import asyncio
import json
import logging
import os
import socket
import urllib.error
import urllib.parse
import urllib.request
from collections import defaultdict
from functools import lru_cache
from pathlib import Path
from urllib.parse import parse_qsl, urlencode, urljoin, urlparse, urlunparse

import psutil

from defence360agent.contracts.config import ANTIVIRUS_MODE
from defence360agent.contracts.license import LicenseCLN
from defence360agent.utils import CheckRunError, async_lru_cache, check_run
from defence360agent.utils.common import get_hostname

_TIMEOUT = 300  # timeout for network operations
_IMUNIFY_EMAIL_CONFIG_EXECUTABLE = Path("/usr/sbin/ie-config")
logger = logging.getLogger(__name__)
IE_SUPPORTED_CMD = (
    "wget -qq -O  -"
    " https://repo.imunify360.cloudlinux.com/defence360/imunifyemail-deploy.sh"
    " | bash -s 'is-supported'"
)


@async_lru_cache(maxsize=1)
async def is_imunify_email_supported() -> bool:
    try:
        await check_run(IE_SUPPORTED_CMD, shell=True)
    except CheckRunError as e:
        if e.returncode != 100:
            logger.error(f"imunify-email check failed {str(e)}")
        return False
    return True


async def get_imunify_email_status():
    """Try to get imunify-email status"""
    if ANTIVIRUS_MODE:
        return False
    if not _IMUNIFY_EMAIL_CONFIG_EXECUTABLE.exists():
        return False
    try:
        output = await check_run(
            [str(_IMUNIFY_EMAIL_CONFIG_EXECUTABLE), "status"]
        )
    except CheckRunError:
        return False
    return "spamfilter exim configuration: enabled" in output.decode()


class CLNError(Exception):
    def __init__(self, status=None, message=None):
        self.message = message
        self.status = status

    def __str__(self):
        if self.message:
            return self.message

        return "Unexpected status code from CLN: {}".format(self.status)


class InvalidLicenseError(Exception):
    pass


class BackupNotFound(CLNError):
    GB = 1024 * 1024 * 1024

    def __init__(self, url):
        self.url = url

    def __str__(self):
        return "Backup not found in CLN"

    def add_used_space(self):
        if self.url is None:
            return

        pu = urlparse(self.url)
        query = dict(parse_qsl(pu.query))
        query["used_space"] = self._disk_usage()

        return urlunparse(
            (
                pu.scheme,
                pu.netloc,
                pu.path,
                pu.params,
                urlencode(query),
                pu.fragment,
            )
        )

    def _disk_usage(self):
        total_used = 0
        partitions = psutil.disk_partitions()
        processed = set()
        for p in partitions:
            if (
                (p.device not in processed)
                and ("noauto" not in p.opts)
                and (not p.device.startswith("/dev/loop"))
            ):
                total_used += psutil.disk_usage(p.mountpoint).used
                processed.add(p.device)
        return round(total_used / self.GB)


def _post_request(url, data=None, headers=None, timeout=None):
    """To be used by RestCLN._request()."""
    kwargs = {}
    if headers is not None:
        kwargs["headers"] = headers
    if data is not None:
        if isinstance(data, bytes):
            kwargs.setdefault(
                "headers", {"Content-type": "application/octet-stream"}
            )
        elif isinstance(data, str):
            data = data.encode("utf-8")
            kwargs.setdefault(
                "headers", {"Content-type": "text/plain; charset=utf-8"}
            )
        else:  # dict
            data = urllib.parse.urlencode(data).encode("ascii")
            kwargs.setdefault(
                "headers",
                {"Content-type": "application/x-www-form-urlencoded"},
            )
        kwargs["data"] = data
    try:
        resp = urllib.request.urlopen(
            urllib.request.Request(url, **kwargs), timeout=timeout
        )
    except socket.timeout:
        raise TimeoutError("Timed out receiving response")
    except OSError as e:
        if hasattr(e, "code"):  # HTTPError
            if e.code < 400:
                raise CLNError(e.code) from e
            # e.code >= 400
            message = None
            if e.fp is not None:
                logger.warning(
                    "CLN.post(url=%r, data=%r, headers=%r): %d %s",
                    url,
                    data,
                    headers,
                    e.code,
                    e.reason,
                )
                try:
                    resp_data = e.read()
                except socket.timeout:
                    raise TimeoutError("Timed out reading error message")
                # the response may be non-json
                message = resp_data.decode(errors="replace")
            raise CLNError(message=message, status=e.code) from e
        else:
            logger.warning(
                "CLN.post(url=%r, data=%r, headers=%r, timeout=%r): %s",
                url,
                data,
                headers,
                timeout,
                e,
            )
            raise
    else:
        with resp:
            if resp.code == 204:
                return resp.code, None
            elif resp.code in (200, 244):
                # 244 - /im/ab/check returns link for backup buy page
                try:
                    content = resp.read()
                except socket.timeout:
                    raise TimeoutError("Timed out reading response")
                else:
                    try:
                        return resp.code, json.loads(content.decode())
                    except json.JSONDecodeError as e:
                        raise CLNError(
                            message=(
                                f"Non-json data from CLN: {content} for"
                                f" code={resp.code}"
                            ),
                            status=resp.code,
                        ) from e
            else:
                raise CLNError(resp.code)


class RestCLN:
    _BASE_URL = os.environ.get(
        "IM360_CLN_API_BASE_URL", "https://cln.cloudlinux.com/api/im/"
    )
    _REGISTER_URL = urljoin(_BASE_URL, "register")
    _UNREGISTER_URL = urljoin(_BASE_URL, "unregister")
    _CHECKIN_URL = urljoin(_BASE_URL, "checkin")
    _ACRONIS_CREDENTIALS_URL = urljoin(_BASE_URL, "ab/credentials")
    _ACRONIS_REMOVE_URL = urljoin(_BASE_URL, "ab/remove")
    _ACRONIS_CHECK_URL = urljoin(_BASE_URL, "ab/check")
    STATUS_OK_PAID_LICENSE = "ok"
    STATUS_OK_TRIAL_LICENSE = "ok-trial"

    @classmethod
    async def _request(cls, url, *, data=None, headers=None, timeout=_TIMEOUT):
        return await asyncio.get_event_loop().run_in_executor(
            None, _post_request, url, data, headers, timeout
        )

    @classmethod
    async def register(cls, key: str) -> dict:
        """
        Register server with key
        :param key: registration key
        :return: license token in case of success
        """
        _, token = await cls._request(cls._REGISTER_URL, data={"key": key})
        return token

    @classmethod
    async def checkin(
        cls,
        server_id: str,
        users_count: int,
        hostname: str = None,
    ):
        """
        Update license token
        :param str server_id: server id
        :param int users_count: users count
        :param str hostname: current server hostname
        :return: dict new license token
        """
        hostname = hostname or get_hostname()
        imunify_email_status = await get_imunify_email_status()
        req = {
            "id": server_id,
            "hostname": hostname,
            "im": {
                "users": users_count,
                "imunifyEmail": imunify_email_status,
                "supported_features": {
                    "IM_EMAIL": await is_imunify_email_supported(),
                },
            },
        }
        data = json.dumps(req)
        logger.info("CLN checkin: %s", data)
        _, token = await cls._request(
            cls._CHECKIN_URL,
            data=data,
            headers={"Content-type": "application/json"},
        )
        return token

    @classmethod
    async def acronis_credentials(cls, server_id: str) -> dict:
        """
        Creates Acronis Backup account and get user & password
        :param server_id: server id
        """
        _, creds = await cls._request(
            cls._ACRONIS_CREDENTIALS_URL, data={"id": server_id}
        )
        return creds

    @classmethod
    async def acronis_remove(cls, server_id: str):
        """
        Removes Acronis Backup account
        :param server_id: server id
        """
        await cls._request(cls._ACRONIS_REMOVE_URL, data={"id": server_id})

    @classmethod
    async def acronis_check(cls, server_id: str) -> dict:
        """
        If Acronis account exists return backup size in GB or if backups
        not exists URL for backups
        :param server_id: server id
        """
        status, response = await cls._request(
            cls._ACRONIS_CHECK_URL, data={"id": server_id}
        )
        if status == 244:  # Backup not found
            raise BackupNotFound(url=None)  # Prohibit purchasing a new backup
        return response

    @classmethod
    async def unregister(cls, server_id=None):
        """
        Unregister server id
        :return: None
        """
        server_id = server_id or LicenseCLN.get_server_id()
        await cls._request(cls._UNREGISTER_URL, data={"id": server_id})


class CLN:
    _CALLBACKS = defaultdict(set)

    @classmethod
    def add_callback_for(cls, method_name, coro_callback):
        cls._CALLBACKS[method_name].add(coro_callback)

    @classmethod
    async def run_callbacks_for(cls, method_name):
        for callback in cls._CALLBACKS[method_name]:
            try:
                await callback()
            except asyncio.CancelledError:
                raise
            except Exception as e:
                logger.exception(
                    "Error '{!r}' happened when run callback {} for"
                    "CLN {} method".format(e, callback, method_name)
                )

    @classmethod
    def is_avp_key(cls, key):
        return key.startswith("IMAVP")

    @classmethod
    async def register(cls, key):
        if cls.is_avp_key(key) and not ANTIVIRUS_MODE:
            raise InvalidLicenseError(
                "Imunify360 can not be registered with ImunifyAV+ key"
            )
        license = await RestCLN.register(key)
        # in case of IP license, we have to register to know if license is
        # valid for server (i.e. Imunify360 license is used for Imunify360)
        if not LicenseCLN.is_valid(license):
            # release registered server id
            await RestCLN.unregister(license["id"])
            raise InvalidLicenseError("License is invalid for this server")
        LicenseCLN.update(license)
        await cls.run_callbacks_for("register")

    @classmethod
    async def unregister(cls):
        await RestCLN.unregister()
        LicenseCLN.delete()
        await cls.run_callbacks_for("unregister")

    @classmethod
    async def refresh_token(cls, token):
        """Refreshes token and returns new one on success, None otherwise"""
        if LicenseCLN.is_free():
            # noop: free license can not be refreshed
            return LicenseCLN.get_token()
        if LicenseCLN.get_token().get("is_alternative"):
            # self-signed licenses are refreshed by customer
            return LicenseCLN.get_token()
        new_token = await RestCLN.checkin(token["id"], LicenseCLN.users_count)

        logger.info("Got new token from CLN: %s", new_token)
        if new_token is None:
            await CLN.unregister()
        else:
            LicenseCLN.update(new_token)
        await cls.run_callbacks_for("refresh_token")

        return LicenseCLN.get_token()


def subscribe_to_license_changes(coro):
    for method_name in ["register", "unregister", "refresh_token"]:
        CLN.add_callback_for(method_name, coro_callback=coro)