"""Fast title probe: a PERIODICALLY RESTARTED x11grab stream + glyph count.

🔴 DO NOT run one x11grab stream for the whole session. Measured 2026-08-29: a
single long-lived stream degrades from 3.98 fps to 1.60 fps and then FREEZES,
reporting a stale frame indefinitely. Cross-checked at one moment against an
independent `import` grab: the stream said surface mean 5.21 while `import` said
125.65, and the stream repeated that same value for four consecutive 30 s marks.
Any negative result from a stalled stream is worthless -- an earlier "2391
frames, zero hits" claim came from exactly that failure.

So the stream is torn down and restarted every RESTART_S seconds. Startup costs
~0.3 s, which is cheap against the title's few-second window and buys a
guarantee that the frames are live.

Replaces the two-`screenshot` polling loop, which costs ~4-11 s per grab while
xenia runs and so samples every ~41 s -- slower than the title screen lasts.
Counter is byte-identical to is_title.py (controlled: 753 on the committed title
capture, 327 on the main menu).
"""
import subprocess, sys, time
import numpy as np
W,H = 1280,720
LIMIT = float(sys.argv[1]) if len(sys.argv)>1 else 120
NEED  = int(sys.argv[2]) if len(sys.argv)>2 else 400
RESTART_S = 30          # tear down and restart the stream this often
def _open():
    return subprocess.Popen(["ffmpeg","-loglevel","error","-f","x11grab","-draw_mouse","0",
        "-video_size",f"{W}x{H}","-i",":98","-r","4","-f","rawvideo","-pix_fmt","rgb24","-"],
        stdout=subprocess.PIPE, bufsize=W*H*3*2)
p=_open()
n=W*H*3; t0=time.time(); frames=0; best=0; hits=0; seg=time.time()
while time.time()-t0 < LIMIT:
    if time.time()-seg > RESTART_S:      # a stalled stream reports stale frames forever
        p.kill(); p=_open(); seg=time.time()
    buf=p.stdout.read(n)
    if len(buf)<n:
        p.kill(); p=_open(); seg=time.time(); continue
    a=np.frombuffer(buf,np.uint8).reshape(H,W,3).astype(int)
    r,g,b=a[:,:,0],a[:,:,1],a[:,:,2]
    c=int(((g>130)&(g-r>45)&(g-b>45)).sum())
    frames+=1
    if c>best:
        best=c
        if c>=NEED:
            from PIL import Image
            Image.fromarray(a.astype(np.uint8)).save("/sylph-home/re/shots/fast-title.png")
    if c>=NEED:
        hits+=1
        if hits==1: print(f"TITLE at t={time.time()-t0:.1f}s glyph={c} (frame {frames})", flush=True)
p.kill()
dt=time.time()-t0
print(f"{frames} frames in {dt:.1f}s = {frames/dt:.2f} fps; max glyph {best}; hits {hits}")