Added ECHO cmd and fixed some timing issues

goTool/webui/index.html

@@ -403,6 +403,12 @@
                                   title="ESP-NOW Unicast-Test">
                             Test
                           </button>
+                          <button type="button" class="btn btn-outline-info btn-sm"
+                                  @click="echoPing(c.id)"
+                                  :disabled="busy || !state.uart_connected || !c.available"
+                                  title="ESP-NOW Timestamp-Echo (Round-Trip-Latenz)">
+                            Ping
+                          </button>
                           <button type="button" class="btn btn-outline-info btn-sm"
                                   @click="ledRing({ clientId: c.id })"
                                   :disabled="busy || !state.uart_connected || !c.available"
@@ -640,6 +646,7 @@
         busy: false,
         configMsg: '',
         configMsgOk: false,
+        _flashTimer: null,
         led: {
           mode: 'color',
           r: 0,
@@ -1031,10 +1038,14 @@
             this.busy = false;
           }
         },
-        flash(msg, ok) {
+        flash(msg, ok, durationMs = 5000) {
           this.configMsg = msg;
           this.configMsgOk = ok;
-          setTimeout(() => { this.configMsg = ''; }, 5000);
+          if (this._flashTimer) clearTimeout(this._flashTimer);
+          this._flashTimer = setTimeout(() => {
+            this.configMsg = '';
+            this._flashTimer = null;
+          }, durationMs);
         },
         async setDeadzone(clientId, deadzone, opts = {}) {
           if (deadzone == null || deadzone < 0) {
@@ -1258,6 +1269,43 @@
             this.busy = false;
           }
         },
+        formatMs(v) {
+          return v != null && Number.isFinite(Number(v)) ? Number(v).toFixed(3) : '—';
+        },
+        formatUsAsMs(us) {
+          return us != null && Number.isFinite(Number(us))
+            ? (Number(us) / 1000).toFixed(3)
+            : '—';
+        },
+        async echoPing(clientId) {
+          this.busy = true;
+          try {
+            const r = await fetch('/api/echo-ping', {
+              method: 'POST',
+              headers: { 'Content-Type': 'application/json' },
+              body: JSON.stringify({ client_id: clientId })
+            });
+            const data = await r.json();
+            if (!r.ok) {
+              this.flash(data.error || `Echo-Ping Slave ${clientId} fehlgeschlagen`, false);
+              return;
+            }
+            if (!data.success) {
+              this.flash(`Echo-Ping Slave ${clientId} fehlgeschlagen (${this.formatMs(data.rtt_ms)} ms)`, false);
+              return;
+            }
+            this.flash(
+              `Echo-Ping Slave ${clientId}: Host ${this.formatMs(data.rtt_ms)} ms, ` +
+              `ESP ${this.formatUsAsMs(data.esp_rtt_us)} ms`,
+              true,
+              5000
+            );
+          } catch (e) {
+            this.flash(String(e), false);
+          } finally {
+            this.busy = false;
+          }
+        },
         async restart(clientId = 0) {
           this.busy = true;
           try {