"""Lightweight cos monitor for ep_hr02: probe each new ckpt, log step->cos(g_EP,exact-adjoint).
Fire on: cos degrades <0.90 (gradient going bad) / survived to step>=9500 (cleared old danger zone) / death."""
import time, os, re, subprocess, shutil
WD = "/home/yurenh2/ept/ep_run"; os.chdir(WD)
LOG, CK, FROZEN, COSLOG, PID = "runs/ep_hr02.log", "runs/ep_hr02.pt", "runs/ep_hr02_cosprobe.pt", "runs/cos_monitor.log", 1684249
def alive():
    try: os.kill(PID, 0); return True
    except Exception: return False
def cur_step():
    try:
        ls = [l for l in open(LOG) if l.startswith("step")]
        if ls: return int(re.search(r"step (\d+)", ls[-1]).group(1))
    except Exception: pass
    return 0
open(COSLOG, "a").write(f"# cos monitor start (ep_hr02, hr=0.2)\n")
last = -1; fired = None; traj = []; t0 = time.time()
while fired is None and time.time() - t0 < 18 * 3600:
    time.sleep(120)
    if not alive(): fired = f"ep_hr02 EXITED at step {cur_step()}"; break
    step = cur_step()
    if step >= last + 450 and os.path.exists(CK) and os.path.getsize(CK) > 1e6:
        try: shutil.copy2(CK, FROZEN)
        except Exception: continue
        last = step
        env = dict(os.environ, CUDA_VISIBLE_DEVICES="0", PYTORCH_CUDA_ALLOC_CONF="expandable_segments:True")
        cosv, zres = None, "?"
        try:
            r = subprocess.run(["python3", "asym_probe.py", "--ckpt", FROZEN, "--B", "8"],
                               env=env, capture_output=True, text=True, timeout=600)
            out = r.stdout + r.stderr
            m = re.search(r"cos\(g_EP, ?g_transpose\)=([+-][0-9.]+)", out)
            zr = re.search(r"z\* residual.*?step_rel=([0-9.eE+-]+)", out)
            cosv = float(m.group(1)) if m else None
            zres = zr.group(1) if zr else "?"
        except Exception as e:
            zres = f"probe-err:{e}"
        # also grab current val from the training log
        val = "?"
        try: val = re.search(r"val CE ([\d.eE+-]+)", [l for l in open(LOG) if l.startswith("step")][-1]).group(1)
        except Exception: pass
        line = f"step {step}: cos={cosv}  val={val}  z_res={zres}"
        traj.append((step, cosv, val)); open(COSLOG, "a").write(line + "\n"); print(line, flush=True)
        if cosv is not None and cosv < 0.82:   # below the historical per-batch floor (~0.85) => real degradation, not variance
            fired = f"COS DEGRADED to {cosv:.3f} at step {step} (val {val}) — below historical floor, real gradient degradation"; break
        if step >= 9500:
            fired = f"ep_hr02 SURVIVED to step {step} (val {val}) with cos staying high — cleared the old ~9200 danger zone"; break
print("=== COS MONITOR FIRED ==="); print("trigger:", fired or "18h timeout")
print("cos trajectory (step | cos | val):")
for s, c, v in traj: print(f"  {s:6d} | {c} | {v}")