#!/usr/bin/env python3
# Copyright 2018 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.

"""Run cpplint with the right settings."""

from pathlib import Path
import sys
from typing import List

import libdot


# The set of file extensions we support as cpplint needs to be told explicitly.
EXTENSIONS = {'c', 'cc', 'cpp', 'h', 'hpp'}


# The commit in depot_tools that we're pinned to.
CHROMIUM_REF = 'c4fb1974191f0d09fcb932f76ae7b5abce1f0ce5'

# Full path to Chromium's fork of the cpplint.py script.
CPPLINT_URL = ('https://chromium.googlesource.com/chromium/tools/depot_tools/+/'
               f'{CHROMIUM_REF}/cpplint.py')

# Our local cache of the script.
CPPLINT = libdot.BIN_DIR / f'.cpplint.{CHROMIUM_REF}'


def filter_known_files(paths: List[Path]) -> List[Path]:
    """Figure out what files this linter supports."""
    ret = []
    for path in paths:
        path = Path(path)

        if 'third_party' in path.parts:
            # Ignore code we didn't author.
            continue
        elif path.suffix[1:] in EXTENSIONS:
            ret += [path]

    return [str(x) for x in ret]


def setup():
    """Initialize the tool settings."""
    if CPPLINT.exists():
        return

    for path in libdot.BIN_DIR.glob('.cpplint.*'):
        path.unlink()

    libdot.fetch(f'{CPPLINT_URL}?format=TEXT', CPPLINT, b64=True)
    CPPLINT.chmod(0o755)


def run(argv=(), **kwargs):
    """Run the tool directly."""
    setup()

    cmd = [CPPLINT, f'--extensions={",".join(EXTENSIONS)}'] + list(argv)
    return libdot.run(cmd, **kwargs)


def perform(argv=(), paths=(), fix=False, gerrit_comments_file=None):  # pylint: disable=unused-argument
    """Run high level tool logic."""
    ret = True
    argv = list(argv)
    paths = list(paths)

    # Cpplint doesn't have any automatic fixing logic.
    if fix:
        return ret

    # TODO(vapier): Add support for Gerrit comments.

    result = run(argv + paths, check=False)
    return result.returncode == 0


def get_parser():
    """Get a command line parser."""
    parser = libdot.ArgumentParser(description=__doc__, short_options=False)
    parser.add_argument('--gerrit-comments-file',
                        help='Save errors for posting files to Gerrit.')
    parser.add_argument('paths', nargs='*',
                        help='Paths to lint.')
    return parser


def main(argv):
    """The main func!"""
    parser = get_parser()
    opts, args = parser.parse_known_args(argv)

    return 0 if perform(argv=args, paths=opts.paths,
                        gerrit_comments_file=opts.gerrit_comments_file) else 1


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