# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
#
# 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.

import argparse
import re
import sys
import os
import datetime

COPYRIGHT = '''Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.

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.'''

def _generate_copyright(comment_mark):
    copyright=COPYRIGHT.split(os.linesep)
    header = copyright[0].rstrip()

    p = re.search(r'(\d{4})', header).group(0)
    now = datetime.datetime.now()

    header = header.replace(p,str(now.year))

    ans=[comment_mark + " " + header + os.linesep]
    for idx, line in enumerate(copyright[1:]):
        ans.append(comment_mark + " " + line.rstrip() + os.linesep)

    return ans

def _get_comment_mark(path):
    lang_type=re.compile(r"\.(py|sh)$")
    if lang_type.search(path) is not None:
        return "#"

    lang_type=re.compile(r"\.(h|c|hpp|cc|cpp|cu|go|cuh|proto)$")
    if lang_type.search(path) is not None:
        return "//"

    return None


RE_ENCODE = re.compile(r"^[ \t\v]*#.*?coding[:=]", re.IGNORECASE)
RE_COPYRIGHT = re.compile(r".*Copyright \(c\) \d{4}", re.IGNORECASE)
RE_SHEBANG = re.compile(r"^[ \t\v]*#[ \t]?\!")

def _check_copyright(path):
    head=[]
    try:
        with open(path, 'r', encoding='utf-8') as f:
            head = [next(f) for x in range(4)]
    except StopIteration:
        pass

    for idx, line in enumerate(head):
        if RE_COPYRIGHT.search(line) is not None:
            return True

    return False

def generate_copyright(path, comment_mark):
    original_contents = open(path, 'r', encoding="utf-8").readlines()
    head = original_contents[0:4]

    insert_line_no=0
    for i, line in enumerate(head):
        if RE_ENCODE.search(line) or RE_SHEBANG.search(line):
            insert_line_no=i+1

    copyright = _generate_copyright(comment_mark)
    if insert_line_no == 0:
        new_contents = copyright
        if len(original_contents) > 0 and len(original_contents[0].strip()) != 0:
            new_contents.append(os.linesep)
        new_contents.extend(original_contents)
    else:
        new_contents=original_contents[0:insert_line_no]
        new_contents.append(os.linesep)
        new_contents.extend(copyright)
        if len(original_contents) > insert_line_no and len(original_contents[insert_line_no].strip()) != 0:
            new_contents.append(os.linesep)
        new_contents.extend(original_contents[insert_line_no:])
    new_contents="".join(new_contents)

    with open(path, 'w', encoding='utf-8') as output_file:
        output_file.write(new_contents)



def main(argv=None):
    parser = argparse.ArgumentParser(
        description='Checker for copyright declaration.')
    parser.add_argument('filenames', nargs='*', help='Filenames to check')
    args = parser.parse_args(argv)

    retv = 0
    for path in args.filenames:
        comment_mark = _get_comment_mark(path)
        if comment_mark is None:
            print("warning:Unsupported file", path, file=sys.stderr)
            continue

        if _check_copyright(path):
            continue

        generate_copyright(path, comment_mark)


if __name__ == '__main__':
    exit(main())
