add signal strength indicator dot to all systems table

internal/site/src/lib/wifi.test.ts

@@ -1,5 +1,6 @@
 import { expect, test } from "bun:test"
-import { connectedWiFi, strongestWiFiSignal, wifiColor } from "./wifi"
+import { MeterState } from "@/lib/enums"
+import { connectedWiFi, strongestWiFiSignal, wifiColor, wifiSignalState } from "./wifi"
 import type { SystemInfo } from "@/types"
 
 const system = (wf?: SystemInfo["wf"], status: "up" | "down" = "up") => ({ status, info: { wf } as SystemInfo })
@@ -26,3 +27,11 @@ test("strongestWiFiSignal returns the strongest current native RSSI", () => {
 	expect(strongestWiFiSignal(system({ wlan0: {} }))).toBeUndefined()
 	expect(strongestWiFiSignal(system({ wlan0: { r: -48 } }, "down"))).toBeUndefined()
 })
+
+test("wifiSignalState thresholds", () => {
+	expect(wifiSignalState(-40)).toBe(MeterState.Good)
+	expect(wifiSignalState(-65)).toBe(MeterState.Good)
+	expect(wifiSignalState(-66)).toBe(MeterState.Warn)
+	expect(wifiSignalState(-75)).toBe(MeterState.Warn)
+	expect(wifiSignalState(-76)).toBe(MeterState.Crit)
+})

internal/site/src/lib/wifi.ts

@@ -1,3 +1,4 @@
+import { MeterState } from "@/lib/enums"
 import type { SystemRecord, WiFi } from "@/types"
 
 // Current system info is independent of the selected historical chart window.
@@ -21,6 +22,11 @@ export function strongestWiFiSignal(system: Pick<SystemRecord, "status" | "info"
 	return strongestWiFi(connectedWiFi(system))?.[1].r
 }
 
+/** Signal quality for an RSSI reading: good at -65 dBm or stronger, warn down to -75 dBm, crit below. */
+export function wifiSignalState(rssi: number): MeterState {
+	return rssi >= -65 ? MeterState.Good : rssi >= -75 ? MeterState.Warn : MeterState.Crit
+}
+
 export function wifiColor(id: string): string {
 	let hash = 0
 	for (const char of id) hash = (Math.imul(hash, 31) + char.charCodeAt(0)) | 0