# -*- coding: utf-8 -*-
"""
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MIoT network utilities.
"""
import asyncio
import logging
import platform
import socket
from dataclasses import dataclass
from enum import Enum, auto
import subprocess
from typing import Callable, Optional
import psutil
import ipaddress

_LOGGER = logging.getLogger(__name__)


class InterfaceStatus(Enum):
    """Interface status."""
    ADD = 0
    UPDATE = auto()
    REMOVE = auto()


@dataclass
class NetworkInfo:
    """Network information."""
    name: str
    ip: str
    netmask: str
    net_seg: str


class MIoTNetwork:
    """MIoT network utilities."""
    PING_ADDRESS_LIST = [
        '1.2.4.8',          # CNNIC sDNS
        '8.8.8.8',          # Google Public DNS
        '233.5.5.5',        # AliDNS
        '1.1.1.1',          # Cloudflare DNS
        '114.114.114.114',  # 114 DNS
        '208.67.222.222',   # OpenDNS
        '9.9.9.9',          # Quad9 DNS
    ]
    _main_loop: asyncio.AbstractEventLoop

    _refresh_interval: int
    _refresh_task: asyncio.Task
    _refresh_timer: asyncio.TimerHandle

    _network_status: bool
    _network_info: dict[str, NetworkInfo]

    _sub_list_network_status: dict[str, Callable[[bool], asyncio.Future]]
    _sub_list_network_info: dict[str, Callable[[
        InterfaceStatus, NetworkInfo], asyncio.Future]]

    _ping_address_priority: int

    _done_event: asyncio.Event

    def __init__(
        self, loop: Optional[asyncio.AbstractEventLoop] = None
    ) -> None:
        self._main_loop = loop or asyncio.get_running_loop()

        self._refresh_interval = None
        self._refresh_task = None
        self._refresh_timer = None

        self._network_status = False
        self._network_info = {}

        self._sub_list_network_status = {}
        self._sub_list_network_info = {}

        self._ping_address_priority = 0

        self._done_event = asyncio.Event()

    @property
    def network_status(self) -> bool:
        return self._network_status

    @property
    def network_info(self) -> dict[str, NetworkInfo]:
        return self._network_info

    async def deinit_async(self) -> None:
        if self._refresh_task:
            self._refresh_task.cancel()
            self._refresh_task = None
        if self._refresh_timer:
            self._refresh_timer.cancel()
            self._refresh_timer = None

        self._refresh_interval = None
        self._network_status = False
        self._network_info.clear()
        self._sub_list_network_status.clear()
        self._sub_list_network_info.clear()
        self._done_event.clear()

    def sub_network_status(
        self, key: str, handler: Callable[[bool], asyncio.Future]
    ) -> None:
        self._sub_list_network_status[key] = handler

    def unsub_network_status(self, key: str) -> None:
        self._sub_list_network_status.pop(key, None)

    def sub_network_info(
        self, key: str,
        handler: Callable[[InterfaceStatus, NetworkInfo], asyncio.Future]
    ) -> None:
        self._sub_list_network_info[key] = handler

    def unsub_network_info(self, key: str) -> None:
        self._sub_list_network_info.pop(key, None)

    async def init_async(self, refresh_interval: int = 30) -> bool:
        self._refresh_interval = refresh_interval
        self.__refresh_timer_handler()
        # MUST get network info before starting
        return await self._done_event.wait()

    async def refresh_async(self) -> None:
        self.__refresh_timer_handler()

    async def get_network_status_async(self, timeout: int = 6) -> bool:
        return await self._main_loop.run_in_executor(
            None, self.__get_network_status, False, timeout)

    async def get_network_info_async(self) -> dict[str, NetworkInfo]:
        return await self._main_loop.run_in_executor(
            None, self.__get_network_info)

    def __calc_network_address(self, ip: str, netmask: str) -> str:
        return str(ipaddress.IPv4Network(
            f'{ip}/{netmask}', strict=False).network_address)

    def __ping(
        self, address: Optional[str] = None, timeout: int = 6
    ) -> bool:
        param = '-n' if platform.system().lower() == 'windows' else '-c'
        command = ['ping', param, '1', address]
        try:
            output = subprocess.run(
                command, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                check=True, timeout=timeout)
            return output.returncode == 0
        except Exception:  # pylint: disable=broad-exception-caught
            return False

    def __get_network_status(
        self, with_retry: bool = True, timeout: int = 6
    ) -> bool:
        if self._ping_address_priority >= len(self.PING_ADDRESS_LIST):
            self._ping_address_priority = 0

        if self.__ping(
                self.PING_ADDRESS_LIST[self._ping_address_priority], timeout):
            return True
        if not with_retry:
            return False
        for index in range(len(self.PING_ADDRESS_LIST)):
            if index == self._ping_address_priority:
                continue
            if self.__ping(self.PING_ADDRESS_LIST[index], timeout):
                self._ping_address_priority = index
                return True
        return False

    def __get_network_info(self) -> dict[str, NetworkInfo]:
        interfaces = psutil.net_if_addrs()
        results: dict[str, NetworkInfo] = {}
        for name, addresses in interfaces.items():
            # Skip hassio and docker* interface
            if name == 'hassio' or name.startswith('docker'):
                continue
            for address in addresses:
                if (
                    address.family != socket.AF_INET
                    or not address.address
                    or not address.netmask
                ):
                    continue
                # skip lo interface
                if address.address == '127.0.0.1':
                    continue
                results[name] = NetworkInfo(
                    name=name,
                    ip=address.address,
                    netmask=address.netmask,
                    net_seg=self.__calc_network_address(
                        address.address, address.netmask))
        return results

    def __call_network_info_change(
        self, status: InterfaceStatus, info: NetworkInfo
    ) -> None:
        for handler in self._sub_list_network_info.values():
            self._main_loop.create_task(handler(status, info))

    async def __update_status_and_info_async(self, timeout: int = 6) -> None:
        try:
            status: bool = await self._main_loop.run_in_executor(
                None, self.__get_network_status, timeout)
            infos = await self._main_loop.run_in_executor(
                None, self.__get_network_info)

            if self._network_status != status:
                for handler in self._sub_list_network_status.values():
                    self._main_loop.create_task(handler(status))
                self._network_status = status

            for name in list(self._network_info.keys()):
                info = infos.pop(name, None)
                if info:
                    # Update
                    if (
                        info.ip != self._network_info[name].ip
                        or info.netmask != self._network_info[name].netmask
                    ):
                        self._network_info[name] = info
                        self.__call_network_info_change(
                            InterfaceStatus.UPDATE, info)
                else:
                    # Remove
                    self.__call_network_info_change(
                        InterfaceStatus.REMOVE,
                        self._network_info.pop(name, None))
            # Add
            for name, info in infos.items():
                self._network_info[name] = info
                self.__call_network_info_change(InterfaceStatus.ADD, info)

            if not self._done_event.is_set():
                self._done_event.set()
        except asyncio.CancelledError:
            _LOGGER.error('update_status_and_info task was cancelled')

    def __refresh_timer_handler(self) -> None:
        if self._refresh_timer:
            self._refresh_timer.cancel()
            self._refresh_timer = None
        if self._refresh_task is None or self._refresh_task.done():
            self._refresh_task = self._main_loop.create_task(
                self.__update_status_and_info_async())
        self._refresh_timer = self._main_loop.call_later(
            self._refresh_interval, self.__refresh_timer_handler)