Add Tasmota timezone handling and dashboard updates

internal/parser/tasmota.go

@@ -22,6 +22,14 @@ var tasmotaTimeLayouts = []string{
 }
 
 func ParseTasmota(message model.RawMessage) ([]model.Record, error) {
+	return ParseTasmotaInLocation(message, time.UTC)
+}
+
+func ParseTasmotaInLocation(message model.RawMessage, timezoneLessTimeLocation *time.Location) ([]model.Record, error) {
+	if timezoneLessTimeLocation == nil {
+		timezoneLessTimeLocation = time.UTC
+	}
+
 	parts := strings.Split(message.Topic, "/")
 	if len(parts) != 3 {
 		return nil, fmt.Errorf("unsupported topic shape: %s", message.Topic)
@@ -52,7 +60,7 @@ func ParseTasmota(message model.RawMessage) ([]model.Record, error) {
 		return nil, fmt.Errorf("no usable fields in payload for topic %s", message.Topic)
 	}
 
-	timestamp := parsePayloadTimestamp(payload, message.ReceivedAt)
+	timestamp := parsePayloadTimestamp(payload, message.ReceivedAt, timezoneLessTimeLocation)
 
 	record := model.Record{
 		Measurement: measurement,
@@ -77,11 +85,14 @@ func parseLWT(message model.RawMessage, measurement string, tags map[string]stri
 	}
 }
 
-func parsePayloadTimestamp(payload map[string]any, fallback time.Time) time.Time {
+func parsePayloadTimestamp(payload map[string]any, fallback time.Time, timezoneLessTimeLocation *time.Location) time.Time {
 	rawTime, ok := payload["Time"].(string)
 	if !ok || strings.TrimSpace(rawTime) == "" {
 		return fallback
 	}
+	if timezoneLessTimeLocation == nil {
+		timezoneLessTimeLocation = time.UTC
+	}
 
 	for _, layout := range tasmotaTimeLayouts {
 		var (
@@ -90,13 +101,13 @@ func parsePayloadTimestamp(payload map[string]any, fallback time.Time) time.Time
 		)
 
 		if layout == "2006-01-02T15:04:05" {
-			parsed, err = time.ParseInLocation(layout, rawTime, time.UTC)
+			parsed, err = time.ParseInLocation(layout, rawTime, timezoneLessTimeLocation)
 		} else {
 			parsed, err = time.Parse(layout, rawTime)
 		}
 
 		if err == nil {
-			return parsed
+			return parsed.UTC()
 		}
 	}
 

internal/parser/tasmota_test.go

@@ -85,6 +85,29 @@ func TestParseTasmotaFixtures(t *testing.T) {
 	}
 }
 
+func TestParseTasmotaInLocationUsesConfiguredTimezoneForTimezoneLessTime(t *testing.T) {
+	location := time.FixedZone("CET", 3600)
+	receivedAt := time.Date(2026, time.March, 16, 11, 55, 30, 0, time.UTC)
+
+	records, err := ParseTasmotaInLocation(model.RawMessage{
+		Topic:      "tele/tasmota_67850B/SENSOR",
+		Payload:    []byte(`{"Time":"2026-03-16T11:55:29","ENERGY":{"Power":9}}`),
+		ReceivedAt: receivedAt,
+	}, location)
+	if err != nil {
+		t.Fatalf("ParseTasmotaInLocation returned error: %v", err)
+	}
+
+	if len(records) != 1 {
+		t.Fatalf("expected 1 record, got %d", len(records))
+	}
+
+	want := time.Date(2026, time.March, 16, 10, 55, 29, 0, time.UTC)
+	if !records[0].Timestamp.Equal(want) {
+		t.Fatalf("unexpected timestamp: got %s want %s", records[0].Timestamp.Format(time.RFC3339), want.Format(time.RFC3339))
+	}
+}
+
 func fieldEquals(got any, want any) bool {
 	switch typedWant := want.(type) {
 	case float64: