class Sidekiq::Processor

def dispatch(job_hash, queue, jobstr)
  # since middleware can mutate the job hash
  # we need to clone it to report the original
  # job structure to the Web UI
  # or to push back to redis when retrying.
  # To avoid costly and, most of the time, useless cloning here,
  # we pass original String of JSON to respected methods
  # to re-parse it there if we need access to the original, untouched job
  @job_logger.prepare(job_hash) do
    @retrier.global(jobstr, queue) do
      @job_logger.call(job_hash, queue) do
        stats(jobstr, queue) do
          # Rails 5 requires a Reloader to wrap code execution.  In order to
          # constantize the worker and instantiate an instance, we have to call
          # the Reloader.  It handles code loading, db connection management, etc.
          # Effectively this block denotes a "unit of work" to Rails.
          @reloader.call do
            klass = Object.const_get(job_hash["class"])
            inst = klass.new
            inst.jid = job_hash["jid"]
            @retrier.local(inst, jobstr, queue) do
              yield inst
            end
          end
        end
      end
    end
  end
end

def execute_job(inst, cloned_args)
  inst.perform(*cloned_args)
end

def fetch
  j = get_one
  if j && @done
    j.requeue
    nil
  else
    j
  end
end

def get_one
  uow = capsule.fetcher.retrieve_work
  if @down
    logger.info { "Redis is online, #{::Process.clock_gettime(::Process::CLOCK_MONOTONIC) - @down} sec downtime" }
    @down = nil
  end
  uow
rescue Sidekiq::Shutdown
rescue => ex
  handle_fetch_exception(ex)
end

def handle_fetch_exception(ex)
  unless @down
    @down = ::Process.clock_gettime(::Process::CLOCK_MONOTONIC)
    logger.error("Error fetching job: #{ex}")
    handle_exception(ex)
  end
  sleep(1)
  nil
end

def initialize(capsule, &block)
  @config = @capsule = capsule
  @callback = block
  @down = false
  @done = false
  @job = nil
  @thread = nil
  @reloader = Sidekiq.default_configuration[:reloader]
  @job_logger = (capsule.config[:job_logger] || Sidekiq::JobLogger).new(logger)
  @retrier = Sidekiq::JobRetry.new(capsule)
end

def kill(wait = false)
  @done = true
  return unless @thread
  # unlike the other actors, terminate does not wait
  # for the thread to finish because we don't know how
  # long the job will take to finish.  Instead we
  # provide a `kill` method to call after the shutdown
  # timeout passes.
  @thread.raise ::Sidekiq::Shutdown
  @thread.value if wait
end

def process(uow)
  jobstr = uow.job
  queue = uow.queue_name
  # Treat malformed JSON as a special case: job goes straight to the morgue.
  job_hash = nil
  begin
    job_hash = Sidekiq.load_json(jobstr)
  rescue => ex
    handle_exception(ex, {context: "Invalid JSON for job", jobstr: jobstr})
    now = Time.now.to_f
    redis do |conn|
      conn.multi do |xa|
        xa.zadd("dead", now.to_s, jobstr)
        xa.zremrangebyscore("dead", "-inf", now - @capsule.config[:dead_timeout_in_seconds])
        xa.zremrangebyrank("dead", 0, - @capsule.config[:dead_max_jobs])
      end
    end
    return uow.acknowledge
  end
  ack = false
  begin
    dispatch(job_hash, queue, jobstr) do |inst|
      config.server_middleware.invoke(inst, job_hash, queue) do
        execute_job(inst, job_hash["args"])
      end
    end
    ack = true
  rescue Sidekiq::Shutdown
    # Had to force kill this job because it didn't finish
    # within the timeout.  Don't acknowledge the work since
    # we didn't properly finish it.
  rescue Sidekiq::JobRetry::Handled => h
    # this is the common case: job raised error and Sidekiq::JobRetry::Handled
    # signals that we created a retry successfully.  We can acknowlege the job.
    ack = true
    e = h.cause || h
    handle_exception(e, {context: "Job raised exception", job: job_hash})
    raise e
  rescue Exception => ex
    # Unexpected error!  This is very bad and indicates an exception that got past
    # the retry subsystem (e.g. network partition).  We won't acknowledge the job
    # so it can be rescued when using Sidekiq Pro.
    handle_exception(ex, {context: "Internal exception!", job: job_hash, jobstr: jobstr})
    raise ex
  ensure
    if ack
      # We don't want a shutdown signal to interrupt job acknowledgment.
      Thread.handle_interrupt(IGNORE_SHUTDOWN_INTERRUPTS) do
        uow.acknowledge
      end
    end
  end
end

def process_one(&block)
  @job = fetch
  process(@job) if @job
  @job = nil
end

def run
  # By setting this thread-local, Sidekiq.redis will access +Sidekiq::Capsule#redis_pool+
  # instead of the global pool in +Sidekiq::Config#redis_pool+.
  Thread.current[:sidekiq_capsule] = @capsule
  process_one until @done
  @callback.call(self)
rescue Sidekiq::Shutdown
  @callback.call(self)
rescue Exception => ex
  @callback.call(self, ex)
end

def start
  @thread ||= safe_thread("#{config.name}/processor", &method(:run))
end

def stats(jobstr, queue)
  WORK_STATE.set(tid, {queue: queue, payload: jobstr, run_at: Time.now.to_i})
  begin
    yield
  rescue Exception
    FAILURE.incr
    raise
  ensure
    WORK_STATE.delete(tid)
    PROCESSED.incr
  end
end

def terminate(wait = false)
  @done = true
  return unless @thread
  @thread.value if wait
end