class Arel::InsertManager

def columns; @ast.columns end

def create_values(values)
  Nodes::ValuesList.new([values])
end

def create_values_list(rows)
  Nodes::ValuesList.new(rows)
end

def initialize(table = nil)
  @ast = Nodes::InsertStatement.new(table)
end

def insert(fields)
  return if fields.empty?
  if String === fields
    @ast.values = Nodes::SqlLiteral.new(fields)
  else
    @ast.relation ||= fields.first.first.relation
    values = []
    fields.each do |column, value|
      @ast.columns << column
      values << value
    end
    @ast.values = create_values(values)
  end
  self
end

def into(table)
  @ast.relation = table
  self
end

def select(select)
  @ast.select = select
end

def values=(val); @ast.values = val; end