qq

internal/engine/collector/engine.go

@@ -119,6 +119,7 @@ func (e *Engine) collect(ctx context.Context, p pg.PointRow) {
 			value = &v
 			quality = 0
 			reason = nil
+			e.manager.MarkConnected(p.DeviceID)
 		} else {
 			reasonText = "read_error"
 			reason = &reasonText

internal/engine/collector/manager.go

@@ -100,8 +100,18 @@ func (m *Manager) Times(id uuid.UUID) (online, offline *time.Time) {
 }
 func (m *Manager) MarkDisconnected(id uuid.UUID) {
 	m.mu.Lock()
+	if m.statuses[id] != "disconnected" {
+		m.lastOffline[id] = time.Now()
+	}
 	m.statuses[id] = "disconnected"
-	m.lastOffline[id] = time.Now()
+	m.mu.Unlock()
+}
+func (m *Manager) MarkConnected(id uuid.UUID) {
+	m.mu.Lock()
+	if m.statuses[id] != "connected" {
+		m.lastOnline[id] = time.Now()
+	}
+	m.statuses[id] = "connected"
 	m.mu.Unlock()
 }
 func (m *Manager) setStatus(id uuid.UUID, s string) {

internal/engine/collector/manager_test.go

@@ -0,0 +1,50 @@
+package collector
+
+import (
+	"github.com/google/uuid"
+	"testing"
+	"time"
+)
+
+func TestManagerStatusRecoversAfterSuccessfulRead(t *testing.T) {
+	m := NewManager(nil, nil)
+	id := uuid.New()
+
+	m.MarkConnected(id)
+	online, offline := m.Times(id)
+	if m.Status(id) != "connected" || online == nil || offline != nil {
+		t.Fatalf("expected connected status with online timestamp, got status=%q online=%v offline=%v", m.Status(id), online, offline)
+	}
+	firstOnline := *online
+
+	m.MarkDisconnected(id)
+	if m.Status(id) != "disconnected" {
+		t.Fatalf("expected disconnected status, got %q", m.Status(id))
+	}
+	_, offline = m.Times(id)
+	if offline == nil {
+		t.Fatal("expected offline timestamp after disconnect")
+	}
+
+	time.Sleep(2 * time.Millisecond)
+	m.MarkConnected(id)
+	online, offline = m.Times(id)
+	if m.Status(id) != "connected" || online == nil || offline == nil {
+		t.Fatalf("expected recovered connected status, got status=%q online=%v offline=%v", m.Status(id), online, offline)
+	}
+	if !online.After(firstOnline) {
+		t.Fatalf("expected reconnect to refresh online timestamp: first=%v current=%v", firstOnline, *online)
+	}
+}
+
+func TestManagerRepeatedConnectedDoesNotRefreshOnlineTimestamp(t *testing.T) {
+	m := NewManager(nil, nil)
+	id := uuid.New()
+	m.MarkConnected(id)
+	first, _ := m.Times(id)
+	m.MarkConnected(id)
+	second, _ := m.Times(id)
+	if first == nil || second == nil || !first.Equal(*second) {
+		t.Fatalf("repeated connected mark changed online timestamp: first=%v second=%v", first, second)
+	}
+}