# See #SOA

# = Start of Authority Record
# Defined in RFC 1035. The SOA defines global parameters for the zone (domain).
# There is only one SOA record allowed in a zone file.
#
# Obtained from http://www.zytrax.com/books/dns/ch8/soa.html
#
class SOA < Record
  validates :domain_id, :uniqueness => true # one SOA per domain
  validates :name, :presence => true, :hostname => true
  validates :content, :presence => true
  validates :primary_ns, :presence => true
  CONTACT_FORMAT = /\A[a-zA-Z0-9\-\.]+@[a-zA-Z0-9-]+\.[a-zA-Z.]{2,6}\z/
  validates :contact, :format => {:with => CONTACT_FORMAT}
  validates :serial, :presence => true, :numericality => {:allow_blank => true, :greater_than_or_equal_to => 0}

  before_validation :assemble_content
  before_update :update_serial
  after_initialize :disassemble_content

  # This allows us to have these convenience attributes act like any other
  # column in terms of validations
  attr_accessor :primary_ns, :contact, :serial

  # Treat contact specially
  # replacing the first period with an @ if no @'s are present
  def contact=(email)
    email.sub!('.', '@') if email.present? && email.index('@').nil?
    @contact = email
  end

  # Hook into #reload
  def reload_with_content
    reload_without_content
    disassemble_content
  end
  alias_method_chain :reload, :content

  # Updates the serial number to the next logical one. Format of the generated
  # serial is YYYYMMDDNN, where NN is the number of the change for the day.
  # 01 for the first change, 02 the seconds, etc...
  #
  # If the serial number is 0, we opt for PowerDNS's automatic serial number
  # generation, that gets triggered by updating the change_date
  def update_serial
    return if self.content_changed?
    date_serial = Time.now.strftime( "%Y%m%d00" ).to_i
    @serial = (@serial.nil? || date_serial > @serial) ? date_serial : @serial + 1
  end

  # Same as #update_serial and saves the record
  def update_serial!
    update_serial
    save
  end

  private
  
  def assemble_content
    self.content = "#{@primary_ns} #{@contact} #{@serial}".strip
  end

  # Update our convenience accessors when the object has changed
  def disassemble_content
    @primary_ns, @contact, @serial = content.split(/\s+/) unless content.blank?
    @serial = @serial.to_i unless @serial.nil?
    update_serial if @serial.nil? || @serial.zero?
  end
end

Soa = SOA