"""HTTP 访问日志与转发内容摘要（可配置是否打出正文预览）。"""

from __future__ import annotations

import logging
import os
import time
from collections.abc import Callable
from typing import Any

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

access_logger = logging.getLogger("tg_bridge.access")


def log_preview_max_chars() -> int:
    """环境变量 BRIDGE_LOG_PREVIEW_CHARS：>0 时在业务日志中附带截断后的正文/回复预览；未设置或 0 则只打长度。"""
    raw = os.environ.get("BRIDGE_LOG_PREVIEW_CHARS", "").strip()
    if not raw:
        return 0
    try:
        return max(0, int(raw))
    except ValueError:
        return 0


def preview_for_log(text: str | None, max_chars: int) -> str:
    if not text or max_chars <= 0:
        return ""
    s = text.replace("\r", "").replace("\n", "\\n")
    if len(s) <= max_chars:
        return s
    return s[:max_chars] + "..."


class AccessLogMiddleware(BaseHTTPMiddleware):
    """记录每条 HTTP 请求的方法、路径、状态码与耗时（不含鉴权头与 Body）。"""

    async def dispatch(self, request: Request, call_next: Callable[[Request], Any]) -> Response:
        start = time.perf_counter()
        client = request.client.host if request.client else "-"
        path = request.url.path
        method = request.method
        try:
            response = await call_next(request)
        except Exception:
            elapsed_ms = (time.perf_counter() - start) * 1000
            access_logger.exception(
                '%s "%s %s" 未捕获异常 %.1fms',
                client,
                method,
                path,
                elapsed_ms,
            )
            raise
        elapsed_ms = (time.perf_counter() - start) * 1000
        access_logger.info(
            '%s "%s %s" %s %.1fms',
            client,
            method,
            path,
            response.status_code,
            elapsed_ms,
        )
        return response