<?php
/**
 * Redis Singleton — phpredis Extension
 */

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

class RedisClient
{
    private static ?\Redis $instance = null;

    private function __construct()
    {
        try {
            self::$instance = new \Redis();
            self::$instance->connect(REDIS_HOST, REDIS_PORT, 2.0);

            if (REDIS_PASSWORD !== null) {
                self::$instance->auth(REDIS_PASSWORD);
            }

            if (REDIS_DB > 0) {
                self::$instance->select(REDIS_DB);
            }

            self::$instance->setOption(\Redis::OPT_SERIALIZER, \Redis::SERIALIZER_JSON);
        } catch (\RedisException $e) {
            $errorMsg = $e->getMessage();
            error_log('Redis connection failed: ' . $errorMsg);
            http_response_code(500);
            echo json_encode(['success' => false, 'message' => 'cache_error', 'error' => $errorMsg]);
            exit;
        } catch (\Exception $e) {
            $errorMsg = $e->getMessage();
            error_log('Unexpected error in Redis: ' . $errorMsg);
            http_response_code(500);
            echo json_encode(['success' => false, 'message' => 'cache_error', 'error' => $errorMsg]);
            exit;
        }
    }

    public static function getInstance(): \Redis
    {
        if (self::$instance === null) {
            new self();
        }
        return self::$instance;
    }

    private function __clone() {}
    public function __wakeup()
    {
        throw new \Exception("Cannot unserialize singleton");
    }
}