# JobQueue abstracts the task of adding work to a queue.
# 
# Beanstalk is fantastic, but maybe not "enterprise grade".
# 
# AMQP is fantastic, but it's bloody complex and has to run inside an
# eventmachine loop.
# 
# Take your pick!
# 
# Before use, an adapter must be chosen:
# 
#   JobQueue.adapter = JobQueue::BeanstalkAdapter.new
# 
# Jobs can then be simply added to the queue with
# 
#   JobQueue.put("flubble bubble")
# 
class JobQueue
  class << self
    attr_accessor :adapter
    attr_accessor :logger
    
    def logger
      @logger ||= begin
        logger = Logger.new(STDOUT)
        logger.level = Logger::WARN
        logger.debug("Created logger")
        logger
      end
    end
  end

  def self.put(string, options = {})
    queue = options[:queue] || 'default'
    priority = options[:priority] || 50
    ttr = options[:ttr] || 60
    adapter.put(string, queue, priority, ttr)
  end

  def self.subscribe(options = {}, &block)
    queue = options[:queue] || 'default'
    error_report = options[:error_report] || Proc.new do |job_body, e|
      JobQueue.logger.error \
        "Job failed\n" \
        "==========\n" \
        "Job content: #{job_body.inspect}\n" \
        "Exception: #{e.message}\n" \
        "#{e.backtrace.join("\n")}\n" \
        "\n"
    end
    cleanup_task = options[:cleanup] || lambda {}
    catch :stop do
      adapter.subscribe(error_report, cleanup_task, queue, &block)
    end
  end

  # Returns a hash of info (exact details dependent on adapter)
  def self.job_stats(job_id)
    adapter.job_stats(job_id)
  end

  def self.queue_length(queue = nil)
    adapter.queue_length(queue)
  end

  class NoConnectionAvailable < RuntimeError
  end

  class ArgumentError < ::ArgumentError
  end
end