Add thermal throttling alert and improve documentation in SystemMonitor

Author: Ruthie-FRC

photon-core/src/main/java/org/photonvision/common/hardware/metrics/SystemMonitor.java

@@ -20,6 +20,8 @@
 import edu.wpi.first.cscore.CameraServerJNI;
 import edu.wpi.first.networktables.NetworkTable;
 import edu.wpi.first.networktables.ProtobufPublisher;
+import edu.wpi.first.wpilibj.Alert;
+import edu.wpi.first.wpilibj.Alert.AlertType;
 import java.io.IOException;
 import java.nio.file.FileStore;
 import java.nio.file.Files;
@@ -62,6 +64,9 @@ private record NetworkTraffic(double sentBitRate, double recvBitRate) {}
                     .getProtobufTopic(CameraServerJNI.getHostname(), DeviceMetrics.proto)
                     .publish();
 
+    private final Alert thermalThrottlingAlert =
+            new Alert("PhotonAlerts", "Thermal throttling detected!", AlertType.kWarning);
+
     private SystemInfo si;
     private CentralProcessor cpu;
     private OperatingSystem os;
@@ -140,7 +145,7 @@ protected SystemMonitor() {
     }
 
     /**
-     * Returns a comma-separated list of addtional thermal zone types that should be checked to get
+     * Returns a comma-separated list of additional thermal zone types that should be checked to get
      * the CPU temperature on Unix systems. The temperature will be reported for the first temperature
      * zone with a type that matches an item of this list. If the CPU temperature isn't being
      * reported correctly for a coprocessor, override this method to return a string with type
@@ -210,6 +215,8 @@ private void publishMetrics() {
 
         metricPublisher.set(metrics);
 
+        thermalThrottlingAlert.set(this.isThermallyThrottling());
+
         if (writeMetricsToLog) {
             logMetrics(metrics);
         }
@@ -446,6 +453,16 @@ public String getCpuThrottleReason() {
         return "";
     }
 
+    /**
+     * Returns true if the device is currently experiencing thermal throttling. Platforms that support
+     * thermal throttling detection will override this method.
+     *
+     * @return true if thermally throttling, false otherwise.
+     */
+    public boolean isThermallyThrottling() {
+        return false;
+    }
+
     /**
      * Returns the total GPU memory in MiB.
      *
@@ -562,4 +579,4 @@ private double timeIt(StringBuilder sb, Supplier<String> source) {
         sb.append(String.format(" %7.3f ms >> %s\n", delta, resp));
         return delta;
     }
-}
+}