<?php
/**
 * 消费生产者-分发任务
 * RPC模式
 */

require_once __DIR__ . '/vendor/autoload.php';
require_once __DIR__ . '/config.php';

use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Message\AMQPMessage;

$host = RABBITMQ_CONF['host'];
$port = RABBITMQ_CONF['port'];
$user = RABBITMQ_CONF['user'];
$password = RABBITMQ_CONF['password'];
$exchange = '';
$queue = 'rpc_queue';

// 连接RabbitMQ服务器
$connection = new AMQPStreamConnection($host, $port, $user, $password);
$channel = $connection->channel();

// 创建队列
$channel->queue_declare($queue, false, false, false, false);

/**
 * 斐波纳契数列
 * 注意：由于该方法是递归，这里是用来测试一些耗时任务
 */
function fib($n)
{
    if ($n == 0) {
        return 0;
    }
    if ($n == 1) {
        return 1;
    }
    return fib($n - 1) + fib($n - 2);
}

echo " [x] Awaiting RPC requests\n";
$callback = function ($req) {
    $n = intval($req->body);
    echo ' [.] fib(', $n, ")\n";

    $msg = new AMQPMessage(
        (string)fib($n),
        array('correlation_id' => $req->get('correlation_id'))
    );

    // 发送消息到交换器，交换器为默认交换器（空交换器）
    $req->delivery_info['channel']->basic_publish(
        $msg,
        $exchange,
        $req->get('reply_to')
    );

    // 消息确认
    $req->ack();
};

// 设置消费者允许的最大未确认消息数量为1
$channel->basic_qos(null, 1, null);

// 定义队列的消费回调，将消息传递给回调函数同时关闭自动消息确认
$channel->basic_consume($queue, '', false, false, false, false, $callback);

// 循环消费/接收消息
while ($channel->is_open()) {
    $channel->wait();
}

// 关闭连接
$channel->close();
$connection->close();