Revert "MQTT: publish the forecast as a single JSON message (#32710)"

This reverts commit 93c182e486.

core/site_tariffs.go

@@ -1,7 +1,6 @@
 package core
 
 import (
-	"encoding/json"
 	"math"
 	"time"
 
@@ -14,24 +13,6 @@ import (
 	"github.com/samber/lo"
 )
 
-// forecastDetails is the published forecast payload. It implements BytesMarshaler
-// so MQTT sends a single JSON message instead of decomposing every slot into an
-// individual topic (several thousand messages per update).
-type forecastDetails struct {
-	Co2         [][]float64   `json:"co2,omitempty"`
-	FeedIn      [][]float64   `json:"feedin,omitempty"`
-	Grid        [][]float64   `json:"grid,omitempty"`
-	Planner     [][]float64   `json:"planner,omitempty"`
-	Solar       *solarDetails `json:"solar,omitempty"`
-	Temperature [][]float64   `json:"temperature,omitempty"`
-}
-
-var _ api.BytesMarshaler = (*forecastDetails)(nil)
-
-func (fc forecastDetails) MarshalBytes() ([]byte, error) {
-	return json.Marshal(fc)
-}
-
 type solarDetails struct {
 	Scale            float64      `json:"scale"`                      // scale factor yield/forecasted today, 1 if unscaled
 	Today            dailyDetails `json:"today,omitempty"`            // tomorrow
@@ -134,7 +115,14 @@ func (site *Site) publishTariffs(greenShareHome float64, greenShareLoadpoints fl
 		site.publish(keys.TariffCo2Loadpoints, v)
 	}
 
-	fc := forecastDetails{
+	fc := struct {
+		Co2         [][]float64   `json:"co2,omitempty"`
+		FeedIn      [][]float64   `json:"feedin,omitempty"`
+		Grid        [][]float64   `json:"grid,omitempty"`
+		Planner     [][]float64   `json:"planner,omitempty"`
+		Solar       *solarDetails `json:"solar,omitempty"`
+		Temperature [][]float64   `json:"temperature,omitempty"`
+	}{
 		Co2:         forecastRates(tariff.Rates(site.GetTariff(api.TariffUsageCo2))),
 		FeedIn:      forecastRates(tariff.Rates(site.GetTariff(api.TariffUsageFeedIn))),
 		Planner:     forecastRates(tariff.Rates(site.GetTariff(api.TariffUsagePlanner))),