"""
HTTP 中间件：request_id 注入。
"""

import uuid

from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request

from app.core.logging import logger
from app.core.telemetry import current_trace_context


class RequestIdMiddleware(BaseHTTPMiddleware):
    """Inject request_id into request.state and response headers, bind to loguru context."""

    async def dispatch(self, request: Request, call_next):
        request_id = request.headers.get("X-Request-ID") or str(uuid.uuid4())
        request.state.request_id = request_id

        bind = {"request_id": request_id, **current_trace_context()}
        with logger.contextualize(**bind):
            response = await call_next(request)

        response.headers["X-Request-ID"] = request_id
        return response