from __future__ import annotations

import abc
from typing import Any, Callable, Dict, Generic, List, Mapping, Type, TypeVar, Union

from baize.exceptions import HTTPException
from pydantic import ValidationError
from typing_extensions import Literal


class RequestValidationError(Exception):
    def __init__(
        self,
        validation_error: ValidationError,
        in_: Literal["path", "query", "header", "cookie", "body"],
    ) -> None:
        self.validation_error = validation_error
        self.in_ = in_

    def errors(self) -> List[Dict[str, Any]]:
        errors = self.validation_error.errors()
        for error in errors:
            error["in"] = self.in_  # type: ignore
        return errors  # type: ignore

    def json(self, *, indent: Union[None, int] = 2) -> str:
        return self.validation_error.json(indent=indent)

    @staticmethod
    def schema() -> Dict[str, Any]:
        return {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "loc": {
                        "title": "Location",
                        "description": "error field",
                        "type": "array",
                        "items": {"type": "string"},
                    },
                    "type": {
                        "title": "Type",
                        "description": "error type",
                        "type": "string",
                    },
                    "msg": {
                        "title": "Message",
                        "description": "error message",
                        "type": "string",
                    },
                    "ctx": {
                        "title": "Context",
                        "description": "error context",
                        "type": "string",
                    },
                    "in": {
                        "title": "In",
                        "type": "string",
                        "enum": ["path", "query", "header", "cookie", "body"],
                    },
                },
                "required": ["loc", "type", "msg"],
            },
        }


ErrorHandlerType = TypeVar("ErrorHandlerType", bound=Callable)


class ExceptionMiddlewareBase(Generic[ErrorHandlerType], abc.ABC):
    def __init__(
        self,
        handlers: Mapping[Union[int, Type[BaseException]], ErrorHandlerType] = {},
    ) -> None:
        self._status_handlers: Dict[int, ErrorHandlerType] = {}
        self._exception_handlers: Dict[Type[BaseException], ErrorHandlerType] = {}
        self._init_internal_handlers()
        for key, value in handlers.items():
            self.add_exception_handler(key, value)

    @abc.abstractmethod
    def _init_internal_handlers(self) -> None:
        raise NotImplementedError

    def add_exception_handler(
        self,
        exc_class_or_status_code: Union[int, Type[BaseException]],
        handler: ErrorHandlerType,
    ) -> None:
        if isinstance(exc_class_or_status_code, int):
            self._status_handlers[exc_class_or_status_code] = handler
        else:
            self._exception_handlers[exc_class_or_status_code] = handler

    def lookup_handler(self, exc: BaseException) -> ErrorHandlerType | None:
        handler = None
        if isinstance(exc, HTTPException):
            handler = self._status_handlers.get(exc.status_code)
        if handler is None:
            handler = self._lookup_exception_handler(type(exc))
        return handler

    def _lookup_exception_handler(
        self, exc_type: Type[BaseException]
    ) -> ErrorHandlerType | None:
        for cls in exc_type.__mro__:
            if cls in self._exception_handlers:
                return self._exception_handlers[cls]
        return None