class CollectiveIdea::Acts::NestedSet::Tree

def increment_indice!(node)
  indices[scope_for_rebuild.call(node)] += 1
end

def initialize(model, validate_nodes)
  @model = model
  @validate_nodes = validate_nodes
  @indices = {}
end

def node_children(node)
  model.where(["#{quoted_parent_column_full_name} = ? #{scope_for_rebuild.call(node)}", node.primary_id]).
        order(order_for_rebuild)
end

def rebuild!
  # Don't rebuild a valid tree.
  return true if model.valid?
  root_nodes.each do |root_node|
    # setup index for this scope
    indices[scope_for_rebuild.call(root_node)] ||= 0
    set_left_and_rights(root_node)
    reset_counter_cache(root_node)
  end
end

def reset_counter_cache(node)
  return unless counter_cache_column_name
  node.class.reset_counters(node.id, :children)
  node.children.each do |child|
    reset_counter_cache(child)
  end
end

def root_nodes
  model.where("#{quoted_parent_column_full_name} IS NULL").order(order_for_rebuild)
end

def set_left!(node)
  node[left_column_name] = increment_indice!(node)
end

def set_left_and_rights(node)
  set_left!(node)
  # find
  node_children(node).each { |n| set_left_and_rights(n) }
  set_right!(node)
  node.save!(:validate => validate_nodes)
end

def set_right!(node)
  node[right_column_name] = increment_indice!(node)
end