<?php
const MVLOG_AUTH_CONFIG = '/etc/mvlog/auth.php';

function mvlog_session_start(): void {
    if (session_status() === PHP_SESSION_ACTIVE) return;
    $secure = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off');
    session_name('MVLOGSESSID');
    session_set_cookie_params([
        'lifetime' => 0,
        'path' => '/mvlog',
        'secure' => $secure,
        'httponly' => true,
        'samesite' => 'Strict',
    ]);
    session_start();
}

function mvlog_auth_config(): array {
    if (!is_file(MVLOG_AUTH_CONFIG)) return ['users' => []];
    $config = require MVLOG_AUTH_CONFIG;
    return is_array($config) ? $config : ['users' => []];
}

function mvlog_login(string $user, string $password): bool {
    mvlog_session_start();
    $users = mvlog_auth_config()['users'] ?? [];
    $hash = is_array($users) ? ($users[$user] ?? null) : null;
    if (!is_string($hash) || !password_verify($password, $hash)) return false;
    session_regenerate_id(true);
    $_SESSION['mvlog_user'] = $user;
    $_SESSION['mvlog_login_at'] = time();
    return true;
}

function mvlog_current_user(): ?string {
    mvlog_session_start();
    return isset($_SESSION['mvlog_user']) && is_string($_SESSION['mvlog_user']) ? $_SESSION['mvlog_user'] : null;
}

function mvlog_require_login(): void {
    if (mvlog_current_user() !== null) return;
    $next = $_SERVER['REQUEST_URI'] ?? '/mvlog/new.php';
    header('Location: login.php?next=' . rawurlencode($next));
    exit;
}

function mvlog_logout(): void {
    mvlog_session_start();
    $_SESSION = [];
    if (ini_get('session.use_cookies')) {
        $params = session_get_cookie_params();
        setcookie(session_name(), '', time() - 42000, $params['path'], $params['domain'] ?? '', $params['secure'], $params['httponly']);
    }
    session_destroy();
}

function mvlog_safe_next(string $next): string {
    if ($next === '' || str_contains($next, "\n") || str_contains($next, "\r")) return 'new.php';
    $parts = parse_url($next);
    if ($parts === false || isset($parts['scheme']) || isset($parts['host'])) return 'new.php';
    return $next;
}