Gaze: say why gaze mode can't work yet, and open the calibration whenever it's missing

Turning gaze mode on without a calibration opened Calibrate only on the
off-to-on change, and only if it could open right then. With the headset
off, the eye tracker silent, or the panel not built, or with gaze mode
already on when the gaze service started, nothing opened and nothing said
why: the pointer just stayed a mouse.

- The gaze service now checks every second: gaze mode on, no calibration
  for the tracker in use, eyes seen -> the full calibration opens. One
  that closes unfinished opens again only after the headset comes off and
  on, gaze mode off and on, or Calibrate, so it doesn't loop. A start that
  fails retries every 10 s.
- Its status says why gaze mode can't work yet (checks.problem): not
  calibrated and opening, open, closed unfinished, or can't open and why.
- Input Settings shows that under the Gaze pointer switch, along with the
  gaze service not installed or not running and our tracker missing its
  frame grabber.
- ft-gazectl on notes a missing calibration.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

gaze/gazecheck.py

@@ -17,9 +17,12 @@ directions: look at each one.
           size, and the tracker's error with it, changes with brightness), each the middle and
           a ring of six (SteamVR's tracker) or eight (ours, whose fit goes wrong past its dots)
           RING degrees out, half that in the middle round, turned 20 degrees a round. It opens
-          when gaze mode comes on without a calibration for the tracker in use, and on
-          "calibrate". Frametop's screens hide while it runs. Quitting it while there's still
-          no calibration turns gaze mode off (POINTER_GAZE=0); turning it on again reopens it.
+          whenever gaze mode is on without a calibration for the tracker in use and someone's
+          in the headset, and on "calibrate". One that closes unfinished (ignored, too few
+          dots) opens again only once the headset comes off and on, or gaze mode off and on.
+          Frametop's screens hide while it runs. Quitting it while there's still no
+          calibration turns gaze mode off (POINTER_GAZE=0); turning it on again reopens it.
+          Why gaze mode can't work yet goes in the status ("problem"), for Input Settings.
 
   fit     the headset fit check (on "fitcheck", Check headset fit on the Gaze page): live, a
           card per eye (tracked or lost, the tracker's signal, how much of the last 10 s it was
@@ -90,6 +93,7 @@ ROUND_BG = (0.03, 0.33, 0.8)
 ROUND_NAMES = ("dark", "medium", "bright")
 RING_SCALE = (1.0, 0.5, 1.0)
 PANEL_RETRY = 10.0
+FULL_RETRY = 10.0      # seconds before an automatic calibration that failed to start tries again
 FIT_TIMEOUT = 300.0    # seconds the fit check stays up
 FIT_EVERY = 0.5        # seconds between its cards' updates (each is a new picture for the panel)
 FIT_HINT_WIDTH = 95    # characters a hint line holds in the panel
@@ -167,7 +171,9 @@ class Checks:
         self.check = None
         self.gaze_on = None
         self.gaze_heard = 0.0
-        self.want_full_until = 0.0  # gaze mode came on before the tracker said whether it's calibrated
+        self.full_armed = True    # gaze mode on without a calibration opens the full one (need_full)
+        self.full_blocked = None  # why it can't open now
+        self.full_retry_at = 0.0
         self.last_quick = 0.0
         self.sample_at = 0.0     # the tracker last sent anything
         self.seen_at = 0.0       # eyes last seen (SteamVR's tracker's variance for them, "unc")
@@ -282,11 +288,47 @@ class Checks:
         return self.eyes_seen() and time.monotonic() - self.svc.last_sample < 2
 
     def on_gaze_on(self):
+        self.full_armed = True
+        self.need_full("gaze mode came on without a calibration")
+
+    def need_full(self, reason):
+        """Gaze mode is on without a calibration: open the full one, once per arming (see the top),
+        or note why it can't open."""
         cal = self.calibrated()
-        if cal is False:
-            self.start("full", "gaze mode came on without a calibration")
-        elif cal is None:
-            self.want_full_until = time.monotonic() + 20
+        if cal:
+            self.full_armed = True  # missing one later (the other tracker picked) is news again
+        if not self.gaze_on or self.check or not self.full_armed or cal is not False:
+            self.full_blocked = None
+            return
+        now = time.monotonic()
+        if not self.can_run():
+            why = ("the eye tracker isn't sending" if now - self.svc.last_sample >= 2
+                   else "no eyes seen (is the headset on?)")
+        elif now < self.full_retry_at:
+            return
+        else:
+            reply = self.start("full", reason)
+            why = None if reply == "ok" else reply.removeprefix("error ")
+            if why:
+                self.full_retry_at = now + FULL_RETRY
+        if why and why != self.full_blocked:
+            log(f"the calibration can't open: {why}")
+        self.full_blocked = why
+        if not why:
+            self.full_armed = False
+
+    def problem(self):
+        """Why gaze mode, on, can't follow your eyes yet, or None. Our tracker not having said
+        yet is None: Input Settings has its own line for our tracker."""
+        if not self.gaze_on or self.calibrated() is not False:
+            return None
+        if self.check and self.check["kind"] == "full":
+            return "Not calibrated yet: the calibration is open in the headset"
+        if self.full_blocked:
+            return f"Not calibrated, and the calibration can't open: {self.full_blocked}"
+        if not self.full_armed:
+            return "Not calibrated: the calibration closed unfinished. Use Calibrate"
+        return "Not calibrated: the calibration opens in the headset"
 
     def auto_quick(self, reason):
         now = time.monotonic()
@@ -703,18 +745,13 @@ class Checks:
             self.gaze_on = None  # the helper isn't answering
         if self.check:
             self.to_helper("calpanel 1")
-        if self.want_full_until:
-            cal = self.calibrated()
-            if cal is not None or now > self.want_full_until:
-                self.want_full_until = 0.0
-                if cal is False and self.gaze_on:
-                    self.start("full", "gaze mode came on without a calibration")
         if not self.eyes_seen(AWAY_MIN):
             self.away, self.back_since = True, None
         elif self.back_since is not None and not self.eyes_seen():
             self.back_since = None  # gone again before DON_DELAY
         elif self.back_since is not None and now - self.back_since >= DON_DELAY:
             self.away, self.back_since = False, None
+            self.full_armed = True  # a calibration that closed unfinished opens again
             self.auto_quick("the headset went on")
         if svc.kind == "own" and now - svc.own_at < 5:
             reseat = any(e.get("reseat") for e in (svc.own.get("eyes") or {}).values())
@@ -723,10 +760,12 @@ class Checks:
             elif not self.reseat_seen and self.can_run():
                 self.reseat_seen = True
                 self.auto_quick("our tracker asked for a click")
+        self.need_full("gaze mode is on without a calibration")
 
     def status(self):
         c = self.check
         st = {"check": None, "gaze_mode": self.gaze_on, "calibrated": self.calibrated(), "eyes": self.eyes_seen(),
+              "problem": self.problem(),
               "panel": self.panel_proc is not None,
               "last_quick_s": round(time.monotonic() - self.last_quick) if self.last_quick else None}
         if c: