#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""ECAT 与 WiFi 两条链路对同一 seq 的 48B STATUS 做逐字节对照。

两条链路读的是 GD32 里同一张 MotorState 表，但读取上下文不同：
  * ECAT 段2 由 buildInput 取表，跑在 PDI_Isr —— 会抢占主循环的写侧（本次修复点）；
  * WiFi 0xC5/buildPayload 与写侧同在主循环 —— 结构上不可能读到中间态。
所以 WiFi 侧可当参照：同一 seq 在两边必须逐字节相同（seq 由 global_seq 唯一确定，
一次更新只产生一个 seq）。不等 ⇒ ECAT 侧那一份是没写完的半成品。

用法: python scripts/probe_ecat_vs_wifi.py [秒数]
"""
import json
import socket
import struct
import sys
import time
import urllib.request

HOST, PORT = "127.0.0.1", 8090
DUR_S = float(sys.argv[1]) if len(sys.argv) > 1 else 60.0
ESP = "192.168.31.127"
REQ = (f"POST /api/motor/state HTTP/1.0\r\nHost: {HOST}:{PORT}\r\n"
       "Content-Type: application/json\r\nContent-Length: 2\r\n"
       "Connection: close\r\n\r\n{}").encode("ascii")


def ecat_once():
    s = socket.create_connection((HOST, PORT))
    try:
        s.sendall(REQ)
        buf = bytearray()
        while True:
            c = s.recv(65536)
            if not c:
                break
            buf.extend(c)
    finally:
        s.close()
    _, _, d = bytes(buf).partition(b"\r\n\r\n")
    return json.loads(d.decode("utf-8", "replace"))


def wifi_once():
    """返回 {node: (seq, 48B)}。协议 ver=2：entry 92B，data 在 +12。"""
    b = urllib.request.urlopen(f"http://{ESP}/motor/state?bin=1", timeout=3).read()
    if len(b) < 12 or struct.unpack_from("<H", b, 0)[0] != 0x4D53 or b[2] != 2:
        return {}
    out, off = {}, 12
    for _ in range(b[9]):
        if off + 92 > len(b):
            break
        out[b[off]] = (struct.unpack_from("<I", b, off + 8)[0],
                       b[off + 12:off + 60])
        off += 92
    return out


def main():
    cache = {}        # node -> {seq: payload}（ECAT 侧见过的每一帧）
    matched = mism = polls = wpolls = 0
    bad = []
    t0 = time.time()
    while time.time() - t0 < DUR_S:
        try:
            snap = ecat_once()
            polls += 1
            for m in snap.get("motors") or []:
                if m.get("online") and m.get("data"):
                    cache.setdefault(m["node"], {})[m["seq"]] = bytes.fromhex(m["data"])
                    if len(cache[m["node"]]) > 4000:
                        for k in sorted(cache[m["node"]])[:2000]:
                            del cache[m["node"]][k]
        except Exception:
            continue
        try:
            w = wifi_once()
            wpolls += 1
        except Exception:
            continue
        for node, (seq, payload) in w.items():
            d = cache.get(node, {}).get(seq)
            if d is None:
                continue          # 该 seq 未被 ECAT 侧采到，跳过
            matched += 1
            if d != payload:
                mism += 1
                bad.append((round(time.time() - t0, 2), node, seq, d.hex(), payload.hex()))
    print(f"轮询 ECAT {polls} 次 / WiFi {wpolls} 次 / {DUR_S:.0f}s")
    print(f"两侧同 seq 可比对 = {matched}   逐字节不一致 = {mism}")
    for t, node, seq, e, w in bad[:6]:
        j = next((i for i in range(48) if e[i] != w[i]), 48)
        print(f"  t={t}s node={node} seq={seq} 首字节差={j}")
        print(f"    ECAT={e}")
        print(f"    WiFi={w}")
    if not matched:
        print("功效不足：ECAT 帧率远高于 WiFi 采样，同 seq 交集为 0，本次判定不作数。")


if __name__ == "__main__":
    main()