#
# CatNet Python Server
#
# Copyright (C) 2023-2024 John Solntsev
#
# 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.  If not, see <https://www.gnu.org/licenses/>.
#

import logging
import os


log = logging.getLogger(__name__)

def file_iterator(filename):
    log.debug("Try access to file \"%s\"", filename)
    if not os.path.isfile(filename):
        raise FileNotFoundError("File \"%s\" not found", filename)

    log.debug("Get size of file \"%s\"", filename)
    yield os.path.getsize(filename)

    log.debug("Open file \"%s\" to byte-read", filename)
    with open(filename, "rb") as f:
        while True:
            file_data = f.read(1024)

            yield file_data

            if len(file_data) >= 1024:
                log.debug("File size greeter 1024 bytes, yield data. Continue to read")
            else:
                log.debug("File size lower 1024 bytes, yield data. Break to read")
                break