import asyncio
import inspect
import os
from asyncio import CancelledError
from importlib import import_module
from multiprocessing import RLock as Lock
from pathlib import Path
from typing import Any, Callable, ClassVar, Dict, Iterator, List, NoReturn, Optional, TYPE_CHECKING, Type, TypeVar

import pytz
from async_timeout import timeout
from telegram.error import NetworkError, TimedOut
from telegram.ext import (
    AIORateLimiter,
    Application as TgApplication,
    CallbackContext,
    Defaults,
    JobQueue,
    MessageHandler,
)
from telegram.ext.filters import StatusUpdate

from core.config import BotConfig, config  # pylint: disable=W0611
from core.error import ServiceNotFoundError
# noinspection PyProtectedMember
from core.plugin import Plugin, _Plugin
from core.service import Service
from utils.const import PLUGIN_DIR, PROJECT_ROOT
from utils.log import logger

if TYPE_CHECKING:
    from telegram import Update

__all__ = ['bot']

T = TypeVar('T')
PluginType = TypeVar('PluginType', bound=_Plugin)


class Bot:
    _lock: ClassVar[Lock] = Lock()
    _instance: ClassVar[Optional["Bot"]] = None

    def __new__(cls, *args, **kwargs) -> "Bot":
        """实现单例"""
        with cls._lock:  # 使线程、进程安全
            if cls._instance is None:
                cls._instance = object.__new__(cls)
        return cls._instance

    app: Optional[TgApplication] = None
    _config: BotConfig = config
    _services: Dict[Type[T], T] = {}
    _running: bool = False

    def _inject(self, signature: inspect.Signature, target: Callable[..., T]) -> T:
        kwargs = {}
        for name, parameter in signature.parameters.items():
            if name != 'self' and parameter.annotation != inspect.Parameter.empty:
                if value := self._services.get(parameter.annotation):
                    kwargs[name] = value
        return target(**kwargs)

    def init_inject(self, target: Callable[..., T]) -> T:
        """用于实例化Plugin的方法。用于给插件传入一些必要组件，如 MySQL、Redis等"""
        if isinstance(target, type):
            signature = inspect.signature(target.__init__)
        else:
            signature = inspect.signature(target)
        return self._inject(signature, target)

    async def async_inject(self, target: Callable[..., T]) -> T:
        return await self._inject(inspect.signature(target), target)

    def _gen_pkg(self, root: Path) -> Iterator[str]:
        """生成可以用于 import_module 导入的字符串"""
        for path in root.iterdir():
            if not path.name.startswith('_'):
                if path.is_dir():
                    yield from self._gen_pkg(path)
                elif path.suffix == '.py':
                    yield str(path.relative_to(PROJECT_ROOT).with_suffix('')).replace(os.sep, '.')

    async def install_plugins(self):
        """安装插件"""
        for pkg in self._gen_pkg(PLUGIN_DIR):
            try:
                import_module(pkg)  # 导入插件
            except Exception as e:  # pylint: disable=W0703
                logger.exception(
                    f'在导入文件 "{pkg}" 的过程中遇到了错误: \n[red bold]{type(e).__name__}: {e}[/]',
                    extra={'markup': True}
                )
                continue  # 如有错误则继续
        callback_dict: Dict[int, List[Callable]] = {}
        for plugin_cls in {*Plugin.__subclasses__(), *Plugin.Conversation.__subclasses__()}:
            path = f"{plugin_cls.__module__}.{plugin_cls.__name__}"
            try:
                plugin: PluginType = self.init_inject(plugin_cls)
                if hasattr(plugin, '__async_init__'):
                    await self.async_inject(plugin.__async_init__)
                handlers = plugin.handlers
                self.app.add_handlers(handlers)
                if handlers:
                    logger.debug(f'插件 "{path}" 添加了 {len(handlers)} 个 handler ')

                # noinspection PyProtectedMember
                for priority, callback in plugin._new_chat_members_handler_funcs():  # pylint: disable=W0212
                    if not callback_dict.get(priority):
                        callback_dict[priority] = []
                    callback_dict[priority].append(callback)

                error_handlers = plugin.error_handlers
                for callback, block in error_handlers.items():
                    self.app.add_error_handler(callback, block)
                if error_handlers:
                    logger.debug(f"插件 \"{path}\" 添加了 {len(error_handlers)} 个 error handler")

                if jobs := plugin.jobs:
                    logger.debug(f'插件 "{path}" 添加了 {len(jobs)} 个任务')
                logger.success(f'插件 "{path}" 载入成功')
            except Exception as e:  # pylint: disable=W0703
                logger.exception(
                    f'在安装插件 \"{path}\" 的过程中遇到了错误: \n[red bold]{type(e).__name__}: {e}[/]',
                    extra={'markup': True}
                )
        if callback_dict:
            num = sum(len(callback_dict[i]) for i in callback_dict)

            async def _new_chat_member_callback(update: 'Update', context: 'CallbackContext'):
                nonlocal callback
                for _, value in callback_dict.items():
                    for callback in value:
                        await callback(update, context)

            self.app.add_handler(MessageHandler(
                callback=_new_chat_member_callback, filters=StatusUpdate.NEW_CHAT_MEMBERS, block=False
            ))
            logger.success(
                f'成功添加了 {num} 个针对 [blue]{StatusUpdate.NEW_CHAT_MEMBERS}[/] 的 [blue]MessageHandler[/]',
                extra={'markup': True}
            )

    async def _start_base_services(self):
        for pkg in self._gen_pkg(PROJECT_ROOT / 'core/base'):
            try:
                import_module(pkg)
            except Exception as e:  # pylint: disable=W0703
                logger.exception(
                    f'在导入文件 "{pkg}" 的过程中遇到了错误: \n[red bold]{type(e).__name__}: {e}[/]',
                    extra={'markup': True}
                )
                continue
        for base_service_cls in Service.__subclasses__():
            try:
                if hasattr(base_service_cls, 'from_config'):
                    instance = base_service_cls.from_config(self._config)
                else:
                    instance = self.init_inject(base_service_cls)
                await instance.start()
                logger.success(f'服务 "{base_service_cls.__name__}" 初始化成功')
                self._services.update({base_service_cls: instance})
            except Exception as e:  # pylint: disable=W0703
                logger.exception(f'服务 "{base_service_cls.__name__}" 初始化失败: {e}')
                continue

    async def start_services(self):
        """启动服务"""
        await self._start_base_services()
        for path in (PROJECT_ROOT / 'core').iterdir():
            if not path.name.startswith('_') and path.is_dir() and path.name != 'base':
                pkg = str(path.relative_to(PROJECT_ROOT).with_suffix('')).replace(os.sep, '.')
                try:
                    import_module(pkg)
                except Exception as e:  # pylint: disable=W0703
                    logger.exception(
                        f'在导入文件 "{pkg}" 的过程中遇到了错误: \n[red bold]{type(e).__name__}: {e}[/]',
                        extra={'markup': True}
                    )
                    continue

    async def stop_services(self):
        """关闭服务"""
        if not self._services:
            return
        logger.info('正在关闭服务')
        for _, service in filter(lambda x: not isinstance(x[1], TgApplication), self._services.items()):
            async with timeout(5):
                try:
                    if hasattr(service, 'stop'):
                        if inspect.iscoroutinefunction(service.stop):
                            await service.stop()
                        else:
                            service.stop()
                        logger.success(f'服务 "{service.__class__.__name__}" 关闭成功')
                except CancelledError:
                    logger.warning(f'服务 "{service.__class__.__name__}" 关闭超时')
                except Exception as e:  # pylint: disable=W0703
                    logger.exception(f"服务 \"{service.__class__.__name__}\" 关闭失败: \n{type(e).__name__}: {e}")

    async def _post_init(self, context: CallbackContext) -> NoReturn:
        self._services.update({CallbackContext: context})
        logger.info('开始初始化服务')
        await self.start_services()
        logger.info('开始安装插件')
        await self.install_plugins()
        logger.info('BOT 初始化成功')

    def launch(self) -> NoReturn:
        """启动机器人"""
        self._running = True
        logger.info('正在初始化BOT')
        self.app = (
            TgApplication.builder()
            .rate_limiter(AIORateLimiter())
            .defaults(Defaults(tzinfo=pytz.timezone("Asia/Shanghai")))
            .token(self._config.bot_token)
            .post_init(self._post_init)
            .build()
        )
        try:
            for _ in range(5):
                try:
                    self.app.run_polling(close_loop=False)
                    break
                except TimedOut:
                    logger.warning("连接至 [blue]telegram[/] 服务器失败，正在重试", extra={'markup': True})
                    continue
                except NetworkError as e:
                    logger.exception()
                    if 'SSLZeroReturnError' in str(e):
                        logger.error("代理服务出现异常, 请检查您的代理服务是否配置成功.")
                    else:
                        logger.error("网络连接出现问题, 请检查您的网络状况.")
                    break
        except (SystemExit, KeyboardInterrupt):
            pass
        except Exception as e:  # pylint: disable=W0703
            logger.exception(f"BOT 执行过程中出现错误: {e}")
        finally:
            loop = asyncio.get_event_loop()
            loop.run_until_complete(self.stop_services())
            loop.close()
        logger.info("BOT 已经关闭")
        self._running = False

    def find_service(self, target: Type[T]) -> T:
        """查找服务。若没找到则抛出 ServiceNotFoundError"""
        if result := self._services.get(target) is None:
            raise ServiceNotFoundError(target)
        return result

    def add_service(self, service: T) -> NoReturn:
        """添加服务。若已经有同类型的服务，则会抛出异常"""
        if type(service) in self._services:
            raise ValueError(f"Service \"{type(service)}\" is already existed.")
        self.update_service(service)

    def update_service(self, service: T):
        """更新服务。若服务不存在，则添加；若存在，则更新"""
        self._services.update({type(service): service})

    def contain_service(self, service: Any) -> bool:
        """判断服务是否存在"""
        if isinstance(service, type):
            return service in self._services
        else:
            return service in self._services.values()

    @property
    def job_queue(self) -> JobQueue:
        return self.app.job_queue

    @property
    def services(self) -> Dict[Type[T], T]:
        return self._services

    @property
    def config(self) -> BotConfig:
        return self._config

    @property
    def is_running(self) -> bool:
        return self._running


bot = Bot()