# frozen_string_literal: true

require 'ipaddr'

# a class that creates facts based on the subnet
class SubnetAttributes
  SUBNET_TO_ATTRIBUTES = {
    '198.18.2.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # router loopbacks
    '198.18.13.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' },
    '198.18.14.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' },
    '198.18.15.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' },
    '198.18.16.0/24' => { environment: 'test', region: 'syd1', country: 'au', zone: 'common' },
    '198.18.17.0/24' => { environment: 'prod', region: 'drw1', country: 'au', zone: 'common' },
    '198.18.18.0/24' => { environment: 'test', region: 'drw1', country: 'au', zone: 'common' },
    '198.18.19.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # loopbacks
    '198.18.20.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # MPLS CORE BLOCKS
    '198.18.21.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # physical network 2.5gbe
    '198.18.22.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # ceph cluster
    '198.18.23.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # ceph public
    '198.18.24.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'dmz' },    # dmz 1
    '198.18.25.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # common node0009
    '198.18.26.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # common node0010
    '198.18.27.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # common node0011
    '198.18.28.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # common node0012
    '198.18.29.0/24' => { environment: 'prod', region: 'syd1', country: 'au', zone: 'common' }, # common node0013
    '198.18.30.0/24' => { environment: 'prod', region: 'syd2', country: 'au', zone: 'dmz' },    # binarylane syd dmz vpc
    '198.18.31.0/24' => { environment: 'prod', region: 'mel1', country: 'au', zone: 'dmz' }     # binarylane mel dmz vpc
  }.freeze

  # Default attributes if no subnet matches, also defined as a constant
  DEFAULT_ATTRIBUTES = { environment: 'unknown', region: 'unknown', country: 'unknown' }.freeze

  # loopbacks and wg /31s sit in syd1 ranges, so they must not decide where a host lives
  SKIPPED_INTERFACES = /\A(lo\z|dum|wg)/.freeze

  # primary ip first, then the remaining interfaces in name order
  def self.from_networking(networking)
    match(networking['ip']) || interface_match(networking['interfaces'] || {}) || DEFAULT_ATTRIBUTES
  end

  def self.interface_match(interfaces)
    interfaces.sort
              .reject { |name, _interface| name.match?(SKIPPED_INTERFACES) }
              .flat_map { |_name, interface| addresses(interface) }
              .lazy.filter_map { |address| match(address) }.first
  end

  def self.addresses(interface)
    (interface['bindings'] || []).map { |binding| binding['address'] }
  end

  def self.match(ip)
    return unless ip

    addr = IPAddr.new(ip)
    SUBNET_TO_ATTRIBUTES.each do |subnet, attrs|
      return attrs if IPAddr.new(subnet).include?(addr)
    end
    nil
  end
end

subnet_attributes = SubnetAttributes.from_networking(Facter.value(:networking))

# Add separate facts for environment, region, and country
Facter.add('environment') { setcode { subnet_attributes[:environment] } }
Facter.add('region') { setcode { subnet_attributes[:region] } }
Facter.add('country') { setcode { subnet_attributes[:country] } }
Facter.add('zone') { setcode { subnet_attributes[:zone] } }