"""
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>
"""
import logging
import time
import queue
import uuid
from collections import defaultdict
from collections.abc import Hashable
from defence360agent.api import inactivity
from defence360agent.contracts.messages import MessageType
from defence360agent.contracts.plugins import (
    MessageSink,
    MessageSource,
    expect,
)
from defence360agent.utils import (
    batched,
    nice_iterator,
    recurring_check,
    safe_cancel_task,
)
from imav.malwarelib.config import VulnerabilityHitStatus
from imav.malwarelib.model import VulnerabilityHit
from imav.malwarelib.vulnerabilities.patcher import (
    PatchResult,
    VulnerabilityPatcher,
)
from imav.malwarelib.vulnerabilities.storage import PatchStorage

logger = logging.getLogger(__name__)


class PatchQueue:
    def __init__(self):
        self._queue = defaultdict(set)

    def put(self, key: Hashable, values: set):
        self._queue[key] |= values

    def get(self) -> tuple[Hashable, set]:
        try:
            return self._queue.popitem()
        except KeyError as exc:
            raise queue.Empty() from exc

    def empty(self) -> bool:
        return not bool(self._queue)


class Patch(MessageSink, MessageSource):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._queue = PatchQueue()
        self._loop = None
        self._sink = None
        self._patcher = None
        self._patch_task = None

    async def create_sink(self, loop):
        pass

    async def create_source(self, loop, sink):
        self._loop = loop
        self._sink = sink
        self._patcher = VulnerabilityPatcher(loop=loop, sink=sink)
        self._patch_task = loop.create_task(self.recurring_patch())

    async def shutdown(self):
        if self._patch_task:
            await safe_cancel_task(self._patch_task)

    @expect(MessageType.VulnerabilityPatchTask)
    async def process_patch_task(self, message: dict):
        source = (
            message.get("cause"),
            message.get("initiator"),
            message.get("manual", False),
        )
        files_to_patch = message.get("filelist", [])
        self._queue.put(source, set(files_to_patch))

    async def _patch_vulnerabilities(self):
        while not self._queue.empty():
            [cause, initiator, manual], files_to_patch = self._queue.get()
            for files_batch in batched(files_to_patch, n=10_000):
                with inactivity.track.task("patch_vulnerabilities"):
                    vulnerable_statuses = [VulnerabilityHitStatus.VULNERABLE]
                    if manual:
                        vulnerable_statuses.append(
                            VulnerabilityHitStatus.REVERTED
                        )
                    hits = VulnerabilityHit.select().where(
                        VulnerabilityHit.orig_file.in_(files_batch),
                        VulnerabilityHit.status.in_(vulnerable_statuses),
                    )
                    (
                        succeeded,
                        failed,
                        not_exist,
                    ) = await PatchStorage.store_all(hits)
                    if failed:
                        for hit in failed:
                            await self._sink.process_message(
                                MessageType.VulnerabilityPatchFailed(
                                    message=(
                                        "Failed to store the original from {}"
                                        " to {}".format(
                                            hit.orig_file, PatchStorage.path
                                        )
                                    ),
                                    timestamp=int(time.time()),
                                )
                            )
                    if not_exist:
                        VulnerabilityHit.delete_hits(
                            [hit.orig_file for hit in not_exist]
                        )
                    user_hits = VulnerabilityHit.group_by_attribute(
                        succeeded,
                        attribute="owner",
                    )
                    for user, hits in user_hits.items():
                        started = time.time()
                        files = [hit.orig_file for hit in hits]
                        # update status to avoid any races
                        VulnerabilityHit.set_status(
                            hits, VulnerabilityHitStatus.PATCH_IN_PROGRESS
                        )
                        result, error, cmd = await self._patcher.start(
                            user, files
                        )
                        await self._sink.process_message(
                            MessageType.VulnerabilityPatch(
                                hits=hits,
                                result=result,
                                cleanup_id=uuid.uuid4().hex,
                                started=started,
                                error=error,
                                cause=cause,
                                initiator=initiator,
                                args=cmd,
                            )
                        )

    @recurring_check(1)
    async def recurring_patch(self):
        if not self._queue.empty():
            await self._patch_vulnerabilities()


class PatchResultProcessor(MessageSink):
    async def create_sink(self, loop):
        pass

    @staticmethod
    def _set_hit_status(
        hits: list[VulnerabilityHit], status: str, patched_at=None
    ):
        VulnerabilityHit.set_status(hits, status, patched_at)
        for hit in hits:
            hit.status = status
            hit.patched_at = patched_at

    @expect(MessageType.VulnerabilityPatch)
    async def process_patch_result(self, message: dict):
        hits: list[VulnerabilityHit] = message["hits"]
        result: PatchResult = message["result"]
        now = time.time()

        processed = [hit for hit in hits if hit in result]
        unprocessed = [hit for hit in hits if hit not in result]
        not_exist = []
        async for hit in nice_iterator(processed, chunk_size=100):
            # in case if procu2.php tries to clean/patch user file in root dirs,
            # it will be marked as non-existent due to 'Permission denied'
            # error which confuses users, consider it as unable to cleanup/patch
            if result[hit].not_exist():
                if hit.orig_file_path.exists():
                    unprocessed.append(hit)
                else:
                    not_exist.append(hit)
        if not_exist:
            VulnerabilityHit.delete_hits([hit.orig_file for hit in not_exist])

        patched, failed = [], []
        for hit in processed:
            # treat as failed unless success is explicitly stated
            if result[hit].is_patched():
                patched.append(hit)
            else:
                failed.append(hit)
        self._set_hit_status(patched, VulnerabilityHitStatus.PATCHED, now)
        if unable_to_path := unprocessed + failed:
            self._set_hit_status(
                unable_to_path, VulnerabilityHitStatus.VULNERABLE
            )