Improving all side of app

internal/server/ws.go

@@ -34,6 +34,9 @@ type inMsg struct {
 	Name  string          `json:"name,omitempty"`
 	Value json.RawMessage `json:"value,omitempty"`
 
+	// dialogResponse — id of the control-logic dialog being answered.
+	ID string `json:"id,omitempty"`
+
 	// history
 	Start     time.Time `json:"start"`
 	End       time.Time `json:"end"`
@@ -101,6 +104,8 @@ type wsHandler struct {
 	policy *access.Policy
 	// audit records signal writes (never nil; audit.Nop when disabled).
 	audit audit.Recorder
+	// dialogs fans control-logic dialogs to clients and routes responses.
+	dialogs *DialogHub
 }
 
 func (h *wsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -143,12 +148,19 @@ func (h *wsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		ip:       clientIP,
 		policy:   h.policy,
 		audit:    rec,
+		dialogs:  h.dialogs,
 		outCh:    make(chan []byte, 512),
 		updateCh: make(chan broker.Update, 1024),
 		subs:     make(map[broker.SignalRef]func()),
 		log:      h.log,
 	}
 
+	// Register for control-logic dialog pushes for this client's identity.
+	if h.dialogs != nil {
+		h.dialogs.add(c)
+		defer h.dialogs.remove(c)
+	}
+
 	var wg sync.WaitGroup
 	wg.Add(3)
 	go func() { defer wg.Done(); c.readLoop(ctx, cancel) }()
@@ -174,8 +186,9 @@ type wsClient struct {
 	log    *slog.Logger
 	user   string         // end-user identity from the trusted proxy header ("" if none)
 	ip     string         // client address, for audit attribution
-	policy *access.Policy // global access-level enforcement
-	audit  audit.Recorder // signal-write audit recorder (never nil)
+	policy  *access.Policy // global access-level enforcement
+	audit   audit.Recorder // signal-write audit recorder (never nil)
+	dialogs *DialogHub     // control-logic dialog fan-out (nil if disabled)
 
 	outCh    chan []byte        // serialised outgoing messages
 	updateCh chan broker.Update // raw updates from the broker
@@ -272,6 +285,8 @@ func (c *wsClient) handleMessage(ctx context.Context, data []byte) {
 		c.handleWrite(ctx, msg)
 	case "history":
 		c.handleHistory(ctx, msg)
+	case "dialogResponse":
+		c.handleDialogResponse(ctx, msg)
 	default:
 		c.sendError(ctx, "UNKNOWN_TYPE", "unknown message type: "+msg.Type)
 	}
@@ -389,6 +404,25 @@ func (c *wsClient) handleWrite(ctx context.Context, msg inMsg) {
 	c.audit.Record(ev)
 }
 
+// handleDialogResponse routes the answer to a control-logic input dialog. An
+// empty/null value means the user dismissed the dialog (drop it without
+// writing); otherwise the numeric value is written to the dialog's target.
+func (c *wsClient) handleDialogResponse(ctx context.Context, msg inMsg) {
+	if c.dialogs == nil || msg.ID == "" {
+		return
+	}
+	if len(msg.Value) == 0 || string(msg.Value) == "null" {
+		c.dialogs.cancel(msg.ID)
+		return
+	}
+	var num float64
+	if err := json.Unmarshal(msg.Value, &num); err != nil {
+		c.dialogs.cancel(msg.ID)
+		return
+	}
+	c.dialogs.respond(ctx, c, msg.ID, num)
+}
+
 func (c *wsClient) handleHistory(ctx context.Context, msg inMsg) {
 	metrics.IncHistoryReqs()
 	ds, ok := c.broker.Source(msg.DS)