import argparse
import asyncio
import importlib.util
import logging
import os.path
import qwarc
import qwarc.utils
import qwarc.version
import sys


logger = logging.getLogger(__name__)


def setup_logging(logFilename, logLevel, logLevelStderr):
	if logLevelStderr is None:
		logLevelStderr = logLevel

	rootLogger = logging.getLogger()
	rootLogger.handlers = []
	rootLogger.setLevel(min(logLevel, logLevelStderr))

	formatter = qwarc.utils.LogFormatter()

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

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


def check_files(specFilename, logFilename):
	success = True
	if not os.path.isfile(specFilename):
		print(f'Error: "{specFilename}" does not exist or is not a regular file', file = sys.stderr)
		success = False
	if os.path.exists(logFilename):
		print(f'Error: "{logFilename}" already exists', 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('--version', action = 'version', version = f'qwarc {qwarc.version.__version__}')
	parser.add_argument('--log', metavar = 'LOGFILE', default = './qwarc.log')
	parser.add_argument('--loglevel', metavar = 'LEVEL', help = 'verbosity of the log file', choices = ('INFO', 'DEBUG'), default = 'INFO')
	parser.add_argument('--loglevelstderr', metavar = 'LEVEL', help = 'verbosity of the log messages on stderr; set equal to the log file level if None', choices = (None, 'CRITICAL', 'ERROR', 'WARNING', 'INFO', 'DEBUG'), default = None)
	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', type = int, help = 'pause when less than LIMIT bytes memory is free; disable if 0', default = 0)
	parser.add_argument('--disklimit', metavar = 'LIMIT', type = int, help = 'pause when less than LIMIT bytes disk space is free; disable if 0', default = 0)
	parser.add_argument('--warcsplit', metavar = 'SIZE', type = int, help = 'split WARCs into files of SIZE bytes; disable if 0', default = 0)
	parser.add_argument('--warcdedupe', action = 'store_true', help = 'enable deduplication of WARC records')
	parser.add_argument('specfile')

	args = parser.parse_args()
	args.loglevel = getattr(logging, args.loglevel)
	args.loglevelstderr = getattr(logging, args.loglevelstderr) if args.loglevelstderr is not None else args.loglevel

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

	setup_logging(args.log, args.loglevel, args.loglevelstderr)

	spec = importlib.util.spec_from_file_location('spec', args.specfile)
	specMod = importlib.util.module_from_spec(spec)
	spec.loader.exec_module(specMod)
	specDependencies = specMod.__dict__.get('specDependencies', qwarc.utils.SpecDependencies())

	a = qwarc.QWARC(
		itemClasses = set(qwarc.Item.get_subclasses()),
		warcBasePath = args.warc,
		dbPath = args.database,
		command = sys.argv,
		specFile = args.specfile,
		specDependencies = specDependencies,
		logFilename = args.log,
		concurrency = args.concurrency,
		memoryLimit = args.memorylimit,
		minFreeDisk = args.disklimit,
		warcSizeLimit = args.warcsplit,
		warcDedupe = args.warcdedupe,
	  )
	loop = asyncio.get_event_loop()
	try:
		loop.run_until_complete(a.run(loop))
	except (Exception, KeyboardInterrupt) as e:
		logger.exception('Unhandled error')
	finally:
		loop.run_until_complete(a.close())
	loop.close()