#!/usr/bin/env ruby
require "netaddr"
require "set"
require_relative "lib/lxc"

def update_hetzner_rdns6(user, password, domain, subnet, network)
  api = Lxc::Hetzner.new(user, password)
  rdns = api.get("/rdns")
  records = {}
  rdns.each do |val|
    rec = val["rdns"]
    cidr = NetAddr::CIDR.create(rec["ip"])
    next unless cidr.version == 6 and subnet.contains?(rec["ip"])
    records[rec["ip"]] = rec["ptr"]
  end
  processed_ips = Set.new

  network.each do |host, data|
    cidr = data["ipv6"]
    next if cidr.nil?
    cidr = NetAddr::CIDR.create(cidr)
    next unless cidr.version == 6 and subnet.contains?(data["ipv6"])
    hostname = data["rdns6"] || "#{host}.#{domain}"
    ip = cidr.ip(Short: true)
    next if processed_ips.include?(ip)
    processed_ips << ip
    ptr = records.delete(ip)
    if ptr.nil? or ptr != hostname
      puts "add ptr: #{ip} -> #{hostname}"
      api.post("/rdns/#{ip}", ptr: hostname)
    end
  end
  records.each do |ip, ptr|
    puts "delete ptr: #{ip} -> #{ptr}"
    api.delete("/rnds/#{ip}")
  end
end

registry = Lxc::Registry.new
registry.data["zone"] ||= {}
domain = registry.data["zone"]["domain"] || "lxc"
subnet = registry.data["zone"]["v6_subnet"]
if subnet
  subnet_cidr = NetAddr::CIDR.create(subnet)
  credentials = File.read(Lxc::CONFIG_ROOT.join("hetzner.key"))
  user, password = credentials.split(":")
  network = registry.data["network"] || {}
  update_hetzner_rdns6(user, password, domain, subnet_cidr, network)
else
  puts "no v6_subnet specified in container.json. skip rdns records"
end