// ==UserScript==
// @name         网页表格导出工具（含数字精度保护）
// @namespace    http://tampermonkey.net/
// @version      0.32
// @description  为网页表格添加 Excel 导出功能；>11 位数字导出前可选择文本化，防止精度丢失；修复中文标题下划线乱码问题
// @author       HiKey
// @match        *://*/*
// @require      https://cdn.jsdelivr.net/npm/xlsx@0.18.5/dist/xlsx.full.min.js
// @require      https://cdnjs.cloudflare.com/ajax/libs/FileSaver.js/2.0.5/FileSaver.min.js
// @grant        GM_addStyle
// ==/UserScript==

(function () {
    'use strict';

    /* ---------- 样式 ---------- */
    GM_addStyle(`
        .export-btn-group {
            position: absolute;
            top: 2px;
            right: 2px;
            z-index: 1000;
            opacity: 0.8;
            transition: opacity 0.3s;
        }
        .export-btn-group:hover { opacity: 1; }
        .export-btn {
            padding: 3px 8px;
            background: rgba(76, 175, 80, 0.7);
            color: white;
            border: none;
            border-radius: 2px;
            cursor: pointer;
            font-size: 11px;
            font-family: Arial;
            box-shadow: 0 1px 3px rgba(0,0,0,0.1);
            transition: background 0.2s;
        }
        .export-btn:hover { background: rgba(68, 157, 68, 0.9); }
    `);

    /* 安全文件名：保留中文、字母、数字、部分符号，其余变 _，合并连续 _，去头尾，长度 30 */
    function safeFileName(rawTitle) {
        const txt = (rawTitle || 'table').replace(/&[a-zA-Z0-9#]+;/g, ' ').trim();
        let s = txt.replace(/[^\u4e00-\u9fa5\u3040-\u309f\u30a0-\u30ff\uac00-\ud7afa-zA-Z0-9\-_. ]/g, '_');
        s = s.replace(/_+/g, '_').replace(/^_|_$/g, '');
        if (!s) s = 'table';
        return s.substring(0, 30);
    }

    /* 询问数字处理模式 */
    function askNumberMode(hasLong) {
        if (!hasLong) return 0;
        const msg = '检测到 >11 位数字，文本化处理可防止表格上数字精度丢失：\n' +
                    '【0】不处理\n' +
                    '【1】仅对 >11 位数字处理\n' +
                    '【2】全部数字处理为文本';
        let ans;
        do {
            ans = prompt(msg, '1');
            if (ans === null) return 0;
            ans = ans.trim();
        } while (!['0', '1', '2'].includes(ans));
        return Number(ans);
    }

    /* 按选择处理 worksheet */
    function processNumbers(ws, mode) {
        if (mode === 0) return;
        const range = XLSX.utils.decode_range(ws['!ref']);
        for (let R = range.s.r; R <= range.e.r; R++) {
            for (let C = range.s.c; C <= range.e.c; C++) {
                const cellRef = XLSX.utils.encode_cell({ r: R, c: C });
                const cell = ws[cellRef];
                if (!cell || cell.t !== 'n') continue;
                const v = cell.v;
                if (typeof v !== 'number') continue;
                const str = String(v);
                const shouldText =
                    mode === 2 ||
                    (mode === 1 && str.replace(/\./, '').length > 11);
                if (shouldText) {
                    cell.t = 's';
                    cell.v = str;
                }
            }
        }
    }

    /* 导出主函数 */
    function exportTable(table) {
        let hasLong = false;
        table.querySelectorAll('td, th').forEach(td => {
            if (hasLong) return;
            const txt = td.innerText.trim();
            if (/^\d+(\.\d+)?$/.test(txt) && txt.replace(/\./, '').length > 11) {
                hasLong = true;
            }
        });
        const mode = askNumberMode(hasLong);
        const wb = XLSX.utils.book_new();
        const ws = XLSX.utils.table_to_sheet(table);
        processNumbers(ws, mode);
        XLSX.utils.book_append_sheet(wb, ws, '数据');
        const title   = safeFileName(document.title);
        const timestamp = new Date().toISOString().slice(0, 10);
        XLSX.writeFile(wb, `${title}_${timestamp}.xlsx`);
    }

    /* 按钮注入与动态监听 */
    function processTables() {
        document.querySelectorAll('table').forEach(table => {
            if (table.dataset.processed) return;
            const btnGroup = document.createElement('div');
            btnGroup.className = 'export-btn-group';
            const btnXLSX = document.createElement('button');
            btnXLSX.className = 'export-btn';
            btnXLSX.textContent = '导出 Excel';
            btnXLSX.title = '点击导出为 Excel 文件';
            btnXLSX.addEventListener('click', () => exportTable(table));
            btnGroup.appendChild(btnXLSX);
            const wrapper = document.createElement('div');
            wrapper.style.position = 'relative';
            wrapper.style.display = 'inline-block';
            table.parentNode.insertBefore(wrapper, table);
            wrapper.appendChild(table);
            wrapper.appendChild(btnGroup);
            table.dataset.processed = true;
        });
    }

    const init = () => {
        processTables();
        new MutationObserver(() => processTables())
            .observe(document.body, { childList: true, subtree: true });
    };
    if (document.readyState === 'complete') init();
    else window.addEventListener('load', init);
})();