"""
事件响应器
==========

该模块实现事件响应器的创建与运行，并提供一些快捷方法来帮助用户更好的与机器人进行 对话 。
"""

import inspect
from functools import wraps
from datetime import datetime
from contextvars import ContextVar
from collections import defaultdict
from typing import Type, List, Dict, Union, Callable, Optional, NoReturn, TYPE_CHECKING

from nonebot.rule import Rule
from nonebot.log import logger
from nonebot.permission import Permission, USER
from nonebot.typing import T_State, T_StateFactory, T_Handler, T_ArgsParser
from nonebot.exception import PausedException, RejectedException, FinishedException, StopPropagation

if TYPE_CHECKING:
    from nonebot.adapters import Bot, Event, Message, MessageSegment

matchers: Dict[int, List[Type["Matcher"]]] = defaultdict(list)
"""
:类型: ``Dict[int, List[Type[Matcher]]]``
:说明: 用于存储当前所有的事件响应器
"""
current_bot: ContextVar = ContextVar("current_bot")
current_event: ContextVar = ContextVar("current_event")


class MatcherMeta(type):

    def __repr__(self) -> str:
        return (f"<Matcher from {self.module or 'unknow'}, "  # type: ignore
                f"type={self.type}, priority={self.priority}, "  # type: ignore
                f"temp={self.temp}>")  # type: ignore

    def __str__(self) -> str:
        return repr(self)


class Matcher(metaclass=MatcherMeta):
    """事件响应器类"""
    module: Optional[str] = None
    """
    :类型: ``Optional[str]``
    :说明: 事件响应器所在模块名称
    """

    type: str = ""
    """
    :类型: ``str``
    :说明: 事件响应器类型
    """
    rule: Rule = Rule()
    """
    :类型: ``Rule``
    :说明: 事件响应器匹配规则
    """
    permission: Permission = Permission()
    """
    :类型: ``Permission``
    :说明: 事件响应器触发权限
    """
    handlers: List[T_Handler] = []
    """
    :类型: ``List[T_Handler]``
    :说明: 事件响应器拥有的事件处理函数列表
    """
    priority: int = 1
    """
    :类型: ``int``
    :说明: 事件响应器优先级
    """
    block: bool = False
    """
    :类型: ``bool``
    :说明: 事件响应器是否阻止事件传播
    """
    temp: bool = False
    """
    :类型: ``bool``
    :说明: 事件响应器是否为临时
    """
    expire_time: Optional[datetime] = None
    """
    :类型: ``Optional[datetime]``
    :说明: 事件响应器过期时间点
    """

    _default_state: T_State = {}
    """
    :类型: ``T_State``
    :说明: 事件响应器默认状态
    """
    _default_state_factory: Optional[T_StateFactory] = None
    """
    :类型: ``Optional[T_State]``
    :说明: 事件响应器默认工厂函数
    """

    _default_parser: Optional[T_ArgsParser] = None
    """
    :类型: ``Optional[T_ArgsParser]``
    :说明: 事件响应器默认参数解析函数
    """

    def __init__(self):
        """实例化 Matcher 以便运行"""
        self.handlers = self.handlers.copy()
        self.state = self._default_state.copy()

    def __repr__(self) -> str:
        return (f"<Matcher from {self.module or 'unknown'}, type={self.type}, "
                f"priority={self.priority}, temp={self.temp}>")

    def __str__(self) -> str:
        return self.__repr__()

    @classmethod
    def new(cls,
            type_: str = "",
            rule: Optional[Rule] = None,
            permission: Optional[Permission] = None,
            handlers: Optional[List[T_Handler]] = None,
            temp: bool = False,
            priority: int = 1,
            block: bool = False,
            *,
            module: Optional[str] = None,
            default_state: Optional[T_State] = None,
            default_state_factory: Optional[T_StateFactory] = None,
            expire_time: Optional[datetime] = None) -> Type["Matcher"]:
        """
        :说明:

          创建一个新的事件响应器，并存储至 `matchers <#matchers>`_

        :参数:

          * ``type_: str``: 事件响应器类型，与 ``event.get_type()`` 一致时触发，空字符串表示任意
          * ``rule: Optional[Rule]``: 匹配规则
          * ``permission: Optional[Permission]``: 权限
          * ``handlers: Optional[List[T_Handler]]``: 事件处理函数列表
          * ``temp: bool``: 是否为临时事件响应器，即触发一次后删除
          * ``priority: int``: 响应优先级
          * ``block: bool``: 是否阻止事件向更低优先级的响应器传播
          * ``module: Optional[str]``: 事件响应器所在模块名称
          * ``default_state: Optional[T_State]``: 默认状态 ``state``
          * ``default_state_factory: Optional[T_StateFactory]``: 默认状态 ``state`` 的工厂函数
          * ``expire_time: Optional[datetime]``: 事件响应器最终有效时间点，过时即被删除

        :返回:

          - ``Type[Matcher]``: 新的事件响应器类
        """

        NewMatcher = type(
            "Matcher", (Matcher,), {
                "module":
                    module,
                "type":
                    type_,
                "rule":
                    rule or Rule(),
                "permission":
                    permission or Permission(),
                "handlers": [
                    cls.process_handler(handler) for handler in handlers
                ] if handlers else [],
                "temp":
                    temp,
                "expire_time":
                    expire_time,
                "priority":
                    priority,
                "block":
                    block,
                "_default_state":
                    default_state or {},
                "_default_state_factory":
                    staticmethod(default_state_factory)
                    if default_state_factory else None
            })

        matchers[priority].append(NewMatcher)

        return NewMatcher

    @classmethod
    async def check_perm(cls, bot: "Bot", event: "Event") -> bool:
        """
        :说明:

          检查是否满足触发权限

        :参数:

          * ``bot: Bot``: Bot 对象
          * ``event: Event``: 上报事件

        :返回:

          - ``bool``: 是否满足权限
        """
        event_type = event.get_type()
        return (event_type == (cls.type or event_type) and
                await cls.permission(bot, event))

    @classmethod
    async def check_rule(cls, bot: "Bot", event: "Event",
                         state: T_State) -> bool:
        """
        :说明:

          检查是否满足匹配规则

        :参数:

          * ``bot: Bot``: Bot 对象
          * ``event: Event``: 上报事件
          * ``state: T_State``: 当前状态

        :返回:

          - ``bool``: 是否满足匹配规则
        """
        event_type = event.get_type()
        return (event_type == (cls.type or event_type) and
                await cls.rule(bot, event, state))

    @classmethod
    def args_parser(cls, func: T_ArgsParser) -> T_ArgsParser:
        """
        :说明:

          装饰一个函数来更改当前事件响应器的默认参数解析函数

        :参数:

          * ``func: T_ArgsParser``: 参数解析函数
        """
        cls._default_parser = func
        return func

    @staticmethod
    def process_handler(handler: T_Handler) -> T_Handler:
        signature = inspect.signature(handler, follow_wrapped=False)
        bot = signature.parameters.get("bot")
        event = signature.parameters.get("event")
        state = signature.parameters.get("state")
        matcher = signature.parameters.get("matcher")
        if not bot:
            raise ValueError("Handler missing parameter 'bot'")
        handler.__params__ = {
            "bot": bot.annotation,
            "event": event.annotation if event else None,
            "state": T_State if state else None,
            "matcher": matcher.annotation if matcher else None
        }
        return handler

    @classmethod
    def append_handler(cls, handler: T_Handler) -> None:
        # Process handler first
        cls.handlers.append(cls.process_handler(handler))

    @classmethod
    def handle(cls) -> Callable[[T_Handler], T_Handler]:
        """
        :说明:

          装饰一个函数来向事件响应器直接添加一个处理函数

        :参数:

          * 无
        """

        def _decorator(func: T_Handler) -> T_Handler:
            cls.append_handler(func)
            return func

        return _decorator

    @classmethod
    def receive(cls) -> Callable[[T_Handler], T_Handler]:
        """
        :说明:

          装饰一个函数来指示 NoneBot 在接收用户新的一条消息后继续运行该函数

        :参数:

          * 无
        """

        async def _receive(bot: "Bot", event: "Event") -> NoReturn:
            raise PausedException

        cls.process_handler(_receive)

        if cls.handlers:
            # 已有前置handlers则接受一条新的消息，否则视为接收初始消息
            cls.append_handler(_receive)

        def _decorator(func: T_Handler) -> T_Handler:
            cls.process_handler(func)
            if not cls.handlers or cls.handlers[-1] is not func:
                cls.append_handler(func)

            _receive.__params__.update({
                "bot":
                    func.__params__["bot"],
                "event":
                    func.__params__["event"] or _receive.__params__["event"]
            })

            return func

        return _decorator

    @classmethod
    def got(
        cls,
        key: str,
        prompt: Optional[Union[str, "Message", "MessageSegment"]] = None,
        args_parser: Optional[T_ArgsParser] = None
    ) -> Callable[[T_Handler], T_Handler]:
        """
        :说明:

          装饰一个函数来指示 NoneBot 当要获取的 ``key`` 不存在时接收用户新的一条消息并经过 ``ArgsParser`` 处理后再运行该函数，如果 ``key`` 已存在则直接继续运行

        :参数:

          * ``key: str``: 参数名
          * ``prompt: Optional[Union[str, Message, MessageSegment]]``: 在参数不存在时向用户发送的消息
          * ``args_parser: Optional[T_ArgsParser]``: 可选参数解析函数，空则使用默认解析函数
        """

        async def _key_getter(bot: "Bot", event: "Event", state: T_State):
            state["_current_key"] = key
            if key not in state:
                if prompt:
                    await bot.send(event=event,
                                   message=str(prompt).format(**state))
                raise PausedException
            else:
                state["_skip_key"] = True

        async def _key_parser(bot: "Bot", event: "Event", state: T_State):
            if key in state and state.get("_skip_key"):
                del state["_skip_key"]
                return
            parser = args_parser or cls._default_parser
            if parser:
                # parser = cast(T_ArgsParser["Bot", "Event"], parser)
                await parser(bot, event, state)
            else:
                state[state["_current_key"]] = str(event.get_message())

        cls.append_handler(_key_getter)
        cls.append_handler(_key_parser)

        def _decorator(func: T_Handler) -> T_Handler:
            if not hasattr(cls.handlers[-1], "__wrapped__"):
                cls.process_handler(func)
                parser = cls.handlers.pop()

                @wraps(func)
                async def wrapper(bot: "Bot", event: "Event", state: T_State,
                                  matcher: Matcher):
                    await matcher.run_handler(parser, bot, event, state)
                    await matcher.run_handler(func, bot, event, state)
                    if "_current_key" in state:
                        del state["_current_key"]

                cls.append_handler(wrapper)

                wrapper.__params__.update({
                    "bot":
                        func.__params__["bot"],
                    "event":
                        func.__params__["event"] or wrapper.__params__["event"]
                })
                _key_getter.__params__.update({
                    "bot":
                        func.__params__["bot"],
                    "event":
                        func.__params__["event"] or wrapper.__params__["event"]
                })
                _key_parser.__params__.update({
                    "bot":
                        func.__params__["bot"],
                    "event":
                        func.__params__["event"] or wrapper.__params__["event"]
                })

            return func

        return _decorator

    @classmethod
    async def send(cls, message: Union[str, "Message", "MessageSegment"],
                   **kwargs):
        """
        :说明:

          发送一条消息给当前交互用户

        :参数:

          * ``message: Union[str, Message, MessageSegment]``: 消息内容
          * ``**kwargs``: 其他传递给 ``bot.send`` 的参数，请参考对应 adapter 的 bot 对象 api
        """
        bot = current_bot.get()
        event = current_event.get()
        await bot.send(event=event, message=message, **kwargs)

    @classmethod
    async def finish(cls,
                     message: Optional[Union[str, "Message",
                                             "MessageSegment"]] = None,
                     **kwargs) -> NoReturn:
        """
        :说明:

          发送一条消息给当前交互用户并结束当前事件响应器

        :参数:

          * ``message: Union[str, Message, MessageSegment]``: 消息内容
          * ``**kwargs``: 其他传递给 ``bot.send`` 的参数，请参考对应 adapter 的 bot 对象 api
        """
        bot = current_bot.get()
        event = current_event.get()
        if message:
            await bot.send(event=event, message=message, **kwargs)
        raise FinishedException

    @classmethod
    async def pause(cls,
                    prompt: Optional[Union[str, "Message",
                                           "MessageSegment"]] = None,
                    **kwargs) -> NoReturn:
        """
        :说明:

          发送一条消息给当前交互用户并暂停事件响应器，在接收用户新的一条消息后继续下一个处理函数

        :参数:

          * ``prompt: Union[str, Message, MessageSegment]``: 消息内容
          * ``**kwargs``: 其他传递给 ``bot.send`` 的参数，请参考对应 adapter 的 bot 对象 api
        """
        bot = current_bot.get()
        event = current_event.get()
        if prompt:
            await bot.send(event=event, message=prompt, **kwargs)
        raise PausedException

    @classmethod
    async def reject(cls,
                     prompt: Optional[Union[str, "Message",
                                            "MessageSegment"]] = None,
                     **kwargs) -> NoReturn:
        """
        :说明:

          发送一条消息给当前交互用户并暂停事件响应器，在接收用户新的一条消息后重新运行当前处理函数

        :参数:

          * ``prompt: Union[str, Message, MessageSegment]``: 消息内容
          * ``**kwargs``: 其他传递给 ``bot.send`` 的参数，请参考对应 adapter 的 bot 对象 api
        """
        bot = current_bot.get()
        event = current_event.get()
        if prompt:
            await bot.send(event=event, message=prompt, **kwargs)
        raise RejectedException

    def stop_propagation(self):
        """
        :说明:

          阻止事件传播
        """
        self.block = True

    async def run_handler(self, handler: T_Handler, bot: "Bot", event: "Event",
                          state: T_State):
        if not hasattr(handler, "__params__"):
            self.process_handler(handler)
        params = getattr(handler, "__params__")

        BotType = ((params["bot"] is not inspect.Parameter.empty) and
                   inspect.isclass(params["bot"]) and params["bot"])
        if BotType and not isinstance(bot, BotType):
            logger.debug(
                f"Matcher {self} bot type {type(bot)} not match annotation {BotType}, ignored"
            )
            return

        EventType = ((params["event"] is not inspect.Parameter.empty) and
                     inspect.isclass(params["event"]) and params["event"])
        if EventType and not isinstance(event, EventType):
            logger.debug(
                f"Matcher {self} event type {type(event)} not match annotation {EventType}, ignored"
            )
            return

        args = {"bot": bot, "event": event, "state": state, "matcher": self}
        await handler(
            **{k: v for k, v in args.items() if params[k] is not None})

    # 运行handlers
    async def run(self, bot: "Bot", event: "Event", state: T_State):
        b_t = current_bot.set(bot)
        e_t = current_event.set(event)
        try:
            # Refresh preprocess state
            state_ = await self._default_state_factory(
                bot, event) if self._default_state_factory else self.state
            state_.update(state)

            for _ in range(len(self.handlers)):
                handler = self.handlers.pop(0)
                await self.run_handler(handler, bot, event, state_)

        except RejectedException:
            self.handlers.insert(0, handler)  # type: ignore
            Matcher.new(
                "message",
                Rule(),
                USER(event.get_session_id(),
                     perm=self.permission),  # type:ignore
                self.handlers,
                temp=True,
                priority=0,
                block=True,
                module=self.module,
                default_state=self.state,
                expire_time=datetime.now() + bot.config.session_expire_timeout)
        except PausedException:
            Matcher.new(
                "message",
                Rule(),
                USER(event.get_session_id(),
                     perm=self.permission),  # type:ignore
                self.handlers,
                temp=True,
                priority=0,
                block=True,
                module=self.module,
                default_state=self.state,
                expire_time=datetime.now() + bot.config.session_expire_timeout)
        except FinishedException:
            pass
        except StopPropagation:
            self.block = True
        finally:
            logger.info(f"Matcher {self} running complete")
            current_bot.reset(b_t)
            current_event.reset(e_t)