#!/usr/bin/env python3

import os
import sys
import time

from datetime import datetime,timezone
from shutil import which
from subprocess import check_output

srcdir = os.path.dirname(os.path.abspath(sys.argv[0]))
git_dir = os.path.join(srcdir, ".git")
git = which('git')

if git and os.path.exists(git_dir):
    version = check_output([git, "-C", srcdir, "describe", "--always", "--tags",
                            "--dirty"], encoding="UTF-8")
    version = version[1:].strip()
else:
    version_path = os.path.join(srcdir, "VERSION")
    with open(version_path, "r") as f:
        version = f.readline().strip()

if len(sys.argv) < 2:
    print(version)
    sys.exit()

ts = float(os.environ.get('SOURCE_DATE_EPOCH', time.time()))
date = datetime.fromtimestamp(ts, timezone.utc)

OLD_REVISION = ""
NEW_REVISION = f'#define VERSION "{version}"'
BUILDDATE = f'#define BUILDDATE "{date.ctime()}"'
MPVCOPYRIGHT = f'#define MPVCOPYRIGHT "Copyright © 2000-2023 mpv/MPlayer/mplayer2 projects"'

if os.path.isfile(sys.argv[1]):
    with open(sys.argv[1], "r") as f:
        OLD_REVISION = f.readline().strip()

if NEW_REVISION != OLD_REVISION or NEW_REVISION.endswith('dirty"'):
    with open(sys.argv[1], "w", encoding="utf-8") as f:
        f.writelines(f"{l}{os.linesep}" for l in [NEW_REVISION, BUILDDATE, MPVCOPYRIGHT])