#!/usr/bin/env node
'use strict';

/**
 * Script to migrate existing partner queue to use dead letter exchange
 * WARNING: This will temporarily delete and recreate the queue!
 * Only run this when no workers are running and no messages are in the queue.
 * 
 * Usage: node scripts/migrate_queue_to_dlx.js [--confirm]
 */

const amqp = require('amqplib');
const env = require('../helpers/env');

const PARTNER_QUEUE = env.PRODUCTION ? env.QUEUE_NAME_PARTNER || 'partner_tasks' : 'dev_partner_tasks';
const DLQ_QUEUE = `${PARTNER_QUEUE}_failed`;

async function migrateQueueToDLX() {
  const args = process.argv.slice(2);
  const isConfirmed = args.includes('--confirm');

  if (!isConfirmed) {
    console.log('⚠️  QUEUE MIGRATION TO DEAD LETTER EXCHANGE');
    console.log('');
    console.log('This script will:');
    console.log('1. Check if the queue has messages');
    console.log('2. Delete the existing queue (if empty)');
    console.log('3. Recreate it with dead letter exchange support');
    console.log('');
    console.log('⚠️  WARNING: This will temporarily delete the queue!');
    console.log('Make sure no workers are running and no messages are queued.');
    console.log('');
    console.log('Run with --confirm to proceed');
    return;
  }

  console.log(`Migrating queue: ${PARTNER_QUEUE}`);

  const conOps = {
    protocol: 'amqp',
    hostname: env.QUEUE_HOST || 'localhost',
    port: env.QUEUE_PORT || 5672,
    username: env.QUEUE_USR || 'agm',
    password: env.QUEUE_PWD,
    vhost: env.QUEUE_VHOST || '/',
    heartbeat: env.QUEUE_HEARTBEAT || 0,
    frameMax: 0
  };

  try {
    const conn = await amqp.connect(conOps);
    const ch = await conn.createChannel();

    // Check if queue exists and has messages
    try {
      const queueInfo = await ch.checkQueue(PARTNER_QUEUE);
      console.log(`Current queue status: ${queueInfo.messageCount} messages, ${queueInfo.consumerCount} consumers`);
      
      if (queueInfo.messageCount > 0) {
        console.log('❌ Queue has messages! Cannot migrate safely.');
        console.log('Please wait for all messages to be processed first.');
        await conn.close();
        return;
      }

      if (queueInfo.consumerCount > 0) {
        console.log('❌ Queue has active consumers! Cannot migrate safely.');
        console.log('Please stop all workers first.');
        await conn.close();
        return;
      }

    } catch (error) {
      if (error.message.includes('NOT_FOUND')) {
        console.log('Queue does not exist yet - will create with DLX');
      } else {
        throw error;
      }
    }

    console.log('✅ Safe to proceed with migration');

    // Step 1: Create DLQ infrastructure (simplified)
    console.log('Creating failed message queue...');
    await ch.assertQueue(DLQ_QUEUE, { durable: true });
    console.log(`✅ Created failed queue: ${DLQ_QUEUE}`);

    // Step 2: Delete existing queue (if it exists)
    try {
      await ch.deleteQueue(PARTNER_QUEUE, { ifEmpty: true });
      console.log(`✅ Deleted existing queue: ${PARTNER_QUEUE}`);
    } catch (error) {
      if (error.message.includes('NOT_FOUND')) {
        console.log(`Queue ${PARTNER_QUEUE} did not exist`);
      } else {
        throw error;
      }
    }

    // Step 3: Recreate queue with simplified DLX
    await ch.assertQueue(PARTNER_QUEUE, {
      durable: true,
      arguments: {
        'x-dead-letter-exchange': '',
        'x-dead-letter-routing-key': DLQ_QUEUE
      }
    });
    console.log(`✅ Created queue with simplified DLX: ${PARTNER_QUEUE}`);

    // Verify the setup
    const newQueueInfo = await ch.checkQueue(PARTNER_QUEUE);
    console.log(`✅ Migration complete! Queue: ${newQueueInfo.messageCount} messages`);

    console.log('');
    console.log('Queue structure:');
    console.log(`  Main Queue: ${PARTNER_QUEUE} (with simplified DLX)`);
    console.log(`  Failed Queue: ${DLQ_QUEUE}`);

    await conn.close();
    
  } catch (error) {
    console.error('❌ Migration failed:', error.message);
    process.exit(1);
  }
}

// Handle command line execution
if (require.main === module) {
  migrateQueueToDLX().catch(console.error);
}

module.exports = { migrateQueueToDLX };