const editor = document.getElementById('editor');
const { Markmap, loadCSS, loadJS, deriveOptions, Transformer } = window.markmap;

let mm;
const transformer = new Transformer();

// ── 思维导图主题（复用 markmap 库内置主题 + 自定义彩色主题）──
// native: true 表示使用库内置主题（含节点样式、连线弧度、线宽、悬停效果等）
// native: false 表示自定义主题，仅设置颜色
const THEMES = {
    '': {
        name: '默认',
        native: false,
        colors: null
    },
    'soft': {
        name: '柔和',
        native: true
    },
    'dark': {
        name: '深色',
        native: true,
        stripCanvas: true
    },
    'forest': {
        name: '森林',
        native: true
    },
    'monochrome': {
        name: '单色',
        native: true
    },
    'minimal': {
        name: '极简',
        native: true
    },
    'colorful': {
        name: '彩色',
        native: false,
        colors: ['#e6194b', '#3cb44b', '#ffe119', '#4363d8', '#f58231', '#911eb4', '#42d4f4', '#f032e6', '#bfef45', '#fabed4']
    }
};

let currentTheme = '';
let currentMode = localStorage.getItem('markmap-mode') || 'day';

// 自动适应窗口：双击"适应窗口"按钮开启，内容变化时自动 fit；再次双击关闭
let autoFitEnabled = false;

// ── 文档历史（localStorage 缓存）──
const DOC_HISTORY_KEY = 'markmap-doc-history';
const MAX_HISTORY = 50;
let currentDocId = null;

// ── 图片数据存储（编辑器中用短占位符，渲染/保存时展开为 Base64）──
const imageDataMap = new Map();
let imageCounter = 0;

function expandImages(text) {
    return text.replace(/local:(img_\d+)/g, (match, id) => {
        const data = imageDataMap.get(id);
        return data || match;
    });
}

function restoreImages(images) {
    imageDataMap.clear();
    imageCounter = 0;
    if (images) {
        Object.entries(images).forEach(([k, v]) => {
            // 跳过空值，避免无效数据进入 imageMap 导致占位符无法展开
            if (v) {
                imageDataMap.set(k, v);
                const num = parseInt(k.replace('img_', ''), 10);
                if (num > imageCounter) imageCounter = num;
            }
        });
    }
}

// 同步 imageMap 与编辑器内容：清除文档中已不引用的孤儿图片数据
// 避免已删除的图片继续占用 imageDataMap 内存和 localStorage 空间
function syncImageMapWithContent(text) {
    // 扫描文本中所有被引用的图片 ID
    const referencedIds = new Set();
    const regex = /local:(img_\d+)/g;
    let m;
    while ((m = regex.exec(text)) !== null) {
        referencedIds.add(m[1]);
    }

    // 移除 imageMap 中未被引用的孤儿图片
    const orphanedIds = [];
    for (const id of imageDataMap.keys()) {
        if (!referencedIds.has(id)) {
            orphanedIds.push(id);
            imageDataMap.delete(id);
        }
    }

    return orphanedIds;
}

// 扫描文本中的 Base64 图片，转为占位符并存入 imageMap
function extractImagesFromContent(text) {
    const regex = /!\[([^\]]*)\]\((data:image\/[^)]+)\)/g;
    return text.replace(regex, (match, alt, dataUrl) => {
        const imgId = `img_${++imageCounter}`;
        imageDataMap.set(imgId, dataUrl);
        return `![${alt}](local:${imgId})`;
    });
}

// 图片压缩：缩放大图并转为 JPEG 以减小 localStorage 占用
async function compressImage(base64, maxWidth = 1200, quality = 0.75) {
    // SVG 是矢量图，canvas 无法正确渲染，不压缩
    if (base64.startsWith('data:image/svg')) return base64;
    // 小图（< 100KB）无需压缩
    if (base64.length < 100000) return base64;

    return new Promise(resolve => {
        const img = new Image();
        img.onload = () => {
            let w = img.width;
            let h = img.height;
            if (w > maxWidth) {
                h = Math.round(h * maxWidth / w);
                w = maxWidth;
            }
            // 限制 canvas 最大高度，防止超高图片超出浏览器 canvas 限制（16384px）
            // 导致 toDataURL 返回空数据或失败
            const MAX_CANVAS_H = 16000;
            if (h > MAX_CANVAS_H) {
                w = Math.round(w * MAX_CANVAS_H / h);
                h = MAX_CANVAS_H;
            }
            const canvas = document.createElement('canvas');
            canvas.width = w;
            canvas.height = h;
            const ctx = canvas.getContext('2d');
            ctx.fillStyle = '#ffffff';
            ctx.fillRect(0, 0, w, h);
            ctx.drawImage(img, 0, 0, w, h);
            try {
                const result = canvas.toDataURL('image/jpeg', quality);
                // 验证压缩结果有效（非空且非空白 data URL）
                if (result && result.length > 100) {
                    resolve(result);
                } else {
                    // 压缩失败，回退到原始数据
                    console.warn('图片压缩结果无效，使用原始数据');
                    resolve(base64);
                }
            } catch (e) {
                console.warn('canvas.toDataURL 失败，使用原始数据:', e);
                resolve(base64);
            }
        };
        img.onerror = () => resolve(base64);
        img.src = base64;
    });
}

// ── IndexedDB 图片存储（大容量，替代 localStorage）──
// localStorage 限制 5-10MB，多张图片容易超出配额导致保存失败
// IndexedDB 容量通常为 50MB-无限制，适合存储 Base64 图片
const IMG_DB_NAME = 'markmap-images';
const IMG_DB_VERSION = 1;
const IMG_STORE = 'images';
let _imgDB = null;

function getImgDB() {
    if (!window.indexedDB) return Promise.resolve(null);
    if (_imgDB) return Promise.resolve(_imgDB);
    return new Promise((resolve) => {
        const req = indexedDB.open(IMG_DB_NAME, IMG_DB_VERSION);
        req.onupgradeneeded = (e) => {
            const db = e.target.result;
            if (!db.objectStoreNames.contains(IMG_STORE)) {
                db.createObjectStore(IMG_STORE);
            }
        };
        req.onsuccess = () => { _imgDB = req.result; resolve(_imgDB); };
        req.onerror = () => resolve(null);
    });
}

// IDB: 保存文档所有图片（key=docId, value={imgId: base64, ...}）
async function saveDocImagesToIDB(docId, images) {
    const db = await getImgDB();
    if (!db) return false;
    return new Promise((resolve) => {
        const tx = db.transaction(IMG_STORE, 'readwrite');
        tx.objectStore(IMG_STORE).put(images || {}, docId);
        tx.oncomplete = () => resolve(true);
        tx.onerror = () => resolve(false);
    });
}

// IDB: 加载文档所有图片
async function loadDocImagesFromIDB(docId) {
    const db = await getImgDB();
    if (!db) return undefined;
    return new Promise((resolve) => {
        const tx = db.transaction(IMG_STORE, 'readonly');
        const req = tx.objectStore(IMG_STORE).get(docId);
        req.onsuccess = () => {
            const images = req.result;
            if (images && typeof images === 'object' && Object.keys(images).length > 0) {
                resolve(images);
            } else {
                resolve(undefined);
            }
        };
        req.onerror = () => resolve(undefined);
    });
}

// IDB: 删除文档图片
async function deleteDocImagesFromIDB(docId) {
    const db = await getImgDB();
    if (!db) return;
    return new Promise((resolve) => {
        const tx = db.transaction(IMG_STORE, 'readwrite');
        tx.objectStore(IMG_STORE).delete(docId);
        tx.oncomplete = () => resolve();
        tx.onerror = () => resolve();
    });
}

// ── localStorage 图片存储（仅作为 IndexedDB 不可用时的回退）──
const IMG_KEY_PREFIX = 'markmap-img-';

function saveDocImagesToLS(docId, images) {
    if (!images) images = {};
    const prefix = `${IMG_KEY_PREFIX}${docId}-`;
    const currentIds = new Set(Object.keys(images));
    const keysToDelete = [];
    for (let i = 0; i < localStorage.length; i++) {
        const key = localStorage.key(i);
        if (key && key.startsWith(prefix)) {
            const oldImgId = key.slice(prefix.length);
            if (!currentIds.has(oldImgId)) {
                keysToDelete.push(key);
            }
        }
    }
    keysToDelete.forEach(key => localStorage.removeItem(key));

    let allSaved = true;
    for (const [imgId, base64] of Object.entries(images)) {
        if (!base64) continue;
        try {
            localStorage.setItem(`${prefix}${imgId}`, base64);
        } catch (e) {
            console.error(`LS 保存图片 ${imgId} 失败:`, e);
            allSaved = false;
        }
    }
    return allSaved;
}

function loadDocImagesFromLS(docId) {
    const prefix = `${IMG_KEY_PREFIX}${docId}-`;
    const images = {};
    for (let i = localStorage.length - 1; i >= 0; i--) {
        const key = localStorage.key(i);
        if (key && key.startsWith(prefix)) {
            const imgId = key.slice(prefix.length);
            const data = localStorage.getItem(key);
            if (data) {
                images[imgId] = data;
            }
        }
    }
    return Object.keys(images).length > 0 ? images : undefined;
}

function deleteDocImagesFromLS(docId) {
    const prefix = `${IMG_KEY_PREFIX}${docId}-`;
    const keysToDelete = [];
    for (let i = 0; i < localStorage.length; i++) {
        const key = localStorage.key(i);
        if (key && key.startsWith(prefix)) {
            keysToDelete.push(key);
        }
    }
    keysToDelete.forEach(key => localStorage.removeItem(key));
}

// ── 统一图片存储接口（IndexedDB 优先，localStorage 回退）──

// 保存：同步接口，内部异步写 IndexedDB（fire-and-forget）
function saveDocImages(docId, images) {
    if (!images) images = {};

    if (window.indexedDB) {
        // 异步保存到 IndexedDB（不阻塞，fire-and-forget）
        saveDocImagesToIDB(docId, images).catch(e => {
            console.error('IndexedDB 保存图片失败，回退到 localStorage:', e);
            saveDocImagesToLS(docId, images);
        });
        return true;
    } else {
        // 无 IndexedDB 时直接用 localStorage
        return saveDocImagesToLS(docId, images);
    }
}

// 加载：异步接口，先查 IndexedDB，再回退 localStorage
async function loadDocImagesAsync(docId) {
    if (window.indexedDB) {
        const idbImages = await loadDocImagesFromIDB(docId);
        if (idbImages) {
            // 迁移：如果 localStorage 中也有该文档的旧图片，清理掉释放空间
            const lsImages = loadDocImagesFromLS(docId);
            if (lsImages) {
                deleteDocImagesFromLS(docId);
            }
            return idbImages;
        }
    }
    // 回退到 localStorage
    return loadDocImagesFromLS(docId);
}

// 删除：同时清理 IndexedDB 和 localStorage
function deleteDocImages(docId) {
    deleteDocImagesFromIDB(docId).catch(() => {});
    deleteDocImagesFromLS(docId);
}

// 一次性迁移：将 localStorage 中的旧图片数据迁移到 IndexedDB
async function migrateImagesToIDB() {
    if (!window.indexedDB) return;
    const docs = getDocHistory();
    for (const doc of docs) {
        const lsImages = loadDocImagesFromLS(doc.id);
        if (lsImages) {
            await saveDocImagesToIDB(doc.id, lsImages);
            deleteDocImagesFromLS(doc.id);
        }
    }
}

// 配置本地资源加载（使用 libs/ 目录中的预构建文件）
// 将带版本号的包名映射为本地清洁目录名
transformer.urlBuilder.setProvider('local', (path) => {
    let p = path;
    // @highlightjs/cdn-assets@11.11.1/... → highlightjs/...
    p = p.replace(/^@highlightjs\/cdn-assets@[\d.]+\//, 'highlightjs/');
    // package@version/... → package/...
    p = p.replace(/^([^@\/]+)@[\d.]+\//, '$1/');
    return `./libs/${p}`;
});
transformer.urlBuilder.provider = 'local';

// ── 内置默认内容（无需服务器也能显示）──
const DEFAULT_CONTENT = `---
title: Markmap
markmap:
  colorFreezeLevel: 2
---

# Markmap 编辑器

## 功能特性

- 实时预览
  - 左侧输入 Markdown
  - 右侧自动生成思维导图
- 配色主题
  - 默认
  - 柔和
  - 深色
  - 森林
  - 单色
  - 极简
  - 彩色
- 日间/夜间模式
  - 一键切换背景配色
- 导出功能
  - SVG 矢量图
  - PNG 图片
  - PDF 文档
- 其他
  - 分享链接
  - 全屏模式
  - 加载/保存文件
  - 历史文档侧边栏
  - 插入本地图片

## 快速开始

- 在左侧文本框中输入 Markdown
- 使用 \`#\` 标题或 \`-\` 列表来组织层级
- 点击右下角工具栏进行缩放和导出

## Markdown 语法示例

### 文本样式

- **粗体文本**
- *斜体文本*
- ~~删除线~~
- \`行内代码\`

### 列表

- 一级项目
  - 二级项目
    - 三级项目
  - 另一个二级项目
- 另一个一级项目

### 代码块

\`\`\`javascript
function hello() {
  console.log('Hello, Markmap!');
}
\`\`\`

### 数学公式

- 行内公式: $E = mc^2$
- 块级公式: $\\int_0^1 x^2 dx = \\frac{1}{3}$

### 链接

- [Markmap 官网](https://markmap.js.org/)
- [GitHub 仓库](https://github.com/gera2ld/markmap)
`;

// ── 防抖工具 ──
function debounce(fn, delay) {
    let timer = null;
    return function (...args) {
        clearTimeout(timer);
        timer = setTimeout(() => fn.apply(this, args), delay);
    };
}

// ── 事件监听器 ──
document.getElementById('new-map')?.addEventListener('click', newMap);
document.getElementById('load-map')?.addEventListener('click', loadMap);
document.getElementById('save-map')?.addEventListener('click', saveMap);
document.getElementById('share-url')?.addEventListener('click', () => {
    shareURL().catch(error => console.error('分享链接生成失败:', error));
});

function newMap() {
    if (confirm('确定要创建新的思维导图吗？当前内容将被保存到历史记录。')) {
        autoSaveToHistory();
        currentDocId = 'doc_' + Date.now();
        restoreImages(null);
        editor.value = '# 新的思维导图\n\n- 主题 1\n  - 子主题 1\n  - 子主题 2\n- 主题 2\n  - 子主题 1\n  - 子主题 2';
        updateMarkmap();
        autoSaveToHistory();
    }
}

function loadMap() {
    const input = document.createElement('input');
    input.type = 'file';
    input.accept = '.md,.markdown,.txt';
    input.onchange = e => {
        const file = e.target.files[0];
        if (!file) return;
        const reader = new FileReader();
        reader.onload = function(e) {
            autoSaveToHistory();
            currentDocId = 'doc_' + Date.now();
            restoreImages(null);
            editor.value = extractImagesFromContent(e.target.result);
            updateMarkmap();
            autoSaveToHistory();
        };
        reader.onerror = function() {
            console.error('读取文件失败');
            alert('文件读取失败，请重试。');
        };
        reader.readAsText(file);
    };
    input.click();
}

function saveMap() {
    const content = expandImages(editor.value);
    const blob = new Blob([content], {type: 'text/markdown;charset=utf-8'});
    saveFileAs(blob, getSuggestedFileName('md'), [{
        description: 'Markdown 文件',
        accept: { 'text/markdown': ['.md'] }
    }]);
}

function toggleFullscreen() {
    document.body.classList.toggle('fullscreen');
    // 等待 CSS 过渡完成后重新渲染
    setTimeout(() => {
        updateMarkmap();
        if (mm) mm.fit();
    }, 100);
}

// 展开所有节点：从根节点开始逐层展开，移除所有 fold 标记
function expandAllNodes() {
    if (!mm || !mm.state || !mm.state.data) return;

    function walkTree(node) {
        if (node.payload && node.payload.fold !== undefined) {
            delete node.payload.fold;
        }
        if (node.children) {
            node.children.forEach(walkTree);
        }
    }

    walkTree(mm.state.data);
    mm.renderData(mm.state.data).then(() => {
        if (autoFitEnabled && mm) mm.fit();
    });
}

// 收起所有节点：保留第一层子节点可见，折叠其下所有层级
function collapseAllNodes() {
    if (!mm || !mm.state || !mm.state.data) return;

    function walkTree(node, depth) {
        // depth=0 是根节点，depth=1 是第一层子节点（保留可见）
        // depth≥2 的有子节点的节点全部折叠
        if (depth >= 1 && node.children && node.children.length > 0) {
            if (!node.payload) node.payload = {};
            node.payload.fold = 1;
        }
        if (node.children) {
            node.children.forEach(child => walkTree(child, depth + 1));
        }
    }

    walkTree(mm.state.data, 0);
    mm.renderData(mm.state.data).then(() => {
        if (autoFitEnabled && mm) mm.fit();
    });
}

// PDF 导出方向选择弹出菜单
function showPdfOrientationMenu(btnElement) {
    // 移除已存在的菜单（再次点击同一按钮时关闭）
    const existing = document.querySelector('.pdf-orientation-menu');
    if (existing) {
        existing.remove();
        return;
    }

    const menu = document.createElement('div');
    menu.className = 'pdf-orientation-menu';

    const options = [
        { label: '自动选择', desc: '根据内容比例', value: 'auto' },
        { label: '横向导出', desc: 'Landscape', value: 'landscape' },
        { label: '纵向导出', desc: 'Portrait', value: 'portrait' }
    ];

    options.forEach(opt => {
        const item = document.createElement('button');
        item.className = 'pdf-orientation-item';
        item.innerHTML = `<span class="pdf-orientation-label">${opt.label}</span><span class="pdf-orientation-desc">${opt.desc}</span>`;
        item.addEventListener('click', () => {
            menu.remove();
            exportPDF(opt.value);
        });
        menu.appendChild(item);
    });

    // 定位到按钮上方
    const rect = btnElement.getBoundingClientRect();
    menu.style.position = 'fixed';
    menu.style.bottom = (window.innerHeight - rect.top + 6) + 'px';
    menu.style.right = (window.innerWidth - rect.right) + 'px';

    document.body.appendChild(menu);

    // 点击外部关闭菜单
    setTimeout(() => {
        const closeHandler = (e) => {
            if (!menu.contains(e.target) && e.target !== btnElement && !btnElement.contains(e.target)) {
                menu.remove();
                document.removeEventListener('click', closeHandler);
            }
        };
        document.addEventListener('click', closeHandler);
    }, 0);
}

function createToolbar(mm) {
    const toolbar = document.createElement('div');
    toolbar.className = 'markmap-toolbar';

    const buttons = [
        {title: '放大', path: 'M15.5 14h-.79l-.28-.27C15.41 12.59 16 11.11 16 9.5 16 5.91 13.09 3 9.5 3S3 5.91 3 9.5 5.91 16 9.5 16c1.61 0 3.09-.59 4.23-1.57l.27.28v.79l5 4.99L20.49 19l-4.99-5zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14zm-2.5-4h2v2h1v-2h2V9h-2V7h-1v2H7v1z', action: () => mm.rescale(1.25)},
        {title: '缩小', path: 'M15.5 14h-.79l-.28-.27C15.41 12.59 16 11.11 16 9.5 16 5.91 13.09 3 9.5 3S3 5.91 3 9.5 5.91 16 9.5 16c1.61 0 3.09-.59 4.23-1.57l.27.28v.79l5 4.99L20.49 19l-4.99-5zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14zM7 9h5v1H7z', action: () => mm.rescale(0.8)},
        {title: '适应窗口', path: 'M5 16h3v3h2v-5H5v2zm3-8H5v2h5V5H8v3zm6 11h2v-3h3v-2h-5v5zm2-11V5h-2v5h5V8h-3z', action: () => mm.fit()},
        {title: '展开全部', path: 'M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z', action: expandAllNodes},
        {title: '收起全部', path: 'M15.41 7.41L14 6l-6 6 6 6 1.41-1.41L10.83 12z', action: collapseAllNodes},
        {title: '全屏', path: 'M7 14H5v5h5v-2H7v-3zm-2-4h2V7h3V5H5v5zm12 7h-3v2h5v-5h-2v3zM14 5v2h3v3h2V5h-5z', action: toggleFullscreen},
        {title: '导出 SVG', path: 'M19 9h-4V3H9v6H5l7 7 7-7zM5 18v2h14v-2H5z', action: exportSVG},
        {title: '导出 PNG', path: 'M21 19V5c0-1.1-.9-2-2-2H5c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h14c1.1 0 2-.9 2-2zM8.5 13.5l2.5 3.01L14.5 12l4.5 6H5l3.5-4.5z', action: exportPNG},
        {title: '导出 PDF', path: 'M20 2H8c-1.1 0-2 .9-2 2v12c0 1.1.9 2 2 2h12c1.1 0 2-.9 2-2V4c0-1.1-.9-2-2-2zm-8.5 7.5c0 .83-.67 1.5-1.5 1.5H9v2H7.5V7H10c.83 0 1.5.67 1.5 1.5v1zm5 2c0 .83-.67 1.5-1.5 1.5h-2.5V7H15c.83 0 1.5.67 1.5 1.5v3zm4-3H19v1h1.5V11H19v2h-1.5V7h3v1.5zM9 9.5h1v-1H9v1zM4 6H2v14c0 1.1.9 2 2 2h14v-2H4V6zm10 5.5h1v-3h-1v3z', action: exportPDF}
    ];

    buttons.forEach(btn => {
        const button = document.createElement('button');
        button.className = 'markmap-btn';
        button.dataset.tooltip = btn.title;
        button.innerHTML = `<svg viewBox="0 0 24 24" width="20" height="20"><path d="${btn.path}"></path></svg>`;

        if (btn.title === '适应窗口') {
            // 单击：适应窗口；双击：切换自动适应模式
            button.addEventListener('click', () => mm.fit());
            button.addEventListener('dblclick', () => {
                autoFitEnabled = !autoFitEnabled;
                button.classList.toggle('autofit-active', autoFitEnabled);
                button.dataset.tooltip = autoFitEnabled ? '自动适应（已开启，双击关闭）' : '适应窗口';
                if (autoFitEnabled && mm) mm.fit();
            });
        } else if (btn.title === '导出 PDF') {
            // PDF 按钮弹出方向选择菜单
            button.addEventListener('click', () => showPdfOrientationMenu(button));
        } else {
            button.addEventListener('click', btn.action);
        }
        toolbar.appendChild(button);
    });

    return toolbar;
}

// 防抖更新，避免输入时频繁渲染
const debouncedUpdate = debounce(updateMarkmap, 300);
// 共享防抖自动保存（500ms 延迟，避免每次按键都写 localStorage）
const debouncedAutoSave = debounce(autoSaveToHistory, 500);

function updateMarkmap() {
    try {
        const fullContent = expandImages(editor.value);
        const { root, features, frontmatter, relations } = transformer.transform(fullContent);
        const { styles, scripts } = transformer.getUsedAssets(features);
        const opts = deriveOptions(frontmatter?.markmap);

        // 从 frontmatter 提取并应用主题
        currentTheme = frontmatter?.markmap?.theme || '';
        applyTheme(currentTheme, opts);

        if (styles) loadCSS(styles);
        if (scripts) loadJS(scripts, { getMarkmap: () => window.markmap });

        if (mm) {
            // 自动适应窗口模式：内容变化后自动 fit
            if (autoFitEnabled) {
                mm.setData(root, opts, relations).then(() => mm.fit());
            } else {
                mm.setData(root, opts, relations);
            }
        } else {
            mm = new Markmap('#markmap', opts);
            mm.setData(root, opts, relations).then(() => mm.fit());

            // 添加浮动工具栏（缩放/全屏/导出）
            const toolbar = createToolbar(mm);
            document.getElementById('markmap-container').appendChild(toolbar);

            // 监听思维导图节点点击：区分单击（切换展开/折叠）和双击（展开该节点下所有内容）
            const svgEl = document.getElementById('markmap');
            if (svgEl) {
                let pendingClickTimer = null;
                const DBLCLICK_DELAY = 250;

                // 捕获阶段拦截节点点击，阻止 markmap 默认 toggle，自行区分单击/双击
                svgEl.addEventListener('click', (e) => {
                    const nodeEl = e.target.closest('.markmap-node');
                    if (!nodeEl) return; // 非节点点击，不拦截

                    // 阻止 markmap 内部的 handleClick（避免双击时 toggle 两次造成闪烁）
                    e.stopPropagation();

                    const nodeData = nodeEl.__data__;

                    if (pendingClickTimer) {
                        // 第二次点击 → 双击：切换该节点直接子节点（一层）的展开/收起
                        clearTimeout(pendingClickTimer);
                        pendingClickTimer = null;

                        if (nodeData && nodeData.children && mm) {
                            // 判断子节点是否全部展开：有任一子节点 fold=1 则视为未全展开
                            const allExpanded = nodeData.children.every(child =>
                                !child.payload || child.payload.fold === undefined
                            );
                            nodeData.children.forEach(child => {
                                if (!child.payload) child.payload = {};
                                if (allExpanded) {
                                    // 全展开 → 收起
                                    child.payload.fold = 1;
                                } else {
                                    // 未全展开 → 展开
                                    delete child.payload.fold;
                                }
                            });
                            mm.renderData(mm.state.data).then(() => {
                                if (autoFitEnabled && mm) mm.fit();
                            });
                        }
                    } else {
                        // 第一次点击 → 等待判断是否为双击
                        pendingClickTimer = setTimeout(() => {
                            pendingClickTimer = null;
                            // 超时无第二次点击 → 单击：执行 markmap 默认 toggle
                            if (nodeData && mm) {
                                mm.toggleNode(nodeData).then(() => {
                                    if (autoFitEnabled) mm.fit();
                                });
                            }
                        }, DBLCLICK_DELAY);
                    }
                }, true); // 捕获阶段

                // 非节点区域点击（背景），自动适应窗口
                svgEl.addEventListener('click', (e) => {
                    if (autoFitEnabled && !e.target.closest('.markmap-node')) {
                        setTimeout(() => { if (mm) mm.fit(); }, 400);
                    }
                });
            }
        }
    } catch (error) {
        console.error('渲染思维导图失败:', error);
    }
}

function loadFromHash() {
    if (window.location.hash) {
        const compressedContent = window.location.hash.slice(1);
        const content = decompressContent(compressedContent);
        if (content) {
            restoreImages(null);
            editor.value = extractImagesFromContent(content);
            updateMarkmap();
            return true;
        }
    }
    return false;
}

// ── 文档历史功能 ──

function getDocHistory() {
    try {
        return JSON.parse(localStorage.getItem(DOC_HISTORY_KEY) || '[]');
    } catch {
        return [];
    }
}

function saveDocHistory(docs) {
    try {
        localStorage.setItem(DOC_HISTORY_KEY, JSON.stringify(docs));
    } catch (e) {
        console.error('保存文档历史失败:', e);
    }
}

function extractDocTitle(content) {
    // 尝试从 frontmatter 提取 title
    const fmMatch = content.match(/^---\r?\n[\s\S]*?title:\s*(.+?)\r?\n/);
    if (fmMatch) return fmMatch[1].trim().replace(/^["']|["']$/g, '');

    // 尝试从第一个 # 标题提取
    const headingMatch = content.match(/^#\s+(.+)$/m);
    if (headingMatch) return headingMatch[1].trim();

    return '未命名文档';
}

function autoSaveToHistory() {
    if (!editor.value.trim()) return;

    if (!currentDocId) {
        currentDocId = 'doc_' + Date.now();
    }

    const docs = getDocHistory();
    const existingIdx = docs.findIndex(d => d.id === currentDocId);

    // 文档元数据（不含图片数据，避免大图导致整体保存失败）
    const doc = {
        id: currentDocId,
        title: extractDocTitle(editor.value),
        content: editor.value,
        updatedAt: new Date().toISOString()
    };

    if (existingIdx >= 0) {
        docs[existingIdx] = doc;
    } else {
        docs.unshift(doc);
        if (docs.length > MAX_HISTORY) {
            docs.length = MAX_HISTORY;
        }
    }

    saveDocHistory(docs);

    // 保存前同步清理：移除编辑器中已删除的孤儿图片，释放内存和存储空间
    syncImageMapWithContent(editor.value);

    // 图片存储到 IndexedDB（大容量），不再受 localStorage 5-10MB 限制
    if (imageDataMap.size > 0) {
        const images = Object.fromEntries(imageDataMap);
        saveDocImages(currentDocId, images);
    } else {
        // 没有图片时也清理该文档的旧图片存储
        saveDocImages(currentDocId, {});
    }

    renderSidebarDocs();
}

function renderSidebarDocs() {
    const container = document.getElementById('sidebar-docs');
    if (!container) return;

    const docs = getDocHistory();
    container.innerHTML = '';

    if (docs.length === 0) {
        container.innerHTML = '<div class="sidebar-empty">暂无历史文档</div>';
        return;
    }

    docs.forEach(doc => {
        const item = document.createElement('div');
        item.className = 'doc-item' + (doc.id === currentDocId ? ' active' : '');

        const time = new Date(doc.updatedAt);
        const timeStr = formatTime(time);

        item.innerHTML = `
            <div class="doc-item-title"></div>
            <div class="doc-item-time">${timeStr}</div>
            <button class="doc-item-delete" title="删除">×</button>
        `;
        item.querySelector('.doc-item-title').textContent = doc.title;

        item.addEventListener('click', (e) => {
            if (e.target.classList.contains('doc-item-delete')) return;
            loadDocFromHistory(doc.id);
        });

        item.querySelector('.doc-item-delete').addEventListener('click', (e) => {
            e.stopPropagation();
            deleteDocFromHistory(doc.id);
        });

        container.appendChild(item);
    });
}

function formatTime(date) {
    const now = new Date();
    const diff = now - date;
    const minutes = Math.floor(diff / 60000);
    const hours = Math.floor(diff / 3600000);
    const days = Math.floor(diff / 86400000);

    if (minutes < 1) return '刚刚';
    if (minutes < 60) return `${minutes} 分钟前`;
    if (hours < 24) return `${hours} 小时前`;
    if (days < 7) return `${days} 天前`;

    return date.toLocaleDateString('zh-CN', { month: 'short', day: 'numeric' });
}

async function loadDocFromHistory(docId) {
    autoSaveToHistory();

    const docs = getDocHistory();
    const doc = docs.find(d => d.id === docId);
    if (!doc) return;

    currentDocId = doc.id;
    // 异步从 IndexedDB 加载图片，回退到 localStorage
    let images = await loadDocImagesAsync(doc.id);
    if (!images && doc.images) {
        // 旧版数据迁移：将内联图片转存到独立存储
        images = doc.images;
        saveDocImages(doc.id, images);
        delete doc.images;
        saveDocHistory(docs);
    }
    restoreImages(images);
    editor.value = doc.content;
    updateMarkmap();
    renderSidebarDocs();
}

async function deleteDocFromHistory(docId) {
    const docs = getDocHistory();
    const doc = docs.find(d => d.id === docId);
    const title = doc ? doc.title : '该文档';
    if (!confirm(`确定要删除「${title}」吗？`)) return;

    let updated = docs.filter(d => d.id !== docId);
    saveDocHistory(updated);
    // 删除该文档关联的图片（IndexedDB + localStorage）
    deleteDocImages(docId);

    if (docId === currentDocId) {
        if (updated.length > 0) {
            // 直接加载下一篇，不调用 loadDocFromHistory（其内部的 autoSaveToHistory 会重新保存已删除文档）
            const nextDoc = updated[0];
            currentDocId = nextDoc.id;
            // 异步加载下一篇图片
            let nextImages = await loadDocImagesAsync(nextDoc.id);
            if (!nextImages && nextDoc.images) {
                nextImages = nextDoc.images;
            }
            restoreImages(nextImages);
            editor.value = nextDoc.content;
            updateMarkmap();
        } else {
            currentDocId = null;
            restoreImages(null);
            editor.value = '';
            updateMarkmap();
        }
    }

    renderSidebarDocs();
}

function initSidebar() {
    const sidebarToggle = document.getElementById('sidebar-toggle');
    const sidebar = document.getElementById('sidebar');
    const sidebarNew = document.getElementById('sidebar-new');

    // 禁用过渡动画，避免刷新时出现收缩动效
    sidebar.classList.add('no-anim');

    // 恢复侧边栏状态（默认收缩，仅当用户之前手动展开时才展开）
    if (localStorage.getItem('markmap-sidebar-collapsed') === 'false') {
        sidebar.classList.remove('collapsed');
    }

    // 下一帧恢复过渡动画，确保后续交互有动效
    requestAnimationFrame(() => {
        requestAnimationFrame(() => {
            sidebar.classList.remove('no-anim');
        });
    });

    if (sidebarToggle && sidebar) {
        sidebarToggle.addEventListener('click', () => {
            sidebar.classList.toggle('collapsed');
            localStorage.setItem('markmap-sidebar-collapsed', sidebar.classList.contains('collapsed'));
            setTimeout(() => { if (mm) mm.fit(); }, 300);
        });
    }

    if (sidebarNew) {
        sidebarNew.addEventListener('click', () => newMap());
    }

    renderSidebarDocs();
}

// ── 主题功能 ──

function applyTheme(theme, opts) {
    const themeConfig = THEMES[theme];

    // 库原生主题：deriveOptions 已处理颜色/节点样式/线宽等，无需覆盖
    // 仅处理需要修正的项
    if (themeConfig?.native) {
        // dark 主题自带 canvasColor，移除以保持背景由日/夜间模式控制
        if (themeConfig.stripCanvas && opts.theme) {
            opts.theme = { ...opts.theme, canvasColor: undefined };
        }
    } else if (themeConfig?.colors) {
        // 自定义主题（如彩色）：使用 scaleOrdinal 按分支路径分配颜色
        const scale = d3.scaleOrdinal(themeConfig.colors);
        opts.color = (node) => scale(`${node.state.path}`);
    }

    updateThemeUI();
}

function setTheme(theme) {
    const content = editor.value;
    const themeValue = theme || '';

    // 匹配 frontmatter 块
    const fmRegex = /^---\r?\n([\s\S]*?)\r?\n---/;
    const fmMatch = content.match(fmRegex);

    if (fmMatch) {
        let fm = fmMatch[1];

        // 检查是否已存在 theme 行
        const themeLineRegex = /^(\s+)theme:\s*.+$/m;
        const themeLineMatch = fm.match(themeLineRegex);

        if (themeLineMatch) {
            if (themeValue) {
                // 替换已有 theme 值
                fm = fm.replace(themeLineRegex, `$1theme: ${themeValue}`);
            } else {
                // 移除 theme 行
                fm = fm.replace(/^\s+theme:.*\r?\n?/m, '');
            }
        } else if (themeValue) {
            // 尚无 theme 行，需添加
            const markmapRegex = /^markmap:\s*\r?\n/m;
            if (markmapRegex.test(fm)) {
                // 在 markmap 段落首行添加 theme
                fm = fm.replace(markmapRegex, `markmap:\n  theme: ${themeValue}\n`);
            } else {
                // 添加 markmap 段落
                fm = fm + `\nmarkmap:\n  theme: ${themeValue}`;
            }
        }

        editor.value = content.replace(fmRegex, `---\n${fm}\n---`);
    } else if (themeValue) {
        // 无 frontmatter，创建一个
        editor.value = `---\nmarkmap:\n  theme: ${themeValue}\n---\n\n${content}`;
    }

    updateMarkmap();
}

function updateThemeUI() {
    const themeDropdown = document.getElementById('theme-dropdown');
    if (!themeDropdown) return;

    themeDropdown.querySelectorAll('button').forEach(btn => {
        const btnTheme = btn.dataset.theme || '';
        btn.classList.toggle('active', btnTheme === currentTheme);
    });
}

function initThemeSelector() {
    const themeBtn = document.getElementById('theme-btn');
    const themeDropdown = document.getElementById('theme-dropdown');
    if (!themeBtn || !themeDropdown) return;

    // 切换下拉菜单
    themeBtn.addEventListener('click', (e) => {
        e.stopPropagation();
        themeDropdown.classList.toggle('show');
    });

    // 点击外部关闭下拉菜单
    document.addEventListener('click', (e) => {
        if (!e.target.closest('.theme-selector')) {
            themeDropdown.classList.remove('show');
        }
    });

    // 主题选择
    themeDropdown.querySelectorAll('button').forEach(btn => {
        btn.addEventListener('click', () => {
            setTheme(btn.dataset.theme);
            themeDropdown.classList.remove('show');
        });
    });
}

// ── 日间/夜间模式 ──

function toggleMode() {
    currentMode = currentMode === 'day' ? 'night' : 'day';
    localStorage.setItem('markmap-mode', currentMode);
    applyMode();
    if (mm) mm.fit();
}

function applyMode() {
    document.body.classList.toggle('night-mode', currentMode === 'night');
    const modeBtn = document.getElementById('mode-toggle');
    if (modeBtn) {
        modeBtn.textContent = currentMode === 'day' ? '日间' : '夜间';
    }
}

function initModeToggle() {
    const modeBtn = document.getElementById('mode-toggle');
    if (!modeBtn) return;
    modeBtn.addEventListener('click', toggleMode);
    applyMode();
}

// ── 移动端菜单 ──
// 点击 ⋮ 按钮展开/收起工具栏下拉浮层
// 选择操作后自动收起（主题按钮除外，它有自己的子菜单）

function initMobileMenu() {
    const menuBtn = document.getElementById('mobile-menu-btn');
    const toolbar = document.querySelector('.toolbar');
    if (!menuBtn || !toolbar) return;

    function closeMenu() {
        toolbar.classList.remove('show');
        menuBtn.classList.remove('menu-active');
    }

    // 点击 ⋮ 按钮切换工具栏显隐
    menuBtn.addEventListener('click', () => {
        const willShow = !toolbar.classList.contains('show');
        toolbar.classList.toggle('show', willShow);
        menuBtn.classList.toggle('menu-active', willShow);
    });

    // 点击工具栏内按钮后自动收起（主题按钮除外，它有自己的子菜单）
    toolbar.querySelectorAll('button').forEach(btn => {
        if (btn.id === 'theme-btn') return;
        btn.addEventListener('click', closeMenu);
    });

    // 点击外部关闭菜单
    document.addEventListener('click', (e) => {
        if (!e.target.closest('#mobile-menu-btn') && !e.target.closest('.toolbar')) {
            closeMenu();
        }
    });
}

// ── 可拖动分割线 ──
// 桌面端：左右拖动调整编辑区宽度
// 移动端：上下拖动调整编辑区高度，支持触屏

function isMobileLayout() {
    return window.matchMedia('(max-width: 768px)').matches;
}

function initSplitter() {
    const splitter = document.getElementById('splitter');
    const editorContainer = document.getElementById('editor-container');
    const main = document.querySelector('main');
    if (!splitter || !editorContainer || !main) return;

    let isDragging = false;

    function onStart(e) {
        isDragging = true;
        splitter.classList.add('dragging');
        document.body.style.cursor = isMobileLayout() ? 'row-resize' : 'col-resize';
        document.body.style.userSelect = 'none';
        e.preventDefault();
    }

    function onMove(e) {
        if (!isDragging) return;

        const rect = main.getBoundingClientRect();

        if (isMobileLayout()) {
            // 移动端：纵向拖动，调整编辑区高度
            const clientY = e.touches ? e.touches[0].clientY : e.clientY;
            const y = clientY - rect.top;
            const percentage = (y / rect.height) * 100;
            const clamped = Math.max(15, Math.min(85, percentage));
            editorContainer.style.height = `${clamped}%`;
            editorContainer.style.width = '100%';
        } else {
            // 桌面端：横向拖动，调整编辑区宽度
            const clientX = e.touches ? e.touches[0].clientX : e.clientX;
            const x = clientX - rect.left;
            const percentage = (x / rect.width) * 100;
            const clamped = Math.max(10, Math.min(90, percentage));
            editorContainer.style.width = `${clamped}%`;
            editorContainer.style.height = '';
        }
    }

    function onEnd() {
        if (isDragging) {
            isDragging = false;
            splitter.classList.remove('dragging');
            document.body.style.cursor = '';
            document.body.style.userSelect = '';
            if (mm) mm.fit();
        }
    }

    // 鼠标事件
    splitter.addEventListener('mousedown', onStart);
    document.addEventListener('mousemove', onMove);
    document.addEventListener('mouseup', onEnd);

    // 触屏事件
    splitter.addEventListener('touchstart', onStart, { passive: false });
    document.addEventListener('touchmove', onMove, { passive: false });
    document.addEventListener('touchend', onEnd);

    // 窗口尺寸变化时重置布局模式
    window.addEventListener('resize', () => {
        if (!isMobileLayout()) {
            // 切回桌面端时清除移动端设置的 height
            editorContainer.style.height = '';
        } else {
            // 切到移动端时清除桌面端设置的 width
            editorContainer.style.width = '100%';
        }
        if (mm) mm.fit();
    });
}

// ── 插入图片（本地文件转 Base64）──

function insertImage() {
    const input = document.createElement('input');
    input.type = 'file';
    input.accept = 'image/png,image/jpeg,image/gif,image/svg+xml,image/webp';

    input.onchange = e => {
        const file = e.target.files[0];
        if (!file) return;

        // 限制图片大小（5MB），避免 Base64 过长撑爆 localStorage
        const maxSize = 5 * 1024 * 1024;
        if (file.size > maxSize) {
            alert('图片过大（超过 5MB），请选择较小的图片或压缩后再插入。');
            return;
        }

        const reader = new FileReader();
        reader.onload = async function(ev) {
            const rawBase64 = ev.target.result;
            // 压缩图片以减小 localStorage 占用（大图缩放至 1200px 宽，转 JPEG 75% 质量）
            const base64 = await compressImage(rawBase64);
            const fileName = file.name.replace(/\.[^.]+$/, ''); // 去扩展名作为描述

            // 将 Base64 存入 imageMap，编辑器中只插入短占位符
            const imgId = `img_${++imageCounter}`;
            imageDataMap.set(imgId, base64);

            // 在光标位置插入 Markdown 图片语法（使用占位符）
            const start = editor.selectionStart;
            const end = editor.selectionEnd;
            const text = editor.value;
            const insertText = `![${fileName}](local:${imgId})`;

            editor.value = text.slice(0, start) + insertText + text.slice(end);
            editor.selectionStart = editor.selectionEnd = start + insertText.length;
            editor.focus();
            updateMarkmap();

            // 立即保存图片到 IndexedDB（不等防抖，防止刷新丢失）
            autoSaveToHistory();
        };
        reader.onerror = function() {
            alert('图片读取失败，请重试。');
        };
        reader.readAsDataURL(file);
    };

    input.click();
}

function loadDefaultContent() {
    fetch('content.md')
        .then(response => {
            if (!response.ok) throw new Error(`HTTP ${response.status}`);
            return response.text();
        })
        .then(content => {
            editor.value = content;
            updateMarkmap();
            autoSaveToHistory();
        })
        .catch(() => {
            // 直接打开 file:// 时 fetch 会失败，使用内置默认内容
            editor.value = DEFAULT_CONTENT;
            updateMarkmap();
            autoSaveToHistory();
        });
}

async function init() {
    // 初始化侧边栏
    initSidebar();

    // 先执行一次性迁移：将 localStorage 中的旧图片数据迁移到 IndexedDB
    await migrateImagesToIDB();

    if (!loadFromHash()) {
        // 尝试从历史记录加载最近的文档
        const docs = getDocHistory();
        if (docs.length > 0) {
            currentDocId = docs[0].id;
            // 异步从 IndexedDB 加载图片，回退到 localStorage
            let images = await loadDocImagesAsync(docs[0].id);
            if (!images && docs[0].images) {
                // 旧版数据迁移：将内联图片转存到独立存储
                images = docs[0].images;
                saveDocImages(docs[0].id, images);
                delete docs[0].images;
                saveDocHistory(docs);
            }
            restoreImages(images);
            editor.value = docs[0].content;
            updateMarkmap();
            renderSidebarDocs();
        } else {
            loadDefaultContent();
        }
    } else {
        // 从分享链接加载（loadFromHash 已提取图片到 imageMap）
        currentDocId = null;
        autoSaveToHistory();
    }

    // 防抖更新与自动保存（使用共享的 debouncedAutoSave）
    editor.addEventListener('input', () => {
        debouncedUpdate();
        debouncedAutoSave();
    });

    // 编辑器失焦时立即保存
    editor.addEventListener('blur', () => autoSaveToHistory());

    // 页面关闭前立即保存
    window.addEventListener('beforeunload', () => autoSaveToHistory());

    // 页面切换到后台时立即保存（移动端切换 App、PC 切换标签页）
    document.addEventListener('visibilitychange', () => {
        if (document.visibilityState === 'hidden') autoSaveToHistory();
    });

    // 初始化主题选择器、模式切换和分割线
    initThemeSelector();
    initModeToggle();
    initMobileMenu();
    initSplitter();

    // 插入图片按钮
    document.getElementById('insert-image')?.addEventListener('click', insertImage);

    // 窗口大小变化时重新适配
    window.addEventListener('resize', debounce(() => {
        if (mm) mm.fit();
    }, 200));

    // 键盘快捷键
    document.addEventListener('keydown', (e) => {
        // Ctrl/Cmd + S: 保存
        if ((e.ctrlKey || e.metaKey) && e.key === 's') {
            e.preventDefault();
            saveMap();
        }
    });
}

// ── 压缩/解压（用于分享链接）──

function compressContent(content) {
    const uint8Array = new TextEncoder().encode(content);
    const compressed = pako.gzip(uint8Array);
    // 分块转换，避免 fromCharCode.apply 栈溢出
    let binaryString = '';
    const chunkSize = 8192;
    for (let i = 0; i < compressed.length; i += chunkSize) {
        binaryString += String.fromCharCode.apply(null, compressed.subarray(i, i + chunkSize));
    }
    return btoa(binaryString)
        .replace(/\+/g, '-')
        .replace(/\//g, '_')
        .replace(/=+$/, '');
}

function decompressContent(compressed) {
    try {
        const binaryString = atob(compressed.replace(/-/g, '+').replace(/_/g, '/'));
        const uint8Array = new Uint8Array(binaryString.length);
        for (let i = 0; i < binaryString.length; i++) {
            uint8Array[i] = binaryString.charCodeAt(i);
        }
        const decompressed = pako.ungzip(uint8Array);
        return new TextDecoder().decode(decompressed);
    } catch (error) {
        console.error('解压内容失败:', error);
        return null;
    }
}

function generateShareableURL() {
    const content = expandImages(editor.value);
    const compressedContent = compressContent(content);
    return `${window.location.origin}${window.location.pathname}#${compressedContent}`;
}

async function shareURL() {
    const url = generateShareableURL();

    if (navigator.clipboard && navigator.clipboard.writeText) {
        try {
            await navigator.clipboard.writeText(url);
            alert('分享链接已复制到剪贴板！');
        } catch (err) {
            console.error('复制链接失败:', err);
            fallbackCopyTextToClipboard(url);
        }
    } else {
        fallbackCopyTextToClipboard(url);
    }
}

function fallbackCopyTextToClipboard(text) {
    const textArea = document.createElement("textarea");
    textArea.value = text;
    textArea.style.top = '0';
    textArea.style.left = '0';
    textArea.style.position = 'fixed';

    document.body.appendChild(textArea);
    textArea.focus();
    textArea.select();

    try {
        const successful = document.execCommand('copy');
        alert(successful ? '分享链接已复制到剪贴板！' : '无法复制链接，请手动复制');
    } catch (err) {
        console.error('回退复制失败:', err);
        prompt('请手动复制此链接进行分享:', text);
    }

    document.body.removeChild(textArea);
}

// 确保 DOM 加载完成后执行
document.addEventListener('DOMContentLoaded', init);