src/main/java/de/nilzbu/mytimetracker/ui/component/ChartJsComponent.java

@@ -1,11 +1,10 @@
 package de.nilzbu.mytimetracker.ui.component;
 
-import com.vaadin.flow.component.HasSize;
-import com.vaadin.flow.component.html.Div;
+import com.vaadin.flow.component.AttachEvent;
+import com.vaadin.flow.component.Tag;
 import com.vaadin.flow.component.dependency.JsModule;
 import com.vaadin.flow.component.dependency.NpmPackage;
-import com.vaadin.flow.component.Tag;
-import com.vaadin.flow.component.AttachEvent;
+import com.vaadin.flow.component.html.Div;
 import elemental.json.Json;
 import elemental.json.JsonArray;
 import elemental.json.JsonObject;
@@ -31,10 +30,14 @@ public class ChartJsComponent extends Div {
 
     @Override
     protected void onAttach(AttachEvent attachEvent) {
+        renderChart();
+    }
+
+    private void renderChart() {
         getElement().executeJs(
                 """
                 const canvas = document.createElement('canvas');
-                this.appendChild(canvas);
+                appendChild(canvas);
                 const ctx = canvas.getContext('2d');
                 new Chart(ctx, {
                   type: $0,
@@ -54,47 +57,55 @@ public class ChartJsComponent extends Div {
                   }
                 });
                 """,
-                getChartTypeFromData(chartData),
+                detectChartType(chartData),
                 chartData,
                 chartTitle
         );
     }
 
-    private String getChartTypeFromData(JsonObject data) {
-        // Default zu bar wenn keine sinnvolle Bestimmung möglich ist
+    /**
+     * Detects chart type based on chart data.
+     * If no definitive type can be determined, defaults to "bar".
+     */
+    private String detectChartType(JsonObject data) {
         try {
             JsonArray datasets = data.getArray("datasets");
             if (datasets.length() > 0) {
-                JsonObject first = datasets.getObject(0);
-                if (first.hasKey("fill") && !first.getBoolean("fill")) {
+                JsonObject firstDataset = datasets.getObject(0);
+                if (firstDataset.hasKey("fill") && !firstDataset.getBoolean("fill")) {
                     return "line";
                 }
             }
-        } catch (Exception ignored) {}
+        } catch (Exception ignored) {
+        }
         return "bar";
     }
 
-    // Balkendiagramm für Kategorien
+    /**
+     * Creates JSON chart data for a bar chart based on category counts.
+     */
     public static JsonObject generateBarChartData(Map<String, Long> categoryCounts) {
         JsonObject data = Json.createObject();
         JsonArray labels = Json.createArray();
         JsonArray values = Json.createArray();
-        JsonArray backgroundColors = Json.createArray();
+        JsonArray colors = Json.createArray();
 
-        String[] defaultColors = {"#1e7e34", "#138496", "#ffc107", "#dc3545", "#6f42c1", "#20c997"};
+        String[] defaultColors = {
+                "#1e7e34", "#138496", "#ffc107", "#dc3545", "#6f42c1", "#20c997"
+        };
 
-        int i = 0;
+        int index = 0;
         for (Map.Entry<String, Long> entry : categoryCounts.entrySet()) {
-            labels.set(i, Json.create(entry.getKey()));
-            values.set(i, Json.create(entry.getValue()));
-            backgroundColors.set(i, Json.create(defaultColors[i % defaultColors.length]));
-            i++;
+            labels.set(index, Json.create(entry.getKey()));
+            values.set(index, Json.create(entry.getValue()));
+            colors.set(index, Json.create(defaultColors[index % defaultColors.length]));
+            index++;
         }
 
         JsonObject dataset = Json.createObject();
-        dataset.put("label", "Einträge nach Kategorie");
+        dataset.put("label", "Entries by Category");
         dataset.put("data", values);
-        dataset.put("backgroundColor", backgroundColors);
+        dataset.put("backgroundColor", colors);
 
         JsonArray datasets = Json.createArray();
         datasets.set(0, dataset);
@@ -105,19 +116,21 @@ public class ChartJsComponent extends Div {
         return data;
     }
 
-    // Liniendiagramm für Überstunden-Saldo (in Stunden)
-    public static JsonObject generateLineChartData(List<LocalDate> dates, List<Double> saldoValues) {
+    /**
+     * Creates JSON chart data for a line chart showing overtime balance.
+     */
+    public static JsonObject generateLineChartData(List<LocalDate> dates, List<Double> balanceValues) {
         JsonObject data = Json.createObject();
         JsonArray labels = Json.createArray();
         JsonArray values = Json.createArray();
 
         for (int i = 0; i < dates.size(); i++) {
             labels.set(i, Json.create(dates.get(i).toString()));
-            values.set(i, Json.create(saldoValues.get(i)));
+            values.set(i, Json.create(balanceValues.get(i)));
         }
 
         JsonObject dataset = Json.createObject();
-        dataset.put("label", "Überstunden-Saldo (h)");
+        dataset.put("label", "Overtime Balance (hours)");
         dataset.put("data", values);
         dataset.put("borderColor", "rgb(54, 162, 235)");
         dataset.put("tension", 0.1);