Add neat arena

src/lib/neatArena/training.worker.ts

@@ -0,0 +1,129 @@
+import type { Population } from './evolution';
+import type { EvolutionConfig } from './evolution';
+import { evaluatePopulation, DEFAULT_MATCH_CONFIG } from './selfPlay';
+import { evolveGeneration, createPopulation, getPopulationStats } from './evolution';
+
+/**
+ * NEAT Training Worker
+ * 
+ * Runs training in a background thread to prevent UI blocking.
+ * The main thread only handles visualization and UI updates.
+ */
+
+export interface TrainingWorkerMessage {
+    type: 'start' | 'pause' | 'step' | 'reset' | 'init';
+    config?: EvolutionConfig;
+}
+
+export interface TrainingWorkerResponse {
+    type: 'update' | 'error' | 'ready';
+    population?: Population;
+    stats?: ReturnType<typeof getPopulationStats>;
+    error?: string;
+}
+
+let population: Population | null = null;
+let isRunning = false;
+let config: EvolutionConfig | null = null;
+
+/**
+ * Handle messages from main thread
+ */
+self.onmessage = async (e: MessageEvent<TrainingWorkerMessage>) => {
+    const message = e.data;
+    
+    try {
+        switch (message.type) {
+            case 'init':
+                if (message.config) {
+                    config = message.config;
+                    population = createPopulation(config);
+                    sendUpdate();
+                    self.postMessage({ type: 'ready' } as TrainingWorkerResponse);
+                }
+                break;
+                
+            case 'start':
+                isRunning = true;
+                runTrainingLoop();
+                break;
+                
+            case 'pause':
+                isRunning = false;
+                break;
+                
+            case 'step':
+                if (population && config) {
+                    const stats = await runSingleGeneration();
+                    sendUpdate(stats);
+                }
+                break;
+                
+            case 'reset':
+                if (config) {
+                    population = createPopulation(config);
+                    isRunning = false;
+                    sendUpdate();
+                }
+                break;
+        }
+    } catch (error) {
+        self.postMessage({
+            type: 'error',
+            error: error instanceof Error ? error.message : 'Unknown error',
+        } as TrainingWorkerResponse);
+    }
+};
+
+/**
+ * Run continuous training loop
+ */
+async function runTrainingLoop() {
+    while (isRunning && population && config) {
+        const stats = await runSingleGeneration();
+        sendUpdate(stats);
+        
+        // Yield to allow pause/stop messages to be processed
+        await new Promise(resolve => setTimeout(resolve, 0));
+    }
+}
+
+/**
+ * Run a single generation
+ */
+async function runSingleGeneration(): Promise<ReturnType<typeof getPopulationStats> | null> {
+    if (!population || !config) return null;
+    
+    console.log('[Worker] Starting generation', population.generation);
+    
+    // Evaluate population
+    const evaluatedPop = evaluatePopulation(population, DEFAULT_MATCH_CONFIG);
+    
+    // Check fitness after evaluation
+    const fitnesses = evaluatedPop.genomes.map(g => g.fitness);
+    const avgFit = fitnesses.reduce((a, b) => a + b, 0) / fitnesses.length;
+    const maxFit = Math.max(...fitnesses);
+    console.log('[Worker] After evaluation - Avg fitness:', avgFit.toFixed(2), 'Max:', maxFit.toFixed(2));
+    
+    // Evolve to next generation
+    population = evolveGeneration(evaluatedPop, config);
+    
+    console.log('[Worker] Generation', population.generation, 'complete');
+    
+    // IMPORTANT: Send stats from the EVALUATED population, not the evolved one
+    // (evolved population has fitness reset to 0)
+    return getPopulationStats(evaluatedPop);
+}
+
+/**
+ * Send population update to main thread
+ */
+function sendUpdate(stats?: ReturnType<typeof getPopulationStats> | null) {
+    if (!population) return;
+    
+    self.postMessage({
+        type: 'update',
+        population,
+        stats: stats || undefined,
+    } as TrainingWorkerResponse);
+}