#!/usr/bin/env python3
# Copyright 2011 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Wrapper for chromite tools.

The script is intend to be symlinked to any number of chromite tools, attempts
to find the path for chromite, and hands off to the right tool via exec if
possible.

It is intended to used strictly outside of the chroot.
"""

import enum
import os
from pathlib import Path
import subprocess
import sys
from typing import List, NamedTuple, Optional, Tuple

# Min version of Python that we *want*.  We warn for older versions.
MIN_PYTHON_VER_SOFT = (3, 8)
# Min version of Python that we *require*.  We abort for older versions.
MIN_PYTHON_VER_HARD = (3, 8)

DEPOT_TOOLS_DIR = Path(__file__).resolve().parent

# Directory where cros-specific CIPD packages are installed.
CIPD_CACHE_DIR = DEPOT_TOOLS_DIR / '.cipd_bin_cros_python2'


class Checkout(NamedTuple):
    """Some details about this checkout."""

    root: Path
    chromite_dir: Path


def _FindChromite(path: Path) -> Optional[Checkout]:
    """Find the chromite dir in a repo, gclient, or submodule checkout."""
    path = path.resolve()
    # Depending on the checkout type (whether repo chromeos or gclient chrome)
    # Chromite lives in a different location.
    roots = (
        # CrOS checkout using normal manifest.
        ('.repo', 'chromite/.git'),
        # CrOS checkout using CitC.
        ('../.citc', 'chromite/__init__.py'),
        # Chromium checkout using gclient+DEPS.
        ('.gclient', 'src/third_party/chromite/.git'),
        # Chromium checkout using git submodules.
        ('src/.gitmodules', 'src/third_party/chromite/.git'),
        # Chromium checkout using CitC.
        ('../.citc', 'third_party/chromite/__init__.py'),
    )

    while path != Path("/"):
        for root, chromite_git_dir in roots:
            if all((path / x).exists() for x in [root, chromite_git_dir]):
                return Checkout(path, (path / chromite_git_dir).parent)
        path = path.parent
    return None


def _MissingErrorOut(target):
    sys.stderr.write("""ERROR: Couldn't find the chromite tool %s.

Please change to a directory inside your ChromiumOS source tree
and retry.  If you need to setup a ChromiumOS source tree, see
  https://chromium.googlesource.com/chromiumos/docs/+/HEAD/developer_guide.md
""" % target)
    return 127


def _CheckPythonVersion():
    """Verify active Python is new enough."""
    if sys.version_info >= MIN_PYTHON_VER_SOFT:
        return

    progname = os.path.basename(sys.argv[0])
    print('%s: ChromiumOS requires Python-%s+, but "%s" is "%s"' %
          (progname, '.'.join(str(x) for x in MIN_PYTHON_VER_SOFT),
           sys.executable, sys.version.replace('\n', ' ')),
          file=sys.stderr)
    if sys.version_info < MIN_PYTHON_VER_HARD:
        print('%s: fatal: giving up since Python is too old.' % (progname, ),
              file=sys.stderr)
        sys.exit(1)

    print(
        'warning: temporarily continuing anyways; you must upgrade soon to '
        'maintain support.',
        file=sys.stderr)


def _BootstrapVpython27():
    """Installs the vpython2.7 packages into the cipd cache directory."""
    subprocess.run([
        'cipd', 'ensure', '-log-level', 'info', '-ensure-file',
        DEPOT_TOOLS_DIR / 'cipd_manifest_cros_python2.txt', '-root',
        CIPD_CACHE_DIR
    ],
                   check=True)


def main():
    _CheckPythonVersion()

    result = _FindChromite(Path.cwd())
    target = os.path.basename(sys.argv[0])
    if result is None:
        return _MissingErrorOut(target)
    root, chromite_dir = result

    is_citc = (root.parent / ".citc").is_dir()
    if is_citc:
        # citc workspaces don't like dirty files like pyc.
        os.environ["PYTHONDONTWRITEBYTECODE"] = "1"

    path = chromite_dir / "bin" / target

    # Check to see if this is a script requiring vpython2.7.
    with path.open("rb") as fp:
        shebang = next(fp).strip()
    interpreter = shebang.split()[-1]
    if interpreter in (b'python', b'python2', b'python2.7', b'vpython'):
        _BootstrapVpython27()
        vpython = CIPD_CACHE_DIR / 'vpython'
        args = [vpython]
        if interpreter != b'vpython':
            args.extend(
                ['-vpython-spec', DEPOT_TOOLS_DIR / 'cros_python2.vpython'])
        args.append(path)
        path = vpython
    else:
        args = [path]

    os.execv(path, args + sys.argv[1:])


if __name__ == '__main__':
    sys.exit(main())