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


def register_exception_handlers(app: FastAPI) -> None:
    @app.exception_handler(RequestValidationError)
    async def request_validation_exception_handler(_: Request, exc: RequestValidationError):
        return JSONResponse(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            content={"detail": exc.errors()},
        )

    @app.exception_handler(HTTPException)
    async def http_exception_handler(_: Request, exc: HTTPException):
        # Не ломаем существующие ответы endpoint-ов и прокидываем исходный detail.
        return JSONResponse(
            status_code=exc.status_code,
            content={"detail": exc.detail},
            headers=exc.headers,
        )

    @app.exception_handler(Exception)
    async def unhandled_exception_handler(_: Request, exc: Exception):
        return JSONResponse(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            content={"detail": "внутренняя ошибка сервера"},
        )