class Aws::Rails::SqsActiveJob::Poller

def boot_rails
  ENV['RACK_ENV'] = ENV['RAILS_ENV'] = @environment
  require "rails"
  require File.expand_path("config/environment.rb")
end

def initialize(args = ARGV)
  @options = parse_args(args)
  # Set_environment must be run before we boot_rails
  set_environment
end

def parse_args(argv)
  out = {}
  parser = ::OptionParser.new { |opts|
    opts.on("-q", "--queue STRING", "[Required] Queue to poll") { |a| out[:queue] = a }
    opts.on("-e", "--environment STRING", "Rails environment (defaults to development). You can also use the APP_ENV or RAILS_ENV environment variables to specify the environment.") { |a| out[:environment] = a }
    opts.on("-t", "--threads INTEGER", Integer, "The maximum number of worker threads to create.  Defaults to 2x the number of processors available on this system.") { |a| out[:threads] = a }
    opts.on("-b", "--backpressure INTEGER", Integer, "The maximum number of messages to have waiting in the Executor queue. This should be a low, but non zero number.  Messages in the Executor queue cannot be picked up by other processes and will slow down shutdown.") { |a| out[:backpressure] = a }
    opts.on("-m", "--max_messages INTEGER", Integer, "Max number of messages to receive in a batch from SQS.") { |a| out[:max_messages] = a }
    opts.on("-v", "--visibility_timeout INTEGER", Integer, "The visibility timeout is the number of seconds that a message will not be processable by any other consumers. You should set this value to be longer than your expected job runtime to prevent other processes from picking up an running job.  See the SQS Visibility Timeout Documentation at https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-visibility-timeout.html.") { |a| out[:visibility_timeout] = a }
    opts.on("-s", "--shutdown_timeout INTEGER", Integer, "The amount of time to wait for a clean shutdown.  Jobs that are unable to complete in this time will not be deleted from the SQS queue and will be retryable after the visibility timeout.") { |a| out[:shutdown_timeout] = a }
  }
  parser.banner = "aws_sqs_active_job [options]"
  parser.on_tail "-h", "--help", "Show help" do
    puts parser
    exit 1
  end
  parser.parse(argv)
  out
end

def poll
  queue_url = Aws::Rails::SqsActiveJob.config.queue_url_for(@options[:queue])
  @logger.info "Polling on: #{@options[:queue]} => #{queue_url}"
  client = Aws::Rails::SqsActiveJob.config.client
  @poller = Aws::SQS::QueuePoller.new(queue_url, client: client)
  poller_options = {
    skip_delete: true,
    max_number_of_messages: @options[:max_messages],
    visibility_timeout: @options[:visibility_timeout]
  }
  # Limit max_number_of_messages for FIFO queues to 1
  # this ensures jobs with the same message_group_id are processed
  # in order
  # Jobs with different message_group_id will be processed in
  # parallel and may be out of order.
  if Aws::Rails::SqsActiveJob.fifo?(queue_url)
    poller_options[:max_number_of_messages] = 1
  end
  single_message = poller_options[:max_number_of_messages] == 1
  @poller.poll(poller_options) do |msgs|
    msgs = [msgs] if single_message
    @logger.info "Processing batch of #{msgs.length} messages"
    msgs.each do |msg|
      @executor.execute(Aws::SQS::Message.new(
        queue_url: queue_url,
        receipt_handle: msg.receipt_handle,
        data: msg,
        client: client
      ))
    end
  end
end

def run
  # exit 0
  boot_rails
  # cannot load config (from file or initializers) until after
  # rails has been booted.
  @options = DEFAULT_OPTS
             .merge(Aws::Rails::SqsActiveJob.config.to_h)
             .merge(@options.to_h)
  validate_config
  # ensure we have a logger configured
  @logger = @options[:logger] || ActiveSupport::Logger.new(STDOUT)
  @logger.info("Starting Poller with options=#{@options}")
  Signal.trap('INT') { raise Interrupt }
  Signal.trap('TERM') { raise Interrupt }
  @executor = Executor.new(max_threads: @options[:threads], logger: @logger, max_queue: @options[:backpressure])
  poll
rescue Interrupt
  @logger.info 'Process Interrupted or killed - attempting to shutdown cleanly.'
  shutdown
  exit
end

def set_environment
  @environment = @options[:environment] || ENV["APP_ENV"] || ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "development"
end

def shutdown
  @executor.shutdown(@options[:shutdown_timeout])
end

def validate_config
  raise ArgumentError, 'You must specify the name of the queue to process jobs from' unless @options[:queue]
end