"""
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/>.

Copyright © 2019 Cloud Linux Software Inc.

This software is also available under ImunifyAV commercial license,
see <https://www.imunify360.com/legal/eula>


Used to fix issue with inability to unserialize stored scans.
See DEF-23158 for details.
"""
import collections
import importlib
import logging
import pickle
from pathlib import Path

logger = logging.getLogger(__name__)

SCANS_PATH = Path("/var/imunify360/aibolit/scans.pickle")
OLD_MALWARELIB = "defence360agent.malwarelib"
NEW_MALWARELIB = "imav.malwarelib"


class AVUnpickler(pickle.Unpickler):
    def find_class(self, module, name):
        try:
            return super().find_class(module, name)
        except (ImportError, ModuleNotFoundError):
            if module.startswith(OLD_MALWARELIB):
                av_module = importlib.import_module(
                    module.replace(OLD_MALWARELIB, NEW_MALWARELIB)
                )
                return getattr(av_module, name)
            raise


def dump(obj, path):
    temp_path = path.with_name(path.name + ".temp")
    with temp_path.open("wb") as f:
        pickle.dump(obj, f)
    # to avoid the possibility of leaving a broken file,
    # if any errors occurred above
    temp_path.replace(path)


def migrate(migrator, *_, fake=False, **__):
    if fake or not SCANS_PATH.exists():
        return

    if OLD_MALWARELIB.encode() in SCANS_PATH.read_bytes():
        try:
            with SCANS_PATH.open("rb") as f:
                scans = AVUnpickler(f).load()
            # convert class instance to a simple dict
            updated = collections.deque(
                {
                    "path": item.path,
                    "scanid": item.scanid,
                    "scan_type": item.scan_type,
                    "created": item.created,
                    "started": item.started,
                    "args": item.args,
                    "resource_type": item.resource_type.value,
                    "state": item.state.value,
                }
                for item in scans
            )
        except Exception as exc:
            logger.exception(
                "Failed to load pickle scans %s: %s", SCANS_PATH, exc
            )
        else:
            dump(updated, SCANS_PATH)


def rollback(migrator, *_, fake=False, **__):
    pass