/* Copyright (c) 2025-2026 马建军. All rights reserved.
 * 专有软件 — 未经授权禁止复制、传播、转售。
 * 详见 LICENSE.zh-CN.txt
 */
(function () {
    var PERMANENT_CSS = ['/static/css/base.css', '/static/css/tech.css', '/static/css/responsive.css'];
    var CORE_SCRIPT_MARKERS = ['theme.js', 'symbol.js', 'page.js', 'nav.js', 'pwa.js', 'turbonav.js'];
    var pageCache = new Map();
    var MAX_CACHE = 10;
    var inflight = null;
    var currentUrl = normalizeUrl(window.location.href);

    function normalizeUrl(href) {
        var u = new URL(href, window.location.origin);
        u.hash = '';
        return u.href;
    }

    function isPermanentStylesheet(el) {
        var href = el.getAttribute('href') || '';
        return PERMANENT_CSS.some(function (p) { return href.indexOf(p) !== -1; });
    }

    function isCoreScript(el) {
        var src = el.getAttribute('src') || '';
        if (!src) return false;
        return CORE_SCRIPT_MARKERS.some(function (m) { return src.indexOf(m) !== -1; });
    }

    function shouldTurboClick(e, link) {
        if (!link || !link.href) return false;
        if (e.defaultPrevented) return false;
        if (e.button !== 0 || e.metaKey || e.ctrlKey || e.shiftKey || e.altKey) return false;
        if (link.target && link.target !== '_self') return false;
        if (link.hasAttribute('download')) return false;
        if (link.origin !== window.location.origin) return false;
        if (normalizeUrl(link.href) === currentUrl) return false;
        return true;
    }

    function parseHtml(html) {
        return new DOMParser().parseFromString(html, 'text/html');
    }

    function fetchPage(url, signal) {
        var key = normalizeUrl(url);
        if (pageCache.has(key)) {
            return Promise.resolve(pageCache.get(key));
        }
        return fetch(key, {
            credentials: 'same-origin',
            headers: { Accept: 'text/html' },
            signal: signal
        }).then(function (res) {
            if (!res.ok) throw new Error('HTTP ' + res.status);
            return res.text();
        }).then(function (html) {
            var doc = parseHtml(html);
            pageCache.set(key, doc);
            if (pageCache.size > MAX_CACHE) {
                var first = pageCache.keys().next().value;
                pageCache.delete(first);
            }
            return doc;
        });
    }

    function collectPageCss(doc) {
        var out = [];
        doc.querySelectorAll('head link[rel="stylesheet"], head style').forEach(function (el) {
            if (el.tagName === 'LINK' && isPermanentStylesheet(el)) return;
            out.push(el);
        });
        doc.querySelectorAll('.main style').forEach(function (el) {
            out.push(el);
        });
        return out;
    }

    function prepareMainHtml(doc) {
        var fetchedMain = doc.querySelector('.main');
        if (!fetchedMain) return '';
        fetchedMain.querySelectorAll('style').forEach(function (el) { el.remove(); });
        return fetchedMain.innerHTML;
    }

    function collectPageScripts(doc) {
        var out = [];
        var pastCore = false;
        doc.body.querySelectorAll(':scope > script').forEach(function (el) {
            if (isCoreScript(el)) {
                if ((el.getAttribute('src') || '').indexOf('pwa.js') !== -1) pastCore = true;
                return;
            }
            if (!pastCore) return;
            if (isCoreScript(el)) return;
            out.push(el);
        });
        return out;
    }

    function removePageAssets() {
        document.querySelectorAll('[data-page-css]').forEach(function (el) { el.remove(); });
        document.querySelectorAll('body script[data-page-js]').forEach(function (el) { el.remove(); });
    }

    function applyPageCss(items) {
        return items.reduce(function (chain, srcEl) {
            return chain.then(function () {
                return new Promise(function (resolve) {
                    var el = srcEl.cloneNode(true);
                    el.setAttribute('data-page-css', '');
                    if (el.tagName === 'LINK') {
                        el.onload = function () { resolve(); };
                        el.onerror = function () { resolve(); };
                        document.head.appendChild(el);
                    } else {
                        document.head.appendChild(el);
                        resolve();
                    }
                });
            });
        }, Promise.resolve());
    }

    function runPageScripts(items) {
        return items.reduce(function (chain, srcEl) {
            return chain.then(function () {
                return new Promise(function (resolve) {
                    var s = document.createElement('script');
                    s.setAttribute('data-page-js', '');
                    var src = srcEl.getAttribute('src');
                    if (src) {
                        var bust = (src.indexOf('?') >= 0 ? '&' : '?') + '_turbo=' + Date.now();
                        s.src = src + bust;
                        s.async = false;
                        s.onload = function () { resolve(); };
                        s.onerror = function () { resolve(); };
                        document.body.appendChild(s);
                    } else {
                        s.textContent = srcEl.textContent;
                        document.body.appendChild(s);
                        resolve();
                    }
                });
            });
        }, Promise.resolve());
    }

    function syncNavActive(doc) {
        var nav = document.getElementById('site-nav');
        var fetchedNav = doc.getElementById('site-nav');
        if (!nav || !fetchedNav) return;
        nav.querySelectorAll('a.active').forEach(function (a) { a.classList.remove('active'); });
        fetchedNav.querySelectorAll('a[href].active').forEach(function (fa) {
            var href = fa.getAttribute('href');
            if (!href) return;
            var local = nav.querySelector('a[href="' + href + '"]')
                || nav.querySelector('a[href="' + new URL(href, window.location.origin).pathname + '"]');
            if (local) local.classList.add('active');
        });
    }

    function setLoading(on) {
        var main = document.querySelector('.main');
        if (main) main.classList.toggle('nav-loading', on);
    }

    function applyDocument(doc, url, fromPopstate) {
        var main = document.querySelector('.main');
        if (!main || !doc.querySelector('.main')) {
            window.location.href = url;
            return Promise.resolve();
        }

        window.dispatchEvent(new Event('qihuo:page-leave'));
        removePageAssets();

        var cssItems = collectPageCss(doc);
        var mainHtml = prepareMainHtml(doc);

        return applyPageCss(cssItems).then(function () {
            main.innerHTML = mainHtml;
            document.title = doc.title || document.title;
            syncNavActive(doc, url);
            return runPageScripts(collectPageScripts(doc));
        }).then(function () {
            currentUrl = normalizeUrl(url);
            if (!fromPopstate) {
                history.pushState({ turbo: true }, '', currentUrl);
            }
            setLoading(false);
            window.scrollTo(0, 0);
            if (window.qihuoEmitPageLoad) window.qihuoEmitPageLoad();
        });
    }

    function navigateTo(url, opts) {
        opts = opts || {};
        var target = normalizeUrl(url);
        if (target === currentUrl && !opts.force) return Promise.resolve();

        if (inflight) inflight.abort();
        var ctrl = new AbortController();
        inflight = ctrl;
        setLoading(true);

        return fetchPage(target, ctrl.signal).then(function (doc) {
            if (ctrl.signal.aborted) return;
            inflight = null;
            return applyDocument(doc, target, !!opts.fromPopstate);
        }).catch(function () {
            if (ctrl.signal.aborted) return;
            inflight = null;
            setLoading(false);
            window.location.href = target;
        });
    }

    function prefetchPage(href) {
        var target = normalizeUrl(href);
        if (target === currentUrl || pageCache.has(target)) return;
        fetchPage(target).catch(function () { /* ignore */ });
    }

    window.qihuoNavigate = navigateTo;
    window.qihuoPrefetchPage = prefetchPage;

    document.addEventListener('click', function (e) {
        var link = e.target.closest('#site-nav a[href]');
        if (!link || !shouldTurboClick(e, link)) return;
        e.preventDefault();
        var navEl = document.getElementById('site-nav');
        if (navEl) {
            navEl.querySelectorAll('a.active').forEach(function (a) { a.classList.remove('active'); });
            link.classList.add('active');
        }
        navigateTo(link.href);
    }, true);

    window.addEventListener('popstate', function () {
        var target = normalizeUrl(window.location.href);
        if (target === currentUrl) return;
        navigateTo(target, { fromPopstate: true, force: true });
    });

    if (window.qihuoEmitPageLoad) window.qihuoEmitPageLoad();
})();