Added ECHO cmd and fixed some timing issues

goTool/api_serve.go

@@ -41,6 +41,19 @@ type unicastAPIResponse struct {
 	Error   string `json:"error,omitempty"`
 }
 
+type echoPingAPIRequest struct {
+	ClientID uint32 `json:"client_id"`
+}
+
+type echoPingAPIResponse struct {
+	Success     bool    `json:"success"`
+	ClientID    uint32  `json:"client_id,omitempty"`
+	TimestampUs uint64  `json:"timestamp_us,omitempty"`
+	RttMs       float64 `json:"rtt_ms"`
+	EspRttUs    uint32  `json:"esp_rtt_us"`
+	Error       string  `json:"error,omitempty"`
+}
+
 type findMeAPIRequest struct {
 	ClientID uint32 `json:"client_id"`
 }
@@ -91,6 +104,13 @@ func mountServeAPI(mux *http.ServeMux, link *managedSerial, hub *wsHub, streamCt
 		}
 		serveUnicastTest(w, r, link)
 	})
+	mux.HandleFunc("/api/echo-ping", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		serveEchoPing(w, r, link)
+	})
 	mux.HandleFunc("/api/find-me", func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodPost {
 			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
@@ -316,6 +336,30 @@ func serveUnicastTest(w http.ResponseWriter, r *http.Request, link *managedSeria
 	})
 }
 
+func serveEchoPing(w http.ResponseWriter, r *http.Request, link *managedSerial) {
+	var body echoPingAPIRequest
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeJSON(w, http.StatusBadRequest, echoPingAPIResponse{Error: "invalid JSON"})
+		return
+	}
+	if body.ClientID == 0 {
+		writeJSON(w, http.StatusBadRequest, echoPingAPIResponse{Error: "client_id required"})
+		return
+	}
+	result, err := link.EchoPing(body.ClientID)
+	if err != nil {
+		writeJSON(w, http.StatusServiceUnavailable, echoPingAPIResponse{Error: err.Error()})
+		return
+	}
+	writeJSON(w, http.StatusOK, echoPingAPIResponse{
+		Success:     result.Success,
+		ClientID:    result.ClientID,
+		TimestampUs: result.TimestampUs,
+		RttMs:       result.RttMs,
+		EspRttUs:    result.EspRttUs,
+	})
+}
+
 func parseUintQuery(r *http.Request, key string, def uint32) (uint32, error) {
 	s := r.URL.Query().Get(key)
 	if s == "" {