import logging
import time
import json

import features

from app import secscan_notification_queue, secscan_api
from workers.queueworker import QueueWorker, JobException
from util.secscan.notifier import process_notification_data


logger = logging.getLogger(__name__)


_READING_SECONDS = 120 # 2 minutes
_PROCESSING_SECONDS = 60 * 60 # 1 hour
_LAYER_LIMIT = 100 # The number of layers to request on each page.


class SecurityNotificationWorker(QueueWorker):
  def process_queue_item(self, data):
    self.perform_notification_work(data)

  def perform_notification_work(self, data):
    """ Performs the work for handling a security notification as referenced by the given data
        object. Returns True on successful handling, False on non-retryable failure and raises
        a JobException on retryable failure.
    """

    notification_name = data['Name']
    current_page = data.get('page', None)

    while True:
      self.extend_processing(_READING_SECONDS, json.dumps(data))
      (response_data, should_retry) = secscan_api.get_notification(notification_name,
                                                                   layer_limit=_LAYER_LIMIT,
                                                                   page=current_page)
      if response_data is None:
        if should_retry:
          raise JobException()
        else:
          # Return to mark the job as "complete", as we'll never be able to finish it.
          logger.error('Failed to handle security notification %s', notification_name)
          return False

      self.extend_processing(_PROCESSING_SECONDS, json.dumps(data))
      notification_data = response_data['Notification']
      if not process_notification_data(notification_data):
        raise JobException()

      # Check for a next page of results. If none, we're done.
      if 'NextPage' not in notification_data:
        # Mark the notification as read and processed.
        if not secscan_api.mark_notification_read(notification_name):
          # Return to mark the job as "complete", as we'll never be able to finish it.
          logger.error('Failed to mark notification %s as read', notification_name)
          return False

        return True

      # Otherwise, save the next page token into the queue item (so we can pick up from here if
      # something goes wrong in the next loop iteration), and continue.
      current_page = notification_data['NextPage']
      data['page'] = current_page


if __name__ == '__main__':
  if not features.SECURITY_SCANNER or not features.SECURITY_NOTIFICATIONS:
    logger.debug('Security scanner disabled; skipping SecurityNotificationWorker')
    while True:
      time.sleep(100000)

  worker = SecurityNotificationWorker(secscan_notification_queue, poll_period_seconds=30,
                                      reservation_seconds=30, retry_after_seconds=30)
  worker.start()