import { processEmailQueue } from './emailService';

let isProcessing = false;
let processorInterval = null;

/**
 * Start the background queue processor
 * Processes the queue every 30 seconds
 */
export function startQueueProcessor() {
  if (processorInterval) {
    console.log('Queue processor already running');
    return;
  }

  console.log('🚀 Starting background queue processor...');

  // Process immediately on start
  processQueue();

  // Then process every 30 seconds
  processorInterval = setInterval(processQueue, 30000);

  console.log('✅ Queue processor started (runs every 30 seconds)');
}

/**
 * Stop the background queue processor
 */
export function stopQueueProcessor() {
  if (processorInterval) {
    clearInterval(processorInterval);
    processorInterval = null;
    console.log('⏸️  Queue processor stopped');
  }
}

/**
 * Process the queue (with lock to prevent concurrent processing)
 */
async function processQueue() {
  const timestamp = new Date().toISOString();

  // Skip if already processing
  if (isProcessing) {
    console.log(`[${timestamp}] ⏭️  Queue processor skipped (already running)`);
    return;
  }

  try {
    isProcessing = true;
    const startTime = Date.now();
    console.log(`[${timestamp}] ⚙️  Processing notification queue...`);

    const results = await processEmailQueue();
    const duration = ((Date.now() - startTime) / 1000).toFixed(2);

    if (results && results.length > 0) {
      const sent = results.filter(r => r.status === 'sent').length;
      const failed = results.filter(r => r.status === 'failed').length;
      const recovered = results.filter(r => r.recovered).length;

      let message = `[${new Date().toISOString()}] ✅ Queue processed in ${duration}s: ${sent} sent, ${failed} failed, ${results.length} total`;
      if (recovered > 0) {
        message += ` (${recovered} recovered from timeout)`;
      }
      console.log(message);

      // Log detailed results for debugging
      console.log(`[${new Date().toISOString()}] 📊 Queue stats: Success rate: ${((sent/results.length)*100).toFixed(1)}%`);
    } else {
      console.log(`[${new Date().toISOString()}] 📭 No queued items to process`);
    }
  } catch (error) {
    console.error(`[${new Date().toISOString()}] ❌ Error processing queue:`, error);
    console.error(`[${new Date().toISOString()}] 📋 Error stack:`, error.stack);
  } finally {
    isProcessing = false;
    console.log(`[${new Date().toISOString()}] 🔓 Queue processor lock released`);
  }
}

/**
 * Manually trigger queue processing
 */
export async function triggerQueueProcessing() {
  return processQueue();
}