<?php
// Run: NUEPAY_TEST_KEY=np_test_... php nuepay.php
// Requires PHP with cURL. This example accepts test keys only.
$key = getenv('NUEPAY_TEST_KEY') ?: '';
$base = rtrim(getenv('NUEPAY_BASE_URL') ?: 'https://api.nuepay.net/v1', '/');
if (!preg_match('/^np_test_[a-f0-9]{48}$/D', $key)) throw new RuntimeException('Set NUEPAY_TEST_KEY to your sandbox key.');
function nuepay(string $method, string $path, ?array $body = null, ?string $idempotency = null): array {
    global $key, $base;
    $headers = ['Authorization: Bearer '.$key, 'Accept: application/json', 'Content-Type: application/json'];
    if ($idempotency) $headers[] = 'Idempotency-Key: '.$idempotency;
    $curl = curl_init($base.$path);
    curl_setopt_array($curl, [CURLOPT_CUSTOMREQUEST => $method, CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HTTPHEADER => $headers, CURLOPT_CONNECTTIMEOUT => 10, CURLOPT_TIMEOUT => 30,
        CURLOPT_FOLLOWLOCATION => false]);
    if ($body !== null) curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($body, JSON_THROW_ON_ERROR));
    $raw = curl_exec($curl);
    $status = curl_getinfo($curl, CURLINFO_RESPONSE_CODE);
    if ($raw === false) throw new RuntimeException('Connection failed. Retry the same payment with its existing idempotency UUID.');
    $response = json_decode($raw, true, 512, JSON_THROW_ON_ERROR);
    if ($status < 200 || $status >= 300) throw new RuntimeException(($response['code'] ?? 'request_failed').': '.($response['message'] ?? '').' Request ID: '.($response['request_id'] ?? ''));
    return $response['data'];
}
$bytes = random_bytes(16); $bytes[6] = chr((ord($bytes[6]) & 15) | 64); $bytes[8] = chr((ord($bytes[8]) & 63) | 128);
$hex = bin2hex($bytes); $uuid = substr($hex,0,8).'-'.substr($hex,8,4).'-'.substr($hex,12,4).'-'.substr($hex,16,4).'-'.substr($hex,20);
// Persist this UUID with the order before sending. Keep it for all retries of this payment.
$payment = nuepay('POST', '/collections', ['amount'=>'500.00', 'currency'=>'UGX', 'phone'=>'0772000000', 'merchant_reference'=>'example-order'], $uuid);
$result = nuepay('POST', '/sandbox/transactions/'.$payment['reference'].'/simulate', ['outcome'=>'success']);
echo json_encode($result, JSON_PRETTY_PRINT | JSON_THROW_ON_ERROR).PHP_EOL;