quickshell: keychron mouse battery in bar

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

hosts/FredOS-Gaming.nix

@@ -36,10 +36,13 @@
     # Nova Pro Wireless base station: open up its vendor HID interface so
     # quickshell's ANC switcher can write to it directly (nova-anc script in
     # settings/quickshell.nix). Single-user desktop, 0666 is fine.
+    # Keychron (receiver + wired mouse) likewise for the bar's mouse-battery
+    # readout; also lets the Keychron Launcher's WebHID reach it.
     services.udev.extraRules = ''
       KERNEL=="hidraw*", ATTRS{idVendor}=="1038", ATTRS{idProduct}=="12e0", MODE="0666"
       KERNEL=="hidraw*", ATTRS{idVendor}=="1038", ATTRS{idProduct}=="12e5", MODE="0666"
       KERNEL=="hidraw*", ATTRS{idVendor}=="1038", ATTRS{idProduct}=="225d", MODE="0666"
+      KERNEL=="hidraw*", ATTRS{idVendor}=="3434", MODE="0666"
     '';
 
     # Force heavy builds off the gaming PC onto the media server so nix updates

settings/quickshell.nix

@@ -280,6 +280,45 @@ in
                   sys.exit(0)
           sys.exit(1)
         '';
+        # Keychron mouse battery, straight off the vendor HID interface
+        # (usage page 0xffc1) of the Ultra-Link receiver or a wired mouse.
+        # Report 0xb3 with cmd 0x06 asks for base info; the 0xb4 reply has
+        # battery at data byte 19 (low 7 bits %, bit 7 charging).
+        # Protocol lifted from the Keychron Launcher's WebHID bundle.
+        mouseBatteryScript = pkgs.writeScript "mouse-battery" ''
+          #!${pkgs.python3}/bin/python3
+          """mouse-battery — prints "<pct>" or "<pct> charging"."""
+          import glob, os, select, sys, time
+
+          def iface():
+              for h in glob.glob("/sys/class/hidraw/hidraw*"):
+                  try:
+                      uevent = open(h + "/device/uevent").read()
+                      desc = open(h + "/device/report_descriptor", "rb").read(3)
+                  except OSError:
+                      continue
+                  if ":00003434:" in uevent and desc == b"\x06\xc1\xff":
+                      return "/dev/" + os.path.basename(h)
+              return None
+
+          dev = iface()
+          if not dev:
+              sys.exit(1)
+          fd = os.open(dev, os.O_RDWR)
+          os.write(fd, bytes([0xb3, 0x06]).ljust(64, b"\0"))
+          deadline = time.time() + 1.0
+          while (left := deadline - time.time()) > 0:
+              if not select.select([fd], [], [], left)[0]:
+                  break
+              pkt = os.read(fd, 64)
+              if len(pkt) > 20 and pkt[0] == 0xb4 and pkt[1] == 0x06:
+                  pct = pkt[20] & 0x7f
+                  if pct == 0:
+                      break  # mouse off / asleep
+                  print(f"{pct} charging" if pkt[20] & 0x80 else pct)
+                  sys.exit(0)
+          sys.exit(1)
+        '';
         weatherFetchScript = pkgs.writeShellScript "weather-fetch" ''
           loc=$(${pkgs.curl}/bin/curl -sf --max-time 5 https://ipinfo.io/loc 2>/dev/null || true)
           case "$loc" in
@@ -880,6 +919,7 @@ in
                 readonly property string weatherFetch: "${weatherFetchScript}"
                 readonly property string ssh: "${pkgs.openssh}/bin/ssh"
                 readonly property string novaAnc: "${novaAncScript}"
+                readonly property string mouseBattery: "${mouseBatteryScript}"
                 // Unprivileged ping works via ICMP dgram sockets — NixOS sets
                 // net.ipv4.ping_group_range for everyone (no wrapper exists).
                 readonly property string ping: "${pkgs.iputils}/bin/ping"
@@ -4065,6 +4105,65 @@ in
                     }
                     ''}
 
+                    ${lib.optionalString (!isMacbook) ''
+                    // Wireless mouse battery — polled off the Keychron
+                    // receiver via the mouse-battery script. Hidden while the
+                    // mouse is off/asleep or the receiver is unplugged.
+                    Item {
+                        id: mouseBatWidget
+                        visible: level > 0
+                        width: Theme.barWidth
+                        height: mouseBatCol.height
+
+                        property int level: 0
+                        property bool charging: false
+                        property color tint: charging ? Theme.accent
+                            : level <= 15 ? Theme.err
+                            : level <= 30 ? Theme.warn
+                            : Theme.base05
+
+                        Process {
+                            id: mouseBatProc
+                            command: [Commands.mouseBattery]
+                            stdout: StdioCollector {
+                                onStreamFinished: {
+                                    const f = text.trim().split(" ");
+                                    mouseBatWidget.level = parseInt(f[0]) || 0;
+                                    mouseBatWidget.charging = f[1] === "charging";
+                                }
+                            }
+                        }
+
+                        Timer {
+                            interval: 60000
+                            repeat: true
+                            running: true
+                            triggeredOnStart: true
+                            onTriggered: mouseBatProc.running = true
+                        }
+
+                        Column {
+                            id: mouseBatCol
+                            anchors.horizontalCenter: parent.horizontalCenter
+                            spacing: 0
+
+                            SIcon {
+                                anchors.horizontalCenter: parent.horizontalCenter
+                                text: "mouse"
+                                color: mouseBatWidget.tint
+                                font.pixelSize: 16
+                            }
+
+                            SText {
+                                anchors.horizontalCenter: parent.horizontalCenter
+                                text: mouseBatWidget.level
+                                color: mouseBatWidget.tint
+                                font.pixelSize: 10
+                            }
+                        }
+                    }
+                    ''}
+
                     // Quick settings — present on every host, so the shared
                     // controls sit in the same place on all of them.
                     Item {