<?php
if (!isset($_GET['user'])) {
    http_response_code(400);
    exit("Missing user");
}

$user = preg_replace('/[^a-zA-Z0-9_-]/', '', $_GET['user']);
header("Content-Type: text/event-stream");
header("Cache-Control: no-cache");
header("Connection: keep-alive");

$tmp_file = sys_get_temp_dir() . "/relay_chat_{$user}.txt";

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

$last_modif = 0;

while (true) {
    clearstatcache();
    $current_modif = filemtime($tmp_file);

    if ($current_modif > $last_modif) {
        $last_modif = $current_modif;
        $data = file_get_contents($tmp_file);
        echo "data: " . trim($data) . "\n\n";
        ob_flush();
        flush();
    }

    sleep(1);
}
?>