#!/usr/bin/env python3
"""Read a Frappe app's stable __version__ from a local file or Git ref."""

from __future__ import annotations

import argparse
import re
import subprocess


def parse_args() -> argparse.Namespace:
	parser = argparse.ArgumentParser()
	parser.add_argument("version_file")
	parser.add_argument("--ref")
	return parser.parse_args()


def main() -> None:
	args = parse_args()
	try:
		if args.ref:
			content = subprocess.check_output(
				["git", "show", f"{args.ref}:{args.version_file}"],
				text=True,
			)
		else:
			with open(args.version_file, encoding="utf-8") as version_file:
				content = version_file.read()
	except (OSError, subprocess.CalledProcessError) as error:
		raise SystemExit(f"Could not load {args.version_file}: {error}") from error

	match = re.search(r'^__version__ = "(\d+\.\d+\.\d+)"$', content, re.MULTILINE)
	if not match:
		raise SystemExit(
			f"Could not read a stable MAJOR.MINOR.PATCH __version__ from {args.version_file}"
		)
	print(match.group(1))


if __name__ == "__main__":
	main()