import logging

from fastapi import FastAPI, Request
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse
from sqlalchemy.exc import SQLAlchemyError

from app.core.exceptions import AppError

logger = logging.getLogger(__name__)


def register_exception_handlers(app: FastAPI) -> None:
    """异常注册：把业务异常转换为统一响应格式。"""

    @app.exception_handler(AppError)
    async def handle_app_error(request: Request, exc: AppError) -> JSONResponse:
        logger.warning(
            "business_error code=%s path=%s user_id=%s",
            exc.code,
            request.url.path,
            request.headers.get("X-User-Id"),
        )
        return JSONResponse(
            status_code=exc.status_code,
            content={"code": exc.code, "message": exc.message, "data": None},
        )

    @app.exception_handler(RequestValidationError)
    async def handle_validation_error(request: Request, exc: RequestValidationError) -> JSONResponse:
        logger.warning(
            "validation_error path=%s user_id=%s errors=%s",
            request.url.path,
            request.headers.get("X-User-Id"),
            exc.errors(),
        )
        return JSONResponse(
            status_code=422,
            content={"code": "VALIDATION_ERROR", "message": "request validation failed", "data": {"errors": exc.errors()}},
        )

    @app.exception_handler(SQLAlchemyError)
    async def handle_database_error(request: Request, exc: SQLAlchemyError) -> JSONResponse:
        logger.exception(
            "database_error path=%s user_id=%s",
            request.url.path,
            request.headers.get("X-User-Id"),
        )
        return JSONResponse(
            status_code=500,
            content={"code": "DATABASE_ERROR", "message": "database operation failed", "data": None},
        )

    @app.exception_handler(Exception)
    async def handle_unexpected_error(request: Request, exc: Exception) -> JSONResponse:
        logger.exception(
            "unexpected_error path=%s user_id=%s",
            request.url.path,
            request.headers.get("X-User-Id"),
        )
        return JSONResponse(
            status_code=500,
            content={"code": "INTERNAL_ERROR", "message": "internal server error", "data": None},
        )