#!/usr/bin/env python3.8
# Copyright 2020 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import os
import sys
from pathlib import Path

FUCHSIA_DIR = Path(os.environ["FUCHSIA_DIR"])


def main(args):
    """Given a newline separate list of files as stdin (probably generated by
    using a tool like `find` or similar), check to see if we can add a
    `deprecated_syntax` token to them, and do so if one does not already exist.
    For example, when the pwd is root, and we are building to out/default in
    this repo, we would pipe the result of

      find ./out/default/. -name "*.fidl" -type f | xargs readlink -f

    into this script.
    """

    root_path = Path(args.root)
    for filepath in sys.stdin:
        path = Path(filepath.strip())
        if not path.is_file():
            continue
        relpath = str(path.relative_to(root_path))
        if relpath.startswith('out/default') or relpath.startswith('prebuilt/'):
            continue
        if relpath.endswith('goodformat.test.fidl'):
            continue

        with open(path, 'r') as f:
            lines = f.readlines()
            # already converted from a previous run; skip
            if any(l.startswith('deprecated_syntax;') for l in lines):
                continue

            lib_line = None
            for i, line in enumerate(lines):
                is_comment = line.startswith(
                    '//') and not line.startswith('///')
                if not is_comment:
                    lib_line = i
                    break
            if lib_line is None:
                print(path)
            lines.insert(lib_line, 'deprecated_syntax;\n')

        with open(path, 'w') as f:
            f.writelines(lines)


if __name__ == '__main__':
    parser = argparse.ArgumentParser(
        description='Add `deprecated_syntax` token '
        'to all FIDL files in GN-ified a '
        'repo.')
    parser.add_argument(
        'root', help='The root path of the repo being converted')
    main(parser.parse_args())