import argparse
import asyncio
import importlib.util
import logging
import os.path
import qwarc
import sys
import time


def setup_logging(logFilename):
	rootLogger = logging.getLogger()
	rootLogger.handlers = []
	rootLogger.setLevel(logging.INFO)

	formatter = logging.Formatter('%(asctime)s.%(msecs)03dZ %(levelname)s %(message)s', datefmt = '%Y-%m-%d %H:%M:%S')
	formatter.converter = time.gmtime

	fileHandler = logging.FileHandler(logFilename)
	fileHandler.setFormatter(formatter)
	rootLogger.addHandler(fileHandler)

	stderrHandler = logging.StreamHandler()
	stderrHandler.setFormatter(formatter)
	rootLogger.addHandler(stderrHandler)


def check_files(specFilename, logFilename):
	success = True
	if not os.path.isfile(specFilename):
		print('Error: "{}" does not exist or is not a regular file', file = sys.stderr)
		success = False
	if os.path.exists(logFilename):
		print('Error: "{}" already exists'.format(logFilename), file = sys.stderr)
		success = False
	if os.path.exists('STOP'):
		print('Error: "STOP" exists', file = sys.stderr)
		success = False
	return success


def main():
	parser = argparse.ArgumentParser(formatter_class = argparse.ArgumentDefaultsHelpFormatter)
	parser.add_argument('--log', metavar = 'LOGFILE', default = './qwarc.log')
	parser.add_argument('--database', metavar = 'DBFILE', default = './qwarc.db')
	parser.add_argument('--warc', metavar = 'PREFIX', help = 'prefix for the WARC filenames', default = './qwarc')
	parser.add_argument('--concurrency', type = int, default = 1)
	parser.add_argument('--memorylimit', metavar = 'LIMIT', help = 'pause when less than LIMIT bytes memory is free; disable if 0', default = 0)
	parser.add_argument('--disklimit', metavar = 'LIMIT', help = 'pause when less than LIMIT bytes disk space is free; disable if 0', default = 0)
	parser.add_argument('--warcsplit', metavar = 'SIZE', help = 'split WARCs into files of SIZE bytes; disable if 0', default = 0)
	parser.add_argument('specfile')

	args = parser.parse_args()

	if not check_files(args.specfile, args.log):
		sys.exit(1)

	setup_logging(args.log)

	spec = importlib.util.spec_from_file_location('spec', args.specfile)
	specMod = importlib.util.module_from_spec(spec)
	spec.loader.exec_module(specMod)

	a = qwarc.QWARC(
		itemClasses = qwarc.Item.__subclasses__(),
		warcBasePath = args.warc,
		dbPath = args.database,
		concurrency = args.concurrency,
		memoryLimit = args.memorylimit,
		minFreeDisk = args.disklimit,
		warcSizeLimit = args.warcsplit,
	  )
	if not os.path.exists(args.database):
		a.create_db()

	loop = asyncio.get_event_loop()
	try:
		loop.run_until_complete(a.run(loop))
	except (Exception, KeyboardInterrupt) as e:
		logging.exception('Unhandled error')
	loop.close()