SimpleNav/login.php

<?php
/**
 * 简航 SimpleNav —— 管理员登录 / 首次初始化
 */
declare(strict_types=1);
require_once __DIR__ . '/functions.php';
if (session_status() !== PHP_SESSION_ACTIVE) {
    session_start();
}
send_no_cache();

$hasAdmin = (int)db()->query('SELECT COUNT(*) FROM users')->fetchColumn() > 0;
$err = '';

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $u = trim((string)($_POST['username'] ?? ''));
    $p = (string)($_POST['password'] ?? '');
    if ($u === '' || $p === '') {
        $err = '请输入用户名和密码';
    } elseif (mb_strlen($p) < 4) {
        $err = '密码至少 4 位';
    } elseif (!$hasAdmin) {
        // 首次创建管理员
        $st = db()->prepare('INSERT INTO users (username, password_hash, created_at) VALUES (?,?,?)');
        $st->execute([$u, password_hash($p, PASSWORD_DEFAULT), date('Y-m-d H:i:s')]);
        $_SESSION['uid'] = (int)db()->lastInsertId();
        header('Location: ' . url('admin/'));
        exit;
    } else {
        // 登录校验
        $st = db()->prepare('SELECT * FROM users WHERE username=? LIMIT 1');
        $st->execute([$u]);
        $row = $st->fetch();
        if ($row && password_verify($p, $row['password_hash'])) {
            $_SESSION['uid'] = (int)$row['id'];
            header('Location: ' . url('admin/'));
            exit;
        }
        $err = '用户名或密码错误';
    }
}
$title = $hasAdmin ? '登录' : '初始化管理员';
?><!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title><?= e($title) ?> · <?= e(site_name()) ?></title>
<link rel="stylesheet" href="<?= e(asset('assets/css/style.css')) ?>">
<link rel="stylesheet" href="<?= e(asset('assets/css/admin.css')) ?>">
<?= site_icon_head() ?>
</head>
<body class="admin">
<div class="login-wrap">
  <form class="login-card" method="post" action="">
    <img class="login-logo" src="<?= e(site_icon_url('logo', 512) ?: url('assets/img/logo.svg')) ?>" alt="" onerror="this.style.display='none'">
    <h1><?= e(site_name()) ?></h1>
    <p class="sub"><?= $hasAdmin ? '管理员登录' : '首次使用，请创建管理员账号' ?></p>
    <?php if ($err): ?><div class="alert"><?= e($err) ?></div><?php endif; ?>
    <input type="text" name="username" placeholder="用户名" autocomplete="username" required>
    <input type="password" name="password" placeholder="密码" autocomplete="<?= $hasAdmin ? 'current-password' : 'new-password' ?>" required>
    <button type="submit" class="btn primary block"><?= $hasAdmin ? '登录' : '创建并进入' ?></button>
  </form>
</div>
</body>
</html>