# Copyright 2018 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Generates an umbrella header for an iOS framework."""

import argparse
import datetime
import os
import re
import string


HEADER_TEMPLATE = string.Template('''\
// Copyright $year The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// This file is auto-generated by //build/ios/config/generate_umbrella_header.py

#ifndef $header_guard
#define $header_guard

$imports

#endif  // $header_guard
''')


def ComputeHeaderGuard(file_path):
    """Computes the header guard for a file path.

    Args:
      file_path: The path to convert into an header guard.
    Returns:
      The header guard string for the file_path.
    """
    return re.sub(r'[.+/\\]', r'_', file_path.upper()) + '_'


def WriteUmbrellaHeader(output_path, imported_headers):
    """Writes the umbrella header.

    Args:
      output_path: The path to the umbrella header.
      imported_headers: A list of headers to #import in the umbrella header.
    """
    year = datetime.date.today().year
    header_guard = ComputeHeaderGuard(output_path)
    imports = '\n'.join(
        [
            '#import "%s"' % os.path.basename(header)
            for header in sorted(imported_headers)
        ]
    )
    with open(output_path, 'w') as output_file:
        output_file.write(
            HEADER_TEMPLATE.safe_substitute(
                {
                    'year': year,
                    'header_guard': header_guard,
                    'imports': imports,
                }
            )
        )


def Main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        '--output-path',
        required=True,
        type=str,
        help='Path to the generated umbrella header.',
    )
    parser.add_argument(
        'imported_headers',
        type=str,
        nargs='+',
        help='Headers to #import in the umbrella header.',
    )
    options = parser.parse_args()

    return WriteUmbrellaHeader(options.output_path, options.imported_headers)


if __name__ == '__main__':
    Main()