#!/usr/bin/env python3
# Copyright 2020 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Wrapper around repo to auto-update depot_tools during sync.

gclient keeps depot_tools up-to-date automatically for Chromium developers.

We only want to do this on `repo sync` operations as that implies a network
operation, and update_depot_tools is not cheap.
"""

import os
from pathlib import Path
import subprocess
import sys

# Some useful paths.
DEPOT_TOOLS_DIR = Path(__file__).resolve().parent
UPDATE_DEPOT_TOOLS = DEPOT_TOOLS_DIR / 'update_depot_tools'
REPO = DEPOT_TOOLS_DIR / 'repo_launcher'


def _UpdateDepotTools():
    """Help CrOS users keep their depot_tools checkouts up-to-date."""
    if os.getenv('DEPOT_TOOLS_UPDATE') == '0':
        return

    # We don't update the copy that's part of the CrOS repo client checkout.
    path = DEPOT_TOOLS_DIR
    while path != path.parent:
        if (path / '.repo').is_dir() and (path / 'chromite').is_dir():
            return
        if (path / '.citc').is_dir():
            return
        path = path.parent

    if UPDATE_DEPOT_TOOLS.exists():
        subprocess.run([UPDATE_DEPOT_TOOLS], check=True)
    else:
        print(
            f'warning: {UPDATE_DEPOT_TOOLS} does not exist; export '
            'DEPOT_TOOLS_UPDATE=0 to disable.',
            file=sys.stderr)


def main(argv):
    # This is a bit hacky, but should be "good enough".  If repo itself gains
    # support for sync hooks, we could switch to that.
    if argv and argv[0] == 'sync':
        _UpdateDepotTools()

    os.execv(sys.executable, [sys.executable, str(REPO)] + argv)


if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))