#
# 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 intermediate file for using in making a compilation database.

The intermediate file is also a JSON file, but only encodes the data for a
single output.
"""
from __future__ import print_function

import argparse
import json
import os

from shlex import join

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

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

    parser.add_argument(
        '-d',
        '--directory',
        type=os.path.realpath,  # type: ignore
        help='Working directory for the compile command.')

    parser.add_argument('-f', '--file', help='Source file.')
    parser.add_argument('--object-file', help='Object file.')

    parser.add_argument(
        '--command-file',
        type=os.path.realpath,  # type: ignore
        help='Compilation command list file.')

    parser.add_argument(
        'compile_command',
        metavar='COMPILE_COMMAND',
        nargs=argparse.REMAINDER,
        help='Compilation command.')

    return parser


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

    if args.command_file and args.compile_command:
        parser.error(
            '--command-file and COMPILE_COMMAND are mutually exclusive')

    if not args.command_file and not args.compile_command:
        parser.error('Either --command-file or COMPILE_COMMAND is required.')

    command = join(args.compile_command)
    if args.command_file:
        with open(args.command_file) as command_file:
            command = command_file.read().strip()

    with open(args.output, 'w') as out_file:
        json.dump({
            'directory': args.directory,
            'file': args.file,
            'output': args.object_file,
            'command': command,
        }, out_file)


if __name__ == '__main__':
    main()