MediaWiki:Timeless.js：修订间差异

/* 将为Timeless皮肤的用户加载此处的所有JavaScript */

// 目标容器：确认一下你们布局里“右侧侧边栏”对应哪个元素。
// Timeless 默认布局中，#mw-site-navigation 是左侧站点导航，
// #mw-related-navigation 才是右侧栏；如果确实要放右侧，把下面的选择器换掉。
const SIDEBAR_SELECTOR = '#mw-site-navigation';

class HeadingTracker {
    constructor(rootElement) {
        this.rootElement = rootElement;
        this.headings = [];
        this.cacheExpired = true;
        this.init();
    }

    init() {
        this.collectHeadings();
        window.addEventListener('resize', () => this.cacheExpired = true);
        window.addEventListener('DOMContentLoaded', () => this.cacheExpired = true);
    }

    collectHeadings() {
        const rawHeadings = Array.from(this.rootElement.querySelectorAll('h1, h2, h3, h4, h5, h6'));
        this.headings = rawHeadings
            .map(heading => ({
                element: heading,
                top: heading.getBoundingClientRect().top + window.scrollY
            }))
            .sort((a, b) => a.top - b.top);
        this.cacheExpired = false;
    }

    getNearestHeadingAboveViewport() {
        if (this.cacheExpired) this.collectHeadings();

        const scrollY = window.scrollY + 60;
        let left = 0, right = this.headings.length - 1;
        let result = null;

        while (left <= right) {
            const mid = Math.floor((left + right) / 2);
            if (this.headings[mid].top <= scrollY) {
                result = this.headings[mid].element;
                left = mid + 1;
            } else {
                right = mid - 1;
            }
        }
        return result;
    }
}

class FloatingToC {
    constructor(toc) {
        this.element = toc;
        this.ignoreScrollUpdate = false;

        const tocTextList = Array.from(toc.querySelectorAll('.toctext'));
        this.tocTexts = new Map(tocTextList.map(t => {
            const textContent = t.textContent;
            t.parentElement.onclick = () => {
                this.ignoreScrollUpdate = true;
                this.setCurrentHeading(textContent);
            };
            return [textContent, t];
        }));

        this.tracker = new HeadingTracker(
            document.getElementById('mw-content-text'));

        this.scrollHandler = this.onScroll.bind(this);
        window.addEventListener('scroll', this.scrollHandler);
    }

    remove() {
        window.removeEventListener('scroll', this.scrollHandler);
        this.element.remove();
    }

    setCurrentHeading(heading) {
        const lastHeading = this.lastHeading;
        if (heading === lastHeading) return;

        if (lastHeading) {
            const text = this.tocTexts.get(lastHeading);
            if (text) text.classList.remove('current-heading');
        }
        this.lastHeading = heading;
        if (heading) {
            const text = this.tocTexts.get(heading);
            if (text) text.classList.add('current-heading');
        }
    }

    onScroll() {
        if (window.innerWidth < 1100) return;
        if (this.ignoreScrollUpdate) {
            this.ignoreScrollUpdate = false;
            return;
        }
        const heading = this.tracker.getNearestHeadingAboveViewport();
        this.setCurrentHeading(heading ? heading.textContent : null);
    }
}

const userAgent = navigator.userAgent;
// 原来的 isSafari 会把 Chrome/Edge 也误判成 Safari（它们的 UA 里都带 Safari），这里排除一下
const isSafari = /Safari/i.test(userAgent)
    && !/Chrome|Chromium|CriOS|Edg|OPR/i.test(userAgent);

mw.hook('ve.newTarget').add(target => {
    if (target.constructor.static.name !== 'article') {
        return;
    }
    target.on('teardown', () => {
        const event = new CustomEvent('pageupdate');
        document.dispatchEvent(event);
    });
});

let toc = null;
let tocInitialParent = null;
let tocAnchor = null;   // toc 在文章里的原始“下一个兄弟节点”，用于放回去
let floatingToC = null;
let siteNavigation = null;

// 关键修复1：先查一次初始 DOM，元素已经存在就直接回调；
// MutationObserver 只在元素是“之后”被插入时才兜底。
// 原来只挂 observer，而皮肤脚本运行时 DOM 早已解析完，
// #toc / #mw-site-navigation 已经存在，observer 永远不会触发，整段逻辑成了死代码。
function waitForElement(selector, callback) {
    const existing = document.querySelector(selector);
    if (existing) {
        callback(existing);
        return;
    }

    // body 还没生成时先观察 documentElement，避免 observe(null) 直接抛错中断脚本
    const root = document.body || document.documentElement;
    const observer = new MutationObserver(() => {
        const element = document.querySelector(selector);
        if (element) {
            observer.disconnect();
            callback(element);
        }
    });
    observer.observe(root, { childList: true, subtree: true });
}

const isWideEnough = () =>
    (isSafari ? window.innerWidth > 1354 : window.innerWidth > 1339);

const updateToCParent = () => {
    if (siteNavigation == null || toc == null) return;

    if (isWideEnough()) {
        // 宽屏：确保 toc 挂在侧边栏里
        if (toc.parentNode !== siteNavigation) {
            siteNavigation.appendChild(toc);
        }
    } else if (toc.parentNode === siteNavigation) {
        // 窄屏：放回文章里原来的位置。
        // 原来那句 siteNavigation.parentNode.lastChild.before(toc)
        // 会把它插到导航容器的某个兄弟节点前面，既不是文章原位，位置也不可控。
        if (tocAnchor && tocAnchor.parentNode === tocInitialParent) {
            tocInitialParent.insertBefore(toc, tocAnchor);
        } else {
            tocInitialParent.appendChild(toc);
        }
    }
};

const initToC = (tocElement) => {
    if (floatingToC) {
        floatingToC.remove();
        floatingToC = null;
    }
    toc = tocElement;
    tocInitialParent = tocElement.parentNode;
    tocAnchor = tocElement.nextSibling;
    floatingToC = new FloatingToC(tocElement);
    updateToCParent();
};

document.addEventListener('pageupdate', () => {
    const newToC = document.querySelector('.mw-parser-output > #toc');
    if (!newToC) return;

    // 同一颗 toc（比如事件重复派发），没必要先移除再重建
    if (newToC === toc && floatingToC) {
        updateToCParent();
        return;
    }
    initToC(newToC);
});

// 关键修复2：侧边栏回调里也补一次 updateToCParent。
// 如果 #toc 先初始化而 #mw-site-navigation 还没就位，
// 原来 updateToCParent 会直接 return，之后没有任何地方再触发它，toc 就永远卡在文章里。
waitForElement(SIDEBAR_SELECTOR, elem => {
    siteNavigation = elem;
    updateToCParent();
});

waitForElement('#toc', initToC);

// 关键修复3：窗口在断点两侧变化时也要重新摆放 toc
let resizeTimer = null;
window.addEventListener('resize', () => {
    clearTimeout(resizeTimer);
    resizeTimer = setTimeout(updateToCParent, 150);
});