<?php
class Api
{
    public $api_url = 'https://www.smmexchanges.info/api.php';
    public $api_key = '';

    public function __construct($api_key)
    {
        $this->api_key = $api_key;
    }

    public function order($data)
    {
        $post = array_merge(array('key' => $this->api_key, 'action' => 'add'), $data);
        return json_decode($this->connect($post));
    }

    public function status($order_id)
    {
        return json_decode($this->connect(array(
            'key' => $this->api_key,
            'action' => 'status',
            'order' => $order_id
        )));
    }

    public function services()
    {
        return json_decode($this->connect(array(
            'key' => $this->api_key,
            'action' => 'services'
        )));
    }

    public function balance()
    {
        return json_decode($this->connect(array(
            'key' => $this->api_key,
            'action' => 'balance'
        )));
    }

    private function connect($post)
    {
        $_post = Array();
        if (is_array($post)) {
            foreach ($post as $name => $value) {
                $_post[] = $name.'='.urlencode($value);
            }
        }
        $ch = curl_init($this->api_url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_HEADER, 0);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
        if (is_array($post)) {
            curl_setopt($ch, CURLOPT_POSTFIELDS, join('&', $_post));
        }
        $result = curl_exec($ch);
        curl_close($ch);
        return $result;
    }
}

// Examples
$api = new Api('YOUR_API_KEY');

// Get Services
$services = $api->services();

// Add Order
$order = $api->order(array('service' => 1, 'link' => 'http://example.com/test', 'quantity' => 100));

// Get Status
$status = $api->status($order->order);

// Get Balance
$balance = $api->balance();
?>