// Использовать в index.html, перед закрывающимся тегом /head
<script>
    document.addEventListener("DOMContentLoaded", function () {
        const form = document.querySelector("form");

        form.addEventListener("submit", function (event) {
            event.preventDefault();
            const now = Date.now();
            const requestLogs = JSON.parse(localStorage.getItem('requestLogs')) || [];

            const filteredLogs = requestLogs.filter(log => (now - log.timestamp) < 24 * 60 * 60 * 1000);

            if (filteredLogs.length >= 2) {
                window.location.href = 'error.php';
            } else {
                filteredLogs.push({ timestamp: now });
                localStorage.setItem('requestLogs', JSON.stringify(filteredLogs));
                form.submit();
            }
        });
    });
</script>


// Использовать в api.php, после открывающего тега php

function isDuplicateLead($phone)
{
$file = 'leads.txt';

if (!file_exists($file)) {
file_put_contents($file, '');
}

$leads = file_get_contents($file);
$escapedPhone = preg_quote($phone, '/');
$phonePattern = '/' . $escapedPhone . "\n/";

if (preg_match($phonePattern, $leads)) {
return true;
} else {
file_put_contents($file, $phone . "\n", FILE_APPEND);
return false;
}
}

function cleanPhoneNumber($phoneNumber)
{
return preg_replace('/[^0-9]/', '', $phoneNumber);
}

$cleanedPhone = cleanPhoneNumber($_POST['phone']);

if (isDuplicateLead($cleanedPhone)) {
header('Location: error.php');
exit;
}