"""真人拖动轨迹监视器：等 rmc iframe 出现后 attach，每 0.5s 快照
window.__dragTrace / __lastVerify 到 /tmp，iframe 销毁（验证通过）后保留最后快照退出。"""
import asyncio, json, time, urllib.request as ur
import websockets


def _json(path):
    try:
        with ur.urlopen(f"http://127.0.0.1:9222{path}", timeout=5) as r:
            return json.load(r)
    except (OSError, ValueError):
        return None


async def main():
    ver = _json("/json/version")
    if not ver or not ver.get("webSocketDebuggerUrl"):
        print("CDP 不可达，退出")
        return
    # 等待验证码 iframe 出现（最多 180s）
    ifr = None
    for _ in range(60):
        targets = _json("/json/list") or []
        ifr = next((t for t in targets if "rmc.bytedance.com" in t.get("url", "")), None)
        if ifr:
            break
        await asyncio.sleep(3)
    if not ifr:
        print("无 iframe，退出")
        return
    async with websockets.connect(ver["webSocketDebuggerUrl"], max_size=64 * 1024 * 1024) as ws:
        mid = [0]

        async def cdp(method, params=None, sid=None):
            mid[0] += 1
            m = {"id": mid[0], "method": method, "params": params or {}}
            if sid:
                m["sessionId"] = sid
            await ws.send(json.dumps(m))
            while True:
                try:
                    r = json.loads(await ws.recv())
                except (json.JSONDecodeError, asyncio.TimeoutError):
                    continue
                if r.get("id") == mid[0]:
                    if "error" in r:
                        raise RuntimeError(str(r["error"]))
                    return r.get("result", {})

        isid = (await cdp("Target.attachToTarget", {"targetId": ifr["id"], "flatten": True}))["sessionId"]
        await cdp("Runtime.enable", sid=isid)
        print("trace_watch 就绪", flush=True)
        last_len = -1
        while True:
            try:
                r = await cdp("Runtime.evaluate", {
                    "expression": "JSON.stringify({n:(window.__dragTrace||[]).length,"
                                  "trace:window.__dragTrace||null,v:window.__lastVerify||null})",
                    "returnByValue": True}, sid=isid)
                val = r.get("result", {}).get("value")
                if val:
                    d = json.loads(val)
                    if d["n"] != last_len:
                        last_len = d["n"]
                        with open("/tmp/trace_snap.json", "w") as f:
                            json.dump(d, f)
                        if d["v"]:
                            with open("/tmp/verify_snap.txt", "w") as f:
                                f.write(d["v"])
                        print(f"[{time.strftime('%H:%M:%S')}] {d['n']} 事件", flush=True)
                await asyncio.sleep(0.5)
            except (RuntimeError, websockets.exceptions.ConnectionClosed, OSError):
                print("iframe 已销毁，保留最后快照退出", flush=True)
                return


asyncio.run(main())