# Licensed to Elasticsearch B.V under one or more agreements.
# Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
# See the LICENSE file in the project root for more information

module Elasticsearch
  module Transport
    module Transport

      # Handles node discovery ("sniffing")
      #
      class Sniffer
        PROTOCOL = 'http'

        attr_reader   :transport
        attr_accessor :timeout

        # @param transport [Object] A transport instance
        #
        def initialize(transport)
          @transport = transport
          @timeout   = transport.options[:sniffer_timeout] || 1
        end

        # Retrieves the node list from the Elasticsearch's
        # [_Nodes Info API_](http://www.elasticsearch.org/guide/reference/api/admin-cluster-nodes-info/)
        # and returns a normalized Array of information suitable for passing to transport.
        #
        # Shuffles the collection before returning it when the `randomize_hosts` option is set for transport.
        #
        # @return [Array<Hash>]
        # @raise  [SnifferTimeoutError]
        #
        def hosts
          Timeout::timeout(timeout, SnifferTimeoutError) do
            nodes = transport.perform_request('GET', '_nodes/http', {}, nil, nil,
                                              reload_on_failure: false).body

            hosts = nodes['nodes'].map do |id, info|
              if info[PROTOCOL]
                host, port = parse_publish_address(info[PROTOCOL]['publish_address'])

                { :id =>      id,
                  :name =>    info['name'],
                  :version => info['version'],
                  :host =>    host,
                  :port =>    port,
                  :roles =>   info['roles'],
                  :attributes => info['attributes'] }
              end
            end.compact

            hosts.shuffle! if transport.options[:randomize_hosts]
            hosts
          end
        end

        private

        def parse_publish_address(publish_address)
          # publish_address is in the format hostname/ip:port
          if publish_address =~ /\//
            parts = publish_address.partition('/')
            [ parts[0], parse_address_port(parts[2])[1] ]
          else
            parse_address_port(publish_address)
          end
        end

        def parse_address_port(publish_address)
          # address is ipv6
          if publish_address =~ /[\[\]]/
            if parts = publish_address.match(/\A\[(.+)\](?::(\d+))?\z/)
              [ parts[1], parts[2] ]
            end
          else
            publish_address.split(':')
          end
        end
      end
    end
  end
end