#!/usr/bin/env python3

import datetime
import fnmatch
import os
import re
import subprocess
from textwrap import wrap

PROJECT = os.path.dirname(__file__)
EXTENSIONS = ('.c', '.cpp', '.h', '.nsi', '.rc')
START_YEAR = 2017
CURRENT_YEAR = datetime.date.today().year

reignore = re.compile('^vendor/')
recopyright = re.compile(r'\A/\*.*?\*/\s+', re.DOTALL)

header = f'''\
Looking Glass
Copyright (C) {START_YEAR}-{CURRENT_YEAR} The Looking Glass Authors
https://looking-glass.io
'''

paragraphs = ['''\
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option)
any later version.''',
'''\
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.''',
'''\
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc., 59
Temple Place, Suite 330, Boston, MA 02111-1307 USA''']


def make_comment_block():
    lines = ['/**']
    lines += [' * ' + line for line in header.splitlines()]

    for paragraph in paragraphs:
        lines.append(' *')
        lines += wrap(paragraph, width=78, initial_indent=' * ', subsequent_indent=' * ')

    lines.append(' */')
    return '\n'.join(lines) + '\n\n'


def gen_c_literal():
    lines = [''] + header.splitlines()
    for paragraph in paragraphs:
        lines.append('')
        lines += wrap(paragraph, width=79)
    lines.append('')
    return '\n'.join(f'    "{line}\\n"' for line in lines) + '\n'


def update_c_style(file, copyright):
    print(f'Updating copyright for {file}...')
    with open(file, encoding='utf-8') as f:
        data = recopyright.sub('', f.read())
    with open(file, 'w', encoding='utf-8') as f:
        f.write(copyright)
        f.write(data)


def update_config_c(file):
    prefix = []
    suffix = []
    current = prefix

    print(f'Refresh embedded copyright string in {file}...')

    with open(file, encoding='utf-8') as f:
        for line in f:
            if '// BEGIN LICENSE BLOCK' in line:
                prefix.append(line)
                current = []
            elif '// END LICENSE BLOCK' in line:
                suffix.append(line)
                current = suffix
            else:
                current.append(line)

    with open(file, 'w', encoding='utf-8') as f:
        f.writelines(prefix)
        f.write(gen_c_literal())
        f.writelines(suffix)


def main():
    comment_block = make_comment_block()
    files = subprocess.check_output(['git', '-C', PROJECT, 'ls-files', '-z']).decode('utf-8').split('\0')
    for file in files:
        if reignore.match(file):
            continue
        if file.endswith(EXTENSIONS):
            update_c_style(os.path.join(PROJECT, file), comment_block)

    update_config_c(os.path.join(PROJECT, 'client', 'src', 'config.c'))

if __name__ == '__main__':
    main()