<?php
session_start();

// 配置
define('DB_FILE', 'notes.db');
define('UPLOAD_DIR', 'uploads');
define('IMAGES_DIR', 'uploads/images');
define('APP_NAME', '简约记事本');
define('VERSION', '1.0.0');
define('NOTES_PER_PAGE', 25);
define('ENCRYPTION_KEY', 'YourSecretKey123!@#'); // 修改为你自己的密钥

// 确保上传目录存在
if (!file_exists(UPLOAD_DIR)) {
    mkdir(UPLOAD_DIR, 0755, true);
}

// 确保图片目录存在
if (!file_exists(IMAGES_DIR)) {
    mkdir(IMAGES_DIR, 0755, true);
}

// 获取当前页面基础URL
function getBaseUrl() {
    $protocol = isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? 'https' : 'http';
    $host = $_SERVER['HTTP_HOST'];
    $path = dirname($_SERVER['PHP_SELF']);
    return $protocol . '://' . $host . $path;
}

// 获取当前文件名
function getCurrentFile() {
    return basename($_SERVER['PHP_SELF']);
}

// 获取返回首页的URL
function getHomeUrl() {
    $currentFile = getCurrentFile();
    // 如果当前文件是 index.php 或者是目录下的默认文件
    if ($currentFile === 'index.php' || $currentFile === basename(dirname($_SERVER['PHP_SELF'])) . '.php') {
        return getBaseUrl() . '/';
    } else {
        return getBaseUrl() . '/' . $currentFile;
    }
}

// 加密类
class Encryption {
    private static $method = 'AES-256-CBC';
    private static $key = ENCRYPTION_KEY;
    
    public static function encrypt($data) {
        if (empty($data)) return $data;
        $iv = openssl_random_pseudo_bytes(16);
        $encrypted = openssl_encrypt($data, self::$method, self::$key, 0, $iv);
        return base64_encode($iv . $encrypted);
    }
    
    public static function decrypt($data) {
        if (empty($data)) return $data;
        $data = base64_decode($data);
        $iv = substr($data, 0, 16);
        $encrypted = substr($data, 16);
        return openssl_decrypt($encrypted, self::$method, self::$key, 0, $iv);
    }
}

// 处理内容中的链接和图片
function processContent($content) {
    // 自动下载外部图片并替换为本地链接
    $content = processExternalImages($content);
    
    // 自动识别URL并转换为Markdown链接格式
    $content = autoFormatLinks($content);
    
    return $content;
}

// 自动下载外部图片
function processExternalImages($content) {
    // 匹配Markdown图片格式
    $pattern = '/!\[(.*?)\]\((https?:\/\/[^\s)]+)\)/';
    
    $content = preg_replace_callback($pattern, function($matches) {
        $alt = $matches[1];
        $url = $matches[2];
        
        // 检查是否是外部图片URL
        if (isExternalImage($url)) {
            $localPath = downloadAndSaveImage($url);
            if ($localPath) {
                return '![' . $alt . '](' . $localPath . ')';
            }
        }
        
        return $matches[0];
    }, $content);
    
    // 匹配纯图片URL（非Markdown格式）
    $pattern = '/(?<!\]\()https?:\/\/[^\s]*\.(jpg|jpeg|png|gif|webp)(?!\))/i';
    
    $content = preg_replace_callback($pattern, function($matches) {
        $url = $matches[0];
        
        // 检查是否是外部图片URL
        if (isExternalImage($url)) {
            $localPath = downloadAndSaveImage($url);
            if ($localPath) {
                return '![](' . $localPath . ')';
            }
        }
        
        return $url;
    }, $content);
    
    return $content;
}

// 检查是否是外部图片URL
function isExternalImage($url) {
    // 检查是否是HTTP/HTTPS URL
    if (!preg_match('/^https?:\/\//', $url)) {
        return false;
    }
    
    // 检查是否是当前域名的URL
    $baseUrl = getBaseUrl();
    if (strpos($url, $baseUrl) === 0) {
        return false;
    }
    
    // 检查URL是否包含图片扩展名
    $imageExtensions = ['jpg', 'jpeg', 'png', 'gif', 'webp'];
    $extension = strtolower(pathinfo($url, PATHINFO_EXTENSION));
    
    return in_array($extension, $imageExtensions);
}

// 下载并保存图片
function downloadAndSaveImage($url) {
    try {
        // 获取图片内容
        $imageData = file_get_contents($url);
        if (!$imageData) {
            return false;
        }
        
        // 获取图片信息
        $imageInfo = getimagesizefromstring($imageData);
        if (!$imageInfo) {
            return false;
        }
        
        // 生成唯一文件名
        $extension = image_type_to_extension($imageInfo[2]);
        $filename = uniqid() . $extension;
        $filepath = IMAGES_DIR . '/' . $filename;
        
        // 保存图片
        if (file_put_contents($filepath, $imageData)) {
            // 返回相对于当前脚本的路径
            return IMAGES_DIR . '/' . $filename;
        }
        
        return false;
    } catch (Exception $e) {
        return false;
    }
}

// 自动格式化链接
function autoFormatLinks($content) {
    // 匹配非Markdown格式的URL，但排除已经是Markdown链接的部分
    $pattern = '/(?<![\[\(])https?:\/\/[^\s\)]+(?![\)\]])/i';
    
    $content = preg_replace_callback($pattern, function($matches) {
        $url = $matches[0];
        
        // 如果是图片URL，则跳过（已在processExternalImages中处理）
        if (isExternalImage($url)) {
            return $url;
        }
        
        // 转换为Markdown链接格式
        return '[' . $url . '](' . $url . ')';
    }, $content);
    
    return $content;
}

// 初始化数据库
function initDatabase() {
    try {
        $db = new SQLite3(DB_FILE);
        
        // 创建用户表
        $db->exec('
            CREATE TABLE IF NOT EXISTS users (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                username TEXT UNIQUE NOT NULL,
                password TEXT NOT NULL,
                created_at DATETIME DEFAULT CURRENT_TIMESTAMP
            )
        ');
        
        // 创建笔记表（标题不加密，内容加密）
        $db->exec('
            CREATE TABLE IF NOT EXISTS notes (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                title TEXT NOT NULL,
                content_enc TEXT NOT NULL,
                tags TEXT,
                created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
                updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
            )
        ');
        
        // 创建附件表
        $db->exec('
            CREATE TABLE IF NOT EXISTS attachments (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                note_id INTEGER NOT NULL,
                filename TEXT NOT NULL,
                original_name TEXT NOT NULL,
                file_size INTEGER NOT NULL,
                file_type TEXT NOT NULL,
                upload_time DATETIME DEFAULT CURRENT_TIMESTAMP,
                FOREIGN KEY (note_id) REFERENCES notes (id) ON DELETE CASCADE
            )
        ');
        
        // 创建分享表
        $db->exec('
            CREATE TABLE IF NOT EXISTS shares (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                note_id INTEGER NOT NULL,
                share_token TEXT UNIQUE NOT NULL,
                password TEXT,
                view_limit INTEGER DEFAULT 0,
                view_count INTEGER DEFAULT 0,
                expires_at DATETIME,
                created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
                FOREIGN KEY (note_id) REFERENCES notes (id) ON DELETE CASCADE
            )
        ');
        
        // 创建索引
        $db->exec('CREATE INDEX IF NOT EXISTS idx_notes_title ON notes(title)');
        $db->exec('CREATE INDEX IF NOT EXISTS idx_notes_tags ON notes(tags)');
        $db->exec('CREATE INDEX IF NOT EXISTS idx_notes_created ON notes(created_at)');
        $db->exec('CREATE INDEX IF NOT EXISTS idx_attachments_note_id ON attachments(note_id)');
        $db->exec('CREATE INDEX IF NOT EXISTS idx_shares_token ON shares(share_token)');
        $db->exec('CREATE INDEX IF NOT EXISTS idx_shares_note_id ON shares(note_id)');
        
        return $db;
    } catch (Exception $e) {
        die('数据库初始化失败: ' . $e->getMessage());
    }
}

// 获取数据库连接
function getDB() {
    static $db = null;
    if ($db === null) {
        $db = initDatabase();
    }
    return $db;
}

// 检查是否已初始化
function isInitialized() {
    $db = getDB();
    $result = $db->querySingle('SELECT COUNT(*) FROM users');
    return $result > 0;
}

// 验证用户登录
function verifyUser($username, $password) {
    $db = getDB();
    $stmt = $db->prepare('SELECT password FROM users WHERE username = ?');
    $stmt->bindValue(1, $username, SQLITE3_TEXT);
    $result = $stmt->execute();
    $user = $result->fetchArray(SQLITE3_ASSOC);
    
    if ($user && password_verify($password, $user['password'])) {
        return true;
    }
    return false;
}

// 创建用户
function createUser($username, $password) {
    $db = getDB();
    $hashedPassword = password_hash($password, PASSWORD_DEFAULT);
    $stmt = $db->prepare('INSERT INTO users (username, password) VALUES (?, ?)');
    $stmt->bindValue(1, $username, SQLITE3_TEXT);
    $stmt->bindValue(2, $hashedPassword, SQLITE3_TEXT);
    return $stmt->execute();
}

// 更新用户密码
function updatePassword($newPassword) {
    $db = getDB();
    $hashedPassword = password_hash($newPassword, PASSWORD_DEFAULT);
    $stmt = $db->prepare('UPDATE users SET password = ? WHERE id = 1');
    $stmt->bindValue(1, $hashedPassword, SQLITE3_TEXT);
    return $stmt->execute();
}

// 获取笔记总数
function getNotesCount($search = '', $tag = '') {
    $db = getDB();
    $sql = 'SELECT COUNT(*) FROM notes WHERE 1=1';
    $params = [];
    
    if ($search) {
        // 现在可以搜索标题了
        $sql .= ' AND (title LIKE ? OR tags LIKE ?)';
        $searchParam = '%' . $search . '%';
        $params[] = $searchParam;
        $params[] = $searchParam;
    }
    
    if ($tag) {
        $sql .= ' AND tags LIKE ?';
        $params[] = '%' . $tag . '%';
    }
    
    $stmt = $db->prepare($sql);
    foreach ($params as $i => $param) {
        $stmt->bindValue($i + 1, $param, SQLITE3_TEXT);
    }
    
    return $stmt->execute()->fetchArray()[0];
}

// 获取笔记列表（分页）
function getNotes($page = 1, $search = '', $tag = '') {
    $db = getDB();
    $offset = ($page - 1) * NOTES_PER_PAGE;
    
    $sql = 'SELECT * FROM notes WHERE 1=1';
    $params = [];
    
    if ($search) {
        $sql .= ' AND (title LIKE ? OR tags LIKE ?)';
        $params[] = '%' . $search . '%';
        $params[] = '%' . $search . '%';
    }
    
    if ($tag) {
        $sql .= ' AND tags LIKE ?';
        $params[] = '%' . $tag . '%';
    }
    
    $sql .= ' ORDER BY updated_at DESC LIMIT ? OFFSET ?';
    $params[] = NOTES_PER_PAGE;
    $params[] = $offset;
    
    $stmt = $db->prepare($sql);
    foreach ($params as $i => $param) {
        $stmt->bindValue($i + 1, $param, SQLITE3_TEXT);
    }
    
    $result = $stmt->execute();
    $notes = [];
    
    while ($row = $result->fetchArray(SQLITE3_ASSOC)) {
        // 只解密内容，标题不需要解密
        $row['content'] = Encryption::decrypt($row['content_enc']);
        unset($row['content_enc']);
        $notes[] = $row;
    }
    
    return $notes;
}

// 获取单条笔记
function getNote($id) {
    $db = getDB();
    $stmt = $db->prepare('SELECT * FROM notes WHERE id = ?');
    $stmt->bindValue(1, $id, SQLITE3_INTEGER);
    $result = $stmt->execute();
    $note = $result->fetchArray(SQLITE3_ASSOC);
    
    if ($note) {
        // 只解密内容，标题不需要解密
        $note['content'] = Encryption::decrypt($note['content_enc']);
        unset($note['content_enc']);
    }
    
    return $note;
}

// 创建笔记
function createNote($title, $content, $tags) {
    $db = getDB();
    
    // 处理内容中的链接和图片
    $processedContent = processContent($content);
    
    $stmt = $db->prepare('INSERT INTO notes (title, content_enc, tags) VALUES (?, ?, ?)');
    $stmt->bindValue(1, $title, SQLITE3_TEXT);
    $stmt->bindValue(2, Encryption::encrypt($processedContent), SQLITE3_TEXT);
    $stmt->bindValue(3, $tags, SQLITE3_TEXT);
    $stmt->execute();
    return $db->lastInsertRowID();
}

// 更新笔记
function updateNote($id, $title, $content, $tags) {
    $db = getDB();
    
    // 处理内容中的链接和图片
    $processedContent = processContent($content);
    
    $stmt = $db->prepare('UPDATE notes SET title = ?, content_enc = ?, tags = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?');
    $stmt->bindValue(1, $title, SQLITE3_TEXT);
    $stmt->bindValue(2, Encryption::encrypt($processedContent), SQLITE3_TEXT);
    $stmt->bindValue(3, $tags, SQLITE3_TEXT);
    $stmt->bindValue(4, $id, SQLITE3_INTEGER);
    return $stmt->execute();
}

// 删除笔记
function deleteNote($id) {
    $db = getDB();
    $stmt = $db->prepare('DELETE FROM notes WHERE id = ?');
    $stmt->bindValue(1, $id, SQLITE3_INTEGER);
    return $stmt->execute();
}

// 获取笔记附件
function getNoteAttachments($noteId) {
    $db = getDB();
    $stmt = $db->prepare('SELECT * FROM attachments WHERE note_id = ? ORDER BY upload_time DESC');
    $stmt->bindValue(1, $noteId, SQLITE3_INTEGER);
    $result = $stmt->execute();
    $attachments = [];
    
    while ($row = $result->fetchArray(SQLITE3_ASSOC)) {
        $attachments[] = $row;
    }
    
    return $attachments;
}

// 添加附件
function addAttachment($noteId, $filename, $originalName, $fileSize, $fileType) {
    $db = getDB();
    $stmt = $db->prepare('INSERT INTO attachments (note_id, filename, original_name, file_size, file_type) VALUES (?, ?, ?, ?, ?)');
    $stmt->bindValue(1, $noteId, SQLITE3_INTEGER);
    $stmt->bindValue(2, $filename, SQLITE3_TEXT);
    $stmt->bindValue(3, $originalName, SQLITE3_TEXT);
    $stmt->bindValue(4, $fileSize, SQLITE3_INTEGER);
    $stmt->bindValue(5, $fileType, SQLITE3_TEXT);
    return $stmt->execute();
}

// 删除附件
function deleteAttachment($id) {
    $db = getDB();
    $stmt = $db->prepare('SELECT filename FROM attachments WHERE id = ?');
    $stmt->bindValue(1, $id, SQLITE3_INTEGER);
    $result = $stmt->execute();
    $attachment = $result->fetchArray(SQLITE3_ASSOC);
    
    if ($attachment && file_exists(UPLOAD_DIR . '/' . $attachment['filename'])) {
        unlink(UPLOAD_DIR . '/' . $attachment['filename']);
    }
    
    $stmt = $db->prepare('DELETE FROM attachments WHERE id = ?');
    $stmt->bindValue(1, $id, SQLITE3_INTEGER);
    return $stmt->execute();
}

// 获取所有标签
function getAllTags() {
    $db = getDB();
    $result = $db->query('SELECT tags FROM notes WHERE tags IS NOT NULL AND tags != ""');
    $tags = [];
    
    while ($row = $result->fetchArray(SQLITE3_ASSOC)) {
        $noteTags = explode(',', $row['tags']);
        foreach ($noteTags as $tag) {
            $tag = trim($tag);
            if ($tag && !in_array($tag, $tags)) {
                $tags[] = $tag;
            }
        }
    }
    
    sort($tags);
    return $tags;
}

// 处理文件上传
function handleFileUpload($file, $noteId) {
    if ($file['error'] !== UPLOAD_ERR_OK) {
        return false;
    }
    
    $allowedTypes = ['image/jpeg', 'image/png', 'image/gif', 'image/webp', 'application/pdf', 'text/plain', 'application/msword', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'];
    $maxSize = 10 * 1024 * 1024; // 10MB
    
    if (!in_array($file['type'], $allowedTypes) || $file['size'] > $maxSize) {
        return false;
    }
    
    $extension = pathinfo($file['name'], PATHINFO_EXTENSION);
    $filename = uniqid() . '.' . $extension;
    $uploadPath = UPLOAD_DIR . '/' . $filename;
    
    if (move_uploaded_file($file['tmp_name'], $uploadPath)) {
        addAttachment($noteId, $filename, $file['name'], $file['size'], $file['type']);
        return $filename;
    }
    
    return false;
}

// Markdown转HTML（增强版）
function markdownToHtml($markdown) {
    // 简单的Markdown解析
    $html = $markdown;
    
    // 图片（支持本地上传的图片）
    $html = preg_replace('/!\[(.*?)\]\((.*?)\)/', '<img src="$2" alt="$1" style="max-width: 100%; height: auto; border-radius: 6px; margin: 10px 0;">', $html);
    
    // 标题
    $html = preg_replace('/^### (.*$)/m', '<h3>$1</h3>', $html);
    $html = preg_replace('/^## (.*$)/m', '<h2>$1</h2>', $html);
    $html = preg_replace('/^# (.*$)/m', '<h1>$1</h1>', $html);
    
    // 粗体和斜体
    $html = preg_replace('/\*\*(.*?)\*\*/', '<strong>$1</strong>', $html);
    $html = preg_replace('/\*(.*?)\*/', '<em>$1</em>', $html);
    
    // 代码块
    $html = preg_replace('/```(.*?)```/s', '<pre><code>$1</code></pre>', $html);
    $html = preg_replace('/`(.*?)`/', '<code>$1</code>', $html);
    
    // 链接
    $html = preg_replace('/\[(.*?)\]\((.*?)\)/', '<a href="$2" target="_blank">$1</a>', $html);
    
    // 无序列表
    $html = preg_replace('/^\* (.+)$/m', '<li>$1</li>', $html);
    $html = preg_replace('/(<li>.*<\/li>)/s', '<ul>$1</ul>', $html);
    
    // 有序列表
    $html = preg_replace('/^\d+\. (.+)$/m', '<li>$1</li>', $html);
    
    // 引用
    $html = preg_replace('/^> (.+)$/m', '<blockquote>$1</blockquote>', $html);
    
    // 换行
    $html = preg_replace('/\n\n/', '</p><p>', $html);
    $html = preg_replace('/\n/', '<br>', $html);
    
    // 段落
    $html = '<p>' . $html . '</p>';
    
    // 清理多余的段落标签
    $html = preg_replace('/<p><\/p>/', '', $html);
    $html = preg_replace('/<p>(<h[1-6]>)/', '$1', $html);
    $html = preg_replace('/(<\/h[1-6]>)<\/p>/', '$1', $html);
    $html = preg_replace('/<p>(<pre>)/', '$1', $html);
    $html = preg_replace('/(<\/pre>)<\/p>/', '$1', $html);
    $html = preg_replace('/<p>(<ul>)/', '$1', $html);
    $html = preg_replace('/(<\/ul>)<\/p>/', '$1', $html);
    $html = preg_replace('/<p>(<blockquote>)/', '$1', $html);
    $html = preg_replace('/(<\/blockquote>)<\/p>/', '$1', $html);
    $html = preg_replace('/<p>(<li>)/', '$1', $html);
    $html = preg_replace('/(<\/li>)<\/p>/', '$1', $html);
    
    return $html;
}

// 检查登录状态
function isLoggedIn() {
    return isset($_SESSION['user_id']);
}

// 创建分享
function createShare($noteId, $password = null, $viewLimit = 0, $expiresAt = null) {
    $db = getDB();
    
    // 生成唯一的分享令牌
    $shareToken = bin2hex(random_bytes(16));
    
    $stmt = $db->prepare('INSERT INTO shares (note_id, share_token, password, view_limit, expires_at) VALUES (?, ?, ?, ?, ?)');
    $stmt->bindValue(1, $noteId, SQLITE3_INTEGER);
    $stmt->bindValue(2, $shareToken, SQLITE3_TEXT);
    $stmt->bindValue(3, $password ? password_hash($password, PASSWORD_DEFAULT) : null, SQLITE3_TEXT);
    $stmt->bindValue(4, $viewLimit, SQLITE3_INTEGER);
    $stmt->bindValue(5, $expiresAt, SQLITE3_TEXT);
    $stmt->execute();
    
    return $shareToken;
}

// 获取分享信息
function getShareByToken($token) {
    $db = getDB();
    $stmt = $db->prepare('SELECT * FROM shares WHERE share_token = ?');
    $stmt->bindValue(1, $token, SQLITE3_TEXT);
    $result = $stmt->execute();
    $share = $result->fetchArray(SQLITE3_ASSOC);
    
    if ($share) {
        // 检查是否过期
        if ($share['expires_at'] && strtotime($share['expires_at']) < time()) {
            return null;
        }
        
        // 检查查看次数限制
        if ($share['view_limit'] > 0 && $share['view_count'] >= $share['view_limit']) {
            return null;
        }
        
        // 增加查看次数
        $updateStmt = $db->prepare('UPDATE shares SET view_count = view_count + 1 WHERE id = ?');
        $updateStmt->bindValue(1, $share['id'], SQLITE3_INTEGER);
        $updateStmt->execute();
    }
    
    return $share;
}

// 获取笔记的分享列表
function getNoteShares($noteId) {
    $db = getDB();
    $stmt = $db->prepare('SELECT * FROM shares WHERE note_id = ? ORDER BY created_at DESC');
    $stmt->bindValue(1, $noteId, SQLITE3_INTEGER);
    $result = $stmt->execute();
    $shares = [];
    
    while ($row = $result->fetchArray(SQLITE3_ASSOC)) {
        $shares[] = $row;
    }
    
    return $shares;
}

// 删除分享
function deleteShare($id) {
    $db = getDB();
    $stmt = $db->prepare('DELETE FROM shares WHERE id = ?');
    $stmt->bindValue(1, $id, SQLITE3_INTEGER);
    return $stmt->execute();
}

// 处理登录
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action'])) {
    if ($_POST['action'] === 'init') {
        $username = trim($_POST['username'] ?? '');
        $password = $_POST['password'] ?? '';
        
        if ($username && $password) {
            if (createUser($username, $password)) {
                $_SESSION['user_id'] = 1;
                $_SESSION['username'] = $username;
                header('Location: ?');
                exit;
            } else {
                $error = '初始化失败';
            }
        } else {
            $error = '请填写完整信息';
        }
    } elseif ($_POST['action'] === 'login') {
        $username = trim($_POST['username'] ?? '');
        $password = $_POST['password'] ?? '';
        
        if (verifyUser($username, $password)) {
            $_SESSION['user_id'] = 1;
            $_SESSION['username'] = $username;
            header('Location: ?');
            exit;
        } else {
            $error = '用户名或密码错误';
        }
    } elseif ($_POST['action'] === 'change_password') {
        $oldPassword = $_POST['old_password'] ?? '';
        $newPassword = $_POST['new_password'] ?? '';
        
        if (verifyUser($_SESSION['username'], $oldPassword)) {
            if (updatePassword($newPassword)) {
                $success = '密码修改成功';
            } else {
                $error = '密码修改失败';
            }
        } else {
            $error = '原密码错误';
        }
    } elseif ($_POST['action'] === 'save_note') {
        if (!isLoggedIn()) {
            header('Location: ?');
            exit;
        }
        
        $id = intval($_POST['id'] ?? 0);
        $title = trim($_POST['title'] ?? '');
        $content = trim($_POST['content'] ?? '');
        $tags = trim($_POST['tags'] ?? '');
        
        if ($title && $content) {
            if ($id > 0) {
                updateNote($id, $title, $content, $tags);
                $noteId = $id;
            } else {
                $noteId = createNote($title, $content, $tags);
            }
            
            // 处理文件上传
            if (!empty($_FILES['attachments']['name'][0])) {
                foreach ($_FILES['attachments']['name'] as $key => $name) {
                    if (!empty($name)) {
                        $file = [
                            'name' => $name,
                            'type' => $_FILES['attachments']['type'][$key],
                            'tmp_name' => $_FILES['attachments']['tmp_name'][$key],
                            'error' => $_FILES['attachments']['error'][$key],
                            'size' => $_FILES['attachments']['size'][$key]
                        ];
                        handleFileUpload($file, $noteId);
                    }
                }
            }
            
            header('Location: ?');
            exit;
        } else {
            $error = '标题和内容不能为空';
        }
    } elseif ($_POST['action'] === 'create_share') {
        if (!isLoggedIn()) {
            header('Location: ?');
            exit;
        }
        
        $noteId = intval($_POST['note_id'] ?? 0);
        $password = trim($_POST['share_password'] ?? '');
        $viewLimit = intval($_POST['view_limit'] ?? 0);
        $expiresIn = intval($_POST['expires_in'] ?? 0);
        
        // 计算过期时间
        $expiresAt = null;
        if ($expiresIn > 0) {
            $expiresAt = date('Y-m-d H:i:s', time() + $expiresIn * 3600); // 小时转换为秒
        }
        
        $shareToken = createShare($noteId, $password ?: null, $viewLimit, $expiresAt);
        
        if ($shareToken) {
            $shareUrl = getBaseUrl() . '/' . getCurrentFile() . '?share=' . $shareToken;
            $_SESSION['share_success'] = '分享链接已创建: <a href="' . $shareUrl . '" target="_blank">' . $shareUrl . '</a>';
        } else {
            $error = '创建分享失败';
        }
        
        header('Location: ?view=' . $noteId);
        exit;
    }
}

// 处理删除
if (isset($_GET['delete']) && isLoggedIn()) {
    $id = intval($_GET['delete']);
    deleteNote($id);
    header('Location: ?');
    exit;
}

// 处理删除附件
if (isset($_GET['delete_attachment']) && isLoggedIn()) {
    $id = intval($_GET['delete_attachment']);
    deleteAttachment($id);
    header('Location: ' . $_SERVER['HTTP_REFERER']);
    exit;
}

// 处理删除分享
if (isset($_GET['delete_share']) && isLoggedIn()) {
    $id = intval($_GET['delete_share']);
    deleteShare($id);
    header('Location: ' . $_SERVER['HTTP_REFERER']);
    exit;
}

// 处理登出
if (isset($_GET['logout'])) {
    session_destroy();
    header('Location: ?');
    exit;
}

// 获取分页参数
 $page = max(1, intval($_GET['page'] ?? 1));
 $search = $_GET['search'] ?? '';
 $tag = $_GET['tag'] ?? '';

// 获取导航URL
 $homeUrl = getHomeUrl();

// 处理分享访问
if (isset($_GET['share'])) {
    $shareToken = $_GET['share'];
    $share = getShareByToken($shareToken);
    
    if (!$share) {
        $shareError = '分享链接无效或已过期';
    } else {
        $note = getNote($share['note_id']);
        if (!$note) {
            $shareError = '笔记不存在';
        } else {
            // 检查是否需要密码
            if ($share['password'] && !isset($_SESSION['share_authenticated'][$shareToken])) {
                if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action']) && $_POST['action'] === 'verify_share_password') {
                    $password = $_POST['share_password'] ?? '';
                    if (password_verify($password, $share['password'])) {
                        $_SESSION['share_authenticated'][$shareToken] = true;
                    } else {
                        $shareError = '密码错误';
                    }
                }
                
                if (!isset($_SESSION['share_authenticated'][$shareToken])) {
                    // 显示密码输入页面
                    ?>
                    <!DOCTYPE html>
                    <html lang="zh-CN">
                    <head>
                        <meta charset="UTF-8">
                        <meta name="viewport" content="width=device-width, initial-scale=1.0">
                        <title>密码验证 - <?php echo APP_NAME; ?></title>
                        <style>
                            * {
                                margin: 0;
                                padding: 0;
                                box-sizing: border-box;
                            }

                            body {
                                font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
                                background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
                                min-height: 100vh;
                                display: flex;
                                align-items: center;
                                justify-content: center;
                            }

                            .login-container {
                                background: white;
                                padding: 40px;
                                border-radius: 12px;
                                box-shadow: 0 20px 60px rgba(0,0,0,0.3);
                                width: 100%;
                                max-width: 400px;
                            }

                            .login-header {
                                text-align: center;
                                margin-bottom: 30px;
                            }

                            .login-header h1 {
                                font-size: 28px;
                                color: #333;
                                margin-bottom: 10px;
                            }

                            .login-header p {
                                color: #666;
                                font-size: 14px;
                            }

                            .form-group {
                                margin-bottom: 20px;
                            }

                            .form-label {
                                display: block;
                                margin-bottom: 8px;
                                color: #555;
                                font-size: 14px;
                            }

                            .form-input {
                                width: 100%;
                                padding: 12px;
                                border: 1px solid #ddd;
                                border-radius: 6px;
                                font-size: 14px;
                                transition: border-color 0.3s;
                            }

                            .form-input:focus {
                                outline: none;
                                border-color: #667eea;
                            }

                            .login-btn {
                                width: 100%;
                                padding: 12px;
                                background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
                                color: white;
                                border: none;
                                border-radius: 6px;
                                font-size: 16px;
                                cursor: pointer;
                                transition: transform 0.2s;
                            }

                            .login-btn:hover {
                                transform: translateY(-2px);
                            }

                            .error {
                                background: #fee;
                                color: #c33;
                                padding: 10px;
                                border-radius: 6px;
                                margin-bottom: 20px;
                                font-size: 14px;
                            }
                        </style>
                    </head>
                    <body>
                        <div class="login-container">
                            <div class="login-header">
                                <h1><?php echo APP_NAME; ?></h1>
                                <p>此分享需要密码验证</p>
                            </div>
                            
                            <?php if (isset($shareError)): ?>
                            <div class="error"><?php echo $shareError; ?></div>
                            <?php endif; ?>
                            
                            <form method="post">
                                <input type="hidden" name="action" value="verify_share_password">
                                <div class="form-group">
                                    <label class="form-label">请输入分享密码</label>
                                    <input type="password" name="share_password" class="form-input" required>
                                </div>
                                <button type="submit" class="login-btn">验证</button>
                            </form>
                        </div>
                    </body>
                    </html>
                    <?php
                    exit;
                }
            }
            
            // 显示分享的笔记
            ?>
            <!DOCTYPE html>
            <html lang="zh-CN">
            <head>
                <meta charset="UTF-8">
                <meta name="viewport" content="width=device-width, initial-scale=1.0">
                <title><?php echo htmlspecialchars($note['title']); ?> - <?php echo APP_NAME; ?></title>
                <style>
                    * {
                        margin: 0;
                        padding: 0;
                        box-sizing: border-box;
                    }

                    :root {
                        --bg-primary: #ffffff;
                        --bg-secondary: #f8f9fa;
                        --bg-tertiary: #e9ecef;
                        --text-primary: #2c3e50;
                        --text-secondary: #6c757d;
                        --text-muted: #adb5bd;
                        --border-color: #dee2e6;
                        --accent-color: #3498db;
                        --success-color: #27ae60;
                        --danger-color: #e74c3c;
                        --hover-bg: #f1f3f5;
                        --shadow-sm: 0 2px 4px rgba(0,0,0,0.08);
                        --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
                        --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
                    }

                    [data-theme="dark"] {
                        --bg-primary: #1a1a1a;
                        --bg-secondary: #2d2d2d;
                        --bg-tertiary: #404040;
                        --text-primary: #e9ecef;
                        --text-secondary: #adb5bd;
                        --text-muted: #6c757d;
                        --border-color: #495057;
                        --accent-color: #5dade2;
                        --hover-bg: #343434;
                        --shadow-sm: 0 2px 4px rgba(0,0,0,0.3);
                        --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
                    }

                    body {
                        font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
                        background: var(--bg-primary);
                        color: var(--text-primary);
                        line-height: 1.6;
                        transition: var(--transition);
                        min-height: 100vh;
                    }

                    .container {
                        max-width: 900px;
                        margin: 0 auto;
                        padding: 0 20px;
                    }

                    /* Header */
                    header {
                        background: var(--bg-secondary);
                        border-bottom: 1px solid var(--border-color);
                        padding: 20px 0;
                    }

                    .header-content {
                        display: flex;
                        justify-content: space-between;
                        align-items: center;
                    }

                    .logo {
                        font-size: 24px;
                        font-weight: 600;
                        color: var(--text-primary);
                    }

                    .logo-link {
                        text-decoration: none;
                        color: inherit;
                        transition: var(--transition);
                    }

                    .logo-link:hover {
                        opacity: 0.8;
                    }

                    .share-info {
                        color: var(--text-secondary);
                        font-size: 14px;
                    }

                    /* Note View */
                    .note-view {
                        background: var(--bg-secondary);
                        border-radius: 8px;
                        padding: 30px;
                        margin-top: 30px;
                        border: 1px solid var(--border-color);
                    }

                    .note-view-header {
                        margin-bottom: 20px;
                        padding-bottom: 20px;
                        border-bottom: 1px solid var(--border-color);
                    }

                    .note-view-title {
                        font-size: 28px;
                        font-weight: 600;
                        color: var(--text-primary);
                        margin-bottom: 10px;
                    }

                    .note-view-meta {
                        color: var(--text-muted);
                        font-size: 14px;
                    }

                    .note-view-content {
                        line-height: 1.8;
                        font-size: 16px;
                    }

                    .note-view-tags {
                        margin-top: 30px;
                        padding-top: 20px;
                        border-top: 1px solid var(--border-color);
                    }

                    .sidebar-title {
                        font-size: 16px;
                        font-weight: 600;
                        margin-bottom: 15px;
                        color: var(--text-primary);
                    }

                    .tag-list {
                        display: flex;
                        flex-wrap: wrap;
                        gap: 8px;
                    }

                    .tag {
                        padding: 4px 10px;
                        background: var(--bg-tertiary);
                        color: var(--text-secondary);
                        border-radius: 12px;
                        font-size: 12px;
                    }

                    /* Footer */
                    footer {
                        margin-top: 40px;
                        padding: 20px 0;
                        text-align: center;
                        color: var(--text-muted);
                        font-size: 14px;
                        border-top: 1px solid var(--border-color);
                    }

                    /* Responsive */
                    @media (max-width: 768px) {
                        .note-view-title {
                            font-size: 24px;
                        }
                    }
                </style>
            </head>
            <body>
                <header>
                    <div class="container">
                        <div class="header-content">
                            <div class="logo">
                                <a href="<?php echo getBaseUrl(); ?>" class="logo-link">
                                    <?php echo APP_NAME; ?>
                                </a>
                            </div>
                            <div class="share-info">
                                分享笔记
                                <?php if ($share['view_limit'] > 0): ?>
                                · 剩余查看次数: <?php echo $share['view_limit'] - $share['view_count']; ?>
                                <?php endif; ?>
                                <?php if ($share['expires_at']): ?>
                                · 过期时间: <?php echo date('Y-m-d H:i', strtotime($share['expires_at'])); ?>
                                <?php endif; ?>
                            </div>
                        </div>
                    </div>
                </header>

                <div class="container">
                    <div class="note-view">
                        <div class="note-view-header">
                            <div class="note-view-title"><?php echo htmlspecialchars($note['title']); ?></div>
                            <div class="note-view-meta">
                                创建于 <?php echo date('Y-m-d H:i', strtotime($note['created_at'])); ?>
                                <?php if ($note['updated_at'] !== $note['created_at']): ?>
                                · 更新于 <?php echo date('Y-m-d H:i', strtotime($note['updated_at'])); ?>
                                <?php endif; ?>
                            </div>
                        </div>
                        <div class="note-view-content">
                            <?php echo markdownToHtml($note['content']); ?>
                        </div>
                        
                        <?php if ($note['tags']): ?>
                        <div class="note-view-tags">
                            <div class="sidebar-title">标签</div>
                            <div class="tag-list">
                                <?php foreach (explode(',', $note['tags']) as $tag): ?>
                                <span class="tag"><?php echo htmlspecialchars(trim($tag)); ?></span>
                                <?php endforeach; ?>
                            </div>
                        </div>
                        <?php endif; ?>
                    </div>
                </div>

                <footer>
                    <div class="container">
                        <p>由 <?php echo APP_NAME; ?> 强力驱动</p>
                    </div>
                </footer>
            </body>
            </html>
            <?php
            exit;
        }
    }
}

// 如果未初始化，显示初始化页面
if (!isInitialized()) {
?>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>初始化 - <?php echo APP_NAME; ?></title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .init-container {
            background: white;
            padding: 40px;
            border-radius: 12px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.3);
            width: 100%;
            max-width: 400px;
        }

        .init-header {
            text-align: center;
            margin-bottom: 30px;
        }

        .init-header h1 {
            font-size: 28px;
            color: #333;
            margin-bottom: 10px;
        }

        .init-header p {
            color: #666;
            font-size: 14px;
        }

        .form-group {
            margin-bottom: 20px;
        }

        .form-label {
            display: block;
            margin-bottom: 8px;
            color: #555;
            font-size: 14px;
        }

        .form-input {
            width: 100%;
            padding: 12px;
            border: 1px solid #ddd;
            border-radius: 6px;
            font-size: 14px;
            transition: border-color 0.3s;
        }

        .form-input:focus {
            outline: none;
            border-color: #667eea;
        }

        .init-btn {
            width: 100%;
            padding: 12px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 6px;
            font-size: 16px;
            cursor: pointer;
            transition: transform 0.2s;
        }

        .init-btn:hover {
            transform: translateY(-2px);
        }

        .error {
            background: #fee;
            color: #c33;
            padding: 10px;
            border-radius: 6px;
            margin-bottom: 20px;
            font-size: 14px;
        }
    </style>
</head>
<body>
    <div class="init-container">
        <div class="init-header">
            <h1><?php echo APP_NAME; ?></h1>
            <p>首次使用，请创建管理员账号</p>
        </div>
        
        <?php if (isset($error)): ?>
        <div class="error"><?php echo $error; ?></div>
        <?php endif; ?>
        
        <form method="post">
            <input type="hidden" name="action" value="init">
            <div class="form-group">
                <label class="form-label">用户名</label>
                <input type="text" name="username" class="form-input" required>
            </div>
            <div class="form-group">
                <label class="form-label">密码</label>
                <input type="password" name="password" class="form-input" required>
            </div>
            <button type="submit" class="init-btn">创建账号</button>
        </form>
    </div>
</body>
</html>
<?php
exit;
}

// 如果未登录，显示登录页面
if (!isLoggedIn()) {
?>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录 - <?php echo APP_NAME; ?></title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .login-container {
            background: white;
            padding: 40px;
            border-radius: 12px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.3);
            width: 100%;
            max-width: 400px;
        }

        .login-header {
            text-align: center;
            margin-bottom: 30px;
        }

        .login-header h1 {
            font-size: 28px;
            color: #333;
            margin-bottom: 10px;
        }

        .login-header p {
            color: #666;
            font-size: 14px;
        }

        .form-group {
            margin-bottom: 20px;
        }

        .form-label {
            display: block;
            margin-bottom: 8px;
            color: #555;
            font-size: 14px;
        }

        .form-input {
            width: 100%;
            padding: 12px;
            border: 1px solid #ddd;
            border-radius: 6px;
            font-size: 14px;
            transition: border-color 0.3s;
        }

        .form-input:focus {
            outline: none;
            border-color: #667eea;
        }

        .login-btn {
            width: 100%;
            padding: 12px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 6px;
            font-size: 16px;
            cursor: pointer;
            transition: transform 0.2s;
        }

        .login-btn:hover {
            transform: translateY(-2px);
        }

        .error {
            background: #fee;
            color: #c33;
            padding: 10px;
            border-radius: 6px;
            margin-bottom: 20px;
            font-size: 14px;
        }
    </style>
</head>
<body>
    <div class="login-container">
        <div class="login-header">
            <h1><?php echo APP_NAME; ?></h1>
            <p>请登录您的记事本</p>
        </div>
        
        <?php if (isset($error)): ?>
        <div class="error"><?php echo $error; ?></div>
        <?php endif; ?>
        
        <form method="post">
            <input type="hidden" name="action" value="login">
            <div class="form-group">
                <label class="form-label">用户名</label>
                <input type="text" name="username" class="form-input" required>
            </div>
            <div class="form-group">
                <label class="form-label">密码</label>
                <input type="password" name="password" class="form-input" required>
            </div>
            <button type="submit" class="login-btn">登录</button>
        </form>
    </div>
</body>
</html>
<?php
exit;
}

// 已登录，显示主界面
 $totalNotes = getNotesCount($search, $tag);
 $totalPages = ceil($totalNotes / NOTES_PER_PAGE);
 $notes = getNotes($page, $search, $tag);
 $allTags = getAllTags();
 $editNote = null;
 $viewNote = null;

if (isset($_GET['edit'])) {
    $editNote = getNote(intval($_GET['edit']));
} elseif (isset($_GET['view'])) {
    $viewNote = getNote(intval($_GET['view']));
}
?>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title><?php echo APP_NAME; ?></title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        :root {
            --bg-primary: #ffffff;
            --bg-secondary: #f8f9fa;
            --bg-tertiary: #e9ecef;
            --text-primary: #2c3e50;
            --text-secondary: #6c757d;
            --text-muted: #adb5bd;
            --border-color: #dee2e6;
            --accent-color: #3498db;
            --success-color: #27ae60;
            --danger-color: #e74c3c;
            --hover-bg: #f1f3f5;
            --shadow-sm: 0 2px 4px rgba(0,0,0,0.08);
            --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
            --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }

        [data-theme="dark"] {
            --bg-primary: #1a1a1a;
            --bg-secondary: #2d2d2d;
            --bg-tertiary: #404040;
            --text-primary: #e9ecef;
            --text-secondary: #adb5bd;
            --text-muted: #6c757d;
            --border-color: #495057;
            --accent-color: #5dade2;
            --hover-bg: #343434;
            --shadow-sm: 0 2px 4px rgba(0,0,0,0.3);
            --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            background: var(--bg-primary);
            color: var(--text-primary);
            line-height: 1.6;
            transition: var(--transition);
            min-height: 100vh;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        /* Header */
        header {
            background: var(--bg-secondary);
            border-bottom: 1px solid var(--border-color);
            padding: 20px 0;
            position: sticky;
            top: 0;
            z-index: 100;
        }

        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: 24px;
            font-weight: 600;
            color: var(--text-primary);
        }

        .logo-link {
            text-decoration: none;
            color: inherit;
            transition: var(--transition);
        }

        .logo-link:hover {
            opacity: 0.8;
            transform: scale(1.02);
        }

        .header-actions {
            display: flex;
            gap: 15px;
            align-items: center;
        }

        .search-box {
            position: relative;
        }

        .search-input {
            padding: 8px 35px 8px 12px;
            border: 1px solid var(--border-color);
            border-radius: 20px;
            background: var(--bg-primary);
            color: var(--text-primary);
            width: 250px;
            font-size: 14px;
            transition: var(--transition);
        }

        .search-input:focus {
            outline: none;
            border-color: var(--accent-color);
            width: 300px;
        }

        .search-icon {
            position: absolute;
            right: 12px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-muted);
        }

        .btn {
            padding: 8px 16px;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            background: var(--bg-primary);
            color: var(--text-primary);
            text-decoration: none;
            font-size: 14px;
            cursor: pointer;
            transition: var(--transition);
        }

        .btn:hover {
            background: var(--hover-bg);
            transform: translateY(-1px);
        }

        .btn-primary {
            background: var(--accent-color);
            color: white;
            border-color: var(--accent-color);
        }

        .btn-primary:hover {
            opacity: 0.9;
        }

        .theme-toggle {
            background: none;
            border: none;
            font-size: 18px;
            cursor: pointer;
            color: var(--text-primary);
            transition: var(--transition);
        }

        .theme-toggle:hover {
            transform: rotate(180deg);
        }

        /* 面包屑导航 */
        .breadcrumb {
            display: flex;
            align-items: center;
            gap: 8px;
            margin-bottom: 20px;
            padding: 10px 0;
            font-size: 14px;
            color: var(--text-secondary);
        }

        .breadcrumb-item {
            color: var(--text-secondary);
            text-decoration: none;
            transition: var(--transition);
        }

        .breadcrumb-item:hover {
            color: var(--accent-color);
        }

        .breadcrumb-separator {
            color: var(--text-muted);
        }

        .breadcrumb-current {
            color: var(--text-primary);
            font-weight: 500;
        }

        /* 返回按钮 */
        .back-button {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 6px 12px;
            background: var(--bg-tertiary);
            color: var(--text-secondary);
            text-decoration: none;
            border-radius: 6px;
            font-size: 14px;
            transition: var(--transition);
            margin-bottom: 20px;
        }

        .back-button:hover {
            background: var(--hover-bg);
            color: var(--accent-color);
            transform: translateX(-2px);
        }

        /* Main Layout */
        .main-layout {
            display: flex;
            gap: 30px;
            margin-top: 30px;
        }

        .sidebar {
            width: 250px;
            flex-shrink: 0;
        }

        .content {
            flex: 1;
        }

        /* Sidebar */
        .sidebar-section {
            background: var(--bg-secondary);
            border-radius: 8px;
            padding: 20px;
            margin-bottom: 20px;
            border: 1px solid var(--border-color);
        }

        .sidebar-title {
            font-size: 16px;
            font-weight: 600;
            margin-bottom: 15px;
            color: var(--text-primary);
        }

        .tag-list {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
        }

        .tag {
            padding: 4px 10px;
            background: var(--bg-tertiary);
            color: var(--text-secondary);
            border-radius: 12px;
            font-size: 12px;
            text-decoration: none;
            transition: var(--transition);
        }

        .tag:hover {
            background: var(--accent-color);
            color: white;
            transform: scale(1.05);
        }

        .tag.active {
            background: var(--accent-color);
            color: white;
        }

        /* Notes List */
        .notes-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
        }

        .notes-title {
            font-size: 24px;
            font-weight: 600;
        }

        .notes-grid {
            display: grid;
            gap: 20px;
        }

        .note-card {
            background: var(--bg-secondary);
            border-radius: 8px;
            padding: 20px;
            border: 1px solid var(--border-color);
            transition: var(--transition);
            cursor: pointer;
        }

        .note-card:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }

        .note-header {
            display: flex;
            justify-content: space-between;
            align-items: start;
            margin-bottom: 10px;
        }

        .note-title {
            font-size: 18px;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 5px;
        }

        .note-date {
            font-size: 12px;
            color: var(--text-muted);
        }

        .note-content {
            color: var(--text-secondary);
            font-size: 14px;
            line-height: 1.5;
            margin-bottom: 10px;
            overflow: hidden;
            display: -webkit-box;
            -webkit-line-clamp: 3;
            -webkit-box-orient: vertical;
        }

        .note-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 5px;
        }

        .note-tag {
            padding: 2px 8px;
            background: var(--bg-tertiary);
            color: var(--text-secondary);
            border-radius: 10px;
            font-size: 11px;
        }

        .note-actions {
            display: flex;
            gap: 10px;
        }

        .note-btn {
            background: none;
            border: none;
            color: var(--text-muted);
            cursor: pointer;
            font-size: 14px;
            transition: var(--transition);
        }

        .note-btn:hover {
            color: var(--accent-color);
        }

        .note-btn.delete:hover {
            color: var(--danger-color);
        }

        /* Pagination */
        .pagination {
            display: flex;
            justify-content: center;
            align-items: center;
            gap: 10px;
            margin-top: 30px;
        }

        .pagination-info {
            color: var(--text-secondary);
            font-size: 14px;
        }

        .pagination-links {
            display: flex;
            gap: 5px;
        }

        .page-link {
            padding: 6px 12px;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            background: var(--bg-primary);
            color: var(--text-primary);
            text-decoration: none;
            font-size: 14px;
            transition: var(--transition);
        }

        .page-link:hover {
            background: var(--hover-bg);
        }

        .page-link.active {
            background: var(--accent-color);
            color: white;
            border-color: var(--accent-color);
        }

        .page-link.disabled {
            color: var(--text-muted);
            cursor: not-allowed;
        }

        /* Note View */
        .note-view {
            background: var(--bg-secondary);
            border-radius: 8px;
            padding: 30px;
            border: 1px solid var(--border-color);
        }

        .note-view-header {
            display: flex;
            justify-content: space-between;
            align-items: start;
            margin-bottom: 20px;
            padding-bottom: 20px;
            border-bottom: 1px solid var(--border-color);
        }

        .note-view-title {
            font-size: 28px;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 10px;
        }

        .note-view-meta {
            color: var(--text-muted);
            font-size: 14px;
        }

        .note-view-actions {
            display: flex;
            gap: 10px;
        }

        .note-view-content {
            line-height: 1.8;
            font-size: 16px;
        }

        .note-view-tags {
            margin-top: 30px;
            padding-top: 20px;
            border-top: 1px solid var(--border-color);
        }

        /* Editor */
        .editor-container {
            background: var(--bg-secondary);
            border-radius: 8px;
            padding: 30px;
            border: 1px solid var(--border-color);
        }

        .editor-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
        }

        .editor-title {
            font-size: 20px;
            font-weight: 600;
        }

        .editor-actions {
            display: flex;
            gap: 10px;
        }

        .form-group {
            margin-bottom: 20px;
        }

        .form-label {
            display: block;
            margin-bottom: 8px;
            font-size: 14px;
            color: var(--text-secondary);
        }

        .form-input, .form-textarea, .form-select {
            width: 100%;
            padding: 10px;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            background: var(--bg-primary);
            color: var(--text-primary);
            font-size: 14px;
            font-family: inherit;
            transition: var(--transition);
        }

        .form-input:focus, .form-textarea:focus, .form-select:focus {
            outline: none;
            border-color: var(--accent-color);
        }

        .form-textarea {
            min-height: 400px;
            resize: vertical;
        }

        /* Editor Toolbar */
        .editor-toolbar {
            display: flex;
            flex-wrap: wrap;
            gap: 5px;
            padding: 10px;
            background: var(--bg-tertiary);
            border-radius: 6px 6px 0 0;
            border: 1px solid var(--border-color);
            border-bottom: none;
        }

        .toolbar-btn {
            padding: 6px 10px;
            background: var(--bg-primary);
            border: 1px solid var(--border-color);
            border-radius: 4px;
            cursor: pointer;
            font-size: 14px;
            transition: var(--transition);
        }

        .toolbar-btn:hover {
            background: var(--hover-bg);
        }

        .toolbar-btn.active {
            background: var(--accent-color);
            color: white;
            border-color: var(--accent-color);
        }

        .toolbar-separator {
            width: 1px;
            background: var(--border-color);
            margin: 0 5px;
        }

        .editor-tabs {
            display: flex;
            gap: 10px;
            margin-bottom: 0;
        }

        .tab {
            padding: 8px 16px;
            background: var(--bg-tertiary);
            border: 1px solid var(--border-color);
            border-bottom: none;
            border-radius: 6px 6px 0 0;
            cursor: pointer;
            transition: var(--transition);
        }

        .tab.active {
            background: var(--bg-primary);
            color: var(--accent-color);
            border-bottom: 1px solid var(--bg-primary);
            margin-bottom: -1px;
        }

        .editor-content {
            background: var(--bg-primary);
            border: 1px solid var(--border-color);
            border-radius: 0 6px 6px 6px;
            min-height: 400px;
            padding: 20px;
            overflow-y: auto;
        }

        .preview-content {
            line-height: 1.6;
        }

        .preview-content h1, .preview-content h2, .preview-content h3 {
            margin: 20px 0 10px 0;
            color: var(--text-primary);
        }

        .preview-content p {
            margin-bottom: 15px;
        }

        .preview-content code {
            background: var(--bg-tertiary);
            padding: 2px 6px;
            border-radius: 3px;
            font-family: 'Courier New', monospace;
        }

        .preview-content pre {
            background: var(--bg-tertiary);
            padding: 15px;
            border-radius: 6px;
            overflow-x: auto;
            margin: 15px 0;
        }

        .preview-content pre code {
            background: none;
            padding: 0;
        }

        .preview-content a {
            color: var(--accent-color);
            text-decoration: none;
        }

        .preview-content a:hover {
            text-decoration: underline;
        }

        .preview-content ul, .preview-content ol {
            margin: 15px 0;
            padding-left: 30px;
        }

        .preview-content li {
            margin-bottom: 5px;
        }

        .preview-content blockquote {
            border-left: 4px solid var(--accent-color);
            padding-left: 15px;
            margin: 15px 0;
            color: var(--text-secondary);
            font-style: italic;
        }

        /* Attachments */
        .attachments-section {
            margin-top: 20px;
            padding: 15px;
            background: var(--bg-tertiary);
            border-radius: 6px;
        }

        .attachments-title {
            font-size: 14px;
            font-weight: 600;
            margin-bottom: 10px;
            color: var(--text-primary);
        }

        .attachment-list {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
        }

        .attachment-item {
            display: flex;
            align-items: center;
            gap: 8px;
            padding: 8px 12px;
            background: var(--bg-primary);
            border-radius: 4px;
            font-size: 13px;
            transition: var(--transition);
        }

        .attachment-item:hover {
            background: var(--hover-bg);
        }

        .attachment-link {
            color: var(--accent-color);
            text-decoration: none;
        }

        .attachment-link:hover {
            text-decoration: underline;
        }

        .attachment-delete {
            color: var(--danger-color);
            cursor: pointer;
            font-size: 12px;
        }

        .attachment-delete:hover {
            color: #c0392b;
        }

        .upload-area {
            border: 2px dashed var(--border-color);
            border-radius: 6px;
            padding: 20px;
            text-align: center;
            transition: var(--transition);
            cursor: pointer;
        }

        .upload-area:hover {
            border-color: var(--accent-color);
            background: var(--hover-bg);
        }

        .upload-area.dragover {
            border-color: var(--accent-color);
            background: var(--hover-bg);
        }

        .upload-icon {
            font-size: 48px;
            color: var(--text-muted);
            margin-bottom: 10px;
        }

        .upload-text {
            color: var(--text-secondary);
            font-size: 14px;
        }

        .file-input {
            display: none;
        }

        /* Share Section */
        .share-section {
            margin-top: 20px;
            padding: 15px;
            background: var(--bg-tertiary);
            border-radius: 6px;
        }

        .share-title {
            font-size: 14px;
            font-weight: 600;
            margin-bottom: 10px;
            color: var(--text-primary);
        }

        .share-list {
            display: flex;
            flex-direction: column;
            gap: 10px;
        }

        .share-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 10px;
            background: var(--bg-primary);
            border-radius: 4px;
            font-size: 13px;
            transition: var(--transition);
        }

        .share-item:hover {
            background: var(--hover-bg);
        }

        .share-info {
            display: flex;
            flex-direction: column;
            gap: 5px;
        }

        .share-link {
            color: var(--accent-color);
            text-decoration: none;
            font-family: monospace;
            word-break: break-all;
        }

        .share-link:hover {
            text-decoration: underline;
        }

        .share-meta {
            color: var(--text-muted);
            font-size: 11px;
        }

        .share-actions {
            display: flex;
            gap: 5px;
        }

        .share-btn {
            padding: 4px 8px;
            background: none;
            border: none;
            color: var(--text-muted);
            cursor: pointer;
            font-size: 12px;
            transition: var(--transition);
        }

        .share-btn:hover {
            color: var(--accent-color);
        }

        .share-btn.delete:hover {
            color: var(--danger-color);
        }

        .share-form {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-top: 15px;
        }

        .share-form-group {
            flex: 1;
            min-width: 150px;
        }

        .share-form-label {
            display: block;
            margin-bottom: 5px;
            color: var(--text-secondary);
            font-size: 12px;
        }

        .share-form-input {
            width: 100%;
            padding: 8px;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            background: var(--bg-primary);
            color: var(--text-primary);
            font-size: 12px;
            transition: var(--transition);
        }

        .share-form-input:focus {
            outline: none;
            border-color: var(--accent-color);
        }

        .share-form-btn {
            padding: 8px 16px;
            background: var(--accent-color);
            color: white;
            border: none;
            border-radius: 4px;
            font-size: 12px;
            cursor: pointer;
            transition: var(--transition);
        }

        .share-form-btn:hover {
            opacity: 0.9;
        }

        /* Modal */
        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5);
            z-index: 1000;
        }

        .modal.active {
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .modal-content {
            background: var(--bg-primary);
            border-radius: 12px;
            padding: 30px;
            max-width: 400px;
            width: 90%;
            animation: slideUp 0.3s ease;
        }

        .modal-header {
            margin-bottom: 20px;
        }

        .modal-title {
            font-size: 20px;
            font-weight: 600;
        }

        .close-modal {
            float: right;
            font-size: 24px;
            cursor: pointer;
            color: var(--text-muted);
        }

        .close-modal:hover {
            color: var(--text-primary);
        }

        /* Empty State */
        .empty-state {
            text-align: center;
            padding: 60px 20px;
            color: var(--text-muted);
        }

        .empty-icon {
            font-size: 64px;
            margin-bottom: 20px;
        }

        .empty-text {
            font-size: 18px;
            margin-bottom: 20px;
        }

        /* Success Message */
        .success-message {
            background: var(--success-color);
            color: white;
            padding: 10px 15px;
            border-radius: 6px;
            margin-bottom: 20px;
            font-size: 14px;
        }

        .success-message a {
            color: white;
            text-decoration: underline;
        }

        /* Animations */
        @keyframes slideUp {
            from {
                transform: translateY(20px);
                opacity: 0;
            }
            to {
                transform: translateY(0);
                opacity: 1;
            }
        }

        /* Responsive */
        @media (max-width: 768px) {
            .main-layout {
                flex-direction: column;
            }

            .sidebar {
                width: 100%;
            }

            .search-input {
                width: 150px;
            }

            .search-input:focus {
                width: 200px;
            }

            .header-content {
                flex-wrap: wrap;
                gap: 10px;
            }

            .note-view-title {
                font-size: 24px;
            }

            .pagination {
                flex-wrap: wrap;
            }

            .editor-toolbar {
                gap: 2px;
            }

            .toolbar-btn {
                padding: 4px 6px;
                font-size: 12px;
            }

            .share-form {
                flex-direction: column;
            }

            .share-form-group {
                min-width: 100%;
            }
        }
    </style>
</head>
<body>
    <header>
        <div class="container">
            <div class="header-content">
                <div class="logo">
                    <a href="<?php echo $homeUrl; ?>" class="logo-link">
                        <?php echo APP_NAME; ?> 🔒
                    </a>
                </div>
                <div class="header-actions">
                    <div class="search-box">
                        <form method="get">
                            <input type="text" name="search" class="search-input" placeholder="搜索笔记..." value="<?php echo htmlspecialchars($search); ?>">
                            <button type="submit" class="search-icon">🔍</button>
                        </form>
                    </div>
                    <a href="?new" class="btn btn-primary">新建笔记</a>
                    <button class="btn" onclick="openPasswordModal()">修改密码</button>
                    <button class="theme-toggle" onclick="toggleTheme()">🌙</button>
                    <a href="?logout" class="btn">退出</a>
                </div>
            </div>
        </div>
    </header>

    <div class="container">
        <?php if (isset($_GET['view']) || isset($_GET['edit']) || isset($_GET['new'])): ?>
        <!-- 面包屑导航 -->
        <nav class="breadcrumb">
            <a href="<?php echo $homeUrl; ?>" class="breadcrumb-item">
                <?php echo APP_NAME; ?>
            </a>
            <span class="breadcrumb-separator">›</span>
            <?php if (isset($_GET['new'])): ?>
                <span class="breadcrumb-current">新建笔记</span>
            <?php elseif (isset($_GET['edit'])): ?>
                <span class="breadcrumb-current">编辑笔记</span>
            <?php elseif (isset($_GET['view'])): ?>
                <span class="breadcrumb-current">查看笔记</span>
            <?php endif; ?>
        </nav>
        <?php endif; ?>

        <?php if (isset($_GET['view'])): ?>
        <!-- Note View -->
        <div class="note-view">
            <div class="note-view-header">
                <div>
                    <div class="note-view-title"><?php echo htmlspecialchars($viewNote['title']); ?></div>
                    <div class="note-view-meta">
                        创建于 <?php echo date('Y-m-d H:i', strtotime($viewNote['created_at'])); ?>
                        <?php if ($viewNote['updated_at'] !== $viewNote['created_at']): ?>
                        · 更新于 <?php echo date('Y-m-d H:i', strtotime($viewNote['updated_at'])); ?>
                        <?php endif; ?>
                    </div>
                </div>
                <div class="note-view-actions">
                    <button class="btn" onclick="editNote(<?php echo $viewNote['id']; ?>)">编辑</button>
                    <button class="btn" onclick="shareNote(<?php echo $viewNote['id']; ?>)">分享</button>
                    <button class="btn" onclick="deleteNote(<?php echo $viewNote['id']; ?>)" style="color: var(--danger-color);">删除</button>
                </div>
            </div>
            <div class="note-view-content">
                <?php echo markdownToHtml($viewNote['content']); ?>
            </div>
            
            <!-- Attachments -->
            <?php $attachments = getNoteAttachments($viewNote['id']); ?>
            <?php if (!empty($attachments)): ?>
            <div class="attachments-section">
                <div class="attachments-title">附件</div>
                <div class="attachment-list">
                    <?php foreach ($attachments as $attachment): ?>
                    <div class="attachment-item">
                        <?php if (strpos($attachment['file_type'], 'image/') === 0): ?>
                            🖼️
                        <?php elseif (strpos($attachment['file_type'], 'pdf') !== false): ?>
                            📄
                        <?php else: ?>
                            📎
                        <?php endif; ?>
                        <a href="<?php echo UPLOAD_DIR . '/' . $attachment['filename']; ?>" target="_blank" class="attachment-link">
                            <?php echo htmlspecialchars($attachment['original_name']); ?>
                        </a>
                        <span class="attachment-delete" onclick="deleteAttachment(<?php echo $attachment['id']; ?>)">✕</span>
                    </div>
                    <?php endforeach; ?>
                </div>
            </div>
            <?php endif; ?>
            
            <!-- Shares -->
            <?php $shares = getNoteShares($viewNote['id']); ?>
            <?php if (!empty($shares)): ?>
            <div class="share-section">
                <div class="share-title">分享链接</div>
                <div class="share-list">
                    <?php foreach ($shares as $share): ?>
                    <div class="share-item">
                        <div class="share-info">
                            <a href="<?php echo getBaseUrl() . '/' . getCurrentFile() . '?share=' . $share['share_token']; ?>" class="share-link" target="_blank">
                                <?php echo getBaseUrl() . '/' . getCurrentFile() . '?share=' . $share['share_token']; ?>
                            </a>
                            <div class="share-meta">
                                创建于 <?php echo date('Y-m-d H:i', strtotime($share['created_at'])); ?>
                                <?php if ($share['view_limit'] > 0): ?>
                                · 剩余查看: <?php echo $share['view_limit'] - $share['view_count']; ?>
                                <?php endif; ?>
                                <?php if ($share['expires_at']): ?>
                                · 过期: <?php echo date('Y-m-d H:i', strtotime($share['expires_at'])); ?>
                                <?php endif; ?>
                                <?php if ($share['password']): ?>
                                · 有密码保护
                                <?php endif; ?>
                            </div>
                        </div>
                        <div class="share-actions">
                            <button class="share-btn" onclick="copyShareLink('<?php echo getBaseUrl() . '/' . getCurrentFile() . '?share=' . $share['share_token']; ?>')">复制</button>
                            <button class="share-btn delete" onclick="deleteShare(<?php echo $share['id']; ?>)">删除</button>
                        </div>
                    </div>
                    <?php endforeach; ?>
                </div>
            </div>
            <?php endif; ?>
            
            <?php if ($viewNote['tags']): ?>
            <div class="note-view-tags">
                <div class="sidebar-title">标签</div>
                <div class="tag-list">
                    <?php foreach (explode(',', $viewNote['tags']) as $tag): ?>
                    <span class="tag"><?php echo htmlspecialchars(trim($tag)); ?></span>
                    <?php endforeach; ?>
                </div>
            </div>
            <?php endif; ?>
        </div>
        <?php elseif (isset($_GET['new']) || isset($_GET['edit'])): ?>
        <!-- Editor -->
        <div class="editor-container">
            <div class="editor-header">
                <div class="editor-title"><?php echo $editNote ? '编辑笔记' : '新建笔记'; ?></div>
                <div class="editor-actions">
                    <a href="<?php echo $homeUrl; ?>" class="btn">取消</a>
                    <button class="btn btn-primary" onclick="saveNote()">保存</button>
                </div>
            </div>
            <form method="post" id="noteForm" enctype="multipart/form-data">
                <input type="hidden" name="action" value="save_note">
                <input type="hidden" name="id" value="<?php echo $editNote['id'] ?? 0; ?>">
                <div class="form-group">
                    <label class="form-label">标题</label>
                    <input type="text" name="title" class="form-input" value="<?php echo htmlspecialchars($editNote['title'] ?? ''); ?>" required>
                </div>
                <div class="form-group">
                    <label class="form-label">标签（用逗号分隔）</label>
                    <input type="text" name="tags" class="form-input" value="<?php echo htmlspecialchars($editNote['tags'] ?? ''); ?>" placeholder="例如：工作,重要,待办">
                </div>
                <div class="form-group">
                    <div class="editor-toolbar">
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('**', '**')" title="粗体">B</button>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('*', '*')" title="斜体" style="font-style: italic;">I</button>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('`', '`')" title="代码">&lt;/&gt;</button>
                        <div class="toolbar-separator"></div>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('# ', '')" title="标题1">H1</button>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('## ', '')" title="标题2">H2</button>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('### ', '')" title="标题3">H3</button>
                        <div class="toolbar-separator"></div>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('- ', '')" title="无序列表">•</button>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('1. ', '')" title="有序列表">1.</button>
                        <button type="button" class="toolbar-btn" onclick="insertMarkdown('> ', '')" title="引用">"</button>
                        <div class="toolbar-separator"></div>
                        <button type="button" class="toolbar-btn" onclick="insertLink()" title="链接">🔗</button>
                        <button type="button" class="toolbar-btn" onclick="insertImage()" title="图片">🖼️</button>
                        <button type="button" class="toolbar-btn" onclick="insertCode()" title="代码块">{}</button>
                        <div class="toolbar-separator"></div>
                        <button type="button" class="toolbar-btn" onclick="insertTable()" title="表格">⊞</button>
                        <button type="button" class="toolbar-btn" onclick="insertLine()" title="分割线">—</button>
                    </div>
                    <div class="editor-tabs">
                        <button type="button" class="tab active" onclick="switchTab('edit')">编辑</button>
                        <button type="button" class="tab" onclick="switchTab('preview')">预览</button>
                    </div>
                    <textarea name="content" class="form-textarea" id="contentEditor" oninput="updatePreview()"><?php echo htmlspecialchars($editNote['content'] ?? ''); ?></textarea>
                    <div class="editor-content preview-content" id="previewContent" style="display: none;"></div>
                </div>
                
                <!-- File Upload -->
                <div class="form-group">
                    <label class="form-label">附件上传</label>
                    <div class="upload-area" onclick="document.getElementById('fileInput').click()" ondrop="handleDrop(event)" ondragover="handleDragOver(event)" ondragleave="handleDragLeave(event)">
                        <div class="upload-icon">📁</div>
                        <div class="upload-text">点击或拖拽文件到此处上传</div>
                        <div class="upload-text" style="font-size: 12px; margin-top: 5px;">支持图片、PDF、Word文档，最大10MB</div>
                    </div>
                    <input type="file" id="fileInput" class="file-input" multiple accept="image/*,.pdf,.doc,.docx,.txt" onchange="handleFileSelect(event)">
                    <input type="hidden" name="attachments[]" multiple>
                </div>
                
                <!-- Existing Attachments -->
                <?php if ($editNote): ?>
                <?php $attachments = getNoteAttachments($editNote['id']); ?>
                <?php if (!empty($attachments)): ?>
                <div class="attachments-section">
                    <div class="attachments-title">已有附件</div>
                    <div class="attachment-list">
                        <?php foreach ($attachments as $attachment): ?>
                        <div class="attachment-item">
                            <?php if (strpos($attachment['file_type'], 'image/') === 0): ?>
                                🖼️
                            <?php elseif (strpos($attachment['file_type'], 'pdf') !== false): ?>
                                📄
                            <?php else: ?>
                                📎
                            <?php endif; ?>
                            <a href="<?php echo UPLOAD_DIR . '/' . $attachment['filename']; ?>" target="_blank" class="attachment-link">
                                <?php echo htmlspecialchars($attachment['original_name']); ?>
                            </a>
                            <span class="attachment-delete" onclick="deleteAttachment(<?php echo $attachment['id']; ?>)">✕</span>
                        </div>
                        <?php endforeach; ?>
                    </div>
                </div>
                <?php endif; ?>
                <?php endif; ?>
            </form>
        </div>
        <?php else: ?>
        <!-- Notes List -->
        <div class="main-layout">
            <aside class="sidebar">
                <div class="sidebar-section">
                    <div class="sidebar-title">标签</div>
                    <div class="tag-list">
                        <a href="?" class="tag <?php echo !$tag ? 'active' : ''; ?>">全部</a>
                        <?php foreach ($allTags as $tagItem): ?>
                        <a href="?tag=<?php echo urlencode($tagItem); ?>" class="tag <?php echo $tag === $tagItem ? 'active' : ''; ?>">
                            <?php echo htmlspecialchars($tagItem); ?>
                        </a>
                        <?php endforeach; ?>
                    </div>
                </div>
                <div class="sidebar-section">
                    <div class="sidebar-title">统计</div>
                    <div style="color: var(--text-secondary); font-size: 14px;">
                        <div>总笔记数：<?php echo $totalNotes; ?></div>
                        <div>当前页：<?php echo count($notes); ?>/<?php echo NOTES_PER_PAGE; ?></div>
                        <div>总页数：<?php echo $totalPages; ?></div>
                    </div>
                </div>
            </aside>

            <main class="content">
                <div class="notes-header">
                    <div class="notes-title">
                        <?php 
                        if ($search) {
                            echo '搜索结果：' . htmlspecialchars($search);
                        } elseif ($tag) {
                            echo '标签：' . htmlspecialchars($tag);
                        } else {
                            echo '所有笔记';
                        }
                        ?>
                    </div>
                    <div class="notes-count">共 <?php echo $totalNotes; ?> 篇</div>
                </div>

                <?php if (isset($_SESSION['share_success'])): ?>
                <div class="success-message">
                    <?php echo $_SESSION['share_success']; unset($_SESSION['share_success']); ?>
                </div>
                <?php endif; ?>

                <?php if (empty($notes)): ?>
                <div class="empty-state">
                    <div class="empty-icon">📝</div>
                    <div class="empty-text">暂无笔记</div>
                    <a href="?new" class="btn btn-primary">创建第一篇笔记</a>
                </div>
                <?php else: ?>
                <div class="notes-grid">
                    <?php foreach ($notes as $note): ?>
                    <div class="note-card" onclick="viewNote(<?php echo $note['id']; ?>)">
                        <div class="note-header">
                            <div>
                                <div class="note-title"><?php echo htmlspecialchars($note['title']); ?></div>
                                <div class="note-date">
                                    创建于 <?php echo date('Y-m-d H:i', strtotime($note['created_at'])); ?>
                                    <?php if ($note['updated_at'] !== $note['created_at']): ?>
                                    · 更新于 <?php echo date('Y-m-d H:i', strtotime($note['updated_at'])); ?>
                                    <?php endif; ?>
                                </div>
                            </div>
                            <div class="note-actions" onclick="event.stopPropagation()">
                                <button class="note-btn" onclick="viewNote(<?php echo $note['id']; ?>)">👁️</button>
                                <button class="note-btn" onclick="editNote(<?php echo $note['id']; ?>)">✏️</button>
                                <button class="note-btn" onclick="shareNote(<?php echo $note['id']; ?>)">🔗</button>
                                <button class="note-btn delete" onclick="deleteNote(<?php echo $note['id']; ?>)">🗑️</button>
                            </div>
                        </div>
                        <div class="note-content"><?php echo htmlspecialchars(substr(strip_tags($note['content']), 0, 200)); ?>...</div>
                        <?php if ($note['tags']): ?>
                        <div class="note-tags">
                            <?php foreach (explode(',', $note['tags']) as $noteTag): ?>
                            <span class="note-tag"><?php echo htmlspecialchars(trim($noteTag)); ?></span>
                            <?php endforeach; ?>
                        </div>
                        <?php endif; ?>
                    </div>
                    <?php endforeach; ?>
                </div>

                <!-- Pagination -->
                <?php if ($totalPages > 1): ?>
                <div class="pagination">
                    <div class="pagination-info">
                        第 <?php echo $page; ?> 页，共 <?php echo $totalPages; ?> 页
                    </div>
                    <div class="pagination-links">
                        <?php if ($page > 1): ?>
                        <a href="?<?php echo http_build_query(array_merge($_GET, ['page' => $page - 1])); ?>" class="page-link">上一页</a>
                        <?php else: ?>
                        <span class="page-link disabled">上一页</span>
                        <?php endif; ?>
                        
                        <?php
                        $startPage = max(1, $page - 2);
                        $endPage = min($totalPages, $page + 2);
                        
                        if ($startPage > 1) {
                            echo '<a href="?' . http_build_query(array_merge($_GET, ['page' => 1])) . '" class="page-link">1</a>';
                            if ($startPage > 2) {
                                echo '<span class="page-link disabled">...</span>';
                            }
                        }
                        
                        for ($i = $startPage; $i <= $endPage; $i++) {
                            $activeClass = $i == $page ? 'active' : '';
                            echo '<a href="?' . http_build_query(array_merge($_GET, ['page' => $i])) . '" class="page-link ' . $activeClass . '">' . $i . '</a>';
                        }
                        
                        if ($endPage < $totalPages) {
                            if ($endPage < $totalPages - 1) {
                                echo '<span class="page-link disabled">...</span>';
                            }
                            echo '<a href="?' . http_build_query(array_merge($_GET, ['page' => $totalPages])) . '" class="page-link">' . $totalPages . '</a>';
                        }
                        ?>
                        
                        <?php if ($page < $totalPages): ?>
                        <a href="?<?php echo http_build_query(array_merge($_GET, ['page' => $page + 1])); ?>" class="page-link">下一页</a>
                        <?php else: ?>
                        <span class="page-link disabled">下一页</span>
                        <?php endif; ?>
                    </div>
                </div>
                <?php endif; ?>
                <?php endif; ?>
            </main>
        </div>
        <?php endif; ?>
    </div>

    <!-- Share Modal -->
    <div class="modal" id="shareModal">
        <div class="modal-content">
            <div class="modal-header">
                <span class="close-modal" onclick="closeShareModal()">&times;</span>
                <div class="modal-title">分享笔记</div>
            </div>
            <?php if (isset($error)): ?>
            <div style="color: var(--danger-color); margin-bottom: 15px;"><?php echo $error; ?></div>
            <?php endif; ?>
            <form method="post" id="shareForm">
                <input type="hidden" name="action" value="create_share">
                <input type="hidden" name="note_id" id="shareNoteId">
                <div class="form-group">
                    <label class="form-label">分享密码（可选）</label>
                    <input type="password" name="share_password" class="form-input" placeholder="留空则无需密码">
                </div>
                <div class="form-group">
                    <label class="form-label">查看次数限制（0为无限制）</label>
                    <input type="number" name="view_limit" class="form-input" min="0" value="0">
                </div>
                <div class="form-group">
                    <label class="form-label">有效期（小时，0为永久）</label>
                    <select name="expires_in" class="form-select">
                        <option value="0">永久</option>
                        <option value="1">1小时</option>
                        <option value="6">6小时</option>
                        <option value="24">1天</option>
                        <option value="168">1周</option>
                        <option value="720">1月</option>
                    </select>
                </div>
                <button type="submit" class="btn btn-primary" style="width: 100%;">创建分享链接</button>
            </form>
        </div>
    </div>

    <!-- Password Modal -->
    <div class="modal" id="passwordModal">
        <div class="modal-content">
            <div class="modal-header">
                <span class="close-modal" onclick="closePasswordModal()">&times;</span>
                <div class="modal-title">修改密码</div>
            </div>
            <?php if (isset($error)): ?>
            <div style="color: var(--danger-color); margin-bottom: 15px;"><?php echo $error; ?></div>
            <?php endif; ?>
            <?php if (isset($success)): ?>
            <div style="color: var(--success-color); margin-bottom: 15px;"><?php echo $success; ?></div>
            <?php endif; ?>
            <form method="post">
                <input type="hidden" name="action" value="change_password">
                <div class="form-group">
                    <label class="form-label">原密码</label>
                    <input type="password" name="old_password" class="form-input" required>
                </div>
                <div class="form-group">
                    <label class="form-label">新密码</label>
                    <input type="password" name="new_password" class="form-input" required>
                </div>
                <button type="submit" class="btn btn-primary" style="width: 100%;">修改密码</button>
            </form>
        </div>
    </div>

    <script>
        // Theme Toggle
        function toggleTheme() {
            const body = document.body;
            const themeToggle = document.querySelector('.theme-toggle');
            
            if (body.getAttribute('data-theme') === 'dark') {
                body.removeAttribute('data-theme');
                themeToggle.textContent = '🌙';
                localStorage.setItem('theme', 'light');
            } else {
                body.setAttribute('data-theme', 'dark');
                themeToggle.textContent = '☀️';
                localStorage.setItem('theme', 'dark');
            }
        }

        // Load saved theme
        window.addEventListener('DOMContentLoaded', () => {
            const savedTheme = localStorage.getItem('theme');
            if (savedTheme === 'dark') {
                document.body.setAttribute('data-theme', 'dark');
                document.querySelector('.theme-toggle').textContent = '☀️';
            }
        });

        // Editor Functions
        function insertMarkdown(before, after) {
            const textarea = document.getElementById('contentEditor');
            const start = textarea.selectionStart;
            const end = textarea.selectionEnd;
            const text = textarea.value;
            const selectedText = text.substring(start, end);
            
            const replacement = before + selectedText + after;
            textarea.value = text.substring(0, start) + replacement + text.substring(end);
            
            // Set cursor position
            const newCursorPos = start + before.length + selectedText.length;
            textarea.setSelectionRange(newCursorPos, newCursorPos);
            textarea.focus();
            
            updatePreview();
        }

        function insertLink() {
            const url = prompt('请输入链接地址:');
            if (url) {
                insertMarkdown('[', `](${url})`);
            }
        }

        function insertImage() {
            const url = prompt('请输入图片地址:');
            if (url) {
                insertMarkdown('![', `](${url})`);
            }
        }

        function insertCode() {
            const code = prompt('请输入代码:');
            if (code) {
                insertMarkdown('```\n', '\n```');
            }
        }

        function insertTable() {
            const rows = prompt('请输入行数:', '3');
            const cols = prompt('请输入列数:', '3');
            if (rows && cols) {
                let table = '\n';
                for (let i = 0; i < parseInt(rows); i++) {
                    for (let j = 0; j < parseInt(cols); j++) {
                        table += '| 单元格 ';
                    }
                    table += '|\n';
                    if (i === 0) {
                        for (let j = 0; j < parseInt(cols); j++) {
                            table += '| --- ';
                        }
                        table += '|\n';
                    }
                }
                insertAtCursor(table);
            }
        }

        function insertLine() {
            insertAtCursor('\n---\n');
        }

        function insertAtCursor(text) {
            const textarea = document.getElementById('contentEditor');
            const start = textarea.selectionStart;
            const value = textarea.value;
            textarea.value = value.substring(0, start) + text + value.substring(start);
            textarea.setSelectionRange(start + text.length, start + text.length);
            textarea.focus();
            updatePreview();
        }

        // Tab Switch
        function switchTab(tab) {
            const tabs = document.querySelectorAll('.tab');
            const editor = document.getElementById('contentEditor');
            const preview = document.getElementById('previewContent');
            
            tabs.forEach(t => t.classList.remove('active'));
            
            if (tab === 'edit') {
                tabs[0].classList.add('active');
                editor.style.display = 'block';
                preview.style.display = 'none';
            } else {
                tabs[1].classList.add('active');
                editor.style.display = 'none';
                preview.style.display = 'block';
                updatePreview();
            }
        }

        // Update Preview
        function updatePreview() {
            const content = document.getElementById('contentEditor').value;
            const preview = document.getElementById('previewContent');
            
            // 增强的Markdown解析
            let html = content;
            
            // 图片（GitHub风格）
            html = html.replace(/!\[(.*?)\]\((.*?)\)/g, '<img src="$2" alt="$1" style="max-width: 100%; height: auto; border-radius: 6px; margin: 10px 0;">');
            
            // 标题
            html = html.replace(/^### (.*$)/gm, '<h3>$1</h3>');
            html = html.replace(/^## (.*$)/gm, '<h2>$1</h2>');
            html = html.replace(/^# (.*$)/gm, '<h1>$1</h1>');
            
            // 粗体和斜体
            html = html.replace(/\*\*(.*?)\*\*/g, '<strong>$1</strong>');
            html = html.replace(/\*(.*?)\*/g, '<em>$1</em>');
            
            // 代码块
            html = html.replace(/```(.*?)```/gs, '<pre><code>$1</code></pre>');
            html = html.replace(/`(.*?)`/g, '<code>$1</code>');
            
            // 链接
            html = html.replace(/\[(.*?)\]\((.*?)\)/g, '<a href="$2" target="_blank">$1</a>');
            
            // 表格
            html = html.replace(/\|(.+)\|/g, function(match) {
                const cells = match.split('|').filter(cell => cell.trim());
                return '<tr>' + cells.map(cell => `<td>${cell.trim()}</td>`).join('') + '</tr>';
            });
            html = html.replace(/(<tr>.*<\/tr>)/gs, '<table>$1</table>');
            
            // 无序列表
            html = html.replace(/^\* (.+)$/gm, '<li>$1</li>');
            html = html.replace(/(<li>.*<\/li>)/gs, '<ul>$1</ul>');
            
            // 有序列表
            html = html.replace(/^\d+\. (.+)$/gm, '<li>$1</li>');
            
            // 引用
            html = html.replace(/^> (.+)$/gm, '<blockquote>$1</blockquote>');
            
            // 分割线
            html = html.replace(/^---$/gm, '<hr>');
            
            // 换行
            html = html.replace(/\n\n/g, '</p><p>');
            html = html.replace(/\n/g, '<br>');
            
            // 段落
            html = '<p>' + html + '</p>';
            
            // 清理
            html = html.replace(/<p><\/p>/g, '');
            html = html.replace(/<p>(<h[1-6]>)/g, '$1');
            html = html.replace(/(<\/h[1-6]>)<\/p>/g, '$1');
            html = html.replace(/<p>(<pre>)/g, '$1');
            html = html.replace(/(<\/pre>)<\/p>/g, '$1');
            html = html.replace(/<p>(<ul>)/g, '$1');
            html = html.replace(/(<\/ul>)<\/p>/g, '$1');
            html = html.replace(/<p>(<table>)/g, '$1');
            html = html.replace(/(<\/table>)<\/p>/g, '$1');
            html = html.replace(/<p>(<blockquote>)/g, '$1');
            html = html.replace(/(<\/blockquote>)<\/p>/g, '$1');
            html = html.replace(/<p>(<li>)/g, '$1');
            html = html.replace(/(<\/li>)<\/p>/g, '$1');
            html = html.replace(/<p>(<tr>)/g, '$1');
            html = html.replace(/(<\/tr>)<\/p>/g, '$1');
            html = html.replace(/<p>(<hr>)/g, '$1');
            html = html.replace(/(<hr>)<\/p>/g, '$1');
            
            preview.innerHTML = html;
        }

        // File Upload
        let uploadedFiles = [];
        
        function handleFileSelect(event) {
            const files = event.target.files;
            handleFiles(files);
        }

        function handleDrop(event) {
            event.preventDefault();
            event.currentTarget.classList.remove('dragover');
            const files = event.dataTransfer.files;
            handleFiles(files);
        }

        function handleDragOver(event) {
            event.preventDefault();
            event.currentTarget.classList.add('dragover');
        }

        function handleDragLeave(event) {
            event.currentTarget.classList.remove('dragover');
        }

        function handleFiles(files) {
            const uploadText = document.querySelector('.upload-text');
            const fileInput = document.getElementById('fileInput');
            
            // Clear existing files
            uploadedFiles = [];
            const dt = new DataTransfer();
            
            // Add new files
            for (let i = 0; i < files.length; i++) {
                const file = files[i];
                if (file.size > 10 * 1024 * 1024) {
                    alert('文件 ' + file.name + ' 超过10MB限制');
                    continue;
                }
                dt.items.add(file);
                uploadedFiles.push(file);
            }
            
            fileInput.files = dt.files;
            
            // Show selected files
            if (uploadedFiles.length > 0) {
                const fileNames = uploadedFiles.map(f => f.name).join(', ');
                uploadText.textContent = '已选择: ' + fileNames;
            } else {
                uploadText.textContent = '点击或拖拽文件到此处上传';
            }
        }

        // Save Note
        function saveNote() {
            const form = document.getElementById('noteForm');
            const formData = new FormData(form);
            
            // Add uploaded files to form data
            if (uploadedFiles.length > 0) {
                for (let i = 0; i < uploadedFiles.length; i++) {
                    formData.append('attachments[]', uploadedFiles[i]);
                }
            }
            
            // Submit form
            fetch('', {
                method: 'POST',
                body: formData
            }).then(response => {
                if (response.redirected) {
                    window.location.href = response.url;
                } else {
                    window.location.reload();
                }
            });
        }

        // View Note
        function viewNote(id) {
            window.location.href = '?view=' + id;
        }

        // Edit Note
        function editNote(id) {
            window.location.href = '?edit=' + id;
        }

        // Share Note
        function shareNote(id) {
            document.getElementById('shareNoteId').value = id;
            document.getElementById('shareModal').classList.add('active');
        }

        // Delete Note
        function deleteNote(id) {
            if (confirm('确定要删除这篇笔记吗？')) {
                window.location.href = '?delete=' + id;
            }
        }

        // Delete Attachment
        function deleteAttachment(id) {
            if (confirm('确定要删除这个附件吗？')) {
                window.location.href = '?delete_attachment=' + id;
            }
        }

        // Delete Share
        function deleteShare(id) {
            if (confirm('确定要删除这个分享链接吗？')) {
                window.location.href = '?delete_share=' + id;
            }
        }

        // Copy Share Link
        function copyShareLink(url) {
            navigator.clipboard.writeText(url).then(() => {
                alert('分享链接已复制到剪贴板');
            }).catch(err => {
                console.error('复制失败:', err);
                // 降级方案
                const textArea = document.createElement('textarea');
                textArea.value = url;
                document.body.appendChild(textArea);
                textArea.select();
                document.execCommand('copy');
                document.body.removeChild(textArea);
                alert('分享链接已复制到剪贴板');
            });
        }

        // Share Modal
        function closeShareModal() {
            document.getElementById('shareModal').classList.remove('active');
        }

        // Password Modal
        function openPasswordModal() {
            document.getElementById('passwordModal').classList.add('active');
        }

        function closePasswordModal() {
            document.getElementById('passwordModal').classList.remove('active');
        }

        // Close modal when clicking outside
        document.getElementById('shareModal').addEventListener('click', (e) => {
            if (e.target === e.currentTarget) {
                closeShareModal();
            }
        });

        document.getElementById('passwordModal').addEventListener('click', (e) => {
            if (e.target === e.currentTarget) {
                closePasswordModal();
            }
        });

        // Auto-save draft
        let autoSaveTimer;
        document.getElementById('contentEditor')?.addEventListener('input', () => {
            clearTimeout(autoSaveTimer);
            autoSaveTimer = setTimeout(() => {
                localStorage.setItem('note_draft', document.getElementById('contentEditor').value);
            }, 1000);
        });

        // Restore draft
        window.addEventListener('DOMContentLoaded', () => {
            const draft = localStorage.getItem('note_draft');
            if (draft && !document.getElementById('contentEditor').value) {
                document.getElementById('contentEditor').value = draft;
            }
        });
    </script>
</body>
</html>
<?php
// End of file
?>