiveIdea #:nodoc:
Chris@909:   module Acts #:nodoc:
Chris@909:     module NestedSet #:nodoc:
Chris@909:       def self.included(base)
Chris@909:         base.extend(SingletonMethods)
Chris@909:       end
Chris@909: 
Chris@909:       # This acts provides Nested Set functionality. Nested Set is a smart way to implement
Chris@909:       # an _ordered_ tree, with the added feature that you can select the children and all of their
Chris@909:       # descendants with a single query. The drawback is that insertion or move need some complex
Chris@909:       # sql queries. But everything is done here by this module!
Chris@909:       #
Chris@909:       # Nested sets are appropriate each time you want either an orderd tree (menus,
Chris@909:       # commercial categories) or an efficient way of querying big trees (threaded posts).
Chris@909:       #
Chris@909:       # == API
Chris@909:       #
Chris@909:       # Methods names are aligned with acts_as_tree as much as possible, to make replacment from one
Chris@909:       # by another easier, except for the creation:
Chris@909:       #
Chris@909:       # in acts_as_tree:
Chris@909:       #   item.children.create(:name => "child1")
Chris@909:       #
Chris@909:       # in acts_as_nested_set:
Chris@909:       #   # adds a new item at the "end" of the tree, i.e. with child.left = max(tree.right)+1
Chris@909:       #   child = MyClass.new(:name => "child1")
Chris@909:       #   child.save
Chris@909:       #   # now move the item to its right place
Chris@909:       #   child.move_to_child_of my_item
Chris@909:       #
Chris@909:       # You can pass an id or an object to:
Chris@909:       # * <tt>#move_to_child_of</tt>
Chris@909:       # * <tt>#move_to_right_of</tt>
Chris@909:       # * <tt>#move_to_left_of</tt>
Chris@909:       #
Chris@909:       module SingletonMethods
Chris@909:         # Configuration options are:
Chris@909:         #
Chris@909:         # * +:parent_column+ - specifies the column name to use for keeping the position integer (default: parent_id)
Chris@909:         # * +:left_column+ - column name for left boundry data, default "lft"
Chris@909:         # * +:right_column+ - column name for right boundry data, default "rgt"
Chris@909:         # * +:scope+ - restricts what is to be considered a list. Given a symbol, it'll attach "_id"
Chris@909:         #   (if it hasn't been already) and use that as the foreign key restriction. You
Chris@909:         #   can also pass an array to scope by multiple attributes.
Chris@909:         #   Example: <tt>acts_as_nested_set :scope => [:notable_id, :notable_type]</tt>
Chris@909:         # * +:dependent+ - behavior for cascading destroy. If set to :destroy, all the
Chris@909:         #   child objects are destroyed alongside this object by calling their destroy
Chris@909:         #   method. If set to :delete_all (default), all the child objects are deleted
Chris@909:         #   without calling their destroy method.
Chris@909:         #
Chris@909:         # See CollectiveIdea::Acts::NestedSet::ClassMethods for a list of class methods and
Chris@909:         # CollectiveIdea::Acts::NestedSet::InstanceMethods for a list of instance methods added 
Chris@909:         # to acts_as_nested_set models
Chris@909:         def acts_as_nested_set(options = {})
Chris@909:           options = {
Chris@909:             :parent_column => 'parent_id',
Chris@909:             :left_column => 'lft',
Chris@909:             :right_column => 'rgt',
Chris@909:             :order => 'id',
Chris@909:             :dependent => :delete_all, # or :destroy
Chris@909:           }.merge(options)
Chris@909:           
Chris@909:           if options[:scope].is_a?(Symbol) && options[:scope].to_s !~ /_id$/
Chris@909:             options[:scope] = "#{options[:scope]}_id".intern
Chris@909:           end
Chris@909: 
Chris@909:           write_inheritable_attribute :acts_as_nested_set_options, options
Chris@909:           class_inheritable_reader :acts_as_nested_set_options
Chris@909:           
Chris@909:           include Comparable
Chris@909:           include Columns
Chris@909:           include InstanceMethods
Chris@909:           extend Columns
Chris@909:           extend ClassMethods
Chris@909: 
Chris@909:           # no bulk assignment
Chris@909:           attr_protected  left_column_name.intern,
Chris@909:                           right_column_name.intern, 
Chris@909:                           parent_column_name.intern
Chris@909:                           
Chris@909:           before_create :set_default_left_and_right
Chris@909:           before_destroy :prune_from_tree
Chris@909:                           
Chris@909:           # no assignment to structure fields
Chris@909:           [left_column_name, right_column_name, parent_column_name].each do |column|
Chris@909:             module_eval <<-"end_eval", __FILE__, __LINE__
Chris@909:               def #{column}=(x)
Chris@909:                 raise ActiveRecord::ActiveRecordError, "Unauthorized assignment to #{column}: it's an internal field handled by acts_as_nested_set code, use move_to_* methods instead."
Chris@909:               end
Chris@909:             end_eval
Chris@909:           end
Chris@909:           
Chris@909:           named_scope :roots, :conditions => {parent_column_name => nil}, :order => quoted_left_column_name
Chris@909:           named_scope :leaves, :conditions => "#{quoted_right_column_name} - #{quoted_left_column_name} = 1", :order => quoted_left_column_name
Chris@909:           if self.respond_to?(:define_callbacks)
Chris@909:             define_callbacks("before_move", "after_move")              
Chris@909:           end
Chris@909: 
Chris@909:           
Chris@909:         end
Chris@909:         
Chris@909:       end
Chris@909:       
Chris@909:       module ClassMethods
Chris@909:         
Chris@909:         # Returns the first root
Chris@909:         def root
Chris@909:           roots.find(:first)
Chris@909:         end
Chris@909:         
Chris@909:         def valid?
Chris@909:           left_and_rights_valid? && no_duplicates_for_columns? && all_roots_valid?
Chris@909:         end
Chris@909:         
Chris@909:         def left_and_rights_valid?
Chris@909:           count(
Chris@909:             :joins => "LEFT OUTER JOIN #{quoted_table_name} AS parent ON " +
Chris@909:               "#{quoted_table_name}.#{quoted_parent_column_name} = parent.#{primary_key}",
Chris@909:             :conditions =>
Chris@909:               "#{quoted_table_name}.#{quoted_left_column_name} IS NULL OR " +
Chris@909:               "#{quoted_table_name}.#{quoted_right_column_name} IS NULL OR " +
Chris@909:               "#{quoted_table_name}.#{quoted_left_column_name} >= " +
Chris@909:                 "#{quoted_table_name}.#{quoted_right_column_name} OR " +
Chris@909:               "(#{quoted_table_name}.#{quoted_parent_column_name} IS NOT NULL AND " +
Chris@909:                 "(#{quoted_table_name}.#{quoted_left_column_name} <= parent.#{quoted_left_column_name} OR " +
Chris@909:                 "#{quoted_table_name}.#{quoted_right_column_name} >= parent.#{quoted_right_column_name}))"
Chris@909:           ) == 0
Chris@909:         end
Chris@909:         
Chris@909:         def no_duplicates_for_columns?
Chris@909:           scope_string = Array(acts_as_nested_set_options[:scope]).map do |c|
Chris@909:             connection.quote_column_name(c)
Chris@909:           end.push(nil).join(", ")
Chris@909:           [quoted_left_column_name, quoted_right_column_name].all? do |column|
Chris@909:             # No duplicates
Chris@909:             find(:first, 
Chris@909:               :select => "#{scope_string}#{column}, COUNT(#{column})", 
Chris@909:               :group => "#{scope_string}#{column} 
Chris@909:                 HAVING COUNT(#{column}) > 1").nil?
Chris@909:           end
Chris@909:         end
Chris@909:         
Chris@909:         # Wrapper for each_root_valid? that can deal with scope.
Chris@909:         def all_roots_valid?
Chris@909:           if acts_as_nested_set_options[:scope]
Chris@909:             roots(:group => scope_column_names).group_by{|record| scope_column_names.collect{|col| record.send(col.to_sym)}}.all? do |scope, grouped_roots|
Chris@909:               each_root_valid?(grouped_roots)
Chris@909:             end
Chris@909:           else
Chris@909:             each_root_valid?(roots)
Chris@909:           end
Chris@909:         end
Chris@909:         
Chris@909:         def each_root_valid?(roots_to_validate)
Chris@909:           left = right = 0
Chris@909:           roots_to_validate.all? do |root|
Chris@909:             (root.left > left && root.right > right).tap do
Chris@909:               left = root.left
Chris@909:               right = root.right
Chris@909:             end
Chris@909:           end
Chris@909:         end
Chris@909:                 
Chris@909:         # Rebuilds the left & rights if unset or invalid.  Also very useful for converting from acts_as_tree.
Chris@909:         def rebuild!(force=false)
Chris@909:           # Don't rebuild a valid tree.
Chris@909:           # valid? doesn't strictly validate the tree
Chris@909:           return true if !force && valid?
Chris@909:           
Chris@909:           scope = lambda{|node|}
Chris@909:           if acts_as_nested_set_options[:scope]
Chris@909:             scope = lambda{|node| 
Chris@909:               scope_column_names.inject(""){|str, column_name|
Chris@909:                 str << "AND #{connection.quote_column_name(column_name)} = #{connection.quote(node.send(column_name.to_sym))} "
Chris@909:               }
Chris@909:             }
Chris@909:           end
Chris@909:           indices = {}
Chris@909:           
Chris@909:           set_left_and_rights = lambda do |node|
Chris@909:             # set left
Chris@909:             node[left_column_name] = indices[scope.call(node)] += 1
Chris@909:             # find
Chris@909:             find(:all, :conditions => ["#{quoted_parent_column_name} = ? #{scope.call(node)}", node], :order => "#{quoted_left_column_name}, #{quoted_right_column_name}, #{acts_as_nested_set_options[:order]}").each{|n| set_left_and_rights.call(n) }
Chris@909:             # set right
Chris@909:             node[right_column_name] = indices[scope.call(node)] += 1    
Chris@909:             node.save!    
Chris@909:           end
Chris@909:                               
Chris@909:           # Find root node(s)
Chris@909:           root_nodes = find(:all, :conditions => "#{quoted_parent_column_name} IS NULL", :order => "#{quoted_left_column_name}, #{quoted_right_column_name}, #{acts_as_nested_set_options[:order]}").each do |root_node|
Chris@909:             # setup index for this scope
Chris@909:             indices[scope.call(root_node)] ||= 0
Chris@909:             set_left_and_rights.call(root_node)
Chris@909:           end
Chris@909:         end
Chris@909:       end
Chris@909:       
Chris@909:       # Mixed into both classes and instances to provide easy access to the column names
Chris@909:       module Columns
Chris@909:         def left_column_name
Chris@909:           acts_as_nested_set_options[:left_column]
Chris@909:         end
Chris@909:         
Chris@909:         def right_column_name
Chris@909:           acts_as_nested_set_options[:right_column]
Chris@909:         end
Chris@909:         
Chris@909:         def parent_column_name
Chris@909:           acts_as_nested_set_options[:parent_column]
Chris@909:         end
Chris@909:         
Chris@909:         def scope_column_names
Chris@909:           Array(acts_as_nested_set_options[:scope])
Chris@909:         end
Chris@909:         
Chris@909:         def quoted_left_column_name
Chris@909:           connection.quote_column_name(left_column_name)
Chris@909:         end
Chris@909:         
Chris@909:         def quoted_right_column_name
Chris@909:           connection.quote_column_name(right_column_name)
Chris@909:         end
Chris@909:         
Chris@909:         def quoted_parent_column_name
Chris@909:           connection.quote_column_name(parent_column_name)
Chris@909:         end
Chris@909:         
Chris@909:         def quoted_scope_column_names
Chris@909:           scope_column_names.collect {|column_name| connection.quote_column_name(column_name) }
Chris@909:         end
Chris@909:       end
Chris@909: 
Chris@909:       # Any instance method that returns a collection makes use of Rails 2.1's named_scope (which is bundled for Rails 2.0), so it can be treated as a finder.
Chris@909:       #
Chris@909:       #   category.self_and_descendants.count
Chris@909:       #   category.ancestors.find(:all, :conditions => "name like '%foo%'")
Chris@909:       module InstanceMethods
Chris@909:         # Value of the parent column
Chris@909:         def parent_id
Chris@909:           self[parent_column_name]
Chris@909:         end
Chris@909:         
Chris@909:         # Value of the left column
Chris@909:         def left
Chris@909:           self[left_column_name]
Chris@909:         end
Chris@909:         
Chris@909:         # Value of the right column
Chris@909:         def right
Chris@909:           self[right_column_name]
Chris@909:         end
Chris@909: 
Chris@909:         # Returns true if this is a root node.
Chris@909:         def root?
Chris@909:           parent_id.nil?
Chris@909:         end
Chris@909:         
Chris@909:         def leaf?
Chris@909:           new_record? || (right - left == 1)
Chris@909:         end
Chris@909: 
Chris@909:         # Returns true is this is a child node
Chris@909:         def child?
Chris@909:           !parent_id.nil?
Chris@909:         end
Chris@909: 
Chris@909:         # order by left column
Chris@909:         def <=>(x)
Chris@909:           left <=> x.left
Chris@909:         end
Chris@909:         
Chris@909:         # Redefine to act like active record
Chris@909:         def ==(comparison_object)
Chris@909:           comparison_object.equal?(self) ||
Chris@909:             (comparison_object.instance_of?(self.class) &&
Chris@909:               comparison_object.id == id &&
Chris@909:               !comparison_object.new_record?)
Chris@909:         end
Chris@909: 
Chris@909:         # Returns root
Chris@909:         def root
Chris@909:           self_and_ancestors.find(:first)
Chris@909:         end
Chris@909: 
Chris@909:         # Returns the immediate parent
Chris@909:         def parent
Chris@909:           nested_set_scope.find_by_id(parent_id) if parent_id
Chris@909:         end
Chris@909: 
Chris@909:         # Returns the array of all parents and self
Chris@909:         def self_and_ancestors
Chris@909:           nested_set_scope.scoped :conditions => [
Chris@909:             "#{self.class.table_name}.#{quoted_left_column_name} <= ? AND #{self.class.table_name}.#{quoted_right_column_name} >= ?", left, right
Chris@909:           ]
Chris@909:         end
Chris@909: 
Chris@909:         # Returns an array of all parents
Chris@909:         def ancestors
Chris@909:           without_self self_and_ancestors
Chris@909:         end
Chris@909: 
Chris@909:         # Returns the array of all children of the parent, including self
Chris@909:         def self_and_siblings
Chris@909:           nested_set_scope.scoped :conditions => {parent_column_name => parent_id}
Chris@909:         end
Chris@909: 
Chris@909:         # Returns the array of all children of the parent, except self
Chris@909:         def siblings
Chris@909:           without_self self_and_siblings
Chris@909:         end
Chris@909: 
Chris@909:         # Returns a set of all of its nested children which do not have children  
Chris@909:         def leaves
Chris@909:           descendants.scoped :conditions => "#{self.class.table_name}.#{quoted_right_column_name} - #{self.class.table_name}.#{quoted_left_column_name} = 1"
Chris@909:         end    
Chris@909: 
Chris@909:         # Returns the level of this object in the tree
Chris@909:         # root level is 0
Chris@909:         def level
Chris@909:           parent_id.nil? ? 0 : ancestors.count
Chris@909:         end
Chris@909: 
Chris@909:         # Returns a set of itself and all of its nested children
Chris@909:         def self_and_descendants
Chris@909:           nested_set_scope.scoped :conditions => [
Chris@909:             "#{self.class.table_name}.#{quoted_left_column_name} >= ? AND #{self.class.table_name}.#{quoted_right_column_name} <= ?", left, right
Chris@909:           ]
Chris@909:         end
Chris@909: 
Chris@909:         # Returns a set of all of its children and nested children
Chris@909:         def descendants
Chris@909:           without_self self_and_descendants
Chris@909:         end
Chris@909: 
Chris@909:         # Returns a set of only this entry's immediate children
Chris@909:         def children
Chris@909:           nested_set_scope.scoped :conditions => {parent_column_name => self}
Chris@909:         end
Chris@909: 
Chris@909:         def is_descendant_of?(other)
Chris@909:           other.left < self.left && self.left < other.right && same_scope?(other)
Chris@909:         end
Chris@909:         
Chris@909:         def is_or_is_descendant_of?(other)
Chris@909:           other.left <= self.left && self.left < other.right && same_scope?(other)
Chris@909:         end
Chris@909: 
Chris@909:         def is_ancestor_of?(other)
Chris@909:           self.left < other.left && other.left < self.right && same_scope?(other)
Chris@909:         end
Chris@909:         
Chris@909:         def is_or_is_ancestor_of?(other)
Chris@909:           self.left <= other.left && other.left < self.right && same_scope?(other)
Chris@909:         end
Chris@909:         
Chris@909:         # Check if other model is in the same scope
Chris@909:         def same_scope?(other)
Chris@909:           Array(acts_as_nested_set_options[:scope]).all? do |attr|
Chris@909:             self.send(attr) == other.send(attr)
Chris@909:           end
Chris@909:         end
Chris@909: 
Chris@909:         # Find the first sibling to the left
Chris@909:         def left_sibling
Chris@909:           siblings.find(:first, :conditions => ["#{self.class.table_name}.#{quoted_left_column_name} < ?", left],
Chris@909:             :order => "#{self.class.table_name}.#{quoted_left_column_name} DESC")
Chris@909:         end
Chris@909: 
Chris@909:         # Find the first sibling to the right
Chris@909:         def right_sibling
Chris@909:           siblings.find(:first, :conditions => ["#{self.class.table_name}.#{quoted_left_column_name} > ?", left])
Chris@909:         end
Chris@909: 
Chris@909:         # Shorthand method for finding the left sibling and moving to the left of it.
Chris@909:         def move_left
Chris@909:           move_to_left_of left_sibling
Chris@909:         end
Chris@909: 
Chris@909:         # Shorthand method for finding the right sibling and moving to the right of it.
Chris@909:         def move_right
Chris@909:           move_to_right_of right_sibling
Chris@909:         end
Chris@909: 
Chris@909:         # Move the node to the left of another node (you can pass id only)
Chris@909:         def move_to_left_of(node)
Chris@909:           move_to node, :left
Chris@909:         end
Chris@909: 
Chris@909:         # Move the node to the left of another node (you can pass id only)
Chris@909:         def move_to_right_of(node)
Chris@909:           move_to node, :right
Chris@909:         end
Chris@909: 
Chris@909:         # Move the node to the child of another node (you can pass id only)
Chris@909:         def move_to_child_of(node)
Chris@909:           move_to node, :child
Chris@909:         end
Chris@909:         
Chris@909:         # Move the node to root nodes
Chris@909:         def move_to_root
Chris@909:           move_to nil, :root
Chris@909:         end
Chris@909:         
Chris@909:         def move_possible?(target)
Chris@909:           self != target && # Can't target self
Chris@909:           same_scope?(target) && # can't be in different scopes
Chris@909:           # !(left..right).include?(target.left..target.right) # this needs tested more
Chris@909:           # detect impossible move
Chris@909:           !((left <= target.left && right >= target.left) or (left <= target.right && right >= target.right))
Chris@909:         end
Chris@909:         
Chris@909:         def to_text
Chris@909:           self_and_descendants.map do |node|
Chris@909:             "#{'*'*(node.level+1)} #{node.id} #{node.to_s} (#{node.parent_id}, #{node.left}, #{node.right})"
Chris@909:           end.join("\n")
Chris@909:         end
Chris@909:         
Chris@909:       protected
Chris@909:       
Chris@909:         def without_self(scope)
Chris@909:           scope.scoped :conditions => ["#{self.class.table_name}.#{self.class.primary_key} != ?", self]
Chris@909:         end
Chris@909:         
Chris@909:         # All nested set queries should use this nested_set_scope, which performs finds on
Chris@909:         # the base ActiveRecord class, using the :scope declared in the acts_as_nested_set
Chris@909:         # declaration.
Chris@909:         def nested_set_scope
Chris@909:           options = {:order => "#{self.class.table_name}.#{quoted_left_column_name}"}
Chris@909:           scopes = Array(acts_as_nested_set_options[:scope])
Chris@909:           options[:conditions] = scopes.inject({}) do |conditions,attr|
Chris@909:             conditions.merge attr => self[attr]
Chris@909:           end unless scopes.empty?
Chris@909:           self.class.base_class.scoped options
Chris@909:         end
Chris@909:         
Chris@909:         # on creation, set automatically lft and rgt to the end of the tree
Chris@909:         def set_default_left_and_right
Chris@909:           maxright = nested_set_scope.maximum(right_column_name) || 0
Chris@909:           # adds the new node to the right of all existing nodes
Chris@909:           self[left_column_name] = maxright + 1
Chris@909:           self[right_column_name] = maxright + 2
Chris@909:         end
Chris@909:       
Chris@909:         # Prunes a branch off of the tree, shifting all of the elements on the right
Chris@909:         # back to the left so the counts still work.
Chris@909:         def prune_from_tree
Chris@909:           return if right.nil? || left.nil? || !self.class.exists?(id)
Chris@909: 
Chris@909:           self.class.base_class.transaction do
Chris@909:             reload_nested_set
Chris@909:             if acts_as_nested_set_options[:dependent] == :destroy
Chris@909:               children.each(&:destroy)
Chris@909:             else
Chris@909:               nested_set_scope.send(:delete_all,
Chris@909:                 ["#{quoted_left_column_name} > ? AND #{quoted_right_column_name} < ?",
Chris@909:                   left, right]
Chris@909:               )
Chris@909:             end
Chris@909:             reload_nested_set
Chris@909:             diff = right - left + 1
Chris@909:             nested_set_scope.update_all(
Chris@909:               ["#{quoted_left_column_name} = (#{quoted_left_column_name} - ?)", diff],
Chris@909:               ["#{quoted_left_column_name} >= ?", right]
Chris@909:             )
Chris@909:             nested_set_scope.update_all(
Chris@909:               ["#{quoted_right_column_name} = (#{quoted_right_column_name} - ?)", diff],
Chris@909:               ["#{quoted_right_column_name} >= ?", right]
Chris@909:             )
Chris@909:           end
Chris@909:           
Chris@909:           # Reload is needed because children may have updated their parent (self) during deletion.
Chris@909:           reload
Chris@909:         end
Chris@909: 
Chris@909:         # reload left, right, and parent
Chris@909:         def reload_nested_set
Chris@909:           reload(:select => "#{quoted_left_column_name}, " +
Chris@909:             "#{quoted_right_column_name}, #{quoted_parent_column_name}")
Chris@909:         end
Chris@909:         
Chris@909:         def move_to(target, position)
Chris@909:           raise ActiveRecord::ActiveRecordError, "You cannot move a new node" if self.new_record?
Chris@909:           return if callback(:before_move) == false
Chris@909:           transaction do
Chris@909:             if target.is_a? self.class.base_class
Chris@909:               target.reload_nested_set
Chris@909:             elsif position != :root
Chris@909:               # load object if node is not an object
Chris@909:               target = nested_set_scope.find(target)
Chris@909:             end
Chris@909:             self.reload_nested_set
Chris@909:           
Chris@909:             unless position == :root || move_possible?(target)
Chris@909:               raise ActiveRecord::ActiveRecordError, "Impossible move, target node cannot be inside moved tree."
Chris@909:             end
Chris@909:             
Chris@909:             bound = case position
Chris@909:               when :child;  target[right_column_name]
Chris@909:               when :left;   target[left_column_name]
Chris@909:               when :right;  target[right_column_name] + 1
Chris@909:               when :root;   1
Chris@909:               else raise ActiveRecord::ActiveRecordError, "Position should be :child, :left, :right or :root ('#{position}' received)."
Chris@909:             end
Chris@909:           
Chris@909:             if bound > self[right_column_name]
Chris@909:               bound = bound - 1
Chris@909:               other_bound = self[right_column_name] + 1
Chris@909:             else
Chris@909:               other_bound = self[left_column_name] - 1
Chris@909:             end
Chris@909: 
Chris@909:             # there would be no change
Chris@909:             return if bound == self[right_column_name] || bound == self[left_column_name]
Chris@909:           
Chris@909:             # we have defined the boundaries of two non-overlapping intervals, 
Chris@909:             # so sorting puts both the intervals and their boundaries in order
Chris@909:             a, b, c, d = [self[left_column_name], self[right_column_name], bound, other_bound].sort
Chris@909: 
Chris@909:             new_parent = case position
Chris@909:               when :child;  target.id
Chris@909:               when :root;   nil
Chris@909:               else          target[parent_column_name]
Chris@909:             end
Chris@909: 
Chris@909:             self.class.base_class.update_all([
Chris@909:               "#{quoted_left_column_name} = CASE " +
Chris@909:                 "WHEN #{quoted_left_column_name} BETWEEN :a AND :b " +
Chris@909:                   "THEN #{quoted_left_column_name} + :d - :b " +
Chris@909:                 "WHEN #{quoted_left_column_name} BETWEEN :c AND :d " +
Chris@909:                   "THEN #{quoted_left_column_name} + :a - :c " +
Chris@909:                 "ELSE #{quoted_left_column_name} END, " +
Chris@909:               "#{quoted_right_column_name} = CASE " +
Chris@909:                 "WHEN #{quoted_right_column_name} BETWEEN :a AND :b " +
Chris@909:                   "THEN #{quoted_right_column_name} + :d - :b " +
Chris@909:                 "WHEN #{quoted_right_column_name} BETWEEN :c AND :d " +
Chris@909:                   "THEN #{quoted_right_column_name} + :a - :c " +
Chris@909:                 "ELSE #{quoted_right_column_name} END, " +
Chris@909:               "#{quoted_parent_column_name} = CASE " +
Chris@909:                 "WHEN #{self.class.base_class.primary_key} = :id THEN :new_parent " +
Chris@909:                 "ELSE #{quoted_parent_column_name} END",
Chris@909:               {:a => a, :b => b, :c => c, :d => d, :id => self.id, :new_parent => new_parent}
Chris@909:             ], nested_set_scope.proxy_options[:conditions])
Chris@909:           end
Chris@909:           target.reload_nested_set if target
Chris@909:           self.reload_nested_set
Chris@909:           callback(:after_move)
Chris@909:         end
Chris@909: 
Chris@909:       end
Chris@909:       
Chris@909:     end
Chris@909:   end
Chris@909: end