# = ildus/server/backend - ldap domain backend library
#
# Copyright (C) 2005 Paul van Tilburg <paul@luon.net>
#
# Ildus is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your option)
# any later version.

require 'ldap'

module Ildus::Server::DomainBackend

  # = LDAP domain backend
  #
  # The domain backend class that uses an LDAP database.  It uses the LDAP
  # record format used by the PowerDNS backend.  (see: 
  # http://www.linuxnetworks.de/pdnsldap/dnsdomain2.schema) Next to that it
  # uses an extra ildusOwner field to couple LDAP dNSdomain records to
  # users.
  class Ldap < Basic

    # Sets up the LDAP backend by switching to LDAPv3 protocol
    # and binding to the server.
    def initialize(*args)
      super
      @ldap = LDAP::Conn.new(config['host'])
      @ldap.set_option(LDAP::LDAP_OPT_PROTOCOL_VERSION, 3)
      @ldap.simple_bind(config['user'], config['pass'])
    end

    # Updates the serial on the SOA record and calls the inherited
    # commit (invoking the hook).
    def commit
      update_serial
      super
    end

    # Returns the list (a Hash actually) of hosts for the selected user.
    # It looks for A, AAAA and CNAME records.
    def hosts
      entries = Hash.new { |h, k| h[k] = [[], []] }

      all_entries.each do |entry|
        assoc_dom, a_rr, aaaa_rr, cname_rr = 
          ["associatedDomain", "aRecord", 
           "aAAArecord",       "cNAMErecord"].map { |attr| entry[attr] }
        host = assoc_dom.first.gsub(/\.#{config['domain']}$/, '')

        entries[host].first.push(*a_rr)    if a_rr
        entries[host].first.push(*aaaa_rr) if aaaa_rr
        if cname_rr
          cname = cname_rr.first.gsub(/\.#{config['domain']}$/, '')
          entries[cname].last << host
        end
      end # search

      return entries
    end # def hosts

    # Updates the address of _host_ to _addr_ providing that _addr_ is in a
    # correct IPv4 or IPv6 address format.
    def update_host(host, addr)
      entry = all_entries.find do |entry| 
        entry['associatedDomain'][0] == host + "." + config['domain']
      end
      raise Handler::HostNotFoundError if entry.nil?

      if addr.ipv4?
        @ldap.modify(entry['dn'][0], {"aRecord"    => [addr.to_s]})
      elsif addr.ipv6?
        @ldap.modify(entry['dn'][0], {"aAAARecord" => [addr.to_s]})
      else
        return false
      end

      true
    end

    #########
    private
    #########

    # Returns a list of all LDAP IldusRecord entries for the selected
    # user.
    def all_entries
      @ldap.search2(config['base'], LDAP::LDAP_SCOPE_SUBTREE, 
                    "(&(objectClass=ildusRecord)(ildusOwner=#{user}))")
    end

    # Returns the LDAP sOARecord for the configured domain.
    def soa_record
      @ldap.search2(config['base'], LDAP::LDAP_SCOPE_BASE,
                    "(&(associatedDomain=#{config['domain'].downcase})" \
                    "  (sOARecord=*))").first
    end

    # Updates the serial of the SOA record of the configured domain.
    # The serial consists of two parts, the date (yyyymmdd) and 
    # counter (nn) part.  On every update the date is set to the current
    # date, it will increase the counter.  
    #
    # Note that the counter may overflow so that actually the day is
    # incremented.  This is no problem unless there is an almost infinite
    # sequance of days with more then 100 updates/day.
    def update_serial
      record = soa_record
      soa = record['sOARecord'].first.split
      soa[2] = serial_succ(soa[2])
      
      @ldap.modify(record['dn'][0], {"sOARecord" => [soa.join(" ")]})
    end

    # Determines the successor of the current serial number, see
    # also #update_serial().
    def serial_succ(serial)
      date, num = serial.scan(/\d{8}|\d{2}/)
      today = Time.now.strftime("%Y%m%d")

      if (date < today)   
        date, num = today, '00'
      elsif (num == '99')
        date, num = date.succ, '00'
      else                
        num = num.succ
      end

      return "%08s%02s" % [date, num]
    end
    
  end # class Ldap

end # module Ildus::Server::DomainBackend