From cdba28f2ef09c1ec100d82d23a8833b14356735c Mon Sep 17 00:00:00 2001
From: Floke <floke.com@gmail.com>
Date: Wed, 4 Feb 2026 14:02:14 +0000
Subject: [PATCH] fix([2fd88f42]): resolve infinite loop in dynamic legend
 handler

---
 .../frontend/src/components/MapDisplay.tsx    | 61 ++++++++++---------
 1 file changed, 32 insertions(+), 29 deletions(-)

diff --git a/heatmap-tool/frontend/src/components/MapDisplay.tsx b/heatmap-tool/frontend/src/components/MapDisplay.tsx
index b7bda4f9..b8e3ce65 100644
--- a/heatmap-tool/frontend/src/components/MapDisplay.tsx
+++ b/heatmap-tool/frontend/src/components/MapDisplay.tsx
@@ -1,5 +1,5 @@
 // src/components/MapDisplay.tsx
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, useCallback } from 'react';
 import { MapContainer, TileLayer, CircleMarker, Tooltip, useMapEvents } from 'react-leaflet';
 import { HeatmapLayer } from 'react-leaflet-heatmap-layer-v3';
 import 'leaflet/dist/leaflet.css';
@@ -8,6 +8,8 @@ import type { HeatmapPoint, MapMode } from '../App';
 import MarkerClusterGroup from 'react-leaflet-cluster';
 import Legend from './Legend';
 import MapBoundsManager from './MapBoundsManager';
+import { LatLngBounds } from 'leaflet';
+
 
 interface MapDisplayProps {
   heatmapData: HeatmapPoint[];
@@ -15,20 +17,32 @@ interface MapDisplayProps {
   viewMode: MapMode;
 }
 
+// This component listens to map events and calls a callback when the view changes
+const DynamicLegendHandler = ({ onBoundsChange }: { onBoundsChange: (bounds: LatLngBounds) => void }) => {
+    const map = useMapEvents({
+      zoomend: () => onBoundsChange(map.getBounds()),
+      moveend: () => onBoundsChange(map.getBounds()),
+    });
+  
+    // Initial load
+    useEffect(() => {
+        onBoundsChange(map.getBounds());
+    }, []); // Run only once on initial mount
+  
+    return null;
+};
+
+
 const MapDisplay: React.FC<MapDisplayProps> = ({ heatmapData, radiusMultiplier, viewMode }) => {
   const germanyCenter: [number, number] = [51.1657, 10.4515];
   
-  // State for the data currently visible in the map viewport
   const [visibleData, setVisibleData] = useState<HeatmapPoint[]>(heatmapData);
-  
-  // The dynamic max count based only on visible data
   const dynamicMaxCount = Math.max(...visibleData.map(p => p.count), 1);
 
   const calculateRadius = (count: number) => {
     return 3 + Math.log(count + 1) * 5 * radiusMultiplier;
   };
   
-  // getColor now uses the dynamicMaxCount
   const getColor = (count: number) => {
     const ratio = count / dynamicMaxCount;
     if (ratio > 0.8) return '#d73027'; // Red
@@ -36,30 +50,19 @@ const MapDisplay: React.FC<MapDisplayProps> = ({ heatmapData, radiusMultiplier,
     if (ratio > 0.2) return '#fee08b'; // Yellow
     return '#66bd63'; // Green
   };
+  
+  const updateVisibleData = useCallback((bounds: LatLngBounds) => {
+    const visible = heatmapData.filter(p => 
+      bounds.contains([p.lat, p.lon])
+    );
+    setVisibleData(visible.length > 0 ? visible : heatmapData); // Fallback to all data if none are visible
+  }, [heatmapData]);
+  
+  // Reset visible data when heatmapData changes
+  useEffect(() => {
+    setVisibleData(heatmapData);
+  }, [heatmapData]);
 
-  // This component listens to map events and updates the visible data
-  const DynamicLegendHandler = () => {
-    const map = useMapEvents({
-      zoomend: () => updateVisibleData(),
-      moveend: () => updateVisibleData(),
-    });
-
-    const updateVisibleData = () => {
-      const bounds = map.getBounds();
-      const visible = heatmapData.filter(p => 
-        bounds.contains([p.lat, p.lon])
-      );
-      setVisibleData(visible.length > 0 ? visible : heatmapData); // Fallback to all data if none are visible
-    };
-    
-    // Initial load
-    useEffect(() => {
-        updateVisibleData();
-    }, [heatmapData]);
-
-
-    return null;
-  };
 
   const renderPoints = () => (
     <MarkerClusterGroup>
@@ -115,7 +118,7 @@ const MapDisplay: React.FC<MapDisplayProps> = ({ heatmapData, radiusMultiplier,
         attribution='&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
       />
       <MapBoundsManager data={heatmapData} />
-      <DynamicLegendHandler />
+      <DynamicLegendHandler onBoundsChange={updateVisibleData} />
       {viewMode === 'points' ? renderPoints() : renderHeatmap()}
       {viewMode === 'points' && <Legend getColor={getColor} maxCount={dynamicMaxCount} />}
     </MapContainer>