Fix wealth distribution histogram issue by correcting wealth calculation and improving data handling

app/static/js/simulation.js

@@ -21,6 +21,59 @@ window.testWebSocket = async function() {
     }
 };
 
+/**
+ * Test distribution data generation
+ * Call from browser console: testDistributionData()
+ */
+window.testDistributionData = async function() {
+    debugLog('=== DISTRIBUTION DATA TEST ===');
+    
+    try {
+        // First check if we have a simulation ID
+        const simulationId = currentSimulation.id;
+        if (!simulationId) {
+            debugLog('❌ No active simulation found');
+            return;
+        }
+        
+        // Fetch distribution data directly from API
+        debugLog('Fetching distribution data from API...');
+        const response = await fetch(`/api/simulation/${simulationId}/distribution?bins=5`);
+        const data = await response.json();
+        
+        debugLog('Distribution API response', data);
+        
+        if (data.histogram) {
+            debugLog('Histogram data', {
+                labels: data.histogram.labels,
+                counts: data.histogram.counts,
+                total_agents: data.histogram.total_agents
+            });
+            
+            // Try to update chart with this data
+            if (charts.distribution && data.histogram.labels && data.histogram.counts) {
+                debugLog('Attempting to update chart with API data...');
+                try {
+                    charts.distribution.data.labels = data.histogram.labels;
+                    charts.distribution.data.datasets[0].data = data.histogram.counts;
+                    charts.distribution.update();
+                    debugLog('✅ Chart updated successfully with API data');
+                } catch (error) {
+                    debugLog('❌ Error updating chart with API data', error);
+                }
+            } else {
+                debugLog('❌ Cannot update chart - missing chart instance or data');
+            }
+        } else {
+            debugLog('❌ No histogram data in response');
+        }
+    } catch (error) {
+        debugLog('❌ Error fetching distribution data', error);
+    }
+    
+    debugLog('=== DISTRIBUTION DATA TEST COMPLETE ===');
+};
+
 /**
  * Enhanced distribution update test function
  * Call from browser console: testDistributionUpdate()
@@ -483,10 +536,10 @@ function initializeCharts() {
             charts.distribution = new Chart(distributionCtx, {
                 type: 'bar',
                 data: {
-                    labels: [],
+                    labels: [], // Initialize with empty arrays
                     datasets: [{
                         label: 'Number of Agents',
-                        data: [],
+                        data: [], // Initialize with empty array
                         backgroundColor: 'rgba(40, 167, 69, 0.7)',
                         borderColor: '#28a745',
                         borderWidth: 1
@@ -515,7 +568,8 @@ function initializeCharts() {
                             title: {
                                 display: true,
                                 text: 'Number of Agents'
-                            }
+                            },
+                            beginAtZero: true // Ensure y-axis starts at zero
                         }
                     }
                 }
@@ -963,7 +1017,13 @@ function updateSimulationProgress(data) {
             socketConnected: window.MarkovEconomics ? window.MarkovEconomics.isConnected : 'unknown'
         });
         
-        if (data.distribution && data.distribution.labels && data.distribution.counts) {
+        // More robust handling of distribution data
+        if (data.distribution && 
+            Array.isArray(data.distribution.labels) && 
+            Array.isArray(data.distribution.counts) &&
+            data.distribution.labels.length > 0 && 
+            data.distribution.counts.length > 0) {
+            
             debugLog('Updating distribution data', {
                 labelsLength: data.distribution.labels.length,
                 countsLength: data.distribution.counts.length,
@@ -971,6 +1031,7 @@ function updateSimulationProgress(data) {
                 counts: data.distribution.counts
             });
             
+            // Store the distribution data properly
             currentSimulation.data.distribution.labels = [...data.distribution.labels];
             currentSimulation.data.distribution.counts = [...data.distribution.counts];
         } else {
@@ -1015,11 +1076,16 @@ function updateCharts() {
             canvasElement: document.getElementById('distributionChart')
         });
         
+        // Ensure we have valid data before updating
         if (distData.labels && distData.labels.length > 0 && 
             distData.counts && distData.counts.length > 0) {
             try {
-                charts.distribution.data.labels = distData.labels;
-                charts.distribution.data.datasets[0].data = distData.counts;
+                // Make sure we're working with arrays
+                const labels = Array.isArray(distData.labels) ? distData.labels : [];
+                const counts = Array.isArray(distData.counts) ? distData.counts : [];
+                
+                charts.distribution.data.labels = labels;
+                charts.distribution.data.datasets[0].data = counts;
                 charts.distribution.update('none');
                 debugLog('✅ Distribution chart updated successfully');
             } catch (error) {