import logging

from gzip import GzipFile
from tempfile import SpooledTemporaryFile

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


logger = logging.getLogger(__name__)


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


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.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,
    }

    if length > 0:
      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)

    we_updated = model.mark_build_archived(to_archive.uuid)
    if we_updated:
      build_logs.expire_status(to_archive.uuid)
      build_logs.delete_log_entries(to_archive.uuid)
    else:
      logger.debug('Another worker pre-empted us when archiving: %s', to_archive.uuid)


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