#!/usr/bin/env python3
# encoding: utf-8
# Copyright (C) 2024 John Törnblom
#
# 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 3 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; see the file COPYING. If not see
# <http://www.gnu.org/licenses/>.

import argparse
import gzip
import string
import mimetypes


tmpl = string.Template('''
void asset_register(const char*, const void*, unsigned long, const char*, const char*);

static const unsigned char data[] = $data;

__attribute__((constructor)) static void
constructor(void) {
  asset_register("/$path", data, sizeof(data), $mime, $encoding);
}
''')

GZIP_MIMES = {
    'application/javascript',
    'application/json',
    'text/css',
    'text/html',
    'text/javascript',
}


def cstr(value):
    if value is None:
        return '0'
    return '"' + value.replace('\\', '\\\\').replace('"', '\\"') + '"'


def gen_data(data):
    yield '{\n  '

    for n, b in enumerate(data, 1):
        yield hex(b)
        yield ', '

        if n % 16 == 0:
            yield '\n  '

    yield '\n}'

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-p', '--path', default=None)
    parser.add_argument('FILE')
    args = parser.parse_args()

    if args.path is None:
        args.path = args.FILE

    mime = mimetypes.guess_type(args.path)[0]
    encoding = None
    with open(args.FILE, mode='rb') as f:
        payload = f.read()
    if mime in GZIP_MIMES:
        zipped = gzip.compress(payload, compresslevel=9, mtime=0)
        if len(zipped) < len(payload):
            payload = zipped
            encoding = 'gzip'

    data = ''.join(gen_data(payload))
    print(tmpl.substitute(data=data, path=args.path,
                          mime=cstr(mime), encoding=cstr(encoding)))