import inspect
from itertools import chain
from typing import Any, Dict, List, Tuple, Callable, Optional, cast
from contextlib import AsyncExitStack, contextmanager, asynccontextmanager

from .models import Dependent
from nonebot.log import logger
from nonebot.typing import T_State
from nonebot.adapters import Bot, Event
from .models import Depends as DependsClass
from .utils import (generic_get_types, get_typed_signature,
                    generic_check_issubclass)
from nonebot.utils import (run_sync, is_gen_callable, run_sync_ctx_manager,
                           is_async_gen_callable, is_coroutine_callable)


def get_param_sub_dependent(*, param: inspect.Parameter) -> Dependent:
    depends: DependsClass = param.default
    if depends.dependency:
        dependency = depends.dependency
    else:
        dependency = param.annotation
    return get_sub_dependant(
        depends=depends,
        dependency=dependency,
        name=param.name,
    )


def get_parameterless_sub_dependant(*, depends: DependsClass) -> Dependent:
    assert callable(
        depends.dependency
    ), "A parameter-less dependency must have a callable dependency"
    return get_sub_dependant(depends=depends, dependency=depends.dependency)


def get_sub_dependant(
    *,
    depends: DependsClass,
    dependency: Callable[..., Any],
    name: Optional[str] = None,
) -> Dependent:
    sub_dependant = get_dependent(
        func=dependency,
        name=name,
        use_cache=depends.use_cache,
    )
    return sub_dependant


def get_dependent(*,
                  func: Callable[..., Any],
                  name: Optional[str] = None,
                  use_cache: bool = True) -> Dependent:
    signature = get_typed_signature(func)
    params = signature.parameters
    dependent = Dependent(func=func, name=name, use_cache=use_cache)
    for param_name, param in params.items():
        if isinstance(param.default, DependsClass):
            sub_dependent = get_param_sub_dependent(param=param)
            dependent.dependencies.append(sub_dependent)
            continue

        if generic_check_issubclass(param.annotation, Bot):
            if dependent.bot_param_name is not None:
                raise ValueError(f"{func} has more than one Bot parameter: "
                                 f"{dependent.bot_param_name} / {param_name}")
            dependent.bot_param_name = param_name
            dependent.bot_param_type = generic_get_types(param.annotation)
        elif generic_check_issubclass(param.annotation, Event):
            if dependent.event_param_name is not None:
                raise ValueError(f"{func} has more than one Event parameter: "
                                 f"{dependent.event_param_name} / {param_name}")
            dependent.event_param_name = param_name
            dependent.event_param_type = generic_get_types(param.annotation)
        elif generic_check_issubclass(param.annotation, Dict):
            if dependent.state_param_name is not None:
                raise ValueError(f"{func} has more than one State parameter: "
                                 f"{dependent.state_param_name} / {param_name}")
            dependent.state_param_name = param_name
        elif generic_check_issubclass(param.annotation, Matcher):
            if dependent.matcher_param_name is not None:
                raise ValueError(
                    f"{func} has more than one Matcher parameter: "
                    f"{dependent.matcher_param_name} / {param_name}")
            dependent.matcher_param_name = param_name
        else:
            raise ValueError(
                f"Unknown parameter {param_name} with type {param.annotation}")

    return dependent


async def solve_dependencies(
    *,
    dependent: Dependent,
    bot: Bot,
    event: Event,
    state: T_State,
    matcher: Optional["Matcher"],
    stack: Optional[AsyncExitStack] = None,
    sub_dependents: Optional[List[Dependent]] = None,
    dependency_overrides_provider: Optional[Any] = None,
    dependency_cache: Optional[Dict[Callable[..., Any], Any]] = None,
) -> Tuple[Dict[str, Any], Dict[Callable[..., Any], Any], bool]:
    values: Dict[str, Any] = {}
    dependency_cache = dependency_cache or {}

    # solve sub dependencies
    sub_dependent: Dependent
    for sub_dependent in chain(sub_dependents or tuple(),
                               dependent.dependencies):
        sub_dependent.func = cast(Callable[..., Any], sub_dependent.func)
        sub_dependent.cache_key = cast(Callable[..., Any],
                                       sub_dependent.cache_key)
        func = sub_dependent.func

        # check bot and event type
        if sub_dependent.bot_param_type and not isinstance(
                bot, sub_dependent.bot_param_type):
            logger.debug(
                f"Matcher {matcher} bot type {type(bot)} not match depends {func} "
                f"annotation {sub_dependent.bot_param_type}, ignored")
            return values, dependency_cache, True
        elif sub_dependent.event_param_type and not isinstance(
                event, sub_dependent.event_param_type):
            logger.debug(
                f"Matcher {matcher} event type {type(event)} not match depends {func} "
                f"annotation {sub_dependent.event_param_type}, ignored")
            return values, dependency_cache, True

        # dependency overrides
        use_sub_dependant = sub_dependent
        if (dependency_overrides_provider and
                hasattr(dependency_overrides_provider, "dependency_overrides")):
            original_call = sub_dependent.func
            func = getattr(dependency_overrides_provider,
                           "dependency_overrides",
                           {}).get(original_call, original_call)
            use_sub_dependant = get_dependent(
                func=func,
                name=sub_dependent.name,
            )

        # solve sub dependency with current cache
        solved_result = await solve_dependencies(
            dependent=use_sub_dependant,
            bot=bot,
            event=event,
            state=state,
            matcher=matcher,
            dependency_overrides_provider=dependency_overrides_provider,
            dependency_cache=dependency_cache,
        )
        sub_values, sub_dependency_cache, ignored = solved_result
        if ignored:
            return values, dependency_cache, True
        # update cache?
        dependency_cache.update(sub_dependency_cache)

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

        # parameter dependency
        if sub_dependent.name is not None:
            values[sub_dependent.name] = solved
        # save current dependency to cache
        if sub_dependent.cache_key not in dependency_cache:
            dependency_cache[sub_dependent.cache_key] = solved

    # usual dependency
    if dependent.bot_param_name is not None:
        values[dependent.bot_param_name] = bot
    if dependent.event_param_name is not None:
        values[dependent.event_param_name] = event
    if dependent.state_param_name is not None:
        values[dependent.state_param_name] = state
    if dependent.matcher_param_name is not None:
        values[dependent.matcher_param_name] = matcher
    return values, dependency_cache, False


def Depends(dependency: Optional[Callable[..., Any]] = None,
            *,
            use_cache: bool = True) -> Any:
    return DependsClass(dependency=dependency, use_cache=use_cache)


from .handler import Handler as Handler
from .matcher import Matcher as Matcher
from .matcher import matchers as matchers