from PyQt5.QtNetwork import QNetworkCookie, QNetworkCookieJar
import os
import tempfile
import logging


class PersistentCookieJar(QNetworkCookieJar):
    def __init__(self, filename, parent=None):
        super().__init__(parent)
        self.filename = filename
        self.logger = logging.getLogger(self.__class__.__name__)
        self.load()

    def load(self):
        try:
            data = open(self.filename, 'rb').read()
            # вернет пустой список в случае ошибки парсинга
            cookies = QNetworkCookie.parseCookies(data)
            self.setAllCookies(cookies)
            self.logger.debug("cookies loaded %s",
                              os.path.abspath(self.filename))
        except os.error as e:
            self.logger.exception(e)

    def save(self):
        # В Python вообщe есть штатные средства для блокировки файла?
        temp = tempfile.NamedTemporaryFile(
            dir=os.path.dirname(self.filename), delete=False)
        for cookie in self.allCookies():
            if not cookie.isSessionCookie():
                temp.write(cookie.toRawForm())
                temp.write(b'\n')
        self.logger.debug("cookies saved %s", temp.name)
        try:
            os.unlink(self.filename)
            self.logger.debug("deleted %s",
                              os.path.abspath(self.filename))
        # возможно, файла не существует
        except os.error as e:
            self.logger.exception(e)
        try:
            temp.close()
            os.rename(temp.name, self.filename)
            self.logger.debug("%s renamed as %s", temp.name,
                              os.path.abspath(self.filename))
        except os.error as e:
            self.logger.exception(e)

    def __del__(self):
        self.save()