require 'json'
require 'etcdv3'

module RubyPitaya

  class EtcdConnector

    def initialize(server_uuid, desktop_name, server_name, etcd_prefix,
                   etcd_address, allow_reconnect, lease_seconds, log)
      @server_uuid = server_uuid
      @server_name = server_name
      @desktop_name = desktop_name
      @etcd_prefix = etcd_prefix
      @etcd_address = etcd_address
      @allow_reconnect = allow_reconnect
      @lease_seconds = lease_seconds
      @log = log

      @renew_connection_seconds = lease_seconds / 2.0

      @renew_connection_key = nil
      @renew_connection_value = nil
      @renew_connection_thread = nil
    end

    def connect
      connection_key = get_connection_key
      connection_value = get_connection_value

      @connection = Etcdv3.new(endpoints: @etcd_address,
                               allow_reconnect: @allow_reconnect)

      @lease = @connection.lease_grant(@lease_seconds)

      @connection.put(connection_key, connection_value, lease: @lease.ID)

      @renew_connection_key = connection_key
      @renew_connection_value = connection_value

      renew_connection
    end

    def disconnect
      stop_renew_connection
      @connection.del(get_connection_key)
    end

    private

    def get_connection_key
      "#{@etcd_prefix}servers/#{@server_name}/#{@server_uuid}"
    end

    def get_connection_value
      JSON.generate(get_server_data)
    end

    def renew_connection
      stop_renew_connection

      @renew_connection_thread = Thread.new do
        loop do
          sleep(@renew_connection_seconds)

          begin
            @lease = @connection.lease_keep_alive_once(@lease.ID)

            if @lease.TTL == 0
              @lease = @connection.lease_grant(@lease_seconds)
              @connection.put(@renew_connection_key, @renew_connection_value, lease: @lease.ID)
            end

          rescue Exception => error
            @log.error "ETCD RENEW ERROR: #{error.class} | #{error.message}} \n #{error.backtrace.join("\n")}"
          end
        end
      end
    end

    def stop_renew_connection
      @renew_connection_thread.exit.join unless @renew_connection_thread.nil?
      @renew_connection_thread = nil
    end

    def get_server_data
      {
        id: @server_uuid,
        hostname: @desktop_name,
        type: @server_name,
        frontend: false,
        metadata: {
          stack: 'default',
          stackInfo: JSON.generate({
            Maintenance: false,
            Platforms: {
              android: {
                  Max: '9.9.9',
                  Min: '0.0.0'
              },
              ios: {
                  Max: '9.9.9',
                  Min: '0.0.0'
              },
              iphoneplayer: {
                  Max: '9.9.9',
                  Min: '0.0.0'
              },
              mac: {
                  Max: '9.9.9',
                  Min: '0.0.0'
              },
              osxeditor: {
                  Max: '9.9.9',
                  Min: '0.0.0'
              }
            }
          })
        }
      }
    end
  end
end