from rest_framework.views import exception_handler
from rest_framework.response import Response
from rest_framework import status
import logging
import traceback

from django.conf import settings

logger = logging.getLogger('django.request')


def custom_exception_handler(exc, context):
    """
    统一异常处理：所有错误写入终端日志（logger），生产环境响应不泄露细节。
    """
    response = exception_handler(exc, context)
    request = context.get('request')
    path = getattr(request, 'path', 'unknown')
    method = getattr(request, 'method', 'unknown')
    user = request.user if request else None
    user_info = f"用户: {user.id if user and user.is_authenticated else '未登录'}"

    if response is not None:
        logger.error(
            'API异常 path=%s method=%s %s status=%s error=%s',
            path, method, user_info, response.status_code, exc,
            exc_info=exc,
        )
        if settings.DEBUG:
            return response
        error_messages = {
            status.HTTP_400_BAD_REQUEST: {'code': 400, 'message': '请求参数错误'},
            status.HTTP_401_UNAUTHORIZED: {'code': 401, 'message': '请先登录'},
            status.HTTP_403_FORBIDDEN: {'code': 403, 'message': '权限不足'},
            status.HTTP_404_NOT_FOUND: {'code': 404, 'message': '资源不存在'},
            status.HTTP_405_METHOD_NOT_ALLOWED: {'code': 405, 'message': '请求方法不允许'},
            status.HTTP_408_REQUEST_TIMEOUT: {'code': 408, 'message': '请求超时'},
            status.HTTP_429_TOO_MANY_REQUESTS: {'code': 429, 'message': '请求过于频繁'},
            status.HTTP_500_INTERNAL_SERVER_ERROR: {'code': 500, 'message': '服务器内部错误'},
            status.HTTP_502_BAD_GATEWAY: {'code': 502, 'message': '网关错误'},
            status.HTTP_503_SERVICE_UNAVAILABLE: {'code': 503, 'message': '服务暂不可用'},
            status.HTTP_504_GATEWAY_TIMEOUT: {'code': 504, 'message': '网关超时'},
        }
        standard_response = error_messages.get(
            response.status_code,
            {'code': response.status_code, 'message': '请求错误'},
        )
        return Response(standard_response, status=response.status_code)

    # DRF 未处理的异常（数据库字段缺失、AttributeError 等）→ 500 且无日志是常见问题
    logger.error(
        '未处理API异常 path=%s method=%s %s error=%s traceback=%s',
        path,
        method,
        user_info,
        exc,
        traceback.format_exc(),
    )
    if settings.DEBUG:
        return Response(
            {'code': 500, 'message': str(exc), 'detail': traceback.format_exc()},
            status=status.HTTP_500_INTERNAL_SERVER_ERROR,
        )
    return Response(
        {'code': 500, 'message': '服务器内部错误'},
        status=status.HTTP_500_INTERNAL_SERVER_ERROR,
    )