#    Copyright 2017 Midokura SARL, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

require 'netaddr'
require 'socket'

module Puppet::Parser::Functions
  newfunction(:cidr2ip, :type => :rvalue, :doc => <<-EOS
    This function returns an ip address or will raise an error if no iface
    is configured with an IP address inside the specified CIDR.

    If multiples interfaces match, the first one is returned.
    EOS
  ) do |argv|
    unless argv[0] =~ /^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\/[0-9]{,2}$/
      raise ArgumentError, "#{argv[0]} is not a valid CIDR"
    end
    ifaces = Socket.getifaddrs.map { |i| {ip: i.addr.ip_address,name: i.name,cidr: NetAddr::CIDR::create("#{i.addr.ip_address} #{i.netmask.ip_address}").to_s } if i.addr.ipv4? }.compact
    matching_iface = ifaces.select{ |i| i[:cidr] == argv[0]}.first
    return matching_iface[:ip] unless matching_iface.nil?
    raise ("No Matching iface found")
  end
end