#!/usr/bin/env ruby
# -*- coding: utf-8 -*-
#
# Naming Service Agent:
# This agent aims to configure DNS/DHCP daemons or devices to supply
# IP address and Hostname for Instances.

begin
  require 'rubygems'
  require 'bundler'
  Bundler.setup(:default)
rescue Exception
end

require File.expand_path('../../config/path_resolver', __FILE__)

require 'erb'
require 'eventmachine'

class SuperviseDnsmasq < Isono::NodeModules::Base
  include Dcmgr::Logger

  config_section do
    desc "configuration file for dnsmasq dhcp"
    dhcp_hosts_conf File.expand_path('dnsmasq-dhcp.conf', '/var/tmp/')
  end
  
  initialize_hook do
    if manifest.config.network_name.nil?
      abort("network_name is not set yet in nsa.conf")
    end

    # check the dnsmasq binary version
    @conf_ver_253 = false
    if `#{manifest.config.dnsmasq_bin_path} -version`.split("\n").first =~ /Dnsmasq version ([\d\.]+)/
      verstr = $1.split('.')
      if verstr[0].to_i == 2 && verstr[1].to_i >= 53
        @conf_ver_253 = true
      end
      logger.info("Using dnsmasq v#{verstr}: configuration version #{@conf_ver_253 ? '>= 2.53' : '< 2.53'}")
    else
      logger.warn("Failed to detect dnsmasq binary version")
    end
    
    
    opts = sprintf("-k --no-hosts --no-resolv --leasefile-ro --dhcp-leasefile=/dev/null " +
                   "--addn-hosts=%s --dhcp-hostsfile=%s --conf-file=%s",
                   config_section.dhcp_hosts_conf + ".hosts",
                   config_section.dhcp_hosts_conf + ".dhcp",
                   config_section.dhcp_hosts_conf
                   )
    cmd = "#{manifest.config.dnsmasq_bin_path} #{opts}"

    @dnsmasq_pid = fork {
      Process.exec(cmd)
    }
    begin
      if !Process.waitpid(@dnsmasq_pid, Process::WNOHANG).nil?
        abort("dnsmasq is terminated unexpectedly")
      end
    rescue Errno::ECHILD
      abort("Failed to exec dnsmasq process.")
    end
    
    myinstance.refresh_dnsmasq_conf

    event = Isono::NodeModules::EventChannel.new(node)

    event.subscribe('hva/instance_started', '#') do |args|
      logger.info("refresh on instance_started: #{args.inspect}")
      myinstance.refresh_dnsmasq_conf
    end
    
    event.subscribe('hva/instance_terminated', '#') do |args|
      logger.info("refresh on instance_terminated: #{args.inspect}")
      myinstance.refresh_dnsmasq_conf
    end
  end

  terminate_hook do
    system("/bin/kill #{@dnsmasq_pid}")
  end


  def refresh_dnsmasq_conf
    EM.defer {
      begin
        generate_dhcp_conf()
        system("/bin/kill -HUP #{@dnsmasq_pid}")
        logger.info("refreshed dnsmasq conf")
      rescue Exception => e
        logger.error(e)
      end
    }
  end
  
  def generate_dhcp_conf
    rpc = Isono::NodeModules::RpcChannel.new(node)
    # load entier macaddr,ipaddr pairs for all instances from collector.
    confdata = rpc.request('hva-collector', 'get_dhcp_conf', manifest.config.network_name)

      render_conf(config_section.dhcp_hosts_conf, binding, <<'_EOS_') 
server=8.8.8.8
log-facility=/var/log/dnsmasq.log
#log-queries
log-dhcp
<%- confdata.each { |nwid, v| -%>
<%- if @conf_ver_253 -%>
dhcp-range=set:<%= nwid %>,<%= v[:ipv4_first] %>,static,<%= v[:netmask] %>
dhcp-option=tag:<%= nwid %>,option:netmask,<%= v[:netmask] %>
dhcp-option=tag:<%= nwid %>,option:router,<%= v[:ipv4_gw] %>
dhcp-option=tag:<%= nwid %>,option:dns-server,<%= v[:dns_server] %>
dhcp-option=tag:<%= nwid %>,option:domain-name,<%= v[:domain_name] %>
#dhcp-option=tag:<%= nwid %>,option:domain-search,<%= v[:domain_name] %>
<%- else # if @conf_ver_253 -%>
dhcp-range=net:<%= nwid %>,<%= v[:ipv4_first] %>,static,<%= v[:netmask] %>
dhcp-option=<%= nwid %>,option:netmask,<%= v[:netmask] %>
dhcp-option=<%= nwid %>,option:router,<%= v[:ipv4_gw] %>
dhcp-option=<%= nwid %>,option:dns-server,<%= v[:dns_server] %>
dhcp-option=<%= nwid %>,option:domain-name,<%= v[:domain_name] %>
#dhcp-option=<%= nwid %>,option:domain-search,<%= v[:domain_name] %>
<%- end # if @conf_ver_253 -%>
<%- v[:mac2addr].each { |i| -%>
#dhcp-host=<%= i[:mac_addr] %>,net:<%= nwid %>,<%= i[:ipaddr] %>
<%- } -%>
<%- v[:addr2host].each { |i| -%>
#address=/<%= i[:hostname] %>/<%= i[:ipaddr] %>
<%- } -%>
<%- } -%>
_EOS_

    render_conf(config_section.dhcp_hosts_conf + ".dhcp", binding, <<'_EOS_') 
<%- confdata.each { |nwid, v| -%>
<%-   v[:mac2addr].each { |i| -%>
<%= i[:mac_addr] %>,net:<%= nwid %>,<%= i[:ipaddr] %>,infinite
<%-   } -%>
<%- } -%>
_EOS_

    render_conf(config_section.dhcp_hosts_conf + ".hosts", binding, <<'_EOS_')
<%- confdata.each { |nwid, v| -%>
<%-   v[:addr2host].each { |i| -%>
<%= i[:ipaddr] %>  <%= i[:hostname] %>
<%-   } -%>
<%- } -%>
_EOS_
  end

  private
  def render_conf(file, bind, templ)
    File.open(file, 'w') { |f|
      f << ERB.new(templ, nil, '-').result(bind)
    }
  end
end

include Isono::Runner::RpcServer

manifest = DEFAULT_MANIFEST.dup
manifest.instance_eval do
  node_name 'nsa'
  node_instance_id "#{Isono::Util.default_gw_ipaddr}"
  load_module Isono::NodeModules::NodeHeartbeat
  load_module SuperviseDnsmasq
  
  config do |c|
    c.dnsmasq_bin_path = '/usr/sbin/dnsmasq'
    c.network_name = nil
  end

  config_path File.expand_path('config/nsa.conf', app_root)
  load_config
end


start(manifest) do
end