// ==UserScript==
// @name         anti-rickroll
// @namespace    http://tampermonkey.net/
// @version      11.1
// @description  fuck rickroll
// @author       dext
// @match        *://*/*
// @grant        GM_xmlhttpRequest
// @grant        GM_addStyle
// @connect      anti-rickroll.dext.top
// @run-at       document-start
// @downloadURL none
// ==/UserScript==

(function() {
    'use strict';

    const API_ENDPOINT = "https://anti-rickroll.dext.top";
    const cache = new Map();
    const queue = [];
    let activeRequests = 0;
    const MAX_CONCURRENT = 3;

    GM_addStyle(`
        #rick-breaker-overlay { position: fixed; top:0; left:0; width:100%; height:100%; background:rgba(0,0,0,0.95); z-index:2147483647; display:flex; justify-content:center; align-items:center; backdrop-filter:blur(15px); }
        .rick-card { background:#fff; padding:40px; border-radius:20px; width:350px; text-align:center; border:6px solid #ff4444; font-family:sans-serif; box-shadow: 0 10px 30px rgba(0,0,0,0.5); }
        .rick-btn { padding:15px; border-radius:10px; cursor:pointer; border:none; font-weight:bold; width:100%; margin-top:15px; font-size:14px; }
        .btn-safe { background:#eee; color:#333; }
        .btn-danger { background:#ff4444; color:#fff; }
        a.rickroll-danger { border-bottom: 2px dashed #ff4444 !important; color:#ff4444 !important; background:rgba(255,0,0,0.05) !important; }
    `);

    // 1. 脱壳逻辑
    function getRealUrl(url) {
        try {
            const u = new URL(url);
            if (u.hostname.includes('google.com') && u.searchParams.has('q')) return u.searchParams.get('q');
            if (u.hostname.includes('baidu.com') && u.searchParams.has('url')) return u.searchParams.get('url');
        } catch (e) {}
        return url;
    }

    // 2. 入境自检 (已更名为 ASCII 兼容名称)
    function checkIncoming() {
        const url = window.location.href;
        if (url.length < 25 || /google|baidu|bing/.test(window.location.hostname)) return;

        GM_xmlhttpRequest({
            method: "POST",
            url: API_ENDPOINT,
            data: JSON.stringify({ url }),
            headers: { "Content-Type": "application/json" },
            onload: (res) => {
                try {
                    const data = JSON.parse(res.responseText);
                    if (data.isRickroll) {
                        window.stop();
                        renderBlockPage("入境检测拦截", url);
                    }
                } catch (e) {}
            }
        });
    }

    // 3. UI 渲染函数
    function renderBlockPage(title, url) {
        if (document.getElementById('rick-breaker-overlay')) return;
        document.documentElement.innerHTML = "";
        const div = document.createElement('div');
        div.id = 'rick-breaker-overlay';
        div.innerHTML = `
            <div class="rick-card">
                <h1 style="margin:0">🚫</h1>
                <h2 style="color:#ff4444">${title}</h2>
                <p>目标链接经穿透分析确认为 <b>Rickroll</b>。</p>
                <button class="rick-btn btn-safe" id="r-back">← 返回上一页</button>
                <button class="rick-btn btn-danger" id="r-go" style="opacity:0.6;font-size:10px">非要看</button>
            </div>`;
        document.documentElement.appendChild(div);
        document.getElementById('r-back').onclick = () => history.length > 1 ? history.back() : window.close();
        document.getElementById('r-go').onclick = () => {
            const a = document.createElement('a');
            a.href = url;
            a.dataset.rickSafe = '1';
            a.click();
        };
    }

    // 4. 并发预检
    function processQueue() {
        if (queue.length === 0 || activeRequests >= MAX_CONCURRENT) return;
        const url = queue.shift();
        activeRequests++;
        GM_xmlhttpRequest({
            method: "POST",
            url: API_ENDPOINT,
            data: JSON.stringify({ url }),
            headers: { "Content-Type": "application/json" },
            onload: (res) => {
                try {
                    const data = JSON.parse(res.responseText);
                    cache.set(url, data.isRickroll);
                    if (data.isRickroll) {
                        document.querySelectorAll('a').forEach(a => {
                            if(getRealUrl(a.href) === url) a.classList.add('rickroll-danger');
                        });
                    }
                } catch (e) {}
                activeRequests--; processQueue();
            },
            onerror: () => { activeRequests--; processQueue(); }
        });
    }

    function scanPage() {
        const EXCLUDE = /\.(jpg|jpeg|png|gif|css|js|woff|zip|pdf|mp4)($|\?)/i;
        document.querySelectorAll('a[href]').forEach(a => {
            const url = getRealUrl(a.href);
            if (!url.startsWith('http') || url.includes(window.location.hostname) || EXCLUDE.test(url) || cache.has(url)) return;
            cache.set(url, 'pending');
            queue.push(url);
        });
        processQueue();
    }

    // 5. 点击接管
    window.addEventListener('click', function(e) {
        const a = e.target.closest('a');
        if (!a || !a.href || !a.href.startsWith('http') || a.dataset.rickSafe === '1') return;

        const url = getRealUrl(a.href);
        e.preventDefault();
        e.stopPropagation();

        GM_xmlhttpRequest({
            method: "POST",
            url: API_ENDPOINT,
            data: JSON.stringify({ url }),
            headers: { "Content-Type": "application/json" },
            onload: (res) => {
                try {
                    const data = JSON.parse(res.responseText);
                    if (data.isRickroll) {
                        renderBlockPage("重定向拦截", url);
                    } else {
                        a.dataset.rickSafe = '1';
                        a.click();
                    }
                } catch (e) { a.dataset.rickSafe = '1'; a.click(); }
            }
        });
    }, true);

    checkIncoming();
    window.addEventListener('load', () => {
        scanPage();
        setInterval(scanPage, 5000);
    });
})();