fix(series): extremas would be wrong in some cases with in_header: false

Fixes #725

Author: RomRider

.devcontainer/ui-lovelace.yaml

@@ -1211,6 +1211,15 @@ views:
                       }
                     title: Synology NAS
             series:
+              - entity: sensor.random_0_1000
+                name: Test Index
+                float_precision: 0
+                show:
+                  extremas: min
+                  in_chart: false
+                group_by:
+                  duration: 2min
+                  func: avg
               - entity: sensor.random_0_1000
                 name: Min
                 float_precision: 0

src/apexcharts-card.ts

@@ -1024,11 +1024,13 @@ class ChartsCard extends LitElement {
       points: this._config?.series_in_graph.flatMap((serie, index) => {
         if (serie.show.extremas) {
           const { min, max } = this._graphs?.[serie.index]?.minMaxWithTimestamp(
-            this._seriesOffset[index]
-              ? new Date(start.getTime() + this._seriesOffset[index]).getTime()
+            this._seriesOffset[serie.index]
+              ? new Date(start.getTime() + this._seriesOffset[serie.index]).getTime()
               : start.getTime(),
-            this._seriesOffset[index] ? new Date(end.getTime() + this._seriesOffset[index]).getTime() : end.getTime(),
-            this._serverTimeOffset - (this._seriesTimeDelta[index] || 0),
+            this._seriesOffset[serie.index]
+              ? new Date(end.getTime() + this._seriesOffset[serie.index]).getTime()
+              : end.getTime(),
+            this._serverTimeOffset - (this._seriesTimeDelta[serie.index] || 0),
           ) || {
             min: [0, null],
             max: [0, null],
@@ -1042,7 +1044,7 @@ class ChartsCard extends LitElement {
             extremas.push(
               ...this._getPointAnnotationStyle(
                 min,
-                this._seriesOffset[index],
+                this._seriesOffset[serie.index],
                 bgColor,
                 txtColor,
                 serie,
@@ -1058,7 +1060,7 @@ class ChartsCard extends LitElement {
             extremas.push(
               ...this._getPointAnnotationStyle(
                 max,
-                this._seriesOffset[index],
+                this._seriesOffset[serie.index],
                 bgColor,
                 txtColor,
                 serie,