class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter::OID::Range

def extract_bounds(value)
  from, to = value[1..-2].split(',')
  {
    from:          (value[1] == ',' || from == '-infinity') ? infinity(:negative => true) : from,
    to:            (value[-2] == ',' || to == 'infinity') ? infinity : to,
    exclude_start: (value[0] == '('),
    exclude_end:   (value[-1] == ')')
  }
end

def infinity(options = {})
  ::Float::INFINITY * (options[:negative] ? -1 : 1)
end

def infinity?(value)
  value.respond_to?(:infinite?) && value.infinite?
end

def initialize(subtype)
  @subtype = subtype
end

def to_integer(value)
  infinity?(value) ? value : value.to_i
end

def type_cast(value)
  return if value.nil? || value == 'empty'
  return value if value.is_a?(::Range)
  extracted = extract_bounds(value)
  case @subtype
  when :date
    from  = ConnectionAdapters::Column.value_to_date(extracted[:from])
    from -= 1.day if extracted[:exclude_start]
    to    = ConnectionAdapters::Column.value_to_date(extracted[:to])
  when :decimal
    from  = BigDecimal.new(extracted[:from].to_s)
    # FIXME: add exclude start for ::Range, same for timestamp ranges
    to    = BigDecimal.new(extracted[:to].to_s)
  when :time
    from = ConnectionAdapters::Column.string_to_time(extracted[:from])
    to   = ConnectionAdapters::Column.string_to_time(extracted[:to])
  when :integer
    from = to_integer(extracted[:from]) rescue value ? 1 : 0
    from -= 1 if extracted[:exclude_start]
    to   = to_integer(extracted[:to]) rescue value ? 1 : 0
  else
    return value
  end
  ::Range.new(from, to, extracted[:exclude_end])
end