<?php
$file = 'devices.json';

$data = json_decode(file_get_contents($file), true);

$id = $_POST['id'];
$name = $_POST['name'];

$found = false;

foreach ($data['devices'] as &$device) {
    if ($device['id'] === $id) {
        $device['last_seen'] = time();
        $device['status'] = 'online';
        $found = true;
    }
}

if (!$found) {
    $data['devices'][] = [
        "id" => $id,
        "name" => $name,
        "last_seen" => time(),
        "status" => "online"
    ];
}

file_put_contents($file, json_encode($data, JSON_PRETTY_PRINT));
echo "OK";
?>