import logging

from tempfile import SpooledTemporaryFile
from gzip import GzipFile

from data import model
from data.archivedlogs import JSON_MIMETYPE
from data.database import CloseForLongOperation
from app import build_logs, log_archive, app
from util.streamingjsonencoder import StreamingJSONEncoder
from workers.worker import Worker

POLL_PERIOD_SECONDS = 30
MEMORY_TEMPFILE_SIZE = 64 * 1024  # Large enough to handle approximately 99% of builds in memory

logger = logging.getLogger(__name__)

class ArchiveBuildLogsWorker(Worker):
  def __init__(self):
    super(ArchiveBuildLogsWorker, self).__init__()
    self.add_operation(self._archive_redis_buildlogs, POLL_PERIOD_SECONDS)

  def _archive_redis_buildlogs(self):
    """ Archive a single build, choosing a candidate at random. This process must be idempotent to
        avoid needing two-phase commit. """
    # Get a random build to archive
    to_archive = model.build.get_archivable_build()
    if to_archive is None:
      logger.debug('No more builds to archive')
      return

    logger.debug('Archiving: %s', to_archive.uuid)

    length, entries = build_logs.get_log_entries(to_archive.uuid, 0)
    to_encode = {
      'start': 0,
      'total': length,
      'logs': entries,
    }

    with CloseForLongOperation(app.config):
      with SpooledTemporaryFile(MEMORY_TEMPFILE_SIZE) as tempfile:
        with GzipFile('testarchive', fileobj=tempfile) as zipstream:
          for chunk in StreamingJSONEncoder().iterencode(to_encode):
            zipstream.write(chunk)

        tempfile.seek(0)
        log_archive.store_file(tempfile, JSON_MIMETYPE, content_encoding='gzip',
                               file_id=to_archive.uuid)

    to_update = model.build.get_repository_build(to_archive.uuid)
    to_update.logs_archived = True
    to_update.save()

    build_logs.expire_status(to_update.uuid)
    build_logs.delete_log_entries(to_update.uuid)


if __name__ == "__main__":
  worker = ArchiveBuildLogsWorker()
  worker.start()