import inspect
from functools import wraps, partial
from typing import Any, Tuple, Union, TypeVar, Callable, Optional, cast
from contextlib import AsyncExitStack, contextmanager, asynccontextmanager

from pydantic.fields import Required, Undefined

from nonebot.typing import T_State, T_Handler
from nonebot.adapters import Bot, Event, Message
from nonebot.dependencies import Param, Dependent
from nonebot.consts import (
    CMD_KEY,
    PREFIX_KEY,
    REGEX_DICT,
    SHELL_ARGS,
    SHELL_ARGV,
    CMD_ARG_KEY,
    RAW_CMD_KEY,
    REGEX_GROUP,
    REGEX_MATCHED,
    WRAPPER_ASSIGNMENTS,
)
from nonebot.utils import (
    CacheDict,
    get_name,
    run_sync,
    is_gen_callable,
    run_sync_ctx_manager,
    is_async_gen_callable,
    is_coroutine_callable,
    generic_check_issubclass,
)

T = TypeVar("T")


class DependsInner:
    def __init__(
        self,
        dependency: Optional[T_Handler] = None,
        *,
        use_cache: bool = True,
    ) -> None:
        self.dependency = dependency
        self.use_cache = use_cache

    def __repr__(self) -> str:
        dep = get_name(self.dependency)
        cache = "" if self.use_cache else ", use_cache=False"
        return f"{self.__class__.__name__}({dep}{cache})"


def Depends(
    dependency: Optional[T_Handler] = None,
    *,
    use_cache: bool = True,
) -> Any:
    """
    :说明:

      参数依赖注入装饰器

    :参数:

      * ``dependency: Optional[Callable[..., Any]] = None``: 依赖函数。默认为参数的类型注释。
      * ``use_cache: bool = True``: 是否使用缓存。默认为 ``True``。
      * ``allow_types: Optional[List[Type[Param]]] = None``: 允许的参数类型。默认为 ``None``。

    .. code-block:: python

        def depend_func() -> Any:
            return ...

        def depend_gen_func():
            try:
                yield ...
            finally:
                ...

        async def handler(param_name: Any = Depends(depend_func), gen: Any = Depends(depend_gen_func)):
            ...
    """
    return DependsInner(dependency, use_cache=use_cache)


class DependParam(Param):
    @classmethod
    def _check_param(
        cls,
        dependent: Dependent,
        name: str,
        param: inspect.Parameter,
    ) -> Optional["DependParam"]:
        if isinstance(param.default, DependsInner):
            dependency: T_Handler
            if param.default.dependency is None:
                assert param.annotation is not param.empty, "Dependency cannot be empty"
                dependency = param.annotation
            else:
                dependency = param.default.dependency
            dependent = Dependent[Any].parse(
                call=dependency,
                allow_types=dependent.allow_types,
            )
            return cls(Required, use_cache=param.default.use_cache, dependent=dependent)

    @classmethod
    def _check_parameterless(
        cls, dependent: "Dependent", value: Any
    ) -> Optional["Param"]:
        if isinstance(value, DependsInner):
            assert value.dependency, "Dependency cannot be empty"
            dependent = Dependent[Any].parse(
                call=value.dependency, allow_types=dependent.allow_types
            )
            return cls(Required, use_cache=value.use_cache, dependent=dependent)

    async def _solve(
        self,
        stack: Optional[AsyncExitStack] = None,
        dependency_cache: Optional[CacheDict[T_Handler, Any]] = None,
        **kwargs: Any,
    ) -> Any:
        use_cache: bool = self.extra["use_cache"]
        dependency_cache = CacheDict() if dependency_cache is None else dependency_cache

        sub_dependent: Dependent = self.extra["dependent"]
        sub_dependent.call = cast(Callable[..., Any], sub_dependent.call)
        call = sub_dependent.call

        # solve sub dependency with current cache
        sub_values = await sub_dependent.solve(
            stack=stack,
            dependency_cache=dependency_cache,
            **kwargs,
        )

        # run dependency function
        async with dependency_cache:
            if use_cache and call in dependency_cache:
                solved = dependency_cache[call]
            elif is_gen_callable(call) or is_async_gen_callable(call):
                assert isinstance(
                    stack, AsyncExitStack
                ), "Generator dependency should be called in context"
                if is_gen_callable(call):
                    cm = run_sync_ctx_manager(contextmanager(call)(**sub_values))
                else:
                    cm = asynccontextmanager(call)(**sub_values)
                solved = await stack.enter_async_context(cm)
            elif is_coroutine_callable(call):
                return await call(**sub_values)
            else:
                return await run_sync(call)(**sub_values)

            # save current dependency to cache
            if call not in dependency_cache:
                dependency_cache[call] = solved

        return solved


class BotParam(Param):
    @classmethod
    def _check_param(
        cls, dependent: Dependent, name: str, param: inspect.Parameter
    ) -> Optional["BotParam"]:
        if param.default == param.empty and (
            generic_check_issubclass(param.annotation, Bot)
            or (param.annotation == param.empty and name == "bot")
        ):
            return cls(Required)

    async def _solve(self, bot: Bot, **kwargs: Any) -> Any:
        return bot


class EventParam(Param):
    @classmethod
    def _check_param(
        cls, dependent: Dependent, name: str, param: inspect.Parameter
    ) -> Optional["EventParam"]:
        if param.default == param.empty and (
            generic_check_issubclass(param.annotation, Event)
            or (param.annotation == param.empty and name == "event")
        ):
            return cls(Required)

    async def _solve(self, event: Event, **kwargs: Any) -> Any:
        return event


async def _event_type(event: Event) -> str:
    return event.get_type()


def EventType() -> str:
    return Depends(_event_type)


async def _event_message(event: Event) -> Message:
    return event.get_message()


def EventMessage() -> Message:
    return Depends(_event_message)


async def _event_plain_text(event: Event) -> str:
    return event.get_plaintext()


def EventPlainText() -> str:
    return Depends(_event_plain_text)


async def _event_to_me(event: Event) -> bool:
    return event.is_tome()


def EventToMe() -> bool:
    return Depends(_event_to_me)


class StateInner:
    ...


def State() -> T_State:
    return StateInner()  # type: ignore


class StateParam(Param):
    @classmethod
    def _check_param(
        cls, dependent: Dependent, name: str, param: inspect.Parameter
    ) -> Optional["StateParam"]:
        if isinstance(param.default, StateInner):
            return cls(Required)

    async def _solve(self, state: T_State, **kwargs: Any) -> Any:
        return state


def _command(state=State()) -> Message:
    return state[PREFIX_KEY][CMD_KEY]


def Command() -> Tuple[str, ...]:
    return Depends(_command)


def _raw_command(state=State()) -> Message:
    return state[PREFIX_KEY][RAW_CMD_KEY]


def RawCommand() -> str:
    return Depends(_raw_command)


def _command_arg(state=State()) -> Message:
    return state[PREFIX_KEY][CMD_ARG_KEY]


def CommandArg() -> Message:
    return Depends(_command_arg)


class MatcherParam(Param):
    @classmethod
    def _check_param(
        cls, dependent: Dependent, name: str, param: inspect.Parameter
    ) -> Optional["MatcherParam"]:
        if generic_check_issubclass(param.annotation, Matcher) or (
            param.annotation == param.empty and name == "matcher"
        ):
            return cls(Required)

    async def _solve(self, matcher: "Matcher", **kwargs: Any) -> Any:
        return matcher


def _received(matcher: "Matcher", id: str = "", default: T = None) -> Union[Event, T]:
    return matcher.get_receive(id, default)


def Received(id: str = "", default: Any = None) -> Any:
    return Depends(
        wraps(_received, assigned=WRAPPER_ASSIGNMENTS)(
            partial(_received, id=id, default=default)
        )
    )


class ExceptionParam(Param):
    @classmethod
    def _check_param(
        cls, dependent: Dependent, name: str, param: inspect.Parameter
    ) -> Optional["ExceptionParam"]:
        if generic_check_issubclass(param.annotation, Exception) or (
            param.annotation == param.empty and name == "exception"
        ):
            return cls(Required)

    async def _solve(self, exception: Optional[Exception] = None, **kwargs: Any) -> Any:
        return exception


class DefaultParam(Param):
    @classmethod
    def _check_param(
        cls, dependent: Dependent, name: str, param: inspect.Parameter
    ) -> Optional["DefaultParam"]:
        if param.default != param.empty:
            return cls(param.default)

    async def _solve(self, **kwargs: Any) -> Any:
        return Undefined


from nonebot.matcher import Matcher