Unify Signals/Channels around auto-naming, plot-by-channel, and shared vars

Devices: auto-name from OS-reported port description (Device Manager /
udev string) instead of a generic label; default Serial #Channels 1;
consistent simulate-mode checkbox across backends; inline device rename.

Channels: calibration/filters move out of Signals into a Channel
"Operation" (adds Scale/Offset alongside the existing math kinds);
single-physical-source Channels get an embedded Filters block; new
Channels auto-name/auto-ID from their source and reject duplicate
names/IDs on apply; "Create Channel" button on each Signal row; renamed
"Sources" -> "Signals" in the Channels UI; Signals' READ/WRITE dir badge
(was silently-broken IN/OUT) now reflects the real writable flag.

Plot: default layout is one pane per Channel (not per device, not raw
Signals) titled by channel name; "+ Add Channel" is a checkbox dialog
instead of an inline dropdown; traces get up/down reorder; live unit
changes (e.g. a Mark-10 gauge switching lb/kgF/N/ozF) propagate to an
open pane's axis label without clobbering a manually-typed one.

Control Panel: hardware assignment now picks from the same writable-
Signals list instead of a separate device/channel combo with a
hardcoded Arduino pin list; stale visual indicator when a control's
target device/channel disconnects or disappears; documented the `vars`
bridge (Control Panel On Action Script <-> Channel scripts) in both
directions' help text and script templates.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 40 insertions, 1 deletions

diff --git a/ui/control_panel.py b/ui/control_panel.py
index 3499a44..adf48e6 100644
--- a/ui/control_panel.py
+++ b/ui/control_panel.py
@@ -88,6 +88,8 @@ class ControlWidget(QFrame):
             self._compile_action(on_action_script)
         self.setObjectName("controlWidget")
         self._build_frame()
+        self._stale = None
+        self._check_stale()
 
     def _compile_action(self, script: str):
         try:
@@ -96,6 +98,31 @@ class ControlWidget(QFrame):
         except SyntaxError as e:
             print(f"[Control '{self.title}'] script syntax error: {e}")
 
+    def _check_stale(self):
+        """Re-evaluate whether this control's target signal is currently
+        reachable — unbound controls (no device/channel assigned) are never
+        stale, only ones pointing at a signal that's since gone missing."""
+        stale = False
+        if self.device_id and self.channel_id:
+            dev = self.registry.get_instance(self.device_id) if self.registry else None
+            if dev is None:
+                stale = True
+            else:
+                ch = dev.get_channel(self.channel_id)
+                if ch is None or not ch.enabled:
+                    stale = True
+                elif dev.status not in (DeviceStatus.CONNECTED, DeviceStatus.SIMULATED):
+                    stale = True
+        self._set_stale(stale)
+
+    def _set_stale(self, stale: bool):
+        if self._stale == stale:
+            return
+        self._stale = stale
+        self._stale_lbl.setVisible(stale)
+        self.setProperty("stale", "true" if stale else "false")
+        self.style().unpolish(self); self.style().polish(self)
+
     def _logic_level(self, enabled: bool) -> float:
         """Map logical ON/OFF to electrical level, respecting active-low outputs."""
         if self.active_low:
@@ -123,6 +150,11 @@ class ControlWidget(QFrame):
         title_lbl.setAttribute(Qt.WidgetAttribute.WA_TransparentForMouseEvents)
         hdr_lay.addWidget(icon_lbl)
         hdr_lay.addWidget(title_lbl, 1)
+        self._stale_lbl = QLabel("⚠")
+        self._stale_lbl.setObjectName("controlWidgetStale")
+        self._stale_lbl.setToolTip("Target signal not connected")
+        self._stale_lbl.setVisible(False)
+        hdr_lay.addWidget(self._stale_lbl)
         self._header        = hdr
         self._header_layout = hdr_lay
         outer.addWidget(hdr)
@@ -635,13 +667,20 @@ class ControlPanel(QWidget):
 
     controls_changed = pyqtSignal()   # emitted whenever widgets are added/edited/removed
 
-    def __init__(self, registry: DeviceRegistry, processor=None):
+    def __init__(self, registry: DeviceRegistry, processor=None, engine=None):
         super().__init__()
         self.registry  = registry
         self.processor = processor
+        self.engine    = engine
         self._widgets:  list[ControlWidget] = []
         self._specs:    list = []   # parallel list of ControlSpec
         self._build()
+        if engine is not None:
+            engine.device_status_changed.connect(self._on_device_status_changed)
+
+    def _on_device_status_changed(self, device_id: str, status: str):
+        for w in self._widgets:
+            w._check_stale()
 
     # ── Layout ───────────────────────────────────────────────────────────────