# -*- coding: utf-8 -*-
require 'isono'

module Dcmgr
  module NodeModules
    class InstanceHA < Isono::NodeModules::Base
      include Dcmgr::Logger
      
      initialize_hook do
        @thread_pool = Isono::ThreadPool.new(1, 'InstanceHA')
        event = Isono::NodeModules::EventChannel.new(node)
        event.subscribe('hva/fault_instance', '#') { |args|
          @thread_pool.pass {
            inst_id = args[0]
            inst = Models::Instance[inst_id]
            # check if the instance has HA enable.
            next if inst.ha_enabled == 0
            myinstance.restart_instance(inst)
          }
        }
      end

      terminate_hook do
        @thread_pool.shutdown
      end

      def restart_instance(inst)
        # terminate and cleanup
        begin
          jobrpc.run("kvm-handle.#{inst.host_pool.node_id}", 'cleanup', inst.canonical_uuid)
        rescue => e
          # termination may fail
        end
        
        # TODO: pick a new host node
        Isono::NodeModules::DataStore.barrier {
          inst.state = :failingover
          inst.save
        }

        # start a new backup instance
        case inst.image.boot_dev_type
        when Models::Image::BOOT_DEV_SAN
          boot_vol = inst.volume.find {|v| v.boot_dev == 1 }
          res = jobrpc.submit("kvm-handle.#{inst.host_pool.node_id}", 'run_vol_store', inst.canonical_uuid, boot_vol.canonical_uuid)
        when Models::Image::BOOT_DEV_LOCAL
          res = jobrpc.submit("kvm-handle.#{inst.host_pool.node_id}", 'run_local_store', inst.canonical_uuid)
        else
          raise "Unknown boot type"
        end
        logger.info("#{inst.canonical_uuid} has been restarted")
      end
      
      private
      def event
        @event ||= Isono::NodeModules::EventChannel.new(node)
      end

      def jobrpc
        @jobrpc ||= Isono::NodeModules::JobChannel.new(node)
      end

    end
  end
end