"""
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>
"""
from collections import defaultdict
from logging import getLogger
from typing import List

from defence360agent.contracts.config import Malware as Config
from defence360agent.contracts.license import LicenseError
from defence360agent.contracts.messages import MessageType
from defence360agent.contracts.plugins import (
    MessageSink,
    MessageSource,
    expect,
)
from defence360agent.utils import get_results_iterable_expression
from imav.malwarelib.model import MalwareHit
from imav.malwarelib.utils import malware_response
from imav.malwarelib.utils.malware_response import (
    FileTooLargeError,
    UploadFailure,
)

logger = getLogger(__name__)


class MalwareResponsePlugin(MessageSink, MessageSource):
    async def create_source(self, loop, sink):
        self._loop = loop
        self._sink = sink

    async def create_sink(self, loop):
        self._loop = loop

    @expect(MessageType.MalwareResponse)
    async def process_message_malware_response(self, message):
        hashes = self._collect_hashes(message.files)
        unknown_hashes = hashes[MessageType.MalwareResponse.UNKNOWN.lower()]
        if unknown_hashes:
            await self._process_unknown_hash(unknown_hashes)

    async def _process_unknown_hash(self, hashes: set):
        """
        If there is no such file with given hash in database, Imunify360 Client
        should upload file using API endpoint /api/v1/upload.
        """

        if not Config.SEND_FILES:
            logger.info("Sending unknown files to MRS is disabled.")
            return

        orig_files = self._get_orig_files(hashes)
        for orig_file in orig_files:
            logger.info("Unknown file %s. Uploading to MRS.", orig_file)
            try:
                await malware_response.upload_with_retries(orig_file)
            except LicenseError as e:
                logger.warning(
                    "Cannot upload the following files to MRS %r: %s",
                    orig_files,
                    e,
                )
                break
            except UploadFailure as e:
                logger.error("File %s uploading failed. %s.", orig_file, e)
            except FileNotFoundError:
                logger.warning(
                    "File %s not found, skipping upload.", orig_file
                )
            except FileTooLargeError as e:
                logger.warning("File %s uploading failed. %s.", orig_file, e)

    @staticmethod
    def _collect_hashes(files):
        type_to_hash = defaultdict(set)
        for file_hash, hash_type in files.items():
            type_to_hash[hash_type.lower()].add(file_hash)
        return type_to_hash

    @staticmethod
    def _get_orig_files(hashes: set) -> List[str]:
        result = []

        def expression(hashes):
            return MalwareHit.select().where(MalwareHit.hash.in_(hashes))

        for hit in get_results_iterable_expression(expression, hashes):
            try:
                result.append(hit.orig_file)
            except FileNotFoundError:
                logger.warning("File %s not found, skipping.", hit.orig_file)
        return result