// ==UserScript==
// @name         anti-rickroll
// @namespace    http://tampermonkey.net/
// @version      11.3
// @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;

    // 如果 URL 包含强制放行标记，彻底退出
    if (window.location.hash.includes('force-pass')) return;

    GM_addStyle(`
        #rick-breaker-overlay { position: fixed; top:0; left:0; width:100%; height:100%; background:rgba(0,0,0,0.9); z-index:2147483647; display:flex; justify-content:center; align-items:center; backdrop-filter:blur(20px); }
        .rick-card { background:#fff; padding:40px; border-radius:24px; width:350px; text-align:center; border:5px solid #ff4444; box-shadow: 0 20px 50px rgba(0,0,0,0.5); font-family: sans-serif; }
        .rick-btn { padding:14px; border-radius:12px; cursor:pointer; border:none; font-weight:bold; width:100%; margin-top:12px; font-size:15px; }
        .btn-safe { background:#f0f0f0; color:#333; }
        .btn-danger { background:#ff4444; color:#fff; font-size:11px; opacity:0.6; }
        a.rickroll-danger { outline: 2px dashed #ff4444 !important; background: rgba(255,0,0,0.1) !important; }
    `);

    // 核心判定：是否为真正的内链
    function isInternalLink(url) {
        try {
            const target = new URL(url);
            const current = window.location;
            // 只有协议和域名完全一致，才判定为内链
            return target.protocol === current.protocol && target.hostname === current.hostname;
        } catch (e) {
            return true; // 无法解析的通常是相对路径，视为内链
        }
    }

    // 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;
    }

    function silencePage() {
        document.querySelectorAll('video, audio').forEach(m => { m.pause(); m.muted = true; });
    }

    // 拦截 UI 逻辑（兼容本页跳转和新页跳转）
    function renderOverlay(title, url, isIncoming = false) {
        if (document.getElementById('rick-breaker-overlay')) return;
        const silencer = setInterval(silencePage, 200);

        const overlay = document.createElement('div');
        overlay.id = 'rick-breaker-overlay';
        overlay.innerHTML = `
            <div class="rick-card">
                <div style="font-size:50px">🚫</div>
                <h2 style="color:#ff4444; margin:10px 0;">${title}</h2>
                <p style="color:#666; font-size:14px;">已拦截 Rickroll 风险链接。</p>
                <button class="rick-btn btn-safe" id="r-back">立刻返回</button>
                <button class="rick-btn btn-danger" id="r-go">我非要看 (强制放行)</button>
            </div>`;

        (document.body || document.documentElement).appendChild(overlay);

        document.getElementById('r-back').onclick = () => {
            if (isIncoming && window.history.length > 1) {
                window.history.back();
            } else {
                overlay.remove();
                clearInterval(silencer);
                // 如果是本页强行跳过来的，点返回要尝试跳回
                if (!isIncoming) window.stop();
            }
        };

        document.getElementById('r-go').onclick = () => {
            clearInterval(silencer);
            overlay.remove();
            // 拼接强制放行 Hash
            const jumpUrl = url + (url.includes('#') ? '&' : '#') + 'force-pass';
            window.location.href = jumpUrl;
        };
    }

    // 入境自检
    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) {
                        silencePage();
                        renderOverlay("入境风险拦截", url, true);
                    }
                } catch (e) {}
            }
        });
    }

    // 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 rawUrl = a.href;
            const realUrl = getRealUrl(rawUrl);

            // 严格跳过：1. 必须是 http 2. 必须不是内链 3. 排除静态资源 4. 没扫过
            if (!realUrl.startsWith('http') || isInternalLink(realUrl) || EXCLUDE.test(realUrl) || cache.has(realUrl)) return;

            cache.set(realUrl, 'pending');
            queue.push(realUrl);
        });
        processQueue();
    }

    // 点击接管 (核心：拦截本标签页点击)
    window.addEventListener('click', function(e) {
        const a = e.target.closest('a');
        if (!a || !a.href || !a.href.startsWith('http')) return;

        const realUrl = getRealUrl(a.href);
        // 如果是内链，直接放行，不进入拦截逻辑
        if (isInternalLink(realUrl)) return;
        // 如果已经带了标记，放行
        if (realUrl.includes('force-pass') || a.dataset.rickSafe === '1') return;

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

        GM_xmlhttpRequest({
            method: "POST",
            url: API_ENDPOINT,
            data: JSON.stringify({ url: realUrl }),
            headers: { "Content-Type": "application/json" },
            onload: (res) => {
                try {
                    const data = JSON.parse(res.responseText);
                    if (data.isRickroll) {
                        renderOverlay("重定向拦截", realUrl, false);
                    } else {
                        a.dataset.rickSafe = '1';
                        // 判定是否需要新开窗口
                        if (a.target === '_blank' || e.ctrlKey || e.metaKey) {
                            window.open(realUrl, '_blank');
                        } else {
                            window.location.href = realUrl;
                        }
                    }
                } catch (e) { window.location.href = realUrl; }
            }
        });
    }, true);

    checkIncoming();
    window.addEventListener('DOMContentLoaded', scanPage);
    setInterval(scanPage, 5000);
})();