<?php
namespace app\common\service;

use Predis\Client as RedisClient;

class QueueService
{
    protected $redis;

    public function __construct()
    {
        $this->redis = new RedisClient([
            'host' => '127.0.0.1',
            'port' => 6379,
            // 'password' => '', // 如果有密码
        ]);
    }

    // 推送消息到队列
    public function push($queueName, $message)
    {
        $this->redis->rpush($queueName, json_encode($message));
    }

    // 从队列中取出消息
    public function pop($queueName)
    {
        $message = $this->redis->lpop($queueName);
        return $message ? json_decode($message, true) : null;
    }

    /**
     * 延迟推送（ZSET）
     * @param string $queueName
     * @param array|string $data
     * @param int $delay 延迟秒数
     */
    public function laterPush($queueName, $data, $delay)
    {
        $score = time() + $delay;
        $payload = is_string($data) ? $data : json_encode($data, JSON_UNESCAPED_UNICODE);
        return $this->redis->zadd($queueName . ':delayed', [$payload => $score]);
    }

    /**
     * 检查延迟队列，将到期任务迁移到普通队列
     * @param string $queueName
     */
    public function migrateDelayedToReady($queueName)
    {
        $now = time();
        // 获取到期任务
        $tasks = $this->redis->zrangebyscore($queueName . ':delayed', 0, $now);
        if (!empty($tasks)) {
            foreach ($tasks as $task) {
                // 放回普通队列
                $this->push($queueName, $task);
                // 从延迟队列中移除
                $this->redis->zrem($queueName . ':delayed', $task);
            }
        }
    }
}