module Kestrel::Client::StatsHelper

  QUEUE_STAT_NAMES = %w{items bytes total_items logsize expired_items mem_items mem_bytes age discarded}

  def sizeof(queue)
    stat_info = stat(queue)
    stat_info ? stat_info['items'] : 0
  end

  def available_queues
    stats['queues'].keys.sort
  end

  def stats
    merge_stats(servers.map { |server| stats_for_server(server) })
  end

  def stat(queue)
    stats['queues'][queue]
  end

  private

  def stats_for_server(server)
    server_name, port = server.split(/:/)
    socket = TCPSocket.new(server_name, port)
    socket.puts "STATS"

    stats = Hash.new
    stats['queues'] = Hash.new
    while line = socket.readline
      if line =~ /^STAT queue_(\S+?)_(#{QUEUE_STAT_NAMES.join("|")}) (\S+)/
        queue_name, queue_stat_name, queue_stat_value = $1, $2, deserialize_stat_value($3)
        stats['queues'][queue_name] ||= Hash.new
        stats['queues'][queue_name][queue_stat_name] = queue_stat_value
      elsif line =~ /^STAT (\w+) (\S+)/
        stat_name, stat_value = $1, deserialize_stat_value($2)
        stats[stat_name] = stat_value
      elsif line =~ /^END/
        socket.close
        break
      elsif defined?(RAILS_DEFAULT_LOGGER)
        RAILS_DEFAULT_LOGGER.debug("KestrelClient#stats_for_server: Ignoring #{line}")
      end
    end

    stats
  end

  def merge_stats(all_stats)
    result = Hash.new

    all_stats.each do |stats|
      stats.each do |stat_name, stat_value|
        if result.has_key?(stat_name)
          if stat_value.kind_of?(Hash)
            result[stat_name] = merge_stats([result[stat_name], stat_value])
          else
            result[stat_name] += stat_value
          end
        else
          result[stat_name] = stat_value
        end
      end
    end

    result
  end

  def deserialize_stat_value(value)
    case value
    when /^\d+\.\d+$/:
        value.to_f
    when /^\d+$/:
        value.to_i
    else
      value
    end
  end
end