"""
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 asyncio
import json
import logging
import shutil
import time
from dataclasses import dataclass
from pathlib import Path
from typing import List, Optional

import psutil

from defence360agent.contracts.messages import MessageType, ScanFailed
from defence360agent.utils import rmtree
from imav.contracts.messages import MalwareScan
from imav.malwarelib.config import (
    ExitDetachedScanType,
    MalwareScanResourceType,
)
from imav.malwarelib.scan import ScanAlreadyCompleteError
from imav.malwarelib.scan.ai_bolit import AIBOLIT, AIBOLIT_PATH
from imav.malwarelib.scan.ai_bolit.report import (
    parse_report_csv,
    parse_report_json,
)
from imav.malwarelib.scan.detached import DetachedDir, DetachedScan
from imav.malwarelib.scan.utils import trim_file_content

logger = logging.getLogger(__name__)


AIBOLIT_PID_WAIT_TIME = 30


class AiBolitDetachedDir(DetachedDir):
    DETACHED_DIR = "/var/imunify360/aibolit/run"

    csv_report_path: Path
    json_report_path: Path
    listing_file: Path
    scan_info_file: Path

    FILES = {
        **DetachedDir.FILES,
        "csv_report_path": "report.csv",
        "json_report_path": "report.json",
        "listing_file": "file",
        "scan_info_file": "scan_info.json",
    }

    def __init__(self, detached_id, tmp_listing_file=None):
        """
        NOTE: Initialization should not create any files
        """
        super().__init__(detached_id)
        self.tmp_listing_file = tmp_listing_file

    def __enter__(self):
        super().__enter__()

        # Needed in case of internal finder
        if self.tmp_listing_file is not None:
            shutil.copyfile(self.tmp_listing_file.name, str(self.listing_file))

        return self


@dataclass
class FileScanInfo:
    cmd: List[str]
    scan_type: Optional[str]


class AiBolitDetachedScan(DetachedScan):
    DETACHED_DIR_CLS = AiBolitDetachedDir

    @property
    def RESOURCE_TYPE(self):
        return MalwareScanResourceType.FILE

    def _parse_report(self):
        """Parse json/csv ai-bolit report

        Parse whichever one exists. We can't use the use_json flag to
        decide which one should exist, because the flag could be changed
        after the report has been created.
        """
        if self.detached_dir.csv_report_path.is_file():
            return parse_report_csv(self.detached_dir.csv_report_path)

        with self.detached_dir.json_report_path.open() as fp:
            report = json.load(fp)
        return parse_report_json(report)

    def get_reported_summary(self):
        """Get scan performance metrics if present in the summary"""

        with self.detached_dir.json_report_path.open() as f:
            summary = json.load(f).get("summary", {})
        stats = {
            k: v
            for k, v in summary.items()
            if k
            in (
                "scan_time",
                "report_time",
                "finder_time",
                "cas_time",
                "deobfuscate_time",
                "scan_time_hs",
                "scan_time_preg",
                "smart_time_hs",
                "smart_time_preg",
                "mem_peak",
                "total_files",
                "cpu_user",
                "cpu_system",
                "rchar",
                "wchar",
                "syscr",
                "syscw",
                "read_bytes",
                "write_bytes",
                "cancelled_write_bytes",
                "decision_stats",
                "errors",
            )
        }
        if "ai_version" in summary:
            stats["aibolit_version"] = summary["ai_version"]
        if "db_version" in summary:
            stats["signatures_version"] = summary["db_version"]
        return stats

    def _get_progress_info(self):
        try:
            with self.detached_dir.progress_file.open() as fp:
                return json.load(fp)
        except (FileNotFoundError, json.JSONDecodeError):
            return {}

    def _is_scan_finished(self):
        return self.detached_dir.done_file.exists()

    @property
    def progress(self):
        try:
            return int(float(self._get_progress_info()["progress"]))
        except KeyError:
            return 100 if self._is_scan_finished() else 0

    @property
    def total_resources(self):
        try:
            return int(self._get_progress_info()["files_total"])
        except (KeyError, ValueError):
            return 0

    @property
    def phase(self):
        if self.progress == 0:
            return "preparing file list"

        return "{} scanning".format(AIBOLIT)

    def _load_scan_info(self) -> FileScanInfo:
        try:
            with self.detached_dir.scan_info_file.open() as fp:
                info = json.load(fp)
        except (FileNotFoundError, json.JSONDecodeError):
            info = {}
        return FileScanInfo(
            cmd=info.get("cmd", []), scan_type=info.get("scan_type")
        )

    async def complete(self) -> MalwareScan:
        # TODO: test this method
        scan_info = self._load_scan_info()
        message = {
            "summary": {
                "args": scan_info.cmd,
                "scanid": self.detached_id,
                "type": scan_info.scan_type,
                "stderr": self.extract_stderr(),
                "stdout": self.extract_stdout(),
            },
            "results": [],
        }

        try:
            reported_summary = self.get_reported_summary()
        except FileNotFoundError as e:
            raise ScanAlreadyCompleteError from e
        try:
            scan_data = self._parse_report()
        except FileNotFoundError as e:
            raise ScanAlreadyCompleteError from e
        except Exception as e:
            message["summary"]["error"] = str(e)
            logger.exception("Unable to parse AI-BOLIT report")
        else:
            message["summary"].update(reported_summary)
            message["results"] = list(scan_data)

        return MalwareScan(message)

    def extract_stdout(self) -> str:
        try:
            return self.detached_dir.log_file.read_text()
        except FileNotFoundError:
            return ""

    def extract_stderr(self) -> str:
        try:
            return self.detached_dir.err_file.read_text()
        except FileNotFoundError:
            return ""

    @classmethod
    def process_is_suitable(cls, proc) -> bool:
        if proc:
            return AIBOLIT_PATH in proc.cmdline()
        return False

    async def kill_running_scan_process(self, timer=time.monotonic):
        error = None
        deadline = timer() + AIBOLIT_PID_WAIT_TIME
        while timer() < deadline:
            try:
                pid = self.get_pid()
                break
            except (FileNotFoundError, ValueError) as err:
                await asyncio.sleep(1)
                error = err
        else:
            logger.warning(
                "Cannot find the aibolit process to kill (%s): %r."
                " Assuming it's already dead.",
                self.detached_id,
                error,
            )
            return
        try:
            proc = psutil.Process(pid)
            if self.process_is_suitable(proc):
                proc.kill()
        except psutil.Error as err:
            logger.warning(
                "Problem when killing the running aibolit process: %s", err
            )

    async def handle_aborted_process(
        self,
        *,
        sink,
        exit_type: str = ExitDetachedScanType.ABORTED,
        kill: bool = True,
        scan_path: Optional[str] = None,
        scan_type: Optional[str] = None,
        scan_started: Optional[float] = None,
    ) -> None:
        if kill:
            await self.kill_running_scan_process()
        scan_dir = self.detached_dir
        stdout = trim_file_content(scan_dir.log_file)
        stderr = trim_file_content(scan_dir.err_file)
        cmd = self._load_scan_info().cmd
        if scan_path is None and cmd:
            index = cmd.index("--path")
            scan_path = cmd[index + 1]

        logger.info("Scan %s was aborted", self.detached_id)
        scan_info = self._load_scan_info()
        scan_result = {
            "summary": {
                "scanid": self.detached_id,
                "total_files": 0,
                "total_malicious": 0,
                "completed": time.time(),
                "error": exit_type,
                "started": scan_started or 0.0,
                "type": scan_type or scan_info.scan_type,
                "path": scan_path,
                "stdout": stdout,
                "stderr": stderr,
                "args": cmd or scan_info.cmd,
            },
            "results": {},
        }
        await sink.process_message(MessageType.MalwareScan(**scan_result))
        if exit_type == ExitDetachedScanType.ABORTED:
            msg = ScanFailed()
            msg["out"] = stdout
            msg["err"] = stderr
            logger.warning(
                "Scan was aborted: %s", msg["err"] + ", " + msg["out"]
            )
            msg["command"] = cmd
            msg["message"] = "aborted"
            msg["scan_id"] = self.detached_id
            msg["path"] = scan_path
            await sink.process_message(msg)
        if not scan_dir.path.is_dir():
            logger.warning("No such directory: %s", scan_dir)
        else:
            rmtree(str(scan_dir))