# an initializer
# gem install bunny
# written by: Tam Nguyen (twitter: @nguyentamvn)

require 'bunny'
require 'json'

class RabbitPublisher
  def initialize(options = {})
    bunny_config = {
      host: options[:host] || 'localhost',
      user: options[:user],
      pass: options[:pass],
      heartbeat_interval: 8,
      automatically_recover: true,
      timeout: 7
    }
    rabbit_connection = Bunny.new(bunny_config)
    rabbit_connection.start
    rabbit_channel = rabbit_connection.create_channel

    self.channel = rabbit_channel
    self.connection = rabbit_connection
  end

  def publish(options = {})
    queue_name = options[:queue_name]
    message = options[:message]
    if queue_name.nil? || queue_name.empty?
      puts 'queue_name is missing'
      return
    end

    queue = channel.queue(queue_name, durable: true)
    begin
      puts "Sending message..."
      queue.publish(message.to_json, persistent: true)
    rescue Exception => e
      puts "[ERROR] #{e}"
      close
    end
  end

  def receive(options = {})
    queue_name = options[:queue_name]
    if queue_name.nil? || queue_name.empty?
      puts 'queue_name is missing'
      return
    end

    puts "Waiting queue: #{queue_name}..."
    channel.prefetch(1)
    begin
      queue = channel.queue(queue_name, durable: true)
      queue.subscribe(manual_ack: true, block: true) do |delivery_info, _properties, body|
        yield channel, delivery_info, body
      end
    rescue Exception => e
      puts "[ERROR] #{e}"
      close
    end
  end

  def close
    channel.close
    connection.close
    puts 'Closed rabbitmq connections.'
  end

  private

  attr_accessor :channel
  attr_accessor :connection
end

# how to use
# rabbit = RabbitPublisher.new

# for publishing messages
# rabbit.publish(queue_name: "twitter", message: { name: "tam nguyen" })
# (1..10000).each {|i| rabbit.publish(queue_name: "twitter", message: { name: "tam nguyen #{i}" }); sleep 0.1 }

# for subscribing messages
# rabbit.receive(queue_name: 'twitter') do |channel, delivery_info, body|
#   puts " [x] #{body}"
#   channel.ack(delivery_info.delivery_tag)
# end

# should close connecttions whern completed tasks
# rabbit.close