from datetime import datetime
from typing import Optional

from fastapi import HTTPException, Request
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse


class APIException(Exception):
    """Base API Exception"""

    def __init__(
        self,
        status_code: int,
        message: str,
        error_type: Optional[str] = None,
        details: Optional[dict] = None,
    ):
        self.status_code = status_code
        self.message = message
        self.error_type = error_type or self.__class__.__name__
        self.details = details or {}


class UnauthorizedException(APIException):
    """Exception for unauthorized access (401)"""

    def __init__(
        self,
        message: str = "Authentication required",
        details: Optional[dict] = None,
    ):
        super().__init__(
            status_code=401,
            message=message,
            error_type="UnauthorizedException",
            details=details,
        )


async def api_exception_handler(request: Request, exc: APIException) -> JSONResponse:
    """Custom exception handler for APIException"""
    return JSONResponse(
        status_code=exc.status_code,
        content={
            "status_code": exc.status_code,
            "success": False,
            "timestamp": datetime.utcnow().isoformat(),
            "cause": {
                "type": exc.error_type,
                "message": exc.message,
                "details": exc.details,
                "path": str(request.url),
            },
        },
    )


async def unauthorized_exception_handler(
    request: Request, exc: UnauthorizedException
) -> JSONResponse:
    """Handler specifically for 401 Unauthorized errors"""
    return JSONResponse(
        status_code=401,
        content={
            "status_code": 401,
            "success": False,
            "timestamp": datetime.utcnow().isoformat(),
            "cause": {
                "type": "UnauthorizedException",
                "message": exc.message,
                "details": exc.details,
                "path": str(request.url),
            },
        },
        headers={"WWW-Authenticate": "Bearer"},
    )


async def general_exception_handler(request: Request, exc: Exception) -> JSONResponse:
    """Handler for all unhandled exceptions"""
    return JSONResponse(
        status_code=500,
        content={
            "status_code": 500,
            "success": False,
            "timestamp": datetime.utcnow().isoformat(),
            "cause": {
                "type": "InternalServerError",
                "message": "An unexpected error occurred",
                "details": {"original_error": str(exc)},
                "path": str(request.url),
            },
        },
    )


async def http_exception_handler(request: Request, exc: HTTPException) -> JSONResponse:
    """Handler for FastAPI HTTPException"""
    # Special handling for 401 errors
    headers = {}
    if exc.status_code == 401:
        headers["WWW-Authenticate"] = "Bearer"
    
    return JSONResponse(
        status_code=exc.status_code,
        content={
            "status_code": exc.status_code,
            "success": False,
            "timestamp": datetime.utcnow().isoformat(),
            "cause": {
                "type": "HTTPException",
                "message": exc.detail,
                "details": {},
                "path": str(request.url),
            },
        },
        headers=headers,
    )


async def request_validation_exception_handler(
    request: Request, exc: RequestValidationError
) -> JSONResponse:
    """Handler untuk validasi request body (FastAPI/Pydantic)"""
    errors_serializable = []
    for err in exc.errors():
        err_copy = err.copy()
        if "ctx" in err_copy:
            err_copy["ctx"] = {k: str(v) for k, v in err_copy["ctx"].items()}
        errors_serializable.append(err_copy)

    return JSONResponse(
        status_code=422,
        content={
            "status_code": 422,
            "success": False,
            "timestamp": datetime.utcnow().isoformat(),
            "cause": {
                "type": "ValidationError",
                "message": "Validation error",
                "details": {"errors": errors_serializable},
                "path": str(request.url),
            },
        },
    )