import traceback
from functools import wraps
from typing import Any, Callable, TypeVar

from fastapi import FastAPI, HTTPException, Request, Response, status
from fastapi.responses import JSONResponse
from sqlalchemy.exc import SQLAlchemyError

from app.utils.logger import get_logger

# 로거 설정
logger = get_logger("core")

T = TypeVar("T")


class FastShipError(Exception):
    """Base exception for all exceptions in fastship api"""
    # status_code to be returned for this exception
    # when it is handled
    status = status.HTTP_400_BAD_REQUEST


class EntityNotFound(FastShipError):
    """Entity not found in database"""

    status = status.HTTP_404_NOT_FOUND


class BadPassword(FastShipError):
    """Password is not strong enough or invalid"""

    status = status.HTTP_400_BAD_REQUEST


class ClientNotAuthorized(FastShipError):
    """Client is not authorized to perform the action"""

    status = status.HTTP_401_UNAUTHORIZED


class ClientNotVerified(FastShipError):
    """Client is not verified"""

    status = status.HTTP_401_UNAUTHORIZED


class NothingToUpdate(FastShipError):
    """No data provided to update"""


class BadCredentials(FastShipError):
    """User email or password is incorrect"""

    status = status.HTTP_401_UNAUTHORIZED


class InvalidToken(FastShipError):
    """Access token is invalid or expired"""

    status = status.HTTP_401_UNAUTHORIZED


class DeliveryPartnerNotAvailable(FastShipError):
    """Delivery partner/s do not service the destination"""

    status = status.HTTP_406_NOT_ACCEPTABLE


class DeliveryPartnerCapacityExceeded(FastShipError):
    """Delivery partner has reached their max handling capacity"""

    status = status.HTTP_406_NOT_ACCEPTABLE


# =============================================================================
# 데이터베이스 관련 예외
# =============================================================================


class DatabaseError(FastShipError):
    """Database operation failed"""

    status = status.HTTP_503_SERVICE_UNAVAILABLE


class DatabaseConnectionError(DatabaseError):
    """Database connection failed"""

    status = status.HTTP_503_SERVICE_UNAVAILABLE


class DatabaseTimeoutError(DatabaseError):
    """Database operation timed out"""

    status = status.HTTP_504_GATEWAY_TIMEOUT


# =============================================================================
# 외부 서비스 관련 예외
# =============================================================================


class ExternalServiceError(FastShipError):
    """External service call failed"""

    status = status.HTTP_502_BAD_GATEWAY


class GPTServiceError(ExternalServiceError):
    """GPT API call failed"""

    status = status.HTTP_502_BAD_GATEWAY


class CrawlingError(ExternalServiceError):
    """Web crawling failed"""

    status = status.HTTP_502_BAD_GATEWAY


class BlobStorageError(ExternalServiceError):
    """Azure Blob Storage operation failed"""

    status = status.HTTP_502_BAD_GATEWAY


class CreatomateError(ExternalServiceError):
    """Creatomate API call failed"""

    status = status.HTTP_502_BAD_GATEWAY


# =============================================================================
# 예외 처리 데코레이터
# =============================================================================


def handle_db_exceptions(
    error_message: str = "데이터베이스 작업 중 오류가 발생했습니다.",
):
    """데이터베이스 예외를 처리하는 데코레이터.

    Args:
        error_message: 오류 발생 시 반환할 메시지

    Example:
        @handle_db_exceptions("사용자 조회 중 오류 발생")
        async def get_user(user_id: int):
            ...
    """

    def decorator(func: Callable[..., Any]) -> Callable[..., Any]:
        @wraps(func)
        async def wrapper(*args: Any, **kwargs: Any) -> Any:
            try:
                return await func(*args, **kwargs)
            except HTTPException:
                # HTTPException은 그대로 raise
                raise
            except SQLAlchemyError as e:
                logger.error(f"[DB Error] {func.__name__}: {e}")
                logger.debug(traceback.format_exc())
                raise HTTPException(
                    status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
                    detail=error_message,
                )
            except Exception as e:
                logger.error(f"[Unexpected Error] {func.__name__}: {e}")
                logger.debug(traceback.format_exc())
                raise HTTPException(
                    status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                    detail="서비스 처리 중 예기치 않은 오류가 발생했습니다.",
                )

        return wrapper

    return decorator


def handle_external_service_exceptions(
    service_name: str = "외부 서비스",
    error_message: str | None = None,
):
    """외부 서비스 호출 예외를 처리하는 데코레이터.

    Args:
        service_name: 서비스 이름 (로그용)
        error_message: 오류 발생 시 반환할 메시지

    Example:
        @handle_external_service_exceptions("GPT")
        async def call_gpt():
            ...
    """

    def decorator(func: Callable[..., Any]) -> Callable[..., Any]:
        @wraps(func)
        async def wrapper(*args: Any, **kwargs: Any) -> Any:
            try:
                return await func(*args, **kwargs)
            except HTTPException:
                raise
            except Exception as e:
                msg = error_message or f"{service_name} 서비스 호출 중 오류가 발생했습니다."
                logger.error(f"[{service_name} Error] {func.__name__}: {e}")
                logger.debug(traceback.format_exc())
                raise HTTPException(
                    status_code=status.HTTP_502_BAD_GATEWAY,
                    detail=msg,
                )

        return wrapper

    return decorator


def handle_api_exceptions(
    error_message: str = "요청 처리 중 오류가 발생했습니다.",
):
    """API 엔드포인트 예외를 처리하는 데코레이터.

    Args:
        error_message: 오류 발생 시 반환할 메시지

    Example:
        @handle_api_exceptions("가사 생성 중 오류 발생")
        async def generate_lyric():
            ...
    """

    def decorator(func: Callable[..., Any]) -> Callable[..., Any]:
        @wraps(func)
        async def wrapper(*args: Any, **kwargs: Any) -> Any:
            try:
                return await func(*args, **kwargs)
            except HTTPException:
                raise
            except SQLAlchemyError as e:
                logger.error(f"[API DB Error] {func.__name__}: {e}")
                logger.debug(traceback.format_exc())
                raise HTTPException(
                    status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
                    detail="데이터베이스 연결에 문제가 발생했습니다.",
                )
            except Exception as e:
                logger.error(f"[API Error] {func.__name__}: {e}")
                logger.debug(traceback.format_exc())
                raise HTTPException(
                    status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                    detail=error_message,
                )

        return wrapper

    return decorator


def _get_handler(status: int, detail: str):
    # Define
    def handler(request: Request, exception: Exception) -> Response:
        logger.debug(f"Handled Exception: {exception.__class__.__name__}")

        # Raise HTTPException with given status and detail
        # can return JSONResponse as well
        raise HTTPException(
            status_code=status,
            detail=detail,
        )
    # Return ExceptionHandler required with given
    # status and detail for HTTPExcetion above
    return handler


def add_exception_handlers(app: FastAPI):
    # Get all subclass of 👇, our custom exceptions
    exception_classes = FastShipError.__subclasses__()

    for exception_class in exception_classes:
        # Add exception handler
        app.add_exception_handler(
            # Custom exception class
            exception_class,
            # Get handler function
            _get_handler(
                status=exception_class.status,
                detail=exception_class.__doc__,
            ),
        )

    # SocialException 핸들러 추가
    from app.social.exceptions import SocialException

    @app.exception_handler(SocialException)
    def social_exception_handler(request: Request, exc: SocialException) -> Response:
        logger.debug(f"Handled SocialException: {exc.__class__.__name__} - {exc.message}")
        return JSONResponse(
            status_code=exc.status_code,
            content={
                "detail": exc.message,
                "code": exc.code,
            },
        )

    @app.exception_handler(status.HTTP_500_INTERNAL_SERVER_ERROR)
    def internal_server_error_handler(request, exception):
        return JSONResponse(
            content={"detail": "Something went wrong..."},
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            headers={
                "X-Error": f"{exception}",
            }
        )