// ==UserScript==
// @name         SCUT_Lesson_Table
// @namespace    http://xsjw2018.jw.scut.edu.cn/SCUT_Lesson_table
// @version      6.1
// @description  华工教务导出课表 - 多格式多选导出 + 课程合并
// @author       WanderLandWalker
// @match        http://xsjw2018.jw.scut.edu.cn/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=scut.edu.cn
// @grant        GM_addStyle
// @license      GPL-3.0 License
// ==/UserScript==

(function() {
    'use strict';

    var PERIOD_TIMES = {
        '1':  { start: '08:50', end: '09:35' },
        '2':  { start: '09:40', end: '10:25' },
        '3':  { start: '10:40', end: '11:25' },
        '4':  { start: '11:30', end: '12:15' },
        '5':  { start: '14:00', end: '14:45' },
        '6':  { start: '14:50', end: '15:35' },
        '7':  { start: '15:55', end: '16:40' },
        '8':  { start: '16:45', end: '17:30' },
        '9':  { start: '19:00', end: '19:45' },
        '10': { start: '19:50', end: '20:35' },
        '11': { start: '20:40', end: '21:25' }
    };

    var FIELDS = [
        { key: 'kcmc',    label: '课程名称',    group: 'basic',    defaultOn: true  },
        { key: 'kch',     label: '课程号',      group: 'basic',    defaultOn: true  },
        { key: 'xm',      label: '教师',        group: 'basic',    defaultOn: true  },
        { key: 'zcmc',    label: '教师职称',    group: 'basic',    defaultOn: false },
        { key: 'zfjmc',   label: '主辅讲',      group: 'basic',    defaultOn: false },
        { key: 'xqj_mc',  label: '星期',        group: 'basic',    defaultOn: true  },
        { key: 'jcs',     label: '节次',        group: 'basic',    defaultOn: true  },
        { key: 'zcd',     label: '时间/周次',   group: 'basic',    defaultOn: true  },
        { key: 'cdmc',    label: '上课地点',    group: 'basic',    defaultOn: true  },
        { key: 'xf',      label: '学分',        group: 'basic',    defaultOn: true  },
        { key: 'jxbmc',   label: '教学班',      group: 'extended', defaultOn: false },
        { key: 'jxbzc',   label: '教学班组成',  group: 'extended', defaultOn: false },
        { key: 'xkbz',    label: '选课备注',    group: 'extended', defaultOn: false },
        { key: 'kcxszc',  label: '课程学时组成',group: 'extended', defaultOn: false },
        { key: 'zhxs',    label: '周学时',      group: 'extended', defaultOn: false },
        { key: 'zxs',     label: '总学时',      group: 'extended', defaultOn: false },
        { key: 'kczxs',   label: '课程总学时',  group: 'extended', defaultOn: false },
        { key: 'khfsmc',  label: '考核方式',    group: 'extended', defaultOn: false },
        { key: 'ksfsmc',  label: '考试方式',    group: 'extended', defaultOn: false },
        { key: 'skfsmc',  label: '授课方式名称',group: 'extended', defaultOn: false },
        { key: 'cxbjmc',  label: '重修标记',    group: 'extended', defaultOn: false },
        { key: 'kcxz',    label: '课程性质',    group: 'extended', defaultOn: false },
        { key: 'kcbj',    label: '课程标记',    group: 'extended', defaultOn: false }
    ];

    var courseData = [];
    var studentInfo = null;
    var dataReady = false;
    var panelCreated = false;
    var libCache = {};

    var $btn, $overlay, $panel, $status;

    /* ================================================================
       Utility
       ================================================================ */

    function getFirstMonday(year) {
        var d = new Date(year, 0, 1);
        var day = d.getDay();
        var offset = (day === 0 ? 1 : (day <= 1 ? 1 - day : 8 - day));
        d.setDate(d.getDate() + offset);
        return d;
    }

    function getWeekDate(year, weekNum) {
        var mon = getFirstMonday(year);
        mon.setDate(mon.getDate() + (weekNum - 1) * 7);
        return mon;
    }

    function pad2(n) { return n < 10 ? '0' + n : '' + n; }

    function toIcalDate(year, weekNum, dayOfWeek, timeStr) {
        var d = getWeekDate(year, weekNum);
        d.setDate(d.getDate() + (dayOfWeek - 1));
        var parts = timeStr.split(':');
        return d.getFullYear() + pad2(d.getMonth() + 1) + pad2(d.getDate()) + 'T' + parts[0] + parts[1] + '00';
    }

    function getDayNum(xqj) {
        var map = { '1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,
                    '星期一':1,'星期二':2,'星期三':3,'星期四':4,
                    '星期五':5,'星期六':6,'星期日':7 };
        return map[xqj] || parseInt(xqj, 10) || 0;
    }

    function escapeHtml(s) {
        if (!s) return '';
        return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;')
                .replace(/"/g, '&quot;').replace(/\n/g, ' ');
    }

    function escapeCsv(s) {
        if (!s) return '';
        s = String(s).replace(/\r?\n/g, ' ');
        if (s.indexOf(',') >= 0 || s.indexOf('"') >= 0) return '"' + s.replace(/"/g, '""') + '"';
        return s;
    }

    function escapeIcalText(s) {
        if (!s) return '';
        return s.replace(/\\/g, '\\\\').replace(/;/g, '\\;').replace(/,/g, '\\,').replace(/\n/g, '\\n');
    }

    function getVal(item, key) {
        if (key === 'xqj_mc') {
            var dayNames = { '1':'星期一','2':'星期二','3':'星期三','4':'星期四',
                             '5':'星期五','6':'星期六','7':'星期日' };
            return dayNames[item.xqj] || item.xqj || '';
        }
        return item[key] || '';
    }

    function download(content, fileName, mimeType) {
        var blob = new Blob([content], { type: mimeType || 'text/plain;charset=utf-8' });
        var url = URL.createObjectURL(blob);
        var link = document.createElement('a');
        link.download = fileName;
        link.href = url;
        document.body.appendChild(link);
        link.click();
        document.body.removeChild(link);
        URL.revokeObjectURL(url);
    }

    function getSelectedFields() {
        if (!$panel) return [];
        var selected = [];
        var boxes = $panel.querySelectorAll('.__chk_grid input[type=checkbox]');
        for (var i = 0; i < boxes.length; i++) {
            if (boxes[i].checked) {
                var key = boxes[i].getAttribute('data-field');
                for (var j = 0; j < FIELDS.length; j++) {
                    if (FIELDS[j].key === key) { selected.push(FIELDS[j]); break; }
                }
            }
        }
        return selected;
    }

    function getSelectedFormats() {
        if (!$panel) return [];
        var fmts = [];
        var boxes = $panel.querySelectorAll('.__fmt_grid input[type=checkbox]');
        for (var i = 0; i < boxes.length; i++) {
            if (boxes[i].checked) fmts.push(boxes[i].getAttribute('data-fmt'));
        }
        return fmts;
    }

    function isMergeEnabled() {
        var cb = document.getElementById('__scut_merge_cb');
        return cb ? cb.checked : false;
    }

    function getBaseName() {
        var semName = '';
        if (studentInfo) {
            semName = (studentInfo.XNMC || '').replace(/\s/g, '') + '_' + (studentInfo.XQMMC || '') + '学期';
        }
        return '课表_' + (semName || 'export');
    }

    /* ================================================================
       Week Parsing (advanced: supports 双/单/不连续周次)
       ================================================================ */

    function parseWeekAdvanced(str) {
        if (!str) return [];
        var weeks = [];
        var seen = {};
        var cleaned = str.replace(/周/g, '');
        var parts = cleaned.split(/[,，]/);
        for (var i = 0; i < parts.length; i++) {
            var p = parts[i].trim();
            if (!p) continue;
            var m = p.match(/^(\d+)(?:\s*[-~]\s*(\d+))?(?:\s*\((单|双)\))?$/);
            if (m) {
                var start = parseInt(m[1], 10);
                var end = m[2] ? parseInt(m[2], 10) : start;
                var parity = m[3] || null;
                for (var w = start; w <= end; w++) {
                    if (parity === '双' && w % 2 !== 0) continue;
                    if (parity === '单' && w % 2 === 0) continue;
                    if (!seen[w]) { weeks.push(w); seen[w] = true; }
                }
            } else {
                var n = parseInt(p, 10);
                if (!isNaN(n) && !seen[n]) { weeks.push(n); seen[n] = true; }
            }
        }
        weeks.sort(function(a, b) { return a - b; });
        return weeks;
    }

    function parseSessions(str) {
        if (!str) return [];
        var sessions = [];
        if (str.indexOf('-') >= 0) {
            var range = str.split('-');
            var a = parseInt(range[0], 10);
            var b = parseInt(range[1], 10);
            if (!isNaN(a) && !isNaN(b)) for (var j = a; j <= b; j++) sessions.push(j);
        } else {
            var n = parseInt(str, 10);
            if (!isNaN(n)) sessions.push(n);
        }
        return sessions;
    }

    function formatWeekStr(weeks) {
        if (!weeks || weeks.length === 0) return '';
        var sorted = weeks.slice().sort(function(a, b) { return a - b; });
        var ranges = [];
        var start = sorted[0];
        var end = sorted[0];
        for (var i = 1; i < sorted.length; i++) {
            if (sorted[i] === end + 1) {
                end = sorted[i];
            } else {
                ranges.push(start === end ? start + '周' : start + '-' + end + '周');
                start = sorted[i];
                end = sorted[i];
            }
        }
        ranges.push(start === end ? start + '周' : start + '-' + end + '周');
        return ranges.join(',');
    }

    /* ================================================================
       Course Merge
       Groups by (kch, xqj, jcs, cdmc), merges weeks & teachers
       ================================================================ */

    function mergeCourses(data) {
        var groups = {};
        for (var i = 0; i < data.length; i++) {
            var item = data[i];
            var key = (item.kch || '') + '|' + (item.xqj || '') + '|' + (item.jcs || '');
            if (!groups[key]) groups[key] = [];
            groups[key].push(item);
        }

        var merged = [];
        var keys = Object.keys(groups);
        for (var k = 0; k < keys.length; k++) {
            var group = groups[keys[k]];
            if (group.length === 1) {
                merged.push(group[0]);
                continue;
            }

            var allWeeks = [];
            var seenWeeks = {};
            var teacherSet = {};
            var teacherOrder = [];
            var zfjSet = {};
            var zfjOrder = [];
            var zcmcSet = {};
            var locationSet = {};
            var locationOrder = [];
            var base = group[0];

            for (var g = 0; g < group.length; g++) {
                var entry = group[g];
                var wArr = parseWeekAdvanced(entry.zcd);
                for (var w = 0; w < wArr.length; w++) {
                    if (!seenWeeks[wArr[w]]) { allWeeks.push(wArr[w]); seenWeeks[wArr[w]] = true; }
                }
                var names = (entry.xm || '').split(/[,，]/);
                for (var t = 0; t < names.length; t++) {
                    var name = names[t].trim();
                    if (name && !teacherSet[name]) { teacherSet[name] = true; teacherOrder.push(name); }
                }
                if (entry.zfjmc) {
                    var zfjNames = entry.zfjmc.split(/[,，]/);
                    for (var z = 0; z < zfjNames.length; z++) {
                        var zn = zfjNames[z].trim();
                        if (zn && !zfjSet[zn]) { zfjSet[zn] = true; zfjOrder.push(zn); }
                    }
                }
                if (entry.zcmc) {
                    var zcmcNames = entry.zcmc.split(/[,，]/);
                    for (var c = 0; c < zcmcNames.length; c++) {
                        var cn = zcmcNames[c].trim();
                        if (cn) zcmcSet[cn] = true;
                    }
                }
                var loc = (entry.cdmc || '').trim();
                if (loc && !locationSet[loc]) { locationSet[loc] = true; locationOrder.push(loc); }
            }

            allWeeks.sort(function(a, b) { return a - b; });

            var mergedEntry = {};
            for (var prop in base) {
                if (base.hasOwnProperty(prop)) mergedEntry[prop] = base[prop];
            }
            mergedEntry.xm = teacherOrder.join(',');
            mergedEntry.zcd = formatWeekStr(allWeeks);
            if (zfjOrder.length > 0) mergedEntry.zfjmc = zfjOrder.join(',');
            var zcmcArr = Object.keys(zcmcSet);
            if (zcmcArr.length > 0) mergedEntry.zcmc = zcmcArr.join(',');
            if (locationOrder.length > 0) mergedEntry.cdmc = locationOrder.join('/');

            merged.push(mergedEntry);
        }

        return merged;
    }

    function getExportData() {
        return isMergeEnabled() ? mergeCourses(courseData) : courseData;
    }

    /* ================================================================
       Library Loader (CDN)
       ================================================================ */

    function loadScript(url) {
        if (libCache[url]) return libCache[url];
        libCache[url] = new Promise(function(resolve, reject) {
            var s = document.createElement('script');
            s.src = url;
            s.onload = function() { resolve(); };
            s.onerror = function() { reject(new Error('Failed: ' + url)); };
            document.head.appendChild(s);
        });
        return libCache[url];
    }

    function loadXlsx()  { return loadScript('https://cdn.jsdelivr.net/npm/xlsx@0.18.5/dist/xlsx.full.min.js'); }
    function loadJsPdf() { return loadScript('https://cdn.jsdelivr.net/npm/jspdf@2.5.1/dist/jspdf.umd.min.js'); }
    function loadH2C()   { return loadScript('https://cdn.jsdelivr.net/npm/html2canvas@1.4.1/dist/html2canvas.min.js'); }

    /* ================================================================
       Preview Table (shared by JPG / PDF / DOCX)
       ================================================================ */

    function createPreviewContainer(fields, data) {
        var semTitle = '';
        if (studentInfo) {
            semTitle = (studentInfo.XNMC || '') + '学年 第' + (studentInfo.XQMMC || '') + '学期 课表';
        }
        var byDay = {};
        for (var d = 1; d <= 7; d++) byDay[d] = [];
        for (var i = 0; i < data.length; i++) {
            var dn = getDayNum(data[i].xqj);
            if (dn >= 1 && dn <= 7) byDay[dn].push(data[i]);
        }
        for (var d2 = 1; d2 <= 7; d2++) {
            byDay[d2].sort(function(a, b) { return (parseSessions(a.jcs)[0] || 0) - (parseSessions(b.jcs)[0] || 0); });
        }
        var ths = '';
        for (var h = 0; h < fields.length; h++) ths += '<th>' + escapeHtml(fields[h].label) + '</th>';
        var rows = '';
        for (var day = 1; day <= 7; day++) {
            var list = byDay[day];
            for (var ci = 0; ci < list.length; ci++) {
                var tds = '';
                for (var fi = 0; fi < fields.length; fi++) {
                    tds += '<td>' + escapeHtml(getVal(list[ci], fields[fi].key)) + '</td>';
                }
                rows += '<tr>' + tds + '</tr>';
            }
        }
        var html = '<div style="padding:30px;background:#fff;font-family:Arial,sans-serif;">';
        html += '<h2 style="text-align:center;margin:0 0 6px;color:#333;">' + escapeHtml(semTitle) + '</h2>';
        html += '<p style="text-align:center;margin:0 0 20px;color:#888;font-size:12px;">导出时间：' + new Date().toLocaleString() + '</p>';
        html += '<table style="width:100%;border-collapse:collapse;font-size:13px;">';
        html += '<thead><tr style="background:#0078d4;color:#fff;">' + ths + '</tr></thead>';
        html += '<tbody>' + rows + '</tbody></table></div>';
        var container = document.createElement('div');
        container.style.cssText = 'position:absolute;left:-9999px;top:0;';
        container.innerHTML = html;
        document.body.appendChild(container);
        return container;
    }

    /* ================================================================
       iCal Builder
       ================================================================ */

    function buildIcal(data) {
        var lines = [
            'BEGIN:VCALENDAR','VERSION:2.0','PRODID:-//SCUT Lesson Table//CN',
            'CALSCALE:GREGORIAN','METHOD:PUBLISH','X-WR-CALNAME:SCUT 课表',
            'X-WR-TIMEZONE:Asia/Shanghai',
            'BEGIN:VTIMEZONE','TZID:Asia/Shanghai',
            'BEGIN:STANDARD','DTSTART:19700101T000000','TZOFFSETFROM:+0800','TZOFFSETTO:+0800',
            'END:STANDARD','END:VTIMEZONE'
        ];
        var year = 2025;
        if (studentInfo && studentInfo.XNMC) {
            var m = studentInfo.XNMC.match(/(\d{4})/);
            if (m) year = parseInt(m[1], 10);
        }
        for (var i = 0; i < data.length; i++) {
            var item = data[i];
            var dayNum = getDayNum(item.xqj);
            if (!dayNum) continue;
            var sessions = parseSessions(item.jcs);
            if (!sessions.length) continue;
            var startS = sessions[0];
            var endS = sessions[sessions.length - 1];
            var tStart = PERIOD_TIMES[String(startS)];
            var tEnd   = PERIOD_TIMES[String(endS)];
            if (!tStart || !tEnd) continue;
            var weeks = parseWeekAdvanced(item.zcd);
            if (!weeks.length) continue;
            var name = item.kcmc || '课程';
            var teacher = item.xm || '';
            var zfj = item.zfjmc || '';
            var location = item.cdmc || '';
            var kch = item.kch || '';
            var xf = item.xf || '';
            var kcxz = item.kcxz || '';
            var title = name;
            if (teacher) title += '(' + teacher + ')';
            if (zfj) title += '[辅:' + zfj + ']';
            var desc = '课程号: ' + kch;
            if (teacher) desc += '\\n教师: ' + teacher;
            if (zfj) desc += '\\n主辅讲: ' + zfj;
            if (xf) desc += '\\n学分: ' + xf;
            if (kcxz) desc += '\\n课程性质: ' + kcxz;
            for (var w = 0; w < weeks.length; w++) {
                var wn = weeks[w];
                var dtS = toIcalDate(year, wn, dayNum, tStart.start);
                var dtE = toIcalDate(year, wn, dayNum, tEnd.end);
                var uid = 'scut-' + (kch || i) + '-w' + wn + '-d' + dayNum + '-j' + startS + '@scut.edu.cn';
                lines.push('BEGIN:VEVENT');
                lines.push('DTSTART;TZID=Asia/Shanghai:' + dtS);
                lines.push('DTEND;TZID=Asia/Shanghai:' + dtE);
                lines.push('SUMMARY:' + escapeIcalText(title));
                lines.push('LOCATION:' + escapeIcalText(location));
                lines.push('DESCRIPTION:' + desc);
                lines.push('UID:' + uid);
                lines.push('BEGIN:VALARM','TRIGGER:-PT30M','ACTION:DISPLAY','DESCRIPTION:Reminder','END:VALARM');
                lines.push('END:VEVENT');
            }
        }
        lines.push('END:VCALENDAR');
        return lines.join('\r\n');
    }

    /* ================================================================
       Markdown Builder
       ================================================================ */

    function buildMarkdown(fields, data) {
        var byDay = {};
        for (var d = 1; d <= 7; d++) byDay[d] = [];
        for (var i = 0; i < data.length; i++) {
            var dn = getDayNum(data[i].xqj);
            if (dn >= 1 && dn <= 7) byDay[dn].push(data[i]);
        }
        for (var d2 = 1; d2 <= 7; d2++) {
            byDay[d2].sort(function(a, b) { return (parseSessions(a.jcs)[0] || 0) - (parseSessions(b.jcs)[0] || 0); });
        }
        var lines = [];
        var semTitle = '';
        if (studentInfo) semTitle = (studentInfo.XNMC || '') + ' 第' + (studentInfo.XQMMC || '') + '学期';
        lines.push('# ' + (semTitle || '课表'));
        lines.push('');
        var headers = [], seps = [];
        for (var f = 0; f < fields.length; f++) { headers.push(fields[f].label); seps.push('---'); }
        lines.push('| ' + headers.join(' | ') + ' |');
        lines.push('| ' + seps.join(' | ') + ' |');
        for (var day = 1; day <= 7; day++) {
            var list = byDay[day];
            for (var ci = 0; ci < list.length; ci++) {
                var cells = [];
                for (var fi = 0; fi < fields.length; fi++) {
                    cells.push(String(getVal(list[ci], fields[fi].key)).replace(/\|/g, '\\|').replace(/\n/g, ' '));
                }
                lines.push('| ' + cells.join(' | ') + ' |');
            }
        }
        return lines.join('\n');
    }

    /* ================================================================
       Export: JSON
       ================================================================ */

    function exportJson(fields, baseName) {
        var data = getExportData();
        var arr = [];
        for (var i = 0; i < data.length; i++) {
            var obj = {};
            for (var j = 0; j < fields.length; j++) obj[fields[j].label] = getVal(data[i], fields[j].key);
            arr.push(obj);
        }
        var semName = studentInfo ? (studentInfo.XNMC || '') + ' 第' + (studentInfo.XQMMC || '') + '学期' : '';
        var result = { semester: semName, merged: isMergeEnabled(), exportTime: new Date().toLocaleString(), courses: arr };
        download(JSON.stringify(result, null, 2), baseName + '.json', 'application/json;charset=utf-8');
    }

    /* ================================================================
       Export: CSV
       ================================================================ */

    function exportCsv(fields, baseName) {
        var data = getExportData();
        var bom = '\uFEFF';
        var lines = [];
        var headers = [];
        for (var h = 0; h < fields.length; h++) headers.push(escapeCsv(fields[h].label));
        lines.push(headers.join(','));
        for (var i = 0; i < data.length; i++) {
            var row = [];
            for (var j = 0; j < fields.length; j++) row.push(escapeCsv(getVal(data[i], fields[j].key)));
            lines.push(row.join(','));
        }
        download(bom + lines.join('\r\n'), baseName + '.csv', 'text/csv;charset=utf-8');
    }

    /* ================================================================
       Export: TXT
       ================================================================ */

    function exportTxt(fields, baseName) {
        var data = getExportData();
        var lines = [];
        var semTitle = '';
        if (studentInfo) semTitle = (studentInfo.XNMC || '') + ' 第' + (studentInfo.XQMMC || '') + '学期';
        if (semTitle) { lines.push(semTitle + ' 课表'); lines.push(''); }
        var headers = [];
        for (var h = 0; h < fields.length; h++) headers.push(fields[h].label);
        lines.push(headers.join('\t'));
        lines.push('');
        for (var i = 0; i < data.length; i++) {
            var row = [];
            for (var j = 0; j < fields.length; j++) row.push(String(getVal(data[i], fields[j].key)).replace(/\t/g, ' ').replace(/\n/g, ' '));
            lines.push(row.join('\t'));
        }
        download(lines.join('\r\n'), baseName + '.txt', 'text/plain;charset=utf-8');
    }

    /* ================================================================
       Export: XLSX
       ================================================================ */

    function exportXlsx(fields, baseName) {
        if (typeof XLSX === 'undefined') { alert('XLSX 库加载失败，请检查网络'); return; }
        var data = getExportData();
        var wsData = [];
        var headers = [];
        for (var h = 0; h < fields.length; h++) headers.push(fields[h].label);
        wsData.push(headers);
        for (var i = 0; i < data.length; i++) {
            var row = [];
            for (var j = 0; j < fields.length; j++) row.push(getVal(data[i], fields[j].key));
            wsData.push(row);
        }
        var ws = XLSX.utils.aoa_to_sheet(wsData);
        var colWidths = [];
        for (var c = 0; c < fields.length; c++) {
            var maxLen = fields[c].label.length;
            for (var r = 0; r < data.length; r++) {
                var v = String(getVal(data[r], fields[c].key));
                if (v.length > maxLen) maxLen = v.length;
            }
            colWidths.push({ wch: Math.min(maxLen + 4, 40) });
        }
        ws['!cols'] = colWidths;
        var wb = XLSX.utils.book_new();
        XLSX.utils.book_append_sheet(wb, ws, '课表');
        XLSX.writeFile(wb, baseName + '.xlsx');
    }

    /* ================================================================
       Export: PDF
       ================================================================ */

    function exportPdf(fields, baseName) {
        if (typeof window.jspdf === 'undefined') { alert('jsPDF 库加载失败，请检查网络'); return; }
        if (typeof html2canvas === 'undefined') { alert('html2canvas 库加载失败，请检查网络'); return; }
        var data = getExportData();
        var container = createPreviewContainer(fields, data);
        html2canvas(container.firstChild, { scale: 2, useCORS: true }).then(function(canvas) {
            var jsPDF = window.jspdf.jsPDF;
            var imgW = canvas.width;
            var imgH = canvas.height;
            var isLandscape = imgW > imgH;
            var pdf = new jsPDF({ orientation: isLandscape ? 'landscape' : 'portrait', unit: 'mm', format: 'a4' });
            var pageW = pdf.internal.pageSize.getWidth();
            var pageH = pdf.internal.pageSize.getHeight();
            var margin = 10;
            var usableW = pageW - margin * 2;
            var ratio = usableW / imgW;
            var scaledH = imgH * ratio;
            var imgData = canvas.toDataURL('image/jpeg', 0.95);
            if (scaledH <= pageH - margin * 2) {
                pdf.addImage(imgData, 'JPEG', margin, margin, usableW, scaledH);
            } else {
                var pageUsableH = pageH - margin * 2;
                var sliceHpx = Math.floor(pageUsableH / ratio);
                var yPx = 0;
                var page = 0;
                while (yPx < imgH) {
                    if (page > 0) pdf.addPage();
                    var curSliceH = Math.min(sliceHpx, imgH - yPx);
                    var tmpCanvas = document.createElement('canvas');
                    tmpCanvas.width = imgW;
                    tmpCanvas.height = curSliceH;
                    var ctx = tmpCanvas.getContext('2d');
                    ctx.drawImage(canvas, 0, yPx, imgW, curSliceH, 0, 0, imgW, curSliceH);
                    var sliceData = tmpCanvas.toDataURL('image/jpeg', 0.95);
                    var sliceScaledH = curSliceH * ratio;
                    pdf.addImage(sliceData, 'JPEG', margin, margin, usableW, sliceScaledH);
                    yPx += curSliceH;
                    page++;
                }
            }
            pdf.save(baseName + '.pdf');
            document.body.removeChild(container);
        }).catch(function() {
            alert('PDF 渲染失败');
            if (container.parentNode) document.body.removeChild(container);
        });
    }

    /* ================================================================
       Export: DOCX
       ================================================================ */

    function exportDocx(fields, baseName) {
        var data = getExportData();
        var semTitle = '';
        if (studentInfo) semTitle = (studentInfo.XNMC || '') + '学年 第' + (studentInfo.XQMMC || '') + '学期 课表';
        var byDay = {};
        for (var d = 1; d <= 7; d++) byDay[d] = [];
        for (var i = 0; i < data.length; i++) {
            var dn = getDayNum(data[i].xqj);
            if (dn >= 1 && dn <= 7) byDay[dn].push(data[i]);
        }
        for (var d2 = 1; d2 <= 7; d2++) {
            byDay[d2].sort(function(a, b) { return (parseSessions(a.jcs)[0] || 0) - (parseSessions(b.jcs)[0] || 0); });
        }
        var xmlRows = '';
        var thCells = '';
        for (var h = 0; h < fields.length; h++) {
            thCells += '<w:tc><w:tcPr><w:shd w:val="clear" w:color="auto" w:fill="0078D4"/></w:tcPr>';
            thCells += '<w:p><w:pPr><w:jc w:val="center"/></w:pPr><w:r><w:rPr><w:b/><w:color w:val="FFFFFF"/>';
            thCells += '<w:sz w:val="20"/></w:rPr><w:t>' + escapeHtml(fields[h].label) + '</w:t></w:r></w:p></w:tc>';
        }
        xmlRows += '<w:tr><w:trPr><w:tblHeader/></w:trPr>' + thCells + '</w:tr>';
        var rowIdx = 0;
        for (var day = 1; day <= 7; day++) {
            var list = byDay[day];
            for (var ci = 0; ci < list.length; ci++) {
                var fill = rowIdx % 2 === 0 ? 'F8F9FA' : 'FFFFFF';
                var cells = '';
                for (var fi = 0; fi < fields.length; fi++) {
                    cells += '<w:tc><w:tcPr><w:shd w:val="clear" w:color="auto" w:fill="' + fill + '"/></w:tcPr>';
                    cells += '<w:p><w:r><w:rPr><w:sz w:val="18"/></w:rPr><w:t xml:space="preserve">';
                    cells += escapeHtml(getVal(list[ci], fields[fi].key));
                    cells += '</w:t></w:r></w:p></w:tc>';
                }
                xmlRows += '<w:tr>' + cells + '</w:tr>';
                rowIdx++;
            }
        }
        var docXml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>';
        docXml += '<w:document xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">';
        docXml += '<w:body>';
        docXml += '<w:p><w:pPr><w:jc w:val="center"/></w:pPr><w:r><w:rPr><w:b/><w:sz w:val="32"/></w:rPr>';
        docXml += '<w:t>' + escapeHtml(semTitle) + '</w:t></w:r></w:p>';
        docXml += '<w:tbl>';
        docXml += '<w:tblPr><w:tblW w:w="9000" w:type="dxa"/>';
        docXml += '<w:tblBorders><w:top w:val="single" w:sz="4" w:space="0" w:color="CCCCCC"/>';
        docXml += '<w:left w:val="single" w:sz="4" w:space="0" w:color="CCCCCC"/>';
        docXml += '<w:bottom w:val="single" w:sz="4" w:space="0" w:color="CCCCCC"/>';
        docXml += '<w:right w:val="single" w:sz="4" w:space="0" w:color="CCCCCC"/>';
        docXml += '<w:insideH w:val="single" w:sz="4" w:space="0" w:color="CCCCCC"/>';
        docXml += '<w:insideV w:val="single" w:sz="4" w:space="0" w:color="CCCCCC"/>';
        docXml += '</w:tblBorders></w:tblPr>';
        docXml += xmlRows;
        docXml += '</w:tbl></w:body></w:document>';
        var ctXml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>';
        ctXml += '<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">';
        ctXml += '<Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>';
        ctXml += '<Default Extension="xml" ContentType="application/xml"/>';
        ctXml += '<Override PartName="/word/document.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.document.main+xml"/>';
        ctXml += '</Types>';
        var relsXml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>';
        relsXml += '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">';
        relsXml += '<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="word/document.xml"/>';
        relsXml += '</Relationships>';
        var wordRelsXml = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>';
        wordRelsXml += '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"></Relationships>';
        var zipBin = buildZip([
            { name: '[Content_Types].xml', data: ctXml },
            { name: '_rels/.rels', data: relsXml },
            { name: 'word/_rels/document.xml.rels', data: wordRelsXml },
            { name: 'word/document.xml', data: docXml }
        ]);
        download(zipBin, baseName + '.docx', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document');
    }

    /* ================================================================
       Minimal ZIP builder
       ================================================================ */

    function buildZip(files) {
        var localParts = [], centralParts = [];
        var offset = 0;
        for (var i = 0; i < files.length; i++) {
            var nameBytes = strToBytes(files[i].name);
            var dataBytes = strToBytes(files[i].data);
            var crc = crc32(dataBytes);
            var local = [];
            local.push(u32(0x04034b50)); local.push(u16(20)); local.push(u16(0));
            local.push(u16(0)); local.push(u16(0)); local.push(u16(0));
            local.push(u32(crc)); local.push(u32(dataBytes.length)); local.push(u32(dataBytes.length));
            local.push(u16(nameBytes.length)); local.push(u16(0));
            local.push(nameBytes); local.push(dataBytes);
            var localBin = concatBytes(local);
            localParts.push(localBin);
            var central = [];
            central.push(u32(0x02014b50)); central.push(u16(20)); central.push(u16(20));
            central.push(u16(0)); central.push(u16(0)); central.push(u16(0)); central.push(u16(0));
            central.push(u32(crc)); central.push(u32(dataBytes.length)); central.push(u32(dataBytes.length));
            central.push(u16(nameBytes.length)); central.push(u16(0)); central.push(u16(0));
            central.push(u16(0)); central.push(u16(0)); central.push(u32(0));
            central.push(u32(offset)); central.push(nameBytes);
            centralParts.push(concatBytes(central));
            offset += localBin.length;
        }
        var centralDir = concatBytes(centralParts);
        var eocd = [];
        eocd.push(u32(0x06054b50)); eocd.push(u16(0)); eocd.push(u16(0));
        eocd.push(u16(files.length)); eocd.push(u16(files.length));
        eocd.push(u32(centralDir.length)); eocd.push(u32(offset)); eocd.push(u16(0));
        return concatBytes(localParts.concat([centralDir], eocd)).buffer;
    }

    function strToBytes(str) { return new TextEncoder().encode(str); }

    function u16(v) {
        var b = new Uint8Array(2);
        b[0] = v & 0xFF; b[1] = (v >> 8) & 0xFF;
        return b;
    }

    function u32(v) {
        var b = new Uint8Array(4);
        b[0] = v & 0xFF; b[1] = (v >> 8) & 0xFF; b[2] = (v >> 16) & 0xFF; b[3] = (v >> 24) & 0xFF;
        return b;
    }

    function concatBytes(arrays) {
        var total = 0;
        for (var i = 0; i < arrays.length; i++) total += arrays[i].length;
        var result = new Uint8Array(total);
        var offset = 0;
        for (var j = 0; j < arrays.length; j++) { result.set(arrays[j], offset); offset += arrays[j].length; }
        return result;
    }

    var crcTable = null;
    function crc32(bytes) {
        if (!crcTable) {
            crcTable = new Uint32Array(256);
            for (var i = 0; i < 256; i++) {
                var c = i;
                for (var j = 0; j < 8; j++) c = (c & 1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1);
                crcTable[i] = c;
            }
        }
        var crc = 0xFFFFFFFF;
        for (var k = 0; k < bytes.length; k++) crc = crcTable[(crc ^ bytes[k]) & 0xFF] ^ (crc >>> 8);
        return (crc ^ 0xFFFFFFFF) >>> 0;
    }

    /* ================================================================
       Export: JPG
       ================================================================ */

    function exportJpg(fields, baseName) {
        if (typeof html2canvas === 'undefined') { alert('html2canvas 库加载失败，请检查网络'); return; }
        var data = getExportData();
        var container = createPreviewContainer(fields, data);
        html2canvas(container.firstChild, { scale: 2, useCORS: true }).then(function(canvas) {
            canvas.toBlob(function(blob) {
                var url = URL.createObjectURL(blob);
                var link = document.createElement('a');
                link.download = baseName + '.jpg';
                link.href = url;
                document.body.appendChild(link);
                link.click();
                document.body.removeChild(link);
                URL.revokeObjectURL(url);
                document.body.removeChild(container);
            }, 'image/jpeg', 0.92);
        }).catch(function() {
            alert('JPG 渲染失败');
            if (container.parentNode) document.body.removeChild(container);
        });
    }

    /* ================================================================
       CSS
       ================================================================ */

    function injectStyles() {
        var css = '';
        css += '#__scut_export_btn{position:fixed;bottom:20px;right:20px;z-index:99999;';
        css += 'padding:10px 20px;background:#0078d4;color:#fff;border:none;border-radius:6px;';
        css += 'font-size:14px;cursor:pointer;box-shadow:0 2px 8px rgba(0,0,0,.3);transition:background .2s;}';
        css += '#__scut_export_btn:hover{background:#005fa3;}';
        css += '#__scut_export_btn .__scut_dot{display:none;width:8px;height:8px;';
        css += 'background:#4caf50;border-radius:50%;margin-left:6px;vertical-align:middle;}';
        css += '#__scut_export_overlay{display:none;position:fixed;top:0;left:0;width:100%;height:100%;';
        css += 'background:rgba(0,0,0,.45);z-index:100000;}';
        css += '#__scut_export_panel{display:none;position:fixed;top:50%;left:50%;transform:translate(-50%,-50%);';
        css += 'width:700px;max-height:85vh;background:#fff;border-radius:10px;box-shadow:0 4px 20px rgba(0,0,0,.3);';
        css += 'z-index:100001;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;flex-direction:column;}';
        css += '.__p_head{display:flex;align-items:center;justify-content:space-between;';
        css += 'padding:16px 20px;border-bottom:1px solid #e0e0e0;background:#f8f9fa;border-radius:10px 10px 0 0;}';
        css += '.__p_head h3{margin:0;font-size:17px;color:#333;}';
        css += '.__p_close{background:none;border:none;font-size:22px;cursor:pointer;color:#999;padding:0 4px;line-height:1;}';
        css += '.__p_close:hover{color:#333;}';
        css += '.__p_body{padding:16px 20px;overflow-y:auto;flex:1;}';
        css += '.__sec{margin-bottom:18px;}';
        css += '.__sec_title{font-size:13px;font-weight:600;color:#555;margin-bottom:8px;';
        css += 'display:flex;align-items:center;justify-content:space-between;}';
        css += '.__preset_btn{background:#e8f0fe;color:#1a73e8;border:none;border-radius:4px;';
        css += 'padding:2px 10px;font-size:12px;cursor:pointer;margin-left:6px;}';
        css += '.__preset_btn:hover{background:#d2e3fc;}';
        css += '.__fmt_grid{display:flex;flex-wrap:wrap;gap:8px 16px;margin-bottom:12px;}';
        css += '.__fmt_grid label{display:flex;align-items:center;font-size:13px;cursor:pointer;';
        css += 'white-space:nowrap;color:#444;padding:5px 12px;border:1px solid #ddd;border-radius:5px;transition:all .15s;}';
        css += '.__fmt_grid label:hover{border-color:#90caf9;background:#f5f5f5;}';
        css += '.__fmt_grid input[type=checkbox]{margin-right:5px;}';
        css += '.__chk_grid{display:flex;flex-wrap:wrap;gap:6px 14px;}';
        css += '.__chk_grid label{display:flex;align-items:center;font-size:13px;cursor:pointer;white-space:nowrap;color:#444;}';
        css += '.__chk_grid input[type=checkbox]{margin-right:4px;}';
        css += '.__merge_sec{margin-bottom:14px;padding:10px 14px;background:#fff8e1;border:1px solid #ffe082;border-radius:6px;}';
        css += '.__merge_sec label{display:flex;align-items:center;font-size:13px;cursor:pointer;color:#333;font-weight:500;}';
        css += '.__merge_sec input[type=checkbox]{margin-right:6px;}';
        css += '.__merge_desc{font-size:11px;color:#888;margin-top:4px;padding-left:20px;line-height:1.5;}';
        css += '.__sys_note{font-size:11px;color:#666;margin-top:6px;padding:6px 10px;background:#f0f4f8;border-radius:4px;line-height:1.5;}';
        css += '.__lib_tag{font-size:10px;color:#e65100;background:#fff3e0;padding:1px 5px;border-radius:3px;margin-left:4px;}';
        css += '.__lib_warn{font-size:11px;color:#ff9800;margin-top:6px;}';
        css += '.__status{font-size:12px;color:#888;margin-top:8px;}';
        css += '.__p_foot{display:flex;justify-content:flex-end;gap:10px;';
        css += 'padding:12px 20px;border-top:1px solid #e0e0e0;background:#f8f9fa;border-radius:0 0 10px 10px;}';
        css += '.__btn{padding:8px 22px;border:none;border-radius:5px;font-size:14px;cursor:pointer;}';
        css += '.__btn_cancel{background:#e0e0e0;color:#333;}.__btn_cancel:hover{background:#d0d0d0;}';
        css += '.__btn_export{background:#0078d4;color:#fff;}.__btn_export:hover{background:#005fa3;}';
        var style = document.createElement('style');
        style.textContent = css;
        document.head.appendChild(style);
    }

    /* ================================================================
       UI
       ================================================================ */

    function createUI() {
        if (panelCreated) return;
        panelCreated = true;

        $btn = document.createElement('button');
        $btn.id = '__scut_export_btn';
        $btn.innerHTML = '<span>导出课表</span><span class="__scut_dot"></span>';
        document.body.appendChild($btn);

        $overlay = document.createElement('div');
        $overlay.id = '__scut_export_overlay';
        document.body.appendChild($overlay);

        $panel = document.createElement('div');
        $panel.id = '__scut_export_panel';

        var basicHtml = '', extHtml = '';
        for (var i = 0; i < FIELDS.length; i++) {
            var f = FIELDS[i];
            var checked = f.defaultOn ? 'checked' : '';
            var lbl = '<label><input type="checkbox" data-field="' + f.key + '" ' + checked + '> ' + f.label + '</label>';
            if (f.group === 'basic') basicHtml += lbl;
            else extHtml += lbl;
        }

        var panelHtml = '';
        panelHtml += '<div class="__p_head"><h3>导出课表</h3><button class="__p_close" id="__scut_pclose">&times;</button></div>';
        panelHtml += '<div class="__p_body">';

        // Merge toggle
        panelHtml += '<div class="__merge_sec">';
        panelHtml += '<label><input type="checkbox" id="__scut_merge_cb"> 合并同课程不同教师的条目</label>';
        panelHtml += '<div class="__merge_desc">';
        panelHtml += '同一课程号 + 同星期 + 同节次的条目将合并为一条，';
        panelHtml += '教师名/上课地点用逗号连接，周次自动合并（支持不连续周次如 "1-4周,9-12周"）。';
        panelHtml += '</div></div>';

        // Format selection
        panelHtml += '<div class="__sec">';
        panelHtml += '<div class="__sec_title">导出格式 <span><button class="__preset_btn" id="__scut_fmt_all">全选</button><button class="__preset_btn" id="__scut_fmt_none">取消</button></span></div>';
        panelHtml += '<div class="__fmt_grid">';
        var fmtDefs = [
            { key: 'json',  label: 'JSON',            lib: '' },
            { key: 'csv',   label: 'CSV',             lib: '' },
            { key: 'txt',   label: 'TXT',             lib: '' },
            { key: 'md',    label: 'Markdown (.md)',   lib: '' },
            { key: 'ical',  label: 'iCal (.ics)',      lib: '' },
            { key: 'docx',  label: 'DOCX (Word)',      lib: '' },
            { key: 'pdf',   label: 'PDF',              lib: '需 jsPDF + html2canvas' },
            { key: 'xlsx',  label: 'XLSX (Excel)',     lib: '需 SheetJS' },
            { key: 'jpg',   label: 'JPG',              lib: '需 html2canvas' }
        ];
        for (var fi = 0; fi < fmtDefs.length; fi++) {
            var def = fmtDefs[fi];
            var libNote = def.lib ? ' <span class="__lib_tag">' + def.lib + '</span>' : '';
            panelHtml += '<label><input type="checkbox" data-fmt="' + def.key + '"> ' + def.label + libNote + '</label>';
        }
        panelHtml += '</div>';
        panelHtml += '<div class="__lib_warn" id="__scut_lib_warn" style="display:none;"></div>';
        panelHtml += '</div>';

        // Field selection
        panelHtml += '<div class="__sec">';
        panelHtml += '<div class="__sec_title">基础字段 <span><button class="__preset_btn" data-preset="basic_all">全选</button><button class="__preset_btn" data-preset="basic_none">取消</button></span></div>';
        panelHtml += '<div class="__chk_grid" id="__scut_basic">' + basicHtml + '</div></div>';

        panelHtml += '<div class="__sec">';
        panelHtml += '<div class="__sec_title">扩展字段 <span><button class="__preset_btn" data-preset="ext_all">全选</button><button class="__preset_btn" data-preset="ext_none">取消</button></span></div>';
        panelHtml += '<div class="__chk_grid" id="__scut_ext">' + extHtml + '</div></div>';

        panelHtml += '<div class="__status" id="__scut_status">等待课表数据加载...</div>';
        panelHtml += '</div>';

        panelHtml += '<div class="__p_foot">';
        panelHtml += '<button class="__btn __btn_cancel" id="__scut_pcancel">取消</button>';
        panelHtml += '<button class="__btn __btn_export" id="__scut_pexport">导出</button>';
        panelHtml += '</div>';

        $panel.innerHTML = panelHtml;
        document.body.appendChild($panel);

        $status = document.getElementById('__scut_status');

        var closeFn = function() {
            $overlay.style.display = 'none';
            $panel.style.display = 'none';
        };

        document.getElementById('__scut_pclose').onclick = closeFn;
        document.getElementById('__scut_pcancel').onclick = closeFn;
        $overlay.onclick = closeFn;

        $btn.onclick = function() {
            $overlay.style.display = 'block';
            $panel.style.display = 'flex';
            if (dataReady) {
                var mergeInfo = isMergeEnabled() ? ' (合并后 ' + mergeCourses(courseData).length + ' 条)' : '';
                $status.textContent = '已捕获 ' + courseData.length + ' 条课程数据' + mergeInfo;
                $status.style.color = '#4caf50';
            } else {
                $status.textContent = '等待课表数据加载...请先查询课表';
                $status.style.color = '#f44336';
            }
        };

        document.getElementById('__scut_fmt_all').onclick = function() {
            var boxes = $panel.querySelectorAll('.__fmt_grid input[type=checkbox]');
            for (var i = 0; i < boxes.length; i++) boxes[i].checked = true;
        };
        document.getElementById('__scut_fmt_none').onclick = function() {
            var boxes = $panel.querySelectorAll('.__fmt_grid input[type=checkbox]');
            for (var i = 0; i < boxes.length; i++) boxes[i].checked = false;
        };

        var mergeCb = document.getElementById('__scut_merge_cb');
        mergeCb.onchange = function() {
            if (dataReady) {
                var mergeInfo = this.checked ? ' (合并后 ' + mergeCourses(courseData).length + ' 条)' : '';
                $status.textContent = '已捕获 ' + courseData.length + ' 条课程数据' + mergeInfo;
                $status.style.color = '#4caf50';
            }
        };

        var presets = $panel.querySelectorAll('.__preset_btn[data-preset]');
        for (var p = 0; p < presets.length; p++) {
            presets[p].onclick = function() {
                var preset = this.getAttribute('data-preset');
                var containerId = preset.indexOf('basic') >= 0 ? '__scut_basic' : '__scut_ext';
                var checked = preset.indexOf('_all') >= 0;
                var boxes = document.getElementById(containerId).querySelectorAll('input[type=checkbox]');
                for (var b = 0; b < boxes.length; b++) boxes[b].checked = checked;
            };
        }

        /* ================================================================
           Export Button Handler
           ================================================================ */

        document.getElementById('__scut_pexport').onclick = function() {
            console.log('[SCUT Export] Button clicked, dataReady=', dataReady, 'courseData.length=', courseData.length);
            if (!dataReady || courseData.length === 0) {
                alert('暂无课表数据，请先查询课表！');
                return;
            }

            var selectedFormats = getSelectedFormats();
            console.log('[SCUT Export] Selected formats:', selectedFormats);
            if (selectedFormats.length === 0) {
                alert('请至少选择一种导出格式！');
                return;
            }

            var selectedFields = getSelectedFields();
            console.log('[SCUT Export] Fields:', selectedFields.length);
            if (selectedFields.length === 0) {
                alert('请至少选择一个导出字段！');
                return;
            }

            console.log('[SCUT Export] Fields:', selectedFields.length, 'Formats:', selectedFormats.length);

            var baseName = getBaseName();
            var needXlsx  = selectedFormats.indexOf('xlsx') >= 0;
            var needJsPdf = selectedFormats.indexOf('pdf')  >= 0;
            var needH2C   = selectedFormats.indexOf('pdf') >= 0 || selectedFormats.indexOf('jpg') >= 0;
            var warnEl = document.getElementById('__scut_lib_warn');

            try {
                var promises = [];
                if (needXlsx)  promises.push(loadXlsx());
                if (needJsPdf) promises.push(loadJsPdf());
                if (needH2C)   promises.push(loadH2C());

                if (promises.length > 0) {
                    warnEl.style.display = 'block';
                    warnEl.textContent = '正在加载依赖库，请稍候...';
                    Promise.all(promises).then(function() {
                        warnEl.style.display = 'none';
                        doExport(selectedFormats, selectedFields, baseName);
                    }).catch(function() {
                        warnEl.textContent = '部分库加载失败，对应格式可能无法使用。';
                        doExport(selectedFormats, selectedFields, baseName);
                    });
                } else {
                    doExport(selectedFormats, selectedFields, baseName);
                }
            } catch (e) {
                console.error('[SCUT Export] Error:', e);
                alert('导出出错: ' + e.message);
            }
        };
    }

    /* ================================================================
       doExport
       ================================================================ */

    function doExport(formats, fields, baseName) {
        var errors = [];
        for (var i = 0; i < formats.length; i++) {
            try {
                switch (formats[i]) {
                    case 'json': exportJson(fields, baseName); break;
                    case 'csv':  exportCsv(fields, baseName);  break;
                    case 'txt':  exportTxt(fields, baseName);  break;
                    case 'md':
                        var data = getExportData();
                        download(buildMarkdown(fields, data), baseName + '.md', 'text/markdown;charset=utf-8');
                        break;
                    case 'ical':
                        var d = getExportData();
                        download(buildIcal(d), baseName + '.ics', 'text/calendar;charset=utf-8');
                        break;
                    case 'xlsx': exportXlsx(fields, baseName); break;
                    case 'docx': exportDocx(fields, baseName); break;
                    case 'pdf':  exportPdf(fields, baseName);  break;
                    case 'jpg':  exportJpg(fields, baseName);  break;
                }
            } catch (e) {
                errors.push(formats[i] + ': ' + e.message);
            }
        }
        if (errors.length > 0) alert('部分导出失败:\n' + errors.join('\n'));
        $overlay.style.display = 'none';
        $panel.style.display = 'none';
    }

    function showDataReady() {
        if (!panelCreated) { setTimeout(showDataReady, 200); return; }
        var dot = $btn.querySelector('.__scut_dot');
        if (dot) dot.style.display = 'inline-block';
        if ($status) {
            $status.textContent = '已捕获 ' + courseData.length + ' 条课程数据';
            $status.style.color = '#4caf50';
        }
    }

    /* ================================================================
       AJAX Interceptor
       ================================================================ */

    function attach() {
        injectStyles();
        createUI();

        if (typeof jQuery === 'undefined') {
            console.warn('[SCUT Export] jQuery not found, retrying...');
            setTimeout(attach, 1000);
            return;
        }

        var origAjax = jQuery.ajax;
        jQuery.ajax = function(settings) {
            var origSuccess = settings.success;
            settings = settings || {};
            var url = settings.url || '';
            if (url.indexOf('xskbcx_cxXsgrkb') >= 0) {
                settings.success = function(data) {
                    if (data && data.kbList) {
                        courseData = data.kbList;
                        studentInfo = data.xsxx || null;
                        dataReady = true;
                        showDataReady();
                        console.log('[SCUT Export] Captured', courseData.length, 'courses');
                    }
                    if (origSuccess) origSuccess.apply(this, arguments);
                };
            }
            return origAjax.call(this, settings);
        };
        jQuery.ajax.apply = Function.prototype.apply;

        // Auto-click the search button after page load
        setTimeout(function() {
            var searchBtn = document.getElementById('search_go');
            if (searchBtn) {
                console.log('[SCUT Export] Auto-clicking search button');
                searchBtn.click();
            }
        }, 500);
    }

    /* ================================================================
       Init
       ================================================================ */

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', attach);
    } else {
        attach();
    }
})();