#!/usr/bin/env python3

#
# Copyright (C) 2018-2021 Intel Corporation
#
# SPDX-License-Identifier: MIT
#

"""Usage: ./scripts/lint/set_copyright.py <files>"""

import re
import sys
import os
import datetime
import stat
import argparse


def is_banned(path):
    """Check if path is banned."""

    banned_paths = [
        'scripts/tests/copyright/in',
        'scripts/tests/copyright/out',
        'third_party'
    ]

    banned_files = [
        'scripts/lint/set_copyright.sh'
    ]

    path_banned = False

    for banned_file in banned_files:
        if os.path.normpath(path) == os.path.normpath(banned_file):
            path_banned = True
            break

    if not path_banned:
        dirname = os.path.dirname(path)
        for banned_path in banned_paths:
            if dirname.startswith(banned_path):
                path_banned = True
                break

    return path_banned


def can_be_scanned(path):
    """Check whether we should scan this file"""

    allowed_extensions = [
        'cpp', 'h', 'inl', 'hpp', 'm',
        'cmake',
        'py', 'sh',
        'cl',
        'exports'
    ]

    allowed_extensions_2 = [
        'h.in', 'rc.in',
        'options.txt'
    ]

    allowed_files = [
        'CMakeLists.txt'
    ]

    path_ext = path.split('.')
    path_ok = False
    filename = os.path.basename(path)

    if not os.path.isfile(path):
        print(f'Cannot find file {path}, skipping')
        path_ok = False

    elif is_banned(path):
        path_ok = False

    elif filename in allowed_files:
        path_ok = True

    elif path_ext[-1].lower() in allowed_extensions:
        path_ok = True

    elif '.'.join(path_ext[-2:]) in allowed_extensions_2:
        path_ok = True

    if not path_ok:
        print(f'[MIT] Ignoring file: {path}')

    return path_ok


def _parse_args():
    parser = argparse.ArgumentParser(description='Usage: ./scripts/lint/set_copyright.py <files>')
    parser.add_argument('-c', '--check', action='store_true', help='Checks only, not changing files, fails if wrong copyright')
    parser.add_argument('files', nargs='*')
    args = parser.parse_args()

    return vars(args)


def main(args):
    header_cpp = """/*
 * Copyright (C) {} Intel Corporation
 *
 * SPDX-License-Identifier: MIT
 *
 */
"""

    header_bash_style = """#
# Copyright (C) {} Intel Corporation
#
# SPDX-License-Identifier: MIT
#
"""

    cpp_sharp_lines = [
        '#pragma',
        '#include'
    ]

    status = 0

    for path in args['files']:

        # avoid self scan
        if os.path.abspath(path) == os.path.abspath(sys.argv[0]):
            continue

        if not can_be_scanned(path):
            continue

        print(f'[MIT] Processing file: {path}')

        gathered_lines = []
        gathered_header = []
        start_year = None
        header = header_cpp
        header_start = '/*'
        header_end = '*/'
        comment_char = r'\*'

        # now read line by line
        with open(path) as fin:

            # take care of hashbang
            first_line = fin.readline()
            if not first_line.startswith('#!'):
                line = first_line
                first_line = ''
            else:
                line = fin.readline()
                while(line == '\n'):
                    line = fin.readline()

            is_cpp = False

            # check whether comment type is '#'
            if first_line or line.startswith('#'):
                for i in cpp_sharp_lines:
                    print(f'a: {i} ~ {line}')
                    if line.startswith(i):
                        is_cpp = True
                        break

                if not is_cpp:
                    header_start = '#'
                    header_end = '\n'
                    header = header_bash_style
                    comment_char = '#'

            curr_comment = []

            is_header = None
            is_header_end = None

            # copyright have to be first comment in file
            if line.startswith(header_start):
                is_header = True
                is_header_end = False
            else:
                is_header = False
                is_header_end = True

            is_copyright = False

            while line:
                if is_header:
                    if header_end == '\n' and len(line.strip()) == 0:
                        is_header = False
                        is_header_end = True
                    elif line.strip().endswith(header_end):
                        is_header = False
                        is_header_end = True
                    elif 'Copyright' in line:
                        expr = (rf'^{comment_char} Copyright \([Cc]\) (\d+)( *- *\d+)?')
                        match = re.match(expr, line.strip())
                        if match:
                            start_year = match.groups()[0]
                            curr_comment = []
                            is_copyright = True
                    if not is_copyright:
                        curr_comment.append(line)
                    gathered_header.append(line)

                elif is_copyright and is_header_end:
                    if len(line.strip()) > 0:
                        gathered_lines.append(line)
                        is_header_end = False
                    else:
                        gathered_header.append(line)
                else:
                    gathered_lines.append(line)

                line = fin.readline()

        year = datetime.datetime.now().year
        if start_year is None:
            start_year = str(year)
        elif int(start_year) < year:
            start_year += '-'
            start_year += str(year)

        written_header = [header.format(start_year)]

        if len(curr_comment) > 0 or len(gathered_lines) > 0:
            written_header.append('\n')

        if len(curr_comment) > 0:
            written_header.append(''.join(curr_comment))

        if not args['check']:
            # store file mode because we want to preserve this
            old_mode = os.stat(path)[stat.ST_MODE]
            os.remove(path)
            with open(path, 'w') as fout:
                if first_line:
                    fout.write(f'{first_line}\n')

                fout.write(''.join(written_header))
                contents = ''.join(gathered_lines)
                fout.write(contents)

                # chmod to original value
                os.chmod(path, old_mode)

        if args['check'] and ''.join(gathered_header) != ''.join(written_header):
            _tmp = []
            for _itm in written_header:
                _tmp.extend(f'{_aa}\n' for _aa in _itm.split('\n'))
            print('--- source')
            print('+++ updated')
            print('@@')

            for idx, shl in enumerate(gathered_header):
                if idx>=len(_tmp):
                    print('-%s' % shl.strip())
                elif shl != _tmp[idx]:
                    print('-%s' % shl.strip())
                    print('+%s' % _tmp[idx].strip())
                else:
                    print(' %s' % shl.strip())

            status = 1

    return status


if __name__ == '__main__':
    sys.exit(main(_parse_args()))