if (!defined('PRAXIS_API_TEST_DOMAIN')) define('PRAXIS_API_TEST_DOMAIN', 'https://gateway.cashier-test.com');
if (!defined('PRAXIS_API_LIVE_DOMAIN')) define('PRAXIS_API_LIVE_DOMAIN', 'https://gateway.praxispay.com');

$url = PRAXIS_API_TEST_DOMAIN . '/cashier/cashier';
$merchant_id = '';
$merchant_secret = '';
$application_key = '';
$gateway = null;
$time = time();

if (empty($merchant_id) || empty($merchant_secret) || empty($application_key)) {
    die('Variables must be set: $merchant_id, $merchant_secret, $application_key');
}

$data = [
    'currency' => 'USD',
    'amount' => 300,
    'balance' => 10000,
    'cid' => 'praxistest-' . $time,
    'locale' => 'en-GB',
    'gateway' => $gateway,
    'version' => '1.3',
    'timestamp' => $time,
    'country' => 'GB',
    'merchant_id' => $merchant_id,
    'application_key' => $application_key,
    'intent' => 'payment',
    'customer_data' => [
        'email' => 'praxistest@nomail.com',
        'country' => 'GB',
        'zip' => '123456',
        'city' => 'Some City',
        'address' => 'Some st., 123',
    ],
    'notification_url' => 'https://domain.does.not.exist/notification',
    'return_url' => 'https://domain.does.not.exist/return',
    'order_id' => 'order_' . $time,
];


$signature = [
	$data['merchant_id'],
	$data['application_key'],
	$data['timestamp'],
	$data['intent'],
	$data['cid'],
	$data['order_id'],
];

$signature = implode('', $signature);
$signature = hash('sha384', $signature . $merchant_secret);

$request = curl_init();
curl_setopt_array($request, [
	CURLOPT_URL => $url,
	CURLOPT_CUSTOMREQUEST => 'POST',
	CURLOPT_POSTFIELDS => json_encode($data),
	CURLOPT_RETURNTRANSFER => true,
	CURLOPT_HEADER => false,
	CURLOPT_FOLLOWLOCATION => true,
	CURLOPT_SSL_VERIFYHOST => true,
	CURLOPT_SSL_VERIFYPEER => false,
	CURLINFO_HEADER_OUT => true,
	CURLOPT_HTTPHEADER => [
		'Content-Type: application/json; charset=utf-8',
		'GT-Authentication: ' . $signature,
	],
]);

$response = curl_exec($request);
$info = curl_getinfo($request);
curl_close($request);

try {
    $response_data = json_decode($response, true);

    if (is_array($response_data) && isset($response_data['status']) && $response_data['status'] === 0 && isset($response_data['redirect_url'])) {
        echo $response_data['redirect_url'];
        die;
    } else if (is_array($response_data) && isset($response_data['description'])) {
        echo $response_data['description'];
        die;
    } else {
        echo 'Something went wrong';
        die;
    }
} catch (Exception $e) {
    echo $e->getMessage();
}