// ==UserScript==
// @name         Plusai Fix
// @version      1.3
// @description  修复复制含 LaTeX 内容时产生大量换行的问题，保留 LaTeX 格式，以及粘贴内容过多时的卡顿
// @author       xyan9
// @match        https://ns01.plusai.io/c/*
// @grant        none
// @run-at       document-idle
// @license MIT
// @namespace https://greasyfork.org/users/552924
// @downloadURL https://update.greasyfork.icu/scripts/576814/Plusai%20Fix.user.js
// @updateURL https://update.greasyfork.icu/scripts/576814/Plusai%20Fix.meta.js
// ==/UserScript==


(function () {

    'use strict';

    function getLatex(katexEl) {
        var ann = katexEl.querySelector('.katex-mathml annotation');
        if (!ann) return katexEl.textContent;
        var isDisplay = katexEl.classList.contains('katex-display');
        var src = ann.textContent;
        return isDisplay ? '$$' + src + '$$' : '$' + src + '$';
    }

    function cleanSelection() {
        var sel = window.getSelection();
        if (!sel || sel.isCollapsed || sel.rangeCount === 0) return null;

        var range = sel.getRangeAt(0);
        var frag = range.cloneContents();
        var katexList = frag.querySelectorAll('.katex');
        if (katexList.length === 0) return null;

        katexList.forEach(function (el) {
            var latex = getLatex(el);
            var span = document.createElement('span');
            span.textContent = latex;
            el.parentNode.replaceChild(span, el);
        });

        return frag.textContent || '';
    }

    document.addEventListener('keydown', function (e) {
        if ((e.ctrlKey || e.metaKey) && e.key === 'c') {
            var text = cleanSelection();
            if (text) {
                e.preventDefault();
                e.stopPropagation();
                navigator.clipboard.writeText(text);
            }
        }
    }, true);


    // CSS containment：隔离侧栏和编辑器，减少 reflow 范围
    var style = document.createElement('style');
    style.textContent = [
        'nav[aria-label] { contain: layout paint style; }',
        '.wcDTda_prosemirror-parent { contain: layout paint style; }'
    ].join('\n');
    document.head.appendChild(style);

    document.addEventListener('paste', function(e) {
        var editor = document.querySelector('#prompt-textarea, .ProseMirror');
        if (!editor || !editor.contains(e.target)) return;

        var text = e.clipboardData.getData('text/plain');
        if (!text) return;

        e.preventDefault();
        e.stopPropagation();
        e.stopImmediatePropagation();

        editor.focus();

        var sel = window.getSelection();
        if (!sel.rangeCount) return;
        var range = sel.getRangeAt(0);
        range.deleteContents();

        // 用 DocumentFragment 一次性构建所有节点（0ms）
        var lines = text.split('\n');
        var fragment = document.createDocumentFragment();
        for (var i = 0; i < lines.length; i++) {
            if (i > 0) fragment.appendChild(document.createElement('br'));
            if (lines[i]) fragment.appendChild(document.createTextNode(lines[i]));
        }
        range.insertNode(fragment);

        // 移动光标到插入内容之后
        var lastNode = range.endContainer.nodeType === 3
        ? range.endContainer
        : range.endContainer.lastChild;
        if (lastNode && lastNode.nodeType === 3) {
            range.setStart(lastNode, lastNode.textContent.length);
        } else if (lastNode) {
            range.setStartAfter(lastNode);
        }
        range.collapse(true);
        sel.removeAllRanges();
        sel.addRange(range);
    }, true);
})();