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

/**
 * Simple DLQ Message Retrieval Test (No API, Direct RabbitMQ)
 * Tests the core issue: message retrieval without requeuing
 * 
 * This directly tests the RabbitMQ operations to verify:
 * 1. Publishing messages doesn't duplicate
 * 2. Getting messages with noAck:true doesn't consume them
 * 3. Multiple retrievals return consistent counts
 * 
 * Usage:
 *   node tests/test_dlq_messages_direct.js [--env ./environment.env]
 */

const path = require('path');
const amqp = require('amqplib');

// Parse --env argument
const args = process.argv.slice(2);
let envFile = './environment.env';
for (let i = 0; i < args.length; i++) {
  if (args[i] === '--env' && args[i + 1]) {
    envFile = args[i + 1];
    i++;
  }
}

// Load environment
const envPath = path.resolve(process.cwd(), envFile);
require('dotenv').config({ path: envPath });

const QUEUE_HOST = process.env.QUEUE_HOST || 'localhost';
const QUEUE_PORT = process.env.QUEUE_PORT || 5672;
const QUEUE_USR = process.env.QUEUE_USR || 'guest';
const QUEUE_PWD = process.env.QUEUE_PWD || 'guest';
const QUEUE_VHOST = process.env.QUEUE_VHOST || '/';

const testQueueName = 'test_dlq_messages';
const messageCount = 3;

console.log('╔════════════════════════════════════════════════════════════╗');
console.log('║  DLQ Message Retrieval Test (Direct RabbitMQ)            ║');
console.log('╚════════════════════════════════════════════════════════════╝\n');

async function main() {
  let connection, channel;
  
  try {
    // Connect
    console.log(`Connecting to RabbitMQ at ${QUEUE_HOST}:${QUEUE_PORT}...`);
    const vhostEncoded = encodeURIComponent(QUEUE_VHOST);
    const connUrl = `amqp://${encodeURIComponent(QUEUE_USR)}:${encodeURIComponent(QUEUE_PWD)}@${QUEUE_HOST}:${QUEUE_PORT}/${vhostEncoded}`;
    
    connection = await amqp.connect(connUrl);
    channel = await connection.createChannel();
    await channel.assertQueue(testQueueName, { durable: true });
    console.log('✓ Connected\n');
    
    // Clean up
    console.log('Purging existing messages...');
    await channel.purgeQueue(testQueueName);
    console.log('✓ Queue purged\n');
    
    // Test 1: Publish messages
    console.log('──────────────────────────────────────────────────────────');
    console.log(`Test 1: Publishing ${messageCount} messages`);
    
    for (let i = 0; i < messageCount; i++) {
      const msg = {
        id: `test-${i}`,
        content: `Message ${i + 1}`,
        timestamp: Date.now()
      };
      
      channel.sendToQueue(
        testQueueName,
        Buffer.from(JSON.stringify(msg)),
        { persistent: true, contentType: 'application/json' }
      );
    }
    
    await new Promise(resolve => setTimeout(resolve, 200));
    
    let queueInfo = await channel.checkQueue(testQueueName);
    console.log(`✓ Published ${messageCount} messages`);
    console.log(`  Queue count: ${queueInfo.messageCount}`);
    
    if (queueInfo.messageCount !== messageCount) {
      console.log(`✗ FAILED: Expected ${messageCount}, got ${queueInfo.messageCount}\n`);
      return 1;
    }
    console.log('');
    
    // Test 2: OLD METHOD - noAck:false with nack (causes duplication)
    console.log('──────────────────────────────────────────────────────────');
    console.log('Test 2: OLD METHOD - Get with noAck:false + nack requeue');
    
    const oldMethodMessages = [];
    for (let i = 0; i < 10; i++) {
      const msg = await channel.get(testQueueName, { noAck: false });
      if (!msg) break;
      
      oldMethodMessages.push(JSON.parse(msg.content.toString()));
      channel.nack(msg, false, true); // Requeue - THIS IS THE BUG
    }
    
    queueInfo = await channel.checkQueue(testQueueName);
    console.log(`  Retrieved: ${oldMethodMessages.length} messages`);
    console.log(`  Queue count after: ${queueInfo.messageCount}`);
    
    if (oldMethodMessages.length > messageCount) {
      console.log(`✗ BUG CONFIRMED: Retrieved ${oldMethodMessages.length} messages from queue with only ${messageCount}!`);
      console.log(`  This happens because nack(requeue=true) puts messages back at front of queue`);
    } else {
      console.log(`✓ Retrieved correct count (queue might be empty now)`);
    }
    console.log('');
    
    // Restore messages for next test
    console.log('Restoring messages for next test...');
    await channel.purgeQueue(testQueueName);
    for (let i = 0; i < messageCount; i++) {
      const msg = { id: `test-${i}`, content: `Message ${i + 1}` };
      channel.sendToQueue(
        testQueueName,
        Buffer.from(JSON.stringify(msg)),
        { persistent: true }
      );
    }
    await new Promise(resolve => setTimeout(resolve, 200));
    console.log('✓ Restored\n');
    
    // Test 3: NEW METHOD - noAck:true (no consumption)
    console.log('──────────────────────────────────────────────────────────');
    console.log('Test 3: NEW METHOD - Get with noAck:true (peek only)');
    
    queueInfo = await channel.checkQueue(testQueueName);
    const beforeCount = queueInfo.messageCount;
    console.log(`  Queue count before: ${beforeCount}`);
    
    const newMethodMessages = [];
    for (let i = 0; i < 10; i++) {
      const msg = await channel.get(testQueueName, { noAck: true });
      if (!msg) break;
      
      newMethodMessages.push(JSON.parse(msg.content.toString()));
      // No nack/ack needed - noAck:true auto-acknowledges without consuming
    }
    
    queueInfo = await channel.checkQueue(testQueueName);
    const afterCount = queueInfo.messageCount;
    
    console.log(`  Retrieved: ${newMethodMessages.length} messages`);
    console.log(`  Queue count after: ${afterCount}`);
    
    if (newMethodMessages.length === beforeCount && afterCount === 0) {
      console.log(`✓ CORRECT: Messages were consumed (noAck:true auto-acks)`);
      console.log(`  Note: noAck:true is for consuming, not peeking!`);
    } else if (newMethodMessages.length === beforeCount && afterCount === beforeCount) {
      console.log(`✓ PERFECT: Messages peeked without consumption`);
    } else {
      console.log(`? Unexpected behavior: retrieved=${newMethodMessages.length}, before=${beforeCount}, after=${afterCount}`);
    }
    console.log('');
    
    // Test 4: Management API method (best for peeking)
    console.log('──────────────────────────────────────────────────────────');
    console.log('Test 4: Management API method (HTTP API)');
    console.log('  Note: This requires RabbitMQ Management plugin');
    console.log('  URL: http://localhost:15672/api/queues/%2f/test_dlq_messages/get');
    console.log('  Method: POST with {"count":10,"ackmode":"ack_requeue_false"}');
    console.log('  This is the BEST way to peek without affecting queue state\n');
    
    // Cleanup
    console.log('──────────────────────────────────────────────────────────');
    console.log('Cleanup...');
    await channel.purgeQueue(testQueueName);
    await channel.deleteQueue(testQueueName);
    console.log('✓ Queue deleted\n');
    
    // Summary
    console.log('══════════════════════════════════════════════════════════');
    console.log('Summary');
    console.log('══════════════════════════════════════════════════════════');
    console.log('OLD METHOD (noAck:false + nack requeue):');
    console.log('  ✗ Causes message duplication');
    console.log('  ✗ Can read same message multiple times');
    console.log('  ✗ This was the bug in getDLQMessages_get');
    console.log('');
    console.log('NEW METHOD (noAck:true):');
    console.log('  ✓ No duplication');
    console.log('  ⚠ Messages are auto-acknowledged (consumed)');
    console.log('  ⚠ For true peeking, use checkQueue + limit by actual count');
    console.log('');
    console.log('BEST METHOD (Management API):');
    console.log('  ✓ True peeking without consumption');
    console.log('  ✓ Requires Management plugin');
    console.log('  ✓ More complex to implement');
    console.log('');
    
    return 0;
    
  } catch (error) {
    console.error('\n✗ Test failed:', error.message);
    console.error(error.stack);
    return 1;
  } finally {
    if (channel) await channel.close().catch(() => {});
    if (connection) await connection.close().catch(() => {});
  }
}

main()
  .then(exitCode => process.exit(exitCode))
  .catch(error => {
    console.error('Fatal error:', error);
    process.exit(1);
  });