import logging
import json
import time

from datetime import timedelta, datetime

import features
from app import app, storage
from data.database import UseThenDisconnect
from data.model import db_transaction
from data.model.log import (get_stale_logs, get_stale_logs_start_id,
                            get_stale_logs_cutoff_id, delete_stale_logs)
from util.registry.gzipwrap import GzipWrap
from workers.globalworkerbase import GlobalWorker

logger = logging.getLogger(__name__)

WORKER_FREQUENCY = 3600 * 6
STALE_AFTER = timedelta(days=30)
MIN_LOGS_PER_ROTATION = 10000
SAVE_PATH = app.config.get('ACTION_LOG_ARCHIVE_PATH')
SAVE_LOCATION = app.config.get('ACTION_LOG_ARCHIVE_LOCATION')

class LogRotateWorker(GlobalWorker):
  """ Worker used to rotate old logs out the database and into storage. """
  def __init__(self):
    super(LogRotateWorker, self).__init__(app, sleep_period_seconds=WORKER_FREQUENCY)

  def perform_global_work(self):
    logger.debug('Attempting to rotate log entries')
    while True:
      with UseThenDisconnect(app.config):
        with db_transaction():
          cutoff_date = datetime.now() - STALE_AFTER
          start_id = get_stale_logs_start_id()
          cutoff_id = get_stale_logs_cutoff_id(cutoff_date)

          if start_id is None or cutoff_id is None:
            logger.warning('No logs to be archived.')
            return

          logger.debug('Found starting ID %s and cutoff ID %s', start_id, cutoff_id)

          approx_count = cutoff_id - start_id
          if approx_count < MIN_LOGS_PER_ROTATION:
            logger.debug('Not enough stale logs to warrant rotation (approx %d)', approx_count)
            return

          end_id = start_id + MIN_LOGS_PER_ROTATION
          logs = (pretty_print_in_json(log)
                  for log in get_stale_logs(start_id, end_id))

          logger.debug('Archiving logs from IDs %s to %s', start_id, end_id)
          filename = '%s%d-%d.txt.gz' % (SAVE_PATH, start_id, end_id)
          storage.stream_write(SAVE_LOCATION, filename, GzipWrap(logs))

          delete_stale_logs(start_id, end_id)


def pretty_print_in_json(log):
  """ Pretty prints a LogEntry in JSON. """
  return json.dumps({'kind_id': log.kind_id,
                     'account_id': log.account_id,
                     'performer_id': log.performer_id,
                     'repository_id': log.repository_id,
                     'datetime': str(log.datetime),
                     'ip': str(log.ip),
                     'metadata_json': json.loads(str(log.metadata_json))})


def main():
  if not features.ACTION_LOG_ROTATION or None in [SAVE_PATH, SAVE_LOCATION]:
    while True:
      time.sleep(100000)

  worker = LogRotateWorker()
  worker.start()


if __name__ == "__main__":
  main()