export default defineNitroPlugin((nitroApp) => {
  let lastHeapSnapshot: number = 0;
  const heapSnapshotThreshold = 1024 * 1024 * 1024 * 6; // 6GB
  
  // Monitor memory usage every 30 seconds
  setInterval(() => {
    const memUsage = process.memoryUsage();
    const heapUsedMB = Math.round(memUsage.heapUsed / 1024 / 1024);
    const heapTotalMB = Math.round(memUsage.heapTotal / 1024 / 1024);
    const rssMB = Math.round(memUsage.rss / 1024 / 1024);
    const externalMB = Math.round(memUsage.external / 1024 / 1024);
    
    console.log(`[Memory Monitor] Heap: ${heapUsedMB}MB / ${heapTotalMB}MB | RSS: ${rssMB}MB | External: ${externalMB}MB`);
    
    // Warning if memory usage is high
    if (memUsage.heapUsed > heapSnapshotThreshold) {
      console.warn(`[Memory Monitor] High memory usage detected: ${heapUsedMB}MB`);
      
      // Take heap snapshot if we haven't taken one in the last hour
      const now = Date.now();
      if (now - lastHeapSnapshot > 3600000) { // 1 hour
        lastHeapSnapshot = now;
        console.warn('[Memory Monitor] Memory usage critical - consider taking heap snapshot');
        
        // Force garbage collection if available
        if (global.gc) {
          console.log('[Memory Monitor] Running garbage collection...');
          global.gc();
          
          // Log memory after GC
          setTimeout(() => {
            const afterGC = process.memoryUsage();
            const heapFreed = memUsage.heapUsed - afterGC.heapUsed;
            console.log(`[Memory Monitor] GC freed ${Math.round(heapFreed / 1024 / 1024)}MB`);
          }, 1000);
        }
      }
    }
  }, 30000); // Every 30 seconds
  
  // Monitor event loop lag
  let lastCheck = Date.now();
  setInterval(() => {
    const now = Date.now();
    const lag = now - lastCheck - 1000;
    
    if (lag > 100) {
      console.warn(`[Memory Monitor] Event loop lag detected: ${lag}ms`);
    }
    
    lastCheck = now;
  }, 1000);
  
  // Add memory info to health endpoint
  nitroApp.hooks.hook('request', async (event) => {
    if (event.node.req.url === '/api/health') {
      const memUsage = process.memoryUsage();
      event.context.memoryInfo = {
        heapUsed: Math.round(memUsage.heapUsed / 1024 / 1024),
        heapTotal: Math.round(memUsage.heapTotal / 1024 / 1024),
        rss: Math.round(memUsage.rss / 1024 / 1024),
        external: Math.round(memUsage.external / 1024 / 1024),
        arrayBuffers: Math.round(memUsage.arrayBuffers / 1024 / 1024)
      };
    }
  });
});