#
# Copyright (C) 2018 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""Generates a compile_commands.json file for the given ndk-build project.

The compilation commands for this file are read from the files passed as
arguments to this script.
"""
from __future__ import print_function

import argparse
import json
import os


def parse_args() -> argparse.Namespace:
    """Parses and returns command line arguments."""
    parser = argparse.ArgumentParser()

    parser.add_argument(
        '-o', '--output', type=os.path.realpath, help='Path to output file')  # type: ignore

    def maybe_list_file(arg: str) -> str:
        if arg.startswith('@'):
            return '@' + os.path.realpath(arg[1:])
        return os.path.realpath(arg)

    parser.add_argument(
        'command_files',
        metavar='FILE',
        type=maybe_list_file,
        nargs='+',
        help=('Path to the compilation database for a single object. If the '
              'argument begins with @ it will be treated as a list file '
              'containing paths to the one or more JSON files.'))

    return parser.parse_args()


def main() -> None:
    """Program entry point."""
    args = parse_args()

    all_commands = []
    command_files = []
    for command_file in args.command_files:
        if command_file.startswith('@'):
            with open(command_file[1:]) as list_file:
                command_files.extend(list_file.read().split())
        else:
            command_files.append(command_file)

    for command_file_path in command_files:
        with open(command_file_path) as command_file:
            all_commands.append(json.load(command_file))

    with open(args.output, 'w') as out_file:
        json.dump(
            all_commands,
            out_file,
            sort_keys=True,
            indent=4,
            separators=(',', ': '))


if __name__ == '__main__':
    main()