# Copyright 2010-2018 The NATS Authors
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require 'optparse'

$:.unshift File.expand_path('../../lib', __FILE__)
require 'nats/client'

$count = 100000
$batch = 100

$delay = 0.00001
$dmin  = 0.00001

TRIP  = (2*1024*1024)
TSIZE = 4*1024

$sub  = 'test'
$data_size = 16

$hash  = 2500

STDOUT.sync = true

parser = OptionParser.new do |opts|
  opts.banner = "Usage: pub_perf [options]"

  opts.separator ""
  opts.separator "options:"

  opts.on("-n COUNT",   "Messages to send (default: #{$count}}") { |count| $count = count.to_i }
  opts.on("-s SIZE",    "Message size (default: #{$data_size})") { |size| $data_size = size.to_i }
  opts.on("-S SUBJECT", "Send subject (default: (#{$sub})")      { |sub| $sub = sub }
  opts.on("-b BATCH",   "Batch size (default: (#{$batch})")      { |batch| $batch = batch.to_i }
end

parser.parse(ARGV)

trap("TERM") { exit! }
trap("INT")  { exit! }

NATS.on_error { |err| puts "Server Error: #{err}"; exit! }

$data = Array.new($data_size) { "%01x" % rand(16) }.join('').freeze

NATS.start(:fast_producer => true) do

  $batch = 10 if $data_size >= TSIZE

  $received = 0
  NATS.subscribe($sub) { $received += 1 }

  $start   = Time.now
  $to_send = $count

  def send_batch
    (0..$batch).each do
      $to_send -= 1
      if $to_send == 0
        NATS.publish($sub, $data) { display_final_results }
        return
      else
        NATS.publish($sub, $data)
      end
      printf('+') if $to_send.modulo($hash) == 0
    end

    if (NATS.pending_data_size > TRIP)
      $delay *= 2
    elsif $delay > $dmin
      $delay /= 2
    end

    EM.add_timer($delay) { send_batch }
  end

  def display_final_results
    elapsed = Time.now - $start
    mbytes = sprintf("%.1f", (($data_size*$count)/elapsed)/(1024*1024))
    puts "\nTest completed : #{($count/elapsed).ceil} sent/received msgs/sec (#{mbytes} MB/sec)\n"
    puts "Received #{$received} messages\n"
    NATS.stop
  end

  if false
    EM.add_periodic_timer(0.25) do
      puts "Outstanding data size is #{NATS.client.get_outbound_data_size}"
    end
  end

  puts "Sending #{$count} messages of size #{$data.size} bytes on [#{$sub}]"

  # kick things off..
  send_batch

end
