<?php
declare(strict_types=1);

require_once __DIR__ . '/db.php';

if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
    error_out('Method not allowed', 405);
}

$db  = db();
$row = $db->query(
    "SELECT setting_value FROM `system` WHERE setting_name = 'clickatell_api_key'"
)->fetch();

$api_key = $row['setting_value'] ?? '';
if ($api_key === '') {
    json_out(['error' => 'API key not configured', 'balance' => null]);
}

$ch = curl_init('https://platform.clickatell.com/public-client/balance');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT        => 10,
    CURLOPT_HTTPHEADER     => [
        'Authorization: ' . $api_key,
        'Accept: application/json',
        'Content-Type: application/json',
    ],
]);

$body    = curl_exec($ch);
$status  = curl_getinfo($ch, CURLINFO_HTTP_CODE);
$err     = curl_error($ch);
curl_close($ch);

if ($err !== '') {
    json_out(['error' => 'Request failed: ' . $err, 'balance' => null]);
}

$data = json_decode($body ?: '', true);

if ($status !== 200 || $data === null) {
    json_out(['error' => 'Unexpected response (HTTP ' . $status . ')', 'balance' => null, 'raw' => $body]);
}

$credit = null;
$currency = $data['currency'] ?? null;

if (isset($data['balance']) && is_numeric($data['balance'])) {
    // Flat format: {"balance": 89.99, "currency": "GBP"}
    $credit = $data['balance'];
} elseif (isset($data['balance']) && is_array($data['balance']) && isset($data['balance'][0]['credit'])) {
    // Array format: {"balance": [{"credit": "99.50", ...}]}
    $credit = $data['balance'][0]['credit'];
    $currency = $currency ?? ($data['balance'][0]['currency'] ?? null);
} elseif (isset($data['credit'])) {
    $credit = $data['credit'];
} elseif (isset($data['data']['credit'])) {
    $credit = $data['data']['credit'];
}

json_out(['balance' => $credit, 'currency' => $currency]);