// ==UserScript==
// @name         ET 表格预览器（拖入 .et 文件直接查看）
// @namespace    http://tampermonkey.net/
// @version      1.1.0
// @description  点右下角按钮打开预览页，把 WPS 表格文件（.et/.ett，兼容 .xls/.xlsx/.xlsm/.csv）拖进去就能看；也可直接在任意网页拖入。支持多工作表切换、查找过滤、自动换行、单元格详情、复制、导出 CSV、一键转存 XLSX，大表格渐进加载不卡顿。
// @author       xizi
// @match        *://*/*
// @match        file:///*
// @require      https://cdn.bootcdn.net/ajax/libs/xlsx/0.18.5/xlsx.full.min.js
// @grant        GM_addStyle
// @grant        GM_setClipboard
// @grant        GM_setValue
// @grant        GM_getValue
// @grant        GM_registerMenuCommand
// @grant        GM_unregisterMenuCommand
// @grant        unsafeWindow
// @run-at       document-start
// @noframes
// @license      MIT
// @icon         data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIyNCIgaGVpZ2h0PSIyNCIgdmlld0JveD0iMCAwIDI0IDI0Ij48cmVjdCB3aWR0aD0iMjQiIGhlaWdodD0iMjQiIHJ4PSI1IiBmaWxsPSIjMTYyMTFhIiBzdHJva2U9IiM1YWQwN2EiIHN0cm9rZS13aWR0aD0iMS41Ii8+PHBhdGggZD0iTTYgNy41aDEyTTYgMTJoMTJNNiAxNi41aDEyTTEwLjUgNy41djkiIHN0cm9rZT0iIzVhZDA3YSIgc3Ryb2tlLXdpZHRoPSIxLjYiIHN0cm9rZS1saW5lY2FwPSJyb3VuZCIvPjwvc3ZnPg==
// ==/UserScript==

/*
 * 功能一览
 *   1. 把 .et（WPS 表格）文件拖到网页任意位置，松手即预览；也可以点右下角悬浮按钮 / 油猴菜单选择文件。
 *   2. .et 有两种常见形态：老版本是 OLE2 复合文档（BIFF8），新版本是 ZIP 包（等同 xlsx）。脚本按文件头自动识别，
 *      两种都能直接解析，解析工作由 SheetJS 完成（已在 @require 里内置）。
 *   3. 预览界面：多工作表标签、查找过滤（命中高亮）、自动换行、单元格详情、复制、导出 CSV、转存 XLSX。
 *   4. 大表格渐进渲染：滚动到底部自动追加，导出始终是完整数据。
 *
 * 说明：脚本只接管拖入的表格文件，其它文件的拖放会原样交还给网页，尽量不影响目标站点自身的拖拽功能。
 */

(function () {
    'use strict';

    /* ============================================================
     * 0. 常量与全局状态
     * ============================================================ */

    const VERSION = '1.1.0';
    const ROOT_ID = 'et-preview-root';
    const BALL_ID = 'et-preview-ball';
    const BANNER_ID = 'et-preview-banner';
    const TOAST_ID = 'et-preview-toast';

    // 支持的文件后缀：前两个是脚本的主场（WPS 表格），后面几个是顺带支持
    const EXT_ET = ['et', 'ett'];
    const EXT_OTHER = ['xls', 'xlsx', 'xlsm', 'xlsb', 'csv'];

    // 解析库地址：即使 @require 失败，运行期也会按顺序再试一遍
    const CDN_LIST = [
        'https://cdn.bootcdn.net/ajax/libs/xlsx/0.18.5/xlsx.full.min.js',
        'https://cdn.jsdelivr.net/npm/xlsx@0.18.5/dist/xlsx.full.min.js',
        'https://fastly.jsdelivr.net/npm/xlsx@0.18.5/dist/xlsx.full.min.js',
        'https://unpkg.com/xlsx@0.18.5/dist/xlsx.full.min.js',
        'https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.18.5/xlsx.full.min.js',
        'https://cdn.staticfile.org/xlsx/0.18.5/xlsx.full.min.js'
    ];

    const CHUNK_ROWS = 150;        // 每次追加渲染的行数
    const RENDER_STEP = 20000;     // 提高渲染上限时的步长
    const COVER_LIMIT = 500000;    // 合并区域覆盖点统计上限（防御异常文件）

    const state = {
        wb: null,            // SheetJS 工作簿对象
        fileName: '',
        fileSize: 0,
        sheetIndex: 0,
        models: new Map(),   // 工作表名 -> 渲染模型
        filter: '',
        visibleRows: [],
        rendered: 0,
        renderCap: RENDER_STEP,
        selected: null,      // { r, c }
        xlsxPromise: null
    };

    const refs = {};         // DOM 引用集合
    let xlsxLib = null;      // 解析库缓存
    let dragDepth = 0;
    let toastTimer = 0;

    /* ============================================================
     * 1. 小工具
     * ============================================================ */

    function getXLSX() {
        if (xlsxLib) return xlsxLib;
        let lib = null;
        try { if (typeof unsafeWindow !== 'undefined' && unsafeWindow && unsafeWindow.XLSX) lib = unsafeWindow.XLSX; } catch (e) { /* 忽略 */ }
        if (!lib) { try { if (typeof XLSX !== 'undefined' && XLSX) lib = XLSX; } catch (e) { /* 忽略 */ } }
        if (!lib && window.XLSX) lib = window.XLSX;
        if (lib) xlsxLib = lib;
        return lib;
    }

    /** 确保解析库就绪：@require 已加载则直接命中缓存，否则按 CDN 列表兜底加载 */
    function ensureXLSX() {
        const ready = getXLSX();
        if (ready) return Promise.resolve(ready);
        if (state.xlsxPromise) return state.xlsxPromise;

        state.xlsxPromise = new Promise(function (resolve, reject) {
            let i = 0;
            const next = function () {
                if (i >= CDN_LIST.length) {
                    reject(new Error('解析库加载失败（XLSX），请检查网络或脚本里的 @require 地址'));
                    return;
                }
                const url = CDN_LIST[i++];
                const s = document.createElement('script');
                s.src = url;
                s.async = true;
                s.onload = function () { getXLSX() ? resolve(getXLSX()) : next(); };
                s.onerror = function () { try { s.remove(); } catch (e) { /* 忽略 */ } next(); };
                (document.head || document.documentElement).appendChild(s);
            };
            next();
        }).catch(function (err) {
            state.xlsxPromise = null;
            throw err;
        });
        return state.xlsxPromise;
    }

    function extOf(name) {
        const i = String(name || '').lastIndexOf('.');
        return i < 0 ? '' : String(name).slice(i + 1).toLowerCase();
    }

    function escapeHtml(s) {
        return String(s).replace(/[&<>"']/g, function (ch) {
            return { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[ch];
        });
    }

    function escapeRegExp(s) {
        return String(s).replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
    }

    function fmtInt(n) {
        return Number(n || 0).toLocaleString('zh-CN');
    }

    function fmtSize(n) {
        if (n == null) return '';
        const units = ['B', 'KB', 'MB', 'GB'];
        let i = 0;
        let v = Number(n);
        while (v >= 1024 && i < units.length - 1) { v /= 1024; i++; }
        return (i === 0 ? v : v.toFixed(v < 10 ? 2 : 1)) + ' ' + units[i];
    }

    /** 估算显示宽度：ASCII 记 1，中文等宽字符记 2 */
    function visualUnits(text) {
        let u = 0;
        for (let i = 0; i < text.length; i++) {
            u += text.charCodeAt(i) < 0x2e80 ? 1 : 2;
        }
        return u;
    }

    function firstLine(text) {
        const s = String(text);
        const i = s.search(/\r|\n/);
        return i < 0 ? s : s.slice(0, i);
    }

    function toast(msg, type) {
        let box = document.getElementById(TOAST_ID);
        if (!box) {
            box = document.createElement('div');
            box.id = TOAST_ID;
            (document.body || document.documentElement).appendChild(box);
        }
        box.className = 'et-toast et-show' + (type ? ' et-toast-' + type : '');
        box.innerHTML = escapeHtml(msg).replace(/\n/g, '<br>');
        clearTimeout(toastTimer);
        toastTimer = setTimeout(function () { box.classList.remove('et-show'); }, type === 'error' ? 6000 : 3200);
    }

    function downloadBlob(blob, filename) {
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = filename;
        a.style.display = 'none';
        (document.body || document.documentElement).appendChild(a);
        a.click();
        setTimeout(function () {
            try { a.remove(); } catch (e) { /* 忽略 */ }
            URL.revokeObjectURL(url);
        }, 4000);
    }

    function baseName(name) {
        return String(name || 'workbook').replace(/\.[^.]+$/, '');
    }

    function copyText(text, okMsg) {
        const done = function () { toast(okMsg || '已复制到剪贴板'); };
        try {
            if (typeof GM_setClipboard === 'function') { GM_setClipboard(text, 'text'); done(); return; }
        } catch (e) { /* 继续尝试下面两种方案 */ }
        if (navigator.clipboard && navigator.clipboard.writeText) {
            navigator.clipboard.writeText(text).then(done, function () { fallbackCopy(text, done); });
            return;
        }
        fallbackCopy(text, done);
    }

    function fallbackCopy(text, done) {
        const ta = document.createElement('textarea');
        ta.value = text;
        ta.style.cssText = 'position:fixed;top:-9999px;left:-9999px;opacity:0;';
        (document.body || document.documentElement).appendChild(ta);
        ta.select();
        let ok = false;
        try { ok = document.execCommand('copy'); } catch (e) { ok = false; }
        try { ta.remove(); } catch (e) { /* 忽略 */ }
        if (ok && done) done(); else toast('复制失败，请手动选择后复制', 'error');
    }

    /* ============================================================
     * 2. 样式
     * ============================================================ */

    const CSS = [
        '#' + ROOT_ID + '{position:fixed;inset:0;z-index:2147483600;display:none;align-items:center;justify-content:center;',
        'background:rgba(6,8,12,.55);-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);',
        'font:13px/1.55 -apple-system,"Segoe UI","Microsoft YaHei",system-ui,sans-serif;color:#e9edf5;}',
        '#' + ROOT_ID + '.et-show{display:flex;animation:et-fade .16s ease-out;}',
        '@keyframes et-fade{from{opacity:0}to{opacity:1}}',
        '#' + ROOT_ID + ' *{box-sizing:border-box;}',

        '#' + ROOT_ID + ' .et-panel{display:flex;flex-direction:column;width:min(1520px,96vw);height:min(920px,92vh);overflow:hidden;',
        'background:linear-gradient(180deg,#171b24,#11141b);border:1px solid rgba(255,255,255,.1);border-radius:14px;',
        'box-shadow:0 26px 90px rgba(0,0,0,.62);}',
        '#' + ROOT_ID + '.et-full .et-panel{width:100vw;height:100vh;border-radius:0;border:0;}',

        '#' + ROOT_ID + ' .et-head{display:flex;align-items:center;gap:12px;padding:10px 14px;border-bottom:1px solid rgba(255,255,255,.08);',
        'background:linear-gradient(180deg,rgba(255,255,255,.04),rgba(255,255,255,0));}',
        '#' + ROOT_ID + ' .et-badge{flex:0 0 auto;display:inline-flex;align-items:center;justify-content:center;width:34px;height:24px;border-radius:6px;',
        'background:rgba(90,208,122,.14);border:1px solid rgba(90,208,122,.45);color:#7ee29a;font-size:11px;font-weight:700;letter-spacing:.5px;}',
        '#' + ROOT_ID + ' .et-fname{font-size:14px;font-weight:600;max-width:52vw;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}',
        '#' + ROOT_ID + ' .et-fmeta{color:#8d97a8;font-size:12px;white-space:nowrap;}',
        '#' + ROOT_ID + ' .et-grow{flex:1 1 auto;}',

        '#' + ROOT_ID + ' .et-btn{appearance:none;border:1px solid rgba(255,255,255,.14);background:rgba(255,255,255,.05);color:#dbe3f0;',
        'border-radius:8px;padding:5px 10px;font-size:12px;line-height:1.5;cursor:pointer;white-space:nowrap;transition:.15s;}',
        '#' + ROOT_ID + ' .et-btn:hover{background:rgba(90,208,122,.16);border-color:rgba(90,208,122,.5);color:#c9ffd9;}',
        '#' + ROOT_ID + ' .et-btn:active{transform:translateY(1px);}',
        '#' + ROOT_ID + ' .et-close{width:30px;padding:0;height:28px;font-size:14px;}',

        '#' + ROOT_ID + ' .et-tabs{display:flex;gap:6px;align-items:flex-end;padding:8px 14px 0;overflow-x:auto;overflow-y:hidden;}',
        '#' + ROOT_ID + ' .et-tabs:empty{display:none;}',
        '#' + ROOT_ID + ' .et-tab{flex:0 0 auto;border:1px solid rgba(255,255,255,.1);border-bottom:none;background:rgba(255,255,255,.04);',
        'color:#a9b4c5;border-radius:8px 8px 0 0;padding:6px 12px;font-size:12px;cursor:pointer;max-width:240px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}',
        '#' + ROOT_ID + ' .et-tab:hover{color:#e9edf5;}',
        '#' + ROOT_ID + ' .et-tab.et-on{background:rgba(90,208,122,.16);border-color:rgba(90,208,122,.5);color:#c9ffd9;font-weight:600;}',

        '#' + ROOT_ID + ' .et-toolbar{display:flex;align-items:center;gap:8px;padding:8px 14px;border-bottom:1px solid rgba(255,255,255,.08);flex-wrap:wrap;}',
        '#' + ROOT_ID + ' .et-search{width:min(320px,42vw);background:rgba(0,0,0,.35);border:1px solid rgba(255,255,255,.14);border-radius:8px;',
        'color:#e9edf5;padding:5px 10px;font-size:12px;outline:none;}',
        '#' + ROOT_ID + ' .et-search:focus{border-color:rgba(90,208,122,.6);}',
        '#' + ROOT_ID + ' .et-filterinfo{color:#f7c66b;font-size:12px;}',
        '#' + ROOT_ID + ' .et-chk{display:inline-flex;align-items:center;gap:5px;color:#b8c2d2;font-size:12px;cursor:pointer;user-select:none;}',
        '#' + ROOT_ID + ' .et-chk input{accent-color:#5ad07a;}',

        '#' + ROOT_ID + ' .et-body{flex:1 1 auto;display:flex;min-height:0;position:relative;}',
        '#' + ROOT_ID + ' .et-tablewrap{flex:1 1 auto;overflow:auto;background:#0d1016;position:relative;}',
        '#' + ROOT_ID + ' .et-tablewrap::-webkit-scrollbar{width:12px;height:12px;}',
        '#' + ROOT_ID + ' .et-tablewrap::-webkit-scrollbar-thumb{background:rgba(255,255,255,.16);border-radius:8px;border:3px solid #0d1016;}',
        '#' + ROOT_ID + ' .et-tablewrap::-webkit-scrollbar-thumb:hover{background:rgba(255,255,255,.28);}',
        '#' + ROOT_ID + ' .et-welcome{flex:1 1 auto;display:none;flex-direction:column;align-items:center;justify-content:center;gap:12px;',
        'text-align:center;padding:40px 24px;background:#0d1016;}',
        '#' + ROOT_ID + '.et-empty .et-welcome{display:flex;}',
        '#' + ROOT_ID + '.et-empty .et-tablewrap,#' + ROOT_ID + '.et-empty .et-side{display:none;}',
        '#' + ROOT_ID + ' .et-w-icon{font-size:44px;line-height:1;color:#5ad07a;opacity:.9;}',
        '#' + ROOT_ID + ' .et-w-title{font-size:20px;font-weight:600;color:#e7eef8;}',
        '#' + ROOT_ID + ' .et-w-sub{font-size:13px;color:#8d97a8;}',
        '#' + ROOT_ID + ' .et-w-sub b{color:#a8b6c9;font-weight:600;}',
        '#' + ROOT_ID + ' .et-w-btn{padding:8px 18px;font-size:13px;margin-top:2px;}',
        '#' + ROOT_ID + ' .et-w-hint{font-size:12px;color:#6f7f95;}',
        '#' + ROOT_ID + ' .et-table{border-collapse:separate;border-spacing:0;table-layout:fixed;min-width:100%;font-size:12.5px;}',
        '#' + ROOT_ID + ' .et-table th,#' + ROOT_ID + ' .et-table td{border-right:1px solid rgba(255,255,255,.06);border-bottom:1px solid rgba(255,255,255,.06);',
        'padding:5px 8px;vertical-align:top;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}',
        '#' + ROOT_ID + ' .et-table thead th{position:sticky;top:0;z-index:3;background:#1b2130;color:#93a0b5;font-weight:600;text-align:center;',
        'font-size:11.5px;border-bottom:1px solid rgba(255,255,255,.12);}',
        '#' + ROOT_ID + ' .et-table .et-rh{position:sticky;left:0;z-index:2;background:#161b26;color:#7c8798;text-align:right;font-weight:400;',
        'font-size:11.5px;min-width:52px;font-variant-numeric:tabular-nums;}',
        '#' + ROOT_ID + ' .et-table thead .et-rh{z-index:4;background:#1b2130;}',
        '#' + ROOT_ID + ' .et-table tbody tr:nth-child(even) td{background:rgba(255,255,255,.022);}',
        '#' + ROOT_ID + ' .et-table tbody tr:hover td{background:rgba(90,208,122,.08);}',
        '#' + ROOT_ID + ' .et-table td{cursor:cell;}',
        '#' + ROOT_ID + ' .et-num{text-align:right;color:#cfe6ff;font-variant-numeric:tabular-nums;}',
        '#' + ROOT_ID + ' .et-date{text-align:right;color:#8fd0ff;}',
        '#' + ROOT_ID + ' .et-bool{text-align:center;color:#b39ddb;}',
        '#' + ROOT_ID + ' .et-err{text-align:center;color:#ff8a8a;}',
        '#' + ROOT_ID + ' .et-merge{background:rgba(90,208,122,.05);}',
        '#' + ROOT_ID + ' .et-cell.et-sel{outline:2px solid #5ad07a;outline-offset:-2px;background:rgba(90,208,122,.14)!important;}',
        '#' + ROOT_ID + ' mark{background:rgba(247,198,107,.32);color:#ffe6b0;border-radius:2px;padding:0 1px;}',
        '#' + ROOT_ID + '.et-wrap-on .et-table th,#' + ROOT_ID + '.et-wrap-on .et-table td{white-space:pre-wrap;overflow-wrap:anywhere;}',
        '#' + ROOT_ID + ' .et-merge-tag{color:#7ee29a;font-size:11px;}',

        '#' + ROOT_ID + ' .et-side{flex:0 0 300px;border-left:1px solid rgba(255,255,255,.08);background:#141922;padding:12px;overflow:auto;}',
        '#' + ROOT_ID + ' .et-side-empty{color:#7c8798;font-size:12px;line-height:1.8;}',
        '#' + ROOT_ID + ' .et-side h4{margin:0 0 8px;font-size:12px;color:#93a0b5;font-weight:600;}',
        '#' + ROOT_ID + ' .et-kv{display:grid;grid-template-columns:64px 1fr;gap:4px 8px;font-size:12px;margin-bottom:10px;}',
        '#' + ROOT_ID + ' .et-kv b{color:#7c8798;font-weight:400;}',
        '#' + ROOT_ID + ' .et-sideval{background:rgba(0,0,0,.35);border:1px solid rgba(255,255,255,.09);border-radius:8px;padding:8px;',
        'font-size:12.5px;white-space:pre-wrap;overflow-wrap:anywhere;max-height:44vh;overflow:auto;color:#dfe7f3;}',

        '#' + ROOT_ID + ' .et-foot{display:flex;align-items:center;gap:10px;padding:6px 14px;border-top:1px solid rgba(255,255,255,.08);',
        'color:#8d97a8;font-size:12px;background:#12161e;flex-wrap:wrap;}',
        '#' + ROOT_ID + ' .et-foot b{color:#a8b6c9;font-weight:600;}',

        '#' + ROOT_ID + ' .et-loading{position:absolute;inset:0;display:none;flex-direction:column;align-items:center;justify-content:center;gap:14px;',
        'background:rgba(8,10,15,.72);z-index:9;font-size:13px;color:#c9d3e2;}',
        '#' + ROOT_ID + ' .et-loading.et-show{display:flex;}',
        '#' + ROOT_ID + ' .et-spin{width:34px;height:34px;border-radius:50%;border:3px solid rgba(90,208,122,.25);border-top-color:#5ad07a;animation:et-spin .8s linear infinite;}',
        '@keyframes et-spin{to{transform:rotate(360deg)}}',

        '#' + ROOT_ID + ' .et-help{max-width:560px;width:min(560px,92vw);height:auto;padding:22px 24px;line-height:1.9;font-size:13px;}',
        '#' + ROOT_ID + ' .et-help h3{margin:0 0 12px;font-size:15px;color:#c9ffd9;}',
        '#' + ROOT_ID + ' .et-help code{background:rgba(255,255,255,.08);border-radius:4px;padding:1px 5px;font-size:12px;}',
        '#' + ROOT_ID + ' .et-help ul{margin:6px 0 12px;padding-left:20px;color:#b8c2d2;}',

        '#' + BANNER_ID + '{position:fixed;left:50%;top:16px;transform:translate(-50%,-24px);z-index:2147483600;opacity:0;pointer-events:none;',
        'display:flex;align-items:center;gap:10px;padding:10px 18px;border-radius:12px;background:linear-gradient(180deg,#1d2534,#141922);',
        'border:1px solid rgba(90,208,122,.55);box-shadow:0 12px 40px rgba(0,0,0,.5);color:#d9f7e2;',
        'font:13px/1.4 -apple-system,"Segoe UI","Microsoft YaHei",system-ui,sans-serif;transition:opacity .16s,transform .16s;}',
        '#' + BANNER_ID + '.et-show{opacity:1;transform:translate(-50%,0);}',
        '#' + BANNER_ID + ' .et-dot{width:9px;height:9px;border-radius:50%;background:#5ad07a;box-shadow:0 0 0 4px rgba(90,208,122,.18);}',

        '#' + BALL_ID + '{position:fixed;right:18px;bottom:18px;z-index:2147483590;width:42px;height:42px;border-radius:50%;cursor:pointer;',
        'display:none;align-items:center;justify-content:center;background:linear-gradient(180deg,#1d2534,#12161e);',
        'border:1px solid rgba(90,208,122,.5);box-shadow:0 10px 26px rgba(0,0,0,.45);color:#7ee29a;font-size:18px;user-select:none;transition:.16s;}',
        '#' + BALL_ID + '.et-show{display:flex;}',
        '#' + BALL_ID + ':hover{transform:translateY(-2px);border-color:#5ad07a;color:#c9ffd9;}',

        '#' + TOAST_ID + '{position:fixed;left:50%;bottom:34px;transform:translate(-50%,20px);z-index:2147483610;max-width:min(520px,88vw);',
        'padding:10px 16px;border-radius:10px;background:rgba(20,25,34,.96);border:1px solid rgba(90,208,122,.42);color:#dbe6f2;',
        'font:13px/1.6 -apple-system,"Segoe UI","Microsoft YaHei",system-ui,sans-serif;box-shadow:0 14px 40px rgba(0,0,0,.5);',
        'opacity:0;pointer-events:none;transition:opacity .18s,transform .18s;}',
        '#' + TOAST_ID + '.et-show{opacity:1;transform:translate(-50%,0);}',
        '#' + TOAST_ID + '.et-toast-error{border-color:rgba(255,120,120,.55);color:#ffdada;}'
    ].join('');

    function injectStyles() {
        try {
            if (typeof GM_addStyle === 'function') { GM_addStyle(CSS); return; }
        } catch (e) { /* 忽略，走下面的兜底方案 */ }
        const style = document.createElement('style');
        style.textContent = CSS;
        (document.head || document.documentElement).appendChild(style);
    }

    /* ============================================================
     * 3. 界面构建
     * ============================================================ */

    /** 拖拽提示条（懒创建：脚本在 document-start 就运行，那时可能还没有 body） */
    function ensureBanner() {
        if (refs.banner || !document.body) return refs.banner;
        const banner = document.createElement('div');
        banner.id = BANNER_ID;
        banner.innerHTML = '<span class="et-dot"></span><span>松手即可预览表格文件</span>';
        document.body.appendChild(banner);
        refs.banner = banner;
        return banner;
    }

    /** 右下角悬浮按钮（默认显示，可在油猴菜单里隐藏） */
    function ensureBall() {
        if (refs.ball || !document.body) return refs.ball;
        const ball = document.createElement('div');
        ball.id = BALL_ID;
        ball.title = '打开 ET 预览页（拖入或选择 .et 文件）';
        ball.textContent = '▦';
        ball.addEventListener('click', openPreviewPage);
        document.body.appendChild(ball);
        refs.ball = ball;
        return ball;
    }

    /** 界面只建一次；拖放事件可能在界面建好之前就发生，所以这里做成“按需创建” */
    function ensureUI() {
        if (refs.root || !document.body) return;
        buildUI();
        updateBallVisibility();
    }

    function buildUI() {
        if (refs.root) return;
        ensureBanner();
        ensureBall();

        // 主面板
        const root = document.createElement('div');
        root.id = ROOT_ID;
        root.innerHTML = [
            '<div class="et-panel">',
            '  <div class="et-head">',
            '    <span class="et-badge">ET</span>',
            '    <span class="et-fname" data-ref="fname">未选择文件</span>',
            '    <span class="et-fmeta" data-ref="fmeta"></span>',
            '    <span class="et-grow"></span>',
            '    <button class="et-btn" data-act="full" title="全屏 / 还原">⛶</button>',
            '    <button class="et-btn et-close" data-act="close" title="关闭（Esc）">✕</button>',
            '  </div>',
            '  <div class="et-tabs" data-ref="tabs"></div>',
            '  <div class="et-toolbar">',
            '    <input class="et-search" data-ref="search" type="search" placeholder="查找内容（整表过滤并高亮）">',
            '    <span class="et-filterinfo" data-ref="filterinfo"></span>',
            '    <span class="et-grow"></span>',
            '    <label class="et-chk"><input type="checkbox" data-ref="wrapchk"> 自动换行</label>',
            '    <button class="et-btn" data-act="copy" title="复制当前显示内容（制表符分隔，可直接粘贴进表格软件）">复制</button>',
            '    <button class="et-btn" data-act="csv">导出 CSV</button>',
            '    <button class="et-btn" data-act="xlsx" title="把当前工作簿另存为标准 xlsx 文件">转存 XLSX</button>',
            '  </div>',
            '  <div class="et-body">',
            '    <div class="et-tablewrap" data-ref="wrap">',
            '      <table class="et-table" data-ref="table">',
            '        <colgroup data-ref="colgroup"></colgroup>',
            '        <thead data-ref="thead"></thead>',
            '        <tbody data-ref="tbody"></tbody>',
            '      </table>',
            '    </div>',
            '    <aside class="et-side" data-ref="side">',
            '      <div class="et-side-empty">点击任意单元格，这里会显示它的完整内容（长文本、日期格式、合并区域等）。</div>',
            '    </aside>',
            '    <div class="et-welcome" data-ref="welcome">',
            '      <div class="et-w-icon">▦</div>',
            '      <div class="et-w-title">把 .et 文件拖到这里</div>',
            '      <div class="et-w-sub">支持 WPS 表格的 <b>.et / .ett</b>，顺带支持 <b>.xls / .xlsx / .xlsm / .csv</b></div>',
            '      <button class="et-btn et-w-btn" data-act="pick">选择文件…</button>',
            '      <div class="et-w-hint">拖放完成后自动解析 · Esc 关闭 · ← / → 切换工作表</div>',
            '    </div>',
            '    <div class="et-loading" data-ref="loading"><div class="et-spin"></div><div data-ref="loadtext">解析中…</div></div>',
            '  </div>',
            '  <div class="et-foot" data-ref="foot"></div>',
            '</div>'
        ].join('');
        document.body.appendChild(root);

        root.querySelectorAll('[data-ref]').forEach(function (el) { refs[el.dataset.ref] = el; });
        refs.root = root;
        refs.panel = root.querySelector('.et-panel');

        // 按钮事件（用事件委托，便于动态生成的按钮共用）
        root.addEventListener('click', function (e) {
            const actEl = e.target && e.target.closest ? e.target.closest('[data-act]') : null;
            if (!actEl) return;
            const act = actEl.dataset.act;
            if (act === 'close') closePanel();
            else if (act === 'full') refs.root.classList.toggle('et-full');
            else if (act === 'pick') pickFiles();
            else if (act === 'copy') exportCopy();
            else if (act === 'csv') exportCSV();
            else if (act === 'xlsx') exportXLSX();
            else if (act === 'more') { state.renderCap += RENDER_STEP; renderChunk(); }
        });

        // 点击单元格查看详情
        refs.tbody.addEventListener('click', function (e) {
            const td = e.target && e.target.closest ? e.target.closest('td[data-r]') : null;
            if (!td) return;
            selectCell(Number(td.dataset.r), Number(td.dataset.c));
        });

        // 查找
        let searchTimer = 0;
        refs.search.addEventListener('input', function () {
            clearTimeout(searchTimer);
            searchTimer = setTimeout(function () {
                state.filter = refs.search.value || '';
                applyFilter();
            }, 180);
        });
        // 面板内输入时不要让快捷键跑到页面去
        refs.search.addEventListener('keydown', function (e) { e.stopPropagation(); });

        // 自动换行
        refs.wrapchk.addEventListener('change', function () {
            refs.root.classList.toggle('et-wrap-on', refs.wrapchk.checked);
        });

        // 滚动到底部时继续追加渲染
        let scrollTick = 0;
        refs.tablewrapScroll = function () {
            if (scrollTick) return;
            scrollTick = requestAnimationFrame(function () {
                scrollTick = 0;
                const el = refs.wrap;
                if (!state.wb) return;
                if (el.scrollTop + el.clientHeight >= el.scrollHeight - 320) {
                    if (state.rendered < Math.min(state.visibleRows.length, state.renderCap)) renderChunk();
                }
            });
        };
        refs.wrap.addEventListener('scroll', refs.tablewrapScroll);

        // 点击遮罩空白处关闭
        root.addEventListener('mousedown', function (e) {
            if (e.target === root) closePanel();
        });

        setEmpty(true);
        bindGlobalEvents();
    }

    function updateBallVisibility() {
        const ball = ensureBall();
        if (!ball) return;
        let hidden = false;
        try { hidden = !!GM_getValue('et_hide_ball', false); } catch (e) { hidden = false; }
        ball.classList.toggle('et-show', !hidden);
    }

    function toggleBall() {
        const ball = ensureBall();
        if (!ball) return;
        let hidden = false;
        try { hidden = !!GM_getValue('et_hide_ball', false); } catch (e) { hidden = false; }
        const next = !hidden;
        try { GM_setValue('et_hide_ball', next); } catch (e) { /* 忽略 */ }
        ball.classList.toggle('et-show', !next);
        toast(next ? '悬浮按钮已隐藏（在油猴菜单里可以再打开）' : '悬浮按钮已显示');
    }

    /** 同一个事件会先后经过 window 和 document，这里保证只处理一次 */
    function firstTime(e) {
        if (!e) return true;
        if (e.__etSeen) return false;
        try { e.__etSeen = true; } catch (err) { /* 只读事件对象，忽略 */ }
        return true;
    }

    function bindGlobalEvents() {
        // 拖拽：只在“拖的是文件”时介入
        const onDragEnter = function (e) {
            if (!firstTime(e) || !isFileDrag(e)) return;
            dragDepth++;
            showBanner(true);
        };

        const onDragOver = function (e) {
            if (!firstTime(e) || !isFileDrag(e)) return;
            e.preventDefault();       // 必须拦截，否则浏览器会直接打开或下载这个文件
            try { e.dataTransfer.dropEffect = 'copy'; } catch (err) { /* 忽略 */ }
        };

        const onDragLeave = function (e) {
            if (!firstTime(e) || !isFileDrag(e)) return;
            dragDepth = Math.max(0, dragDepth - 1);
            if (dragDepth === 0) showBanner(false);
        };

        const onDrop = function (e) {
            if (!firstTime(e) || !isFileDrag(e)) return;
            dragDepth = 0;
            showBanner(false);

            const dt = e.dataTransfer;
            const files = Array.prototype.slice.call((dt && dt.files) || []);
            const hit = files.filter(isAcceptedFile);
            if (!hit.length) return;   // 没有认识的文件，交还给网页自己处理

            e.preventDefault();
            e.stopPropagation();
            handleFiles(hit, files.length);
        };

        // 粘贴（剪贴板里带了表格文件时也能用）
        const onPaste = function (e) {
            if (!firstTime(e)) return;
            const dt = e.clipboardData;
            if (!dt || !dt.files || !dt.files.length) return;
            const files = Array.prototype.slice.call(dt.files);
            const hit = files.filter(isAcceptedFile);
            if (hit.length) handleFiles(hit, files.length);
        };

        // window 和 document 都挂一遍：页面自己劫持了其中一层时，另一层仍能兜住
        [window, document].forEach(function (target) {
            target.addEventListener('dragenter', onDragEnter, true);
            target.addEventListener('dragover', onDragOver, true);
            target.addEventListener('dragleave', onDragLeave, true);
            target.addEventListener('drop', onDrop, true);
            target.addEventListener('paste', onPaste, true);
        });

        // 快捷键：Esc 关闭，左右方向键切换工作表
        window.addEventListener('keydown', function (e) {
            if (e.key === 'Escape') {
                if (document.querySelector('#' + ROOT_ID + ' .et-help')) { closeHelp(); return; }
                if (refs.root && refs.root.classList.contains('et-show')) closePanel();
                return;
            }
            if (!refs.root || !refs.root.classList.contains('et-show') || !state.wb) return;
            const tag = (e.target && e.target.tagName) || '';
            if (tag === 'INPUT' || tag === 'TEXTAREA') return;
            if (e.key === 'ArrowRight' || e.key === 'PageDown') switchSheet(state.sheetIndex + 1);
            if (e.key === 'ArrowLeft' || e.key === 'PageUp') switchSheet(state.sheetIndex - 1);
        }, true);
    }

    function isFileDrag(e) {
        const dt = e.dataTransfer;
        if (!dt) return false;
        const types = dt.types || [];
        for (let i = 0; i < types.length; i++) {
            if (types[i] === 'Files') return true;
        }
        return false;
    }

    function isAcceptedFile(file) {
        const ext = extOf(file && file.name);
        return EXT_ET.indexOf(ext) >= 0 || EXT_OTHER.indexOf(ext) >= 0;
    }

    function showBanner(on) {
        if (on) ensureBanner();
        if (refs.banner) refs.banner.classList.toggle('et-show', !!on);
    }

    /* ============================================================
     * 4. 选文件 / 读文件 / 解析
     * ============================================================ */

    function pickFiles() {
        const input = document.createElement('input');
        input.type = 'file';
        input.accept = EXT_ET.concat(EXT_OTHER).map(function (ext) { return '.' + ext; }).join(',');
        input.style.display = 'none';
        input.addEventListener('change', function () {
            const files = Array.prototype.slice.call(input.files || []);
            try { input.remove(); } catch (e) { /* 忽略 */ }
            if (files.length) handleFiles(files, files.length);
        });
        (document.body || document.documentElement).appendChild(input);
        input.click();
    }

    /** 一次拖入多个文件时，只处理第一个可识别的文件 */
    function handleFiles(files, totalCount) {
        const list = Array.prototype.slice.call(files || []);
        if (!list.length) return Promise.resolve();
        const file = list[0];
        ensureUI();
        if (!refs.root) return Promise.resolve();   // body 还没就绪，正常不会走到这里
        openPanel();
        const task = parseAndShow(file);
        if (list.length > 1 || (totalCount && totalCount > 1)) {
            toast('已选择「' + file.name + '」，其余文件未处理');
        }
        return task;
    }

    async function parseAndShow(file) {
        setLoading(true, '正在读取 ' + file.name + ' …');
        try {
            const lib = await ensureXLSX();
            setLoading(true, '正在解析表格数据…');
            const wb = await readWorkbook(lib, file);
            if (!wb.SheetNames || !wb.SheetNames.length) throw new Error('文件里没有找到工作表');

            state.wb = wb;
            state.fileName = file.name;
            state.fileSize = file.size || 0;
            state.models.clear();
            state.sheetIndex = 0;
            state.filter = '';
            state.renderCap = RENDER_STEP;
            state.selected = null;
            refs.search.value = '';
            refs.wrapchk.checked = false;
            refs.root.classList.remove('et-wrap-on');

            refs.fname.textContent = file.name;
            refs.fname.title = file.name;
            refs.fmeta.textContent = fmtSize(file.size) + ' · ' + wb.SheetNames.length + ' 个工作表';
            setEmpty(false);
            buildTabs();
            switchSheet(0);
            setLoading(false);
            toast('已加载「' + file.name + '」');
        } catch (err) {
            setLoading(false);
            showParseError(err, file);
        }
    }

    async function readWorkbook(lib, file) {
        const buf = await file.arrayBuffer();
        const u8 = new Uint8Array(buf);
        // 文件头识别：PK.. = ZIP（新版 .et / xlsx），D0CF11E0 = OLE2 复合文档（老版 .et / xls）
        const isZip = u8.length > 3 && u8[0] === 0x50 && u8[1] === 0x4b &&
            (u8[2] === 0x03 || u8[2] === 0x05 || u8[2] === 0x07);
        const isOle = u8.length > 7 && u8[0] === 0xd0 && u8[1] === 0xcf && u8[2] === 0x11 && u8[3] === 0xe0;

        if (isZip || isOle) {
            return lib.read(buf, { type: 'array', cellDates: false, cellNF: false, cellStyles: false, sheetStubs: false });
        }
        // 其余按文本处理（CSV/TSV）：先 UTF-8，解码失败再退回 GB18030
        return lib.read(decodeText(u8), { type: 'string', cellDates: false });
    }

    function decodeText(u8) {
        try {
            return new TextDecoder('utf-8', { fatal: true }).decode(u8);
        } catch (e) {
            try { return new TextDecoder('gb18030').decode(u8); } catch (e2) { return new TextDecoder('utf-8').decode(u8); }
        }
    }

    function showParseError(err, file) {
        const msg = (err && err.message) || String(err);
        try { console.error('[ET 预览] 解析失败', err); } catch (e) { /* 忽略 */ }
        state.wb = null;
        setEmpty(true);        // 回到引导页，方便直接换一个文件重试
        refs.fname.textContent = file.name;
        refs.fname.title = file.name;
        refs.fmeta.textContent = fmtSize(file.size);
        refs.tabs.innerHTML = '';
        refs.colgroup.innerHTML = '';
        refs.thead.innerHTML = '';
        refs.tbody.innerHTML = '';
        refs.foot.innerHTML = '<span>无法解析这个文件</span>';
        renderSide();
        toast('解析失败：' + msg + '\n如果文件有密码保护，请先在 WPS 里另存为 .xlsx 再试', 'error');
    }

    function setLoading(on, text) {
        if (text) refs.loadtext.textContent = text;
        refs.loading.classList.toggle('et-show', !!on);
    }

    function openPanel() {
        ensureUI();
        if (!refs.root) return;
        refs.root.classList.add('et-show');
    }

    function closePanel() {
        refs.root.classList.remove('et-show');
        refs.root.classList.remove('et-full');
        closeHelp();
    }

    /** 空状态：面板里显示“把 .et 拖到这里”的引导页（尚未打开任何文件时） */
    function setEmpty(on) {
        if (!refs.root) return;
        refs.root.classList.toggle('et-empty', !!on);
    }

    /** 打开预览页：铺满屏幕的拖放引导，用户拖入或点按钮选文件后直接出表格 */
    function openPreviewPage() {
        openPanel();
        if (!state.wb) setEmpty(true);
        refs.root.classList.add('et-full');
    }

    /* ============================================================
     * 5. 工作表模型（单元格文本 / 列宽 / 合并区域）
     * ============================================================ */

    function buildModel(name) {
        const lib = getXLSX();
        const ws = state.wb.Sheets[name];
        const range = lib.utils.decode_range(ws['!ref'] || 'A1');
        const totalRows = range.e.r - range.s.r + 1;
        const totalCols = range.e.c - range.s.c + 1;

        const merges = (ws['!merges'] || []).map(function (mg) {
            return { sr: mg.s.r, sc: mg.s.c, er: mg.e.r, ec: mg.e.c };
        });

        const mergeAt = new Map();   // 合并区域左上角：'r,c' -> 合并信息
        const covered = new Set();   // 被合并覆盖的格子（不需要单独输出）
        let coverCount = 0;
        merges.forEach(function (mg) {
            mergeAt.set(mg.sr + ',' + mg.sc, mg);
            const area = (mg.er - mg.sr + 1) * (mg.ec - mg.sc + 1);
            if (coverCount + area > COVER_LIMIT) return;
            coverCount += area;
            for (let r = mg.sr; r <= mg.er; r++) {
                for (let c = mg.sc; c <= mg.ec; c++) {
                    if (r === mg.sr && c === mg.sc) continue;
                    covered.add(r + ',' + c);
                }
            }
        });

        const model = {
            name: name,
            ws: ws,
            range: range,
            totalRows: totalRows,
            totalCols: totalCols,
            merges: merges,
            mergeAt: mergeAt,
            covered: covered,
            widths: null
        };

        model.cellAt = function (r, c) {
            return ws[lib.utils.encode_cell({ r: r, c: c })] || null;
        };
        model.textAt = function (r, c) {
            return cellText(model.cellAt(r, c));
        };
        // 列宽：抽样若干行，按最长内容估算（中文按 2 个字符宽度计）
        model.widthsOf = function () {
            if (model.widths) return model.widths;
            const step = Math.max(1, Math.floor(totalRows / 80));
            const widths = [];
            for (let ci = 0; ci < totalCols; ci++) {
                const absCol = range.s.c + ci;
                let maxUnits = lib.utils.encode_col(absCol).length;
                for (let r = range.s.r; r <= range.e.r; r += step) {
                    const text = firstLine(cellText(model.cellAt(r, absCol)));
                    if (!text) continue;
                    const u = visualUnits(text);
                    if (u > maxUnits) maxUnits = u;
                    if (maxUnits > 60) break;
                }
                widths.push(Math.max(46, Math.min(520, Math.round(16 + maxUnits * 7.1))));
            }
            model.widths = widths;
            return widths;
        };
        return model;
    }

    function currentModel() {
        const name = state.wb.SheetNames[state.sheetIndex];
        if (!state.models.has(name)) state.models.set(name, buildModel(name));
        return state.models.get(name);
    }

    function cellText(cell) {
        if (!cell) return '';
        if (cell.w != null && cell.w !== '') return String(cell.w);   // 优先用原文件里的显示格式
        const v = cell.v;
        if (v == null) return '';
        if (cell.t === 'b') return v ? 'TRUE' : 'FALSE';
        if (cell.t === 'e') return String(v);
        if (cell.t === 'n') {
            if (typeof v !== 'number' || !isFinite(v)) return String(v);
            return String(Math.round(v * 1e10) / 1e10);
        }
        return String(v);
    }

    function cellKind(cell) {
        if (!cell) return '';
        if (cell.t === 'e') return 'et-err';
        if (cell.t === 'b') return 'et-bool';
        if (cell.t === 'n') {
            const w = cell.w || '';
            if (w && /[年月日\/\-:：]/.test(w) && !/^[\d.,\s:%￥¥$]*$/.test(w)) return 'et-date';
            return 'et-num';
        }
        return 'et-txt';
    }

    function cellTypeName(cell) {
        if (!cell) return '空';
        if (cell.t === 'e') return '错误值';
        if (cell.t === 'b') return '布尔值';
        if (cell.t === 'n') return cellKind(cell) === 'et-date' ? '日期 / 时间' : '数字';
        if (cell.t === 'd') return '日期';
        return '文本';
    }

    /* ============================================================
     * 6. 渲染
     * ============================================================ */

    function buildTabs() {
        if (!state.wb) { refs.tabs.innerHTML = ''; return; }
        refs.tabs.innerHTML = state.wb.SheetNames.map(function (name, i) {
            return '<div class="et-tab' + (i === state.sheetIndex ? ' et-on' : '') +
                '" data-sheet="' + i + '" title="' + escapeHtml(name) + '">' + escapeHtml(name) + '</div>';
        }).join('');
        refs.tabs.querySelectorAll('.et-tab').forEach(function (tab) {
            tab.addEventListener('click', function () { switchSheet(Number(tab.dataset.sheet)); });
        });
    }

    function switchSheet(index) {
        if (!state.wb || !state.wb.SheetNames.length) return;
        const count = state.wb.SheetNames.length;
        if (index < 0) index = count - 1;
        if (index >= count) index = 0;
        state.sheetIndex = index;
        state.rendered = 0;
        state.selected = null;

        refs.tabs.querySelectorAll('.et-tab').forEach(function (tab, i) {
            tab.classList.toggle('et-on', i === index);
        });

        buildHeader();
        applyFilter();
        refs.wrap.scrollTop = 0;
        refs.wrap.scrollLeft = 0;
        renderSide();
    }

    /** 表头 + 列宽（列宽用 <colgroup>，配合 table-layout:fixed 保证长内容不撑破表格） */
    function buildHeader() {
        const lib = getXLSX();
        const m = currentModel();
        const widths = m.widthsOf();
        let totalWidth = 56;
        refs.colgroup.innerHTML = '<col style="width:56px">' + widths.map(function (w) {
            totalWidth += w;
            return '<col style="width:' + w + 'px">';
        }).join('');
        refs.table.style.width = totalWidth + 'px';

        let head = '<tr><th class="et-rh" title="行号">#</th>';
        for (let ci = 0; ci < m.totalCols; ci++) {
            head += '<th>' + lib.utils.encode_col(m.range.s.c + ci) + '</th>';
        }
        refs.thead.innerHTML = head + '</tr>';
    }

    /** 应用查找条件，得到要显示的行号列表 */
    function applyFilter() {
        if (!state.wb) return;
        const m = currentModel();
        const q = state.filter.trim().toLowerCase();
        const rows = [];
        if (!q) {
            for (let r = m.range.s.r; r <= m.range.e.r; r++) rows.push(r);
        } else {
            for (let r = m.range.s.r; r <= m.range.e.r; r++) {
                for (let c = m.range.s.c; c <= m.range.e.c; c++) {
                    const text = m.textAt(r, c);
                    if (text && text.toLowerCase().indexOf(q) >= 0) { rows.push(r); break; }
                }
            }
        }
        state.visibleRows = rows;
        state.rendered = 0;
        refs.tbody.innerHTML = '';
        refs.filterinfo.textContent = q ? ('命中 ' + fmtInt(rows.length) + ' 行') : '';
        renderChunk();
    }

    function renderChunk() {
        if (!state.wb) return;
        const m = currentModel();
        const total = state.visibleRows.length;
        const cap = Math.min(total, state.renderCap);
        const start = state.rendered;
        const end = Math.min(cap, start + CHUNK_ROWS);
        if (end <= start) { updateFoot(); return; }

        refs.tbody.insertAdjacentHTML('beforeend', buildRows(m, start, end, state.filter.trim()));
        state.rendered = end;
        updateFoot();
    }

    function buildRows(m, start, end, q) {
        let html = '';
        for (let i = start; i < end; i++) {
            const r = state.visibleRows[i];
            html += '<tr>';
            html += '<th class="et-rh">' + fmtInt(r - m.range.s.r + 1) + '</th>';
            for (let ci = 0; ci < m.totalCols; ci++) {
                const c = m.range.s.c + ci;
                if (m.covered.has(r + ',' + c)) continue;   // 合并区域内的从属格不输出

                const cell = m.cellAt(r, c);
                const text = cellText(cell);
                const merge = m.mergeAt.get(r + ',' + c);
                let attrs = '';
                let cls = 'et-cell ' + cellKind(cell);
                if (merge) {
                    const rowspan = Math.min(merge.er, m.range.e.r) - r + 1;
                    const colspan = Math.min(merge.ec, m.range.e.c) - c + 1;
                    if (rowspan > 1) attrs += ' rowspan="' + rowspan + '"';
                    if (colspan > 1) attrs += ' colspan="' + colspan + '"';
                    if (rowspan > 1 || colspan > 1) cls += ' et-merge';
                }
                const tip = text.length > 300 ? text.slice(0, 300) + '…' : text;
                const body = text === '' ? '' : (q ? highlight(text, q) : escapeHtml(text));
                html += '<td class="' + cls + '" data-r="' + r + '" data-c="' + c +
                    '" title="' + escapeHtml(tip) + '"' + attrs + '>' + body + '</td>';
            }
            html += '</tr>';
        }
        return html;
    }

    function highlight(text, q) {
        const safe = escapeHtml(text);
        const re = new RegExp('(' + escapeRegExp(escapeHtml(q)) + ')', 'gi');
        return safe.replace(re, '<mark>$1</mark>');
    }

    function updateFoot() {
        if (!state.wb) { refs.foot.innerHTML = ''; return; }
        const m = currentModel();
        const total = state.visibleRows.length;
        const cap = Math.min(total, state.renderCap);
        const parts = [];
        parts.push('<span>工作表 <b>' + escapeHtml(m.name) + '</b></span>');
        parts.push('<span>' + fmtInt(m.totalRows) + ' 行 × ' + fmtInt(m.totalCols) + ' 列</span>');
        parts.push('<span>已显示 ' + fmtInt(state.rendered) + ' 行' +
            (state.filter.trim() ? '（查找命中 ' + fmtInt(total) + ' 行）' : '') + '</span>');
        if (m.merges.length) parts.push('<span>合并区域 ' + fmtInt(m.merges.length) + ' 处</span>');
        if (state.rendered < cap) {
            parts.push('<button class="et-btn" data-act="more">继续加载更多行</button>');
        } else if (state.rendered >= state.renderCap && total > state.renderCap) {
            parts.push('<button class="et-btn" data-act="more">提高渲染上限（+' + fmtInt(RENDER_STEP) + ' 行）</button>');
        }
        parts.push('<span class="et-grow"></span>');
        parts.push('<span>← / → 切换工作表 · Esc 关闭</span>');
        refs.foot.innerHTML = parts.join('');
    }

    function selectCell(r, c) {
        state.selected = { r: r, c: c };
        refs.tbody.querySelectorAll('td.et-sel').forEach(function (el) { el.classList.remove('et-sel'); });
        const td = refs.tbody.querySelector('td[data-r="' + r + '"][data-c="' + c + '"]');
        if (td) td.classList.add('et-sel');
        renderSide();
    }

    function renderSide() {
        if (!state.wb || !state.selected) {
            refs.side.innerHTML = '<div class="et-side-empty">点击任意单元格，这里会显示它的完整内容（长文本、日期格式、合并区域等）。</div>';
            return;
        }
        const lib = getXLSX();
        const m = currentModel();
        const r = state.selected.r;
        const c = state.selected.c;
        const cell = m.cellAt(r, c);
        const text = cellText(cell);
        const addr = lib.utils.encode_cell({ r: r, c: c });

        // 如果点在合并区域的从属格里，就把内容定位到左上角主格
        let merge = m.mergeAt.get(r + ',' + c);
        let ownerCell = cell;
        let ownerText = text;
        let coveredFlag = false;
        if (!merge) {
            for (let i = 0; i < m.merges.length; i++) {
                const mg = m.merges[i];
                if (r >= mg.sr && r <= mg.er && c >= mg.sc && c <= mg.ec) {
                    merge = mg;
                    const oc = m.cellAt(mg.sr, mg.sc);
                    if (oc && cellText(oc)) {
                        ownerCell = oc;
                        ownerText = cellText(oc);
                        coveredFlag = true;
                    }
                    break;
                }
            }
        }

        let html = '<h4>单元格详情</h4>';
        html += '<div class="et-kv">';
        html += '<b>地址</b><span>' + addr + '（第 ' + fmtInt(r + 1) + ' 行，第 ' + fmtInt(c + 1) + ' 列）</span>';
        html += '<b>类型</b><span>' + cellTypeName(ownerCell) + (coveredFlag ? ' · 合并区域从属格' : '') + '</span>';
        html += '</div>';
        if (merge && (merge.er > merge.sr || merge.ec > merge.sc)) {
            html += '<div class="et-kv"><b>合并区域</b><span class="et-merge-tag">' +
                lib.utils.encode_cell({ r: merge.sr, c: merge.sc }) + ':' + lib.utils.encode_cell({ r: merge.er, c: merge.ec }) +
                '（' + (merge.er - merge.sr + 1) + ' 行 × ' + (merge.ec - merge.sc + 1) + ' 列）</span></div>';
        }
        html += '<h4 style="margin-top:12px">完整内容</h4>';
        html += '<div class="et-sideval">' +
            (ownerText === '' ? '<span style="color:#6b7688">（空）</span>' : escapeHtml(ownerText)) + '</div>';
        if (ownerCell && ownerCell.v != null && String(ownerCell.v) !== ownerText) {
            html += '<h4 style="margin-top:12px">原始值</h4>';
            html += '<div class="et-sideval">' + escapeHtml(String(ownerCell.v)) + '</div>';
        }
        html += '<button class="et-btn" data-act="copy-cell">复制该单元格内容</button>';
        refs.side.innerHTML = html;

        const btn = refs.side.querySelector('[data-act="copy-cell"]');
        if (btn) btn.addEventListener('click', function () { copyText(ownerText, '已复制单元格内容'); });
    }

    /* ============================================================
     * 7. 导出（CSV / XLSX / 复制）
     * ============================================================ */

    /** 取当前工作表内容；filtered=true 时只取查找命中的行 */
    function toAOA(filtered) {
        const m = currentModel();
        let rowIndexes;
        if (filtered && state.filter.trim()) {
            rowIndexes = state.visibleRows;
        } else {
            rowIndexes = [];
            for (let r = m.range.s.r; r <= m.range.e.r; r++) rowIndexes.push(r);
        }
        const out = [];
        for (let i = 0; i < rowIndexes.length; i++) {
            const r = rowIndexes[i];
            const row = [];
            for (let c = m.range.s.c; c <= m.range.e.c; c++) {
                if (m.covered.has(r + ',' + c)) continue;
                row.push(m.textAt(r, c));
            }
            out.push(row);
        }
        return out;
    }

    function toDelimited(aoa, sep) {
        const isCSV = sep === ',';
        return aoa.map(function (row) {
            return row.map(function (v) {
                let s = v == null ? '' : String(v);
                if (isCSV) {
                    if (/[",\r\n]/.test(s)) s = '"' + s.replace(/"/g, '""') + '"';
                } else {
                    s = s.replace(/\t/g, ' ').replace(/\r?\n/g, ' ');
                }
                return s;
            }).join(sep);
        }).join('\r\n');
    }

    function exportCSV() {
        if (!state.wb) return;
        const name = baseName(state.fileName) + '-' + currentModel().name + '.csv';
        const text = toDelimited(toAOA(true), ',');
        downloadBlob(new Blob(['\ufeff' + text], { type: 'text/csv;charset=utf-8' }), name);
        toast('已导出 ' + name + (state.filter.trim() ? '（仅当前查找结果）' : ''));
    }

    function exportCopy() {
        if (!state.wb) return;
        copyText(toDelimited(toAOA(true), '\t'), '已复制当前显示内容（可直接粘贴到表格软件）');
    }

    function exportXLSX() {
        if (!state.wb) return;
        try {
            const lib = getXLSX();
            const out = lib.write(state.wb, { bookType: 'xlsx', type: 'array', cellStyles: false });
            const name = baseName(state.fileName) + '.xlsx';
            downloadBlob(new Blob([out], {
                type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
            }), name);
            toast('已转存为 ' + name + '（包含全部工作表，可用 Excel / WPS 打开）');
        } catch (err) {
            toast('转存失败：' + ((err && err.message) || err), 'error');
        }
    }

    /* ============================================================
     * 8. 使用说明
     * ============================================================ */

    function openHelp() {
        closeHelp();
        const box = document.createElement('div');
        box.className = 'et-panel et-help';
        box.innerHTML = [
            '<h3>ET 表格预览器 · 使用说明</h3>',
            '<ul>',
            '  <li>点右下角的 ▦ 按钮 → 打开预览页 → 把 <code>.et</code> 拖进去（或点「选择文件…」）。</li>',
            '  <li>也可以直接在任意网页上拖入 <code>.et</code>，松手就会弹出预览面板。</li>',
            '  <li>油猴菜单里还有「选择表格文件…」和「打开 ET 预览页」两个入口。</li>',
            '  <li>支持 <code>.et / .ett</code>（WPS 表格），顺带支持 <code>.xls / .xlsx / .xlsm / .csv</code>。</li>',
            '  <li>面板内可切换工作表、查找内容、自动换行、查看单元格完整内容。</li>',
            '  <li>「转存 XLSX」可把 .et 另存为标准 xlsx，方便其它软件打开。</li>',
            '</ul>',
            '<div style="color:#8d97a8">提示：在 <code>file://</code> 页面上使用时，需要在扩展详情里开启「允许访问文件网址」。</div>',
            '<button class="et-btn" data-act="help-close" style="margin-top:14px">知道了</button>'
        ].join('');
        refs.root.appendChild(box);
        refs.root.classList.add('et-show');
        box.addEventListener('click', function (e) {
            const btn = e.target && e.target.closest ? e.target.closest('[data-act="help-close"]') : null;
            if (btn || e.target === box) closeHelp();
        });
    }

    function closeHelp() {
        const box = refs.root ? refs.root.querySelector('.et-help') : null;
        if (box) box.remove();
    }

    /* ============================================================
     * 9. 初始化
     * ============================================================ */

    /** body 就绪后执行（脚本在 document-start 运行，那时可能还没有 body） */
    function onReady(fn) {
        if (document.body) { fn(); return; }
        if (document.readyState === 'loading') {
            document.addEventListener('DOMContentLoaded', function handler() {
                document.removeEventListener('DOMContentLoaded', handler);
                fn();
            });
        } else {
            fn();
        }
    }

    function init() {
        // 先注入样式、尽早挂上拖放拦截：这样即使页面还在加载，拖入 .et 也不会被浏览器当成下载
        injectStyles();
        bindGlobalEvents();

        // 菜单和对外接口不依赖 DOM，可以立刻注册
        if (typeof GM_registerMenuCommand === 'function') {
            GM_registerMenuCommand('🖥 打开 ET 预览页（拖入 / 选择文件）', openPreviewPage);
            GM_registerMenuCommand('📄 选择表格文件（.et / Excel）…', pickFiles);
            GM_registerMenuCommand('💡 使用说明', openHelp);
            GM_registerMenuCommand('👁 显示 / 隐藏 悬浮按钮', toggleBall);
        }

        // 对外接口：方便在控制台里调试，也方便其它脚本调用
        const api = {
            version: VERSION,
            open: openPanel,
            close: closePanel,
            openFiles: handleFiles,
            help: openHelp
        };
        try { (typeof unsafeWindow !== 'undefined' ? unsafeWindow : window).ETPreview = api; } catch (e) { /* 忽略 */ }
        try { window.ETPreview = api; } catch (e) { /* 忽略 */ }

        // 界面部分等 body 出来再建
        onReady(function () {
            buildUI();
            updateBallVisibility();

            // 当前页本身就是 .et 链接时给点提示（浏览器不会自动预览，需要拖进来或点悬浮按钮）
            if (/\.(et|ett)$/i.test(location.pathname)) {
                toast('检测到 .et 地址：把文件拖到本页面，或点右下角按钮选择文件即可预览');
            }
        });
    }

    init();
})();