require 'forwardable'
module ClosureTree
  module SupportAttributes

    extend Forwardable
    def_delegators :model_class, :connection, :transaction, :table_name

    # This is the "topmost" class. This will only potentially not be ct_class if you are using STI.
    def base_class
      options[:base_class]
    end

    def attribute_names
      @attribute_names ||= model_class.new.attributes.keys - model_class.protected_attributes.to_a
    end

    def quoted_table_name
      connection.quote_table_name(table_name)
    end

    def quoted_value(value)
      value.is_a?(Numeric) ? value : quote(value)
    end

    def hierarchy_class_name
      options[:hierarchy_class_name] || model_class.to_s + "Hierarchy"
    end

    def parent_column_name
      options[:parent_column_name]
    end

    def parent_column_sym
      parent_column_name.to_sym
    end

    def name_column
      options[:name_column]
    end

    def name_sym
      name_column.to_sym
    end

    # Returns the constant name of the hierarchy_class
    #
    # @return [String] the constant name
    #
    # @example
    #   Namespace::Model.hierarchy_class_name # => "Namespace::ModelHierarchy"
    #   Namespace::Model.short_hierarchy_class_name # => "ModelHierarchy"
    def short_hierarchy_class_name
      hierarchy_class_name.split('::').last
    end

    def quoted_hierarchy_table_name
      connection.quote_table_name hierarchy_table_name
    end

    def quoted_id_column_name
      connection.quote_column_name model_class.primary_key
    end

    def quoted_parent_column_name
      connection.quote_column_name parent_column_name
    end

    def quoted_name_column
      connection.quote_column_name name_column
    end

    def order_by
      options[:order]
    end

    def nulls_last_order_by
      "-#{quoted_order_column} #{order_by_order(reverse = true)}"
    end

    def order_by_order(reverse = false)
      desc = !!(order_by.to_s =~ /DESC\z/)
      desc = !desc if reverse
      desc ? 'DESC' : 'ASC'
    end

    def order_column
      o = order_by
      if o.nil?
        nil
      elsif o.is_a?(String)
        o.split(' ', 2).first
      else
        o.to_s
      end
    end

    def require_order_column
      raise ":order value, '#{options[:order]}', isn't a column" if order_column.nil?
    end

    def order_column_sym
      require_order_column
      order_column.to_sym
    end

    def quoted_order_column(include_table_name = true)
      require_order_column
      prefix = include_table_name ? "#{quoted_table_name}." : ""
      "#{prefix}#{connection.quote_column_name(order_column)}"
    end
  end
end