bugfix wunderground reporting

internal/mqttingest/latest.go

@@ -27,7 +27,9 @@ type Latest struct {
 
 	// rolling sums built from "rain increment" values (mm)
 	rainIncs  []rainIncPoint // last 1h
-	dailyIncs []rainIncPoint // since midnight (or since start; we’ll trim daily by midnight)
+	dailyIncs []rainIncPoint // since midnight in rainDayLoc (or since start; trimmed each update)
+
+	rainDayLoc *time.Location
 }
 
 type rainIncPoint struct {
@@ -35,6 +37,15 @@ type rainIncPoint struct {
 	mm float64 // incremental rainfall at this timestamp (mm)
 }
 
+func NewLatest(rainDayLoc *time.Location) *Latest {
+	if rainDayLoc == nil {
+		rainDayLoc = time.Local
+	}
+	return &Latest{
+		rainDayLoc: rainDayLoc,
+	}
+}
+
 func (l *Latest) Update(ts time.Time, p *WS90Payload) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
@@ -49,9 +60,9 @@ func (l *Latest) Update(ts time.Time, p *WS90Payload) {
 	cutoff := ts.Add(-1 * time.Hour)
 	l.rainIncs = trimBefore(l.rainIncs, cutoff)
 
-	// Track daily increments: trim before local midnight
+	// Track daily increments: trim before midnight in configured rain day timezone.
 	l.dailyIncs = append(l.dailyIncs, rainIncPoint{ts: ts, mm: inc})
-	midnight := localMidnight(ts)
+	midnight := l.rainDayMidnight(ts)
 	l.dailyIncs = trimBefore(l.dailyIncs, midnight)
 }
 
@@ -68,10 +79,13 @@ func trimBefore(a []rainIncPoint, cutoff time.Time) []rainIncPoint {
 	return a
 }
 
-// localMidnight returns midnight in the local timezone of the *process*.
-// If you want a specific timezone (e.g. Australia/Sydney) we can wire that in later.
-func localMidnight(t time.Time) time.Time {
-	lt := t.Local()
+// rainDayMidnight returns midnight in the configured rain day timezone.
+func (l *Latest) rainDayMidnight(t time.Time) time.Time {
+	loc := l.rainDayLoc
+	if loc == nil {
+		loc = time.Local
+	}
+	lt := t.In(loc)
 	return time.Date(lt.Year(), lt.Month(), lt.Day(), 0, 0, 0, 0, lt.Location())
 }