# Copyright (2008) Sandia Corporation.
# Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
# the U.S. Government retains certain rights in this software.
#
# Original Author: Bryan T. Richardson, Sandia National Laboratories <btricha@sandia.gov>
# Derived From: code written by Michael Berg <mjberg@sandia.gov>
#
# This library is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or (at
# your option) any later version.
#
# This library is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this library; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 

# IpInterface class that wraps the ip_interfaces table
# in the ANTFARM database.
#
# * belongs to a layer 3 interface
#
# The node_name and node_device_type attributes are only applicable
# when an existing node is not specified.
#
# The node and layer2_interface_media_type attributes are only
# applicable when an existing layer 2 interface is not specified.
#
# The layer3_network_protocol attribute is only applicable when
# an existing layer 3 network is not specified.
class IpInterface < ActiveRecord::Base
  belongs_to :layer3_interface, :foreign_key => "id"

  before_create :create_layer3_interface

  # Existing layer 3 network the layer 3 interface
  # automatically created for this IP interface
  # should belong to.
  attr_writer :layer3_network

  # Protocol of the layer 3 network automatically
  # created for the layer 3 interface created for
  # this IP interface.
  attr_writer :layer3_network_protocol

  # Protocol of the layer 3 interface automatically
  # created for this IP interface.
  attr_writer :layer3_interface_protocol

  # Ethernet (MAC) address of the ethernet interface
  # to be created for this IP interface.
  attr_writer :ethernet_address

  # Existing layer 2 interface the layer 3 interface
  # automatically created for this IP interface
  # should belong to.
  attr_writer :layer2_interface

  # Media type of the layer 2 interface automatically
  # creted for this layer 3 interface.
  attr_writer :layer2_interface_media_type

  # Existing node the layer 2 interface automatically
  # created for this layer 3 interface should belong to.
  attr_writer :node

  # Name of the node automatically created by the layer 2
  # interface created for this layer 3 interface.
  attr_writer :node_name

  # Device type of the node automatically created by the
  # layer 2 interface created for this layer 3 interface.
  attr_writer :node_device_type

  # Overriding the address setter in order to create an instance variable for an
  # Antfarm::IPAddrExt object ip_addr.  This way the rest of the methods in this
  # class can confidently access the ip address for this interface.  IPAddr also
  # validates the address.
  #
  # the method address= is called by the constructor of this class.
  def address=(ip_addr) #:nodoc:
    @ip_addr = Antfarm::IPAddrExt.new(ip_addr)
    super(@ip_addr.to_s)
  end

  validates_presence_of :address

  # Validate data for requirements before saving interface to the database.
  #
  # Was using validate_on_create, but decided that restraints should occur
  # on anything saved to the database at any time, including a create and an update.
  def validate #:nodoc:
    # Don't save the interface if it's a loopback address.
    unless !@ip_addr.loopback_address?
      errors.add(:address, "loopback address not allowed")
    end
  end

  # This is for ActiveScaffold
  def to_label #:nodoc:
    return address
  end

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

  def create_layer3_interface
    # If we get to this point, then we know an interface does not
    # already exist because validate gets called before
    # this method and we're checking for existing interfaces in
    # validate.  Therefore, we know a new interface needs to be created,
    # unless it was specified by the user.
    unless self.layer3_interface
      layer3_interface = Layer3Interface.new :certainty_factor => 0.75
      layer3_interface.protocol = @layer3_interface_protocol if @layer3_interface_protocol

      if @layer3_network
        layer3_interface.layer3_network = @layer3_network
      else
        # Check to see if a network exists that contains this address.
        # If not, create a small one that does.
        layer3_network = Layer3Network.network_containing(@ip_addr.to_cidr_string)
        unless layer3_network
          network = @ip_addr.clone
          if network == network.network
            network.netmask = network.netmask << 3
          end

          ip_network = IpNetwork.new :address => network.to_cidr_string
          ip_network.layer3_network_protocol = @layer3_network_protocol if @layer3_network_protocol
          if ip_network.save
            logger.info("IpInterface: Created IP Network")
          else
            logger.warn("IpInterface: Errors occured while creating IP Network")
            ip_network.errors.each_full do |msg|
              logger.warn(msg)
            end
          end

          layer3_network = ip_network.layer3_network
        end

        layer3_interface.layer3_network = layer3_network
      end

      if @layer2_interface
        layer3_interface.layer2_interface = @layer2_interface
      else
        if @ethernet_address
          ethernet_interface = EthernetInterface.create :address => @ethernet_address
          layer3_interface.layer2_interface = ethernet_interface.layer2_interface
        end

        layer3_interface.layer2_interface_media_type = @layer2_interface_media_type if @layer2_interface_media_type
        layer3_interface.node = @node if @node
        layer3_interface.node_name = @node_name if @node_name
        layer3_interface.node_device_type = @node_device_type if @node_device_type
      end

      if layer3_interface.save
        logger.info("IpInterface: Created Layer 3 Interface")
      else
        logger.warn("IpInterface: Errors occured while creating Layer 3 Interface")
        layer3_interface.errors.each_full do |msg|
          logger.warn(msg)
        end
      end

      self.layer3_interface = layer3_interface
    end
  end
end