#!/usr/bin/env python3
"""E-02 头阻塞专项台架探针（timeSync 侧，A/B 对照用）。

场景（错误码传播审计.md E-02 的 timeSync 触发形态）：
  1. 一个"挂起"的对时客户端连上 :8888 后不发任何数据（空闲/故障客户端，
     常见工况）——旧固件在此触发 30s 阻塞 net_recv 独占 netTask，
     全体消费者的队列消息停摆最长 30s；
  2. 2s 后从 PC 发起 FTP(:21) 连接，测 banner 到达时延 = 队列响应性：
     修复前 ≈ 25~30s（队头冻结），修复后 ≈ 数百 ms 内；
  3. 34s 时 30s 总预算应已耗尽：设备拆除该连接（修复版落
     "time_sync: no TIME packet in 30s, drop conn" 日志，旧版静默）、
     监听重建，:8888 应能再接受新连接；
  4. 新连接发完整 8 字节 TIME 包 → 设备应落 "wall clock updated"。

用法: python e02_probe.py <run-tag>
退出码: 0 = 队列响应性 PASS；1 = FAIL；2 = 探针自身异常
"""
import socket
import sys
import time

DEV = "192.168.1.100"
tag = sys.argv[1] if len(sys.argv) > 1 else "run"

t0 = time.time()


def log(msg):
    print("[%s] %9.3f %s" % (tag, time.time() - t0, msg), flush=True)


def main():
    # 1. 挂起对时客户端：连接后不发任何数据
    ts = socket.create_connection((DEV, 8888), timeout=5)
    log("time-sync conn open (hung client: sends nothing)")

    # 2. 2s 后测 FTP banner 时延（队列响应性）
    time.sleep(2.0)
    t1 = time.time()
    banner = None
    try:
        ftp = socket.create_connection((DEV, 21), timeout=35)
        banner = ftp.recv(256)
        dt = time.time() - t1
        log("FTP banner after %8.1f ms: %r" % (dt * 1000, banner[:40]))
        ftp.close()
    except Exception as e:
        dt = time.time() - t1
        log("FTP connect FAIL after %8.1f ms: %r" % (dt * 1000, e))
        dt = None
    queue_ok = (banner is not None) and (dt is not None) and (dt < 3.0)
    log("queue responsiveness: %s (banner %s ms)"
        % ("PASS" if queue_ok else "FAIL",
           ("%.0f" % (dt * 1000)) if dt is not None else "n/a"))

    # 3. 等 30s 总预算耗尽（设备应拆除挂起连接、重建监听）
    remain = 34.0 - (time.time() - t0)
    if remain > 0:
        time.sleep(remain)

    # 4. 监听应已重建：新连接可接入，且正常对时路径工作
    t2 = time.time()
    listener_ok = False
    try:
        ts2 = socket.create_connection((DEV, 8888), timeout=5)
        dt2 = time.time() - t2
        epoch = int(time.time())
        log("new time-sync conn in %6.0f ms, sent full TIME packet (epoch=%d)"
            % (dt2 * 1000, epoch))
        ts2.sendall(b"TIME" + epoch.to_bytes(4, "big"))
        time.sleep(1.5)   # 留时间给设备处理并打日志
        ts2.close()
        listener_ok = True
    except Exception as e:
        log("second time-sync conn FAIL: %r" % (e,))
    try:
        ts.close()
    except OSError:
        pass   # 设备已先拆连，本地 close 报 ECONNRESET 属预期
    log("OVERALL: queue=%s listener=%s"
        % ("PASS" if queue_ok else "FAIL", "PASS" if listener_ok else "FAIL"))
    return 0 if (queue_ok and listener_ok) else 1


if __name__ == "__main__":
    try:
        sys.exit(main())
    except Exception as e:
        print("[%s] PROBE ERROR: %r" % (tag, e), flush=True)
        sys.exit(2)