def main():
	parser = OptionParser(usage = "usage: %prog [options] <Variants gvf.gz file> ...")

	parser.add_option("--db", dest="db_path",
		help="Database path")

	parser.add_option("-L", "--log-level", dest="log_level",
		default="info", choices=["debug", "info", "warn", "error", "critical", "notset"],
		help="Which log level: debug, info, warn, error, critical, notset")

	(options, args) = parser.parse_args()

	logging.basicConfig(
		level=LOG_LEVEL[options.log_level],
		format="%(asctime)s %(levelname)-5s : %(message)s")

	log = logging.getLogger("var_db")

	if len(args) < 1:
		log.error("At least one variants file is required")
		parser.print_help()
		exit(-1)

	if options.db_path is None:
		log.error("The database path should be specified")
		parser.print_help()
		exit(-1)

	db_path = options.db_path

	log.info("Opening database ...")

	db = VarXrefsDb(db_path)

	db.open()

	db.begin()

	total_count = 0
	total_start_time = time.time()

	src_var_count = {}
	src_ratio = {}

	chromosomes = set()
	chr_var_count = {}
	strands = set()
	
	try:
		partial_count = 0
		partial_start_time = time.time()
		for xref_path in args:
			log.info("Reading {0} ...".format(xref_path))

			if not os.path.isfile(xref_path):
				log.error("File not found: {0}".format(xref_path))
				exit(-1)

			mtime = datetime.fromtimestamp(os.path.getmtime(xref_path))

			f = tsv.open(xref_path, "r")

			src_count = 0
			src_start_time = time.time()

			line_num = 1

			# discard headers
			line = f.readline()
			while line.startswith("#"):
				line = f.readline()
				line_num += 1

			src_var_count[xref_path] = 0

			for line in f:
				try:
					fields = [x if len(x) > 0 else None for x in line.rstrip("\n").split("\t")]

					chr, source, type, start, end, _1, strand, _2, extra = fields

					start = int(start)
					end = int(end)

					ref = None
					alt = None
					xref = None
					try:
						for var in extra.split(";"):
							try:
								key, value = var.split("=")
								if key == "Dbxref":
									pos = value.index(":")
									xref = value[pos + 1:]
								elif key == "Reference_seq":
									ref = value
								elif key == "Variant_seq":
									alt = value
							except:
								continue
					except:
						pass

					if sum([1 if x is None else 0 for x in [chr, start, strand, ref, alt, source, xref]]) > 0:
						log.warn("Discarding incomplete variant: {0}".format(",".join([chr, str(start), strand, ref, alt, source, xref])))
						continue

					src_var_count[xref_path] += 1

					chromosomes.add(chr)
					if chr in chr_var_count:
						chr_var_count[chr] += 1
					else:
						chr_var_count[chr] = 1
					
					strands.add(strand)

					db.add(chr, start, ref, alt, source, xref, strand)

					total_count += 1
					src_count += 1

					partial_count += 1
					elapsed_time = time.time() - partial_start_time
					if elapsed_time >= 10.0:
						ratio = float(partial_count) / elapsed_time
						log.debug("  {0:.1f} variants/second, {1} variants, {2} total variants".format(ratio,
								hsize(src_count), hsize(total_count)))
						partial_count = 0
						partial_start_time = time.time()

				except Exception as ex:
					log.error("Error at line {0}:\n{1}".format(line_num, line.rstrip("\n")))
					import sys
					import traceback
					traceback.print_exc(file=sys.stdout)
					continue
				finally:
					line_num += 1

			elapsed_time = time.time() - src_start_time
			ratio = float(src_count) / elapsed_time
			src_ratio[xref_path] = ratio
			log.info("  {0:.1f} variants/second, {1} variants, {2} total variants".format(ratio,
					hsize(src_count), hsize(total_count)))

			f.close()

		db.commit()
	except KeyboardInterrupt:
		db.commit()
		log.warn("Interrupted by the user with Ctrl-C")
		exit(-1)
	except:
		db.rollback()
		raise
	finally:
		db.close()

	elapsed_time = time.time() - total_start_time
	total_ratio = float(total_count) / elapsed_time

	log.info("Statistics:")
	log.info("  Sources:")
	for xref_path in args:
		log.info("    {0}: {1} variants".format(os.path.basename(xref_path), src_var_count[xref_path]))
	total_size = 0

	log.info("  Chromosomes:")
	for chr in chromosomes:
		log.info("    {0:>2}: {1:>7} variants".format(chr, str(chr_var_count[chr])))
	log.info("  Strands: {0}".format(", ".join(strands)))

	log.info("  Total {0} variants ({1:.1f} variants/sec)".format(hsize(total_count), total_ratio))