// ==UserScript==
// @name         RSS 订阅链接查找器（扩展版）
// @namespace    https://greasyfork.org/users/1171320
// @version      1.03
// @description  查找并验证网页中的 RSS 链接，在页面右下角显示，支持一键复制。添加了 GitHub 和 Twitter 的自定义规则。
// @author       Lama AI 辅助
// @match        *://*/*
// @exclude      *://challenges.cloudflare.com/*
// @exclude      *://dash.cloudflare.com/*
// @grant        GM_xmlhttpRequest
// @grant        GM_addStyle
// @grant        GM_setClipboard
// @license      MIT
// @downloadURL none
// ==/UserScript==

(function() {
    'use strict';
    if (window.self !== window.top) return; // 排除 iframe

    const rssLinks = new Set();
    const possibleRssPaths = [
        '/rss', '/feed', '/atom.xml', '/rss.xml', '/feed.xml', '/index.xml',
        '/feed.atom', '/rss.json', '/atom', '/index.atom', '/index.rss'
    ];
    const xmlRegex = /<\?xml.*?<rss|<feed/; // 用于检测返回内容是否为 XML/RSS/Atom

    function addStyle() {
        GM_addStyle(`
            #rss-finder-container {
                position: fixed;
                bottom: 20px;
                right: 20px;
                background: #fdfdfd;
                border: 1px solid #ccc;
                padding: 10px;
                max-height: 300px;
                overflow-y: auto;
                z-index: 9999;
            }
            #rss-finder-container h4 {
                margin: 0 0 5px;
            }
            #rss-finder-list {
                list-style: none;
                padding: 0;
            }
            #rss-finder-list li {
                margin-bottom: 5px;
                display: flex;
                align-items: center;
                font-size: 0.8em;
            }
            #rss-finder-list li a {
                color: blue;
                text-decoration: none;
                margin-right: 5px;
            }
            #rss-finder-list li button {
                font-size: 0.6em;
                padding: 2px 5px;
                margin-left: auto;
                cursor: pointer;
            }
        `);
    }

    function addRssLink(url) {
        if (rssLinks.has(url)) return;

        GM_xmlhttpRequest({
            method: 'GET',
            url: url,
            onload: function(response) {
                if (response.status === 200 && xmlRegex.test(response.responseText)) {
                    rssLinks.add(url);
                    updateRssList();
                }
            },
            onerror: function(error) {
                console.log(`加载失败: ${url}`, error);
            }
        });
    }

    function updateRssList() {
        let container = document.getElementById('rss-finder-container');
        if (!container) {
            container = document.createElement('div');
            container.id = 'rss-finder-container';
            container.innerHTML = '<h4>可用RSS订阅:</h4><ul id="rss-finder-list"></ul>';
            document.body.appendChild(container);
            setTimeout(() => {
                if (container) container.style.display = 'none';
            }, 15000);
        }

        const list = container.querySelector('#rss-finder-list');
        list.innerHTML = '';

        rssLinks.forEach(url => {
            const li = document.createElement('li');
            const a = document.createElement('a');
            a.href = url;
            a.target = '_blank';
            a.rel = 'noopener noreferrer';
            a.textContent = url;

            const copyButton = document.createElement('button');
            copyButton.textContent = '复制';
            copyButton.onclick = function() {
                navigator.clipboard.writeText(url).then(() => {
                    alert('已复制');
                }).catch(err => {
                    console.error('复制失败', err);
                });
            };

            li.appendChild(a);
            li.appendChild(copyButton);
            list.appendChild(li);
        });
    }

    function findRssLinks() {
        const rssTags = document.querySelectorAll('link[type="application/rss+xml"], link[type="application/atom+xml"], meta[type="application/rss+xml"], meta[type="application/atom+xml"]');
        rssTags.forEach(tag => {
            const url = tag.getAttribute('href') || tag.getAttribute('content');
            if (url) {
                addRssLink(url);
            }
        });

        possibleRssPaths.forEach(path => {
            const guessedUrl = window.location.origin + path;
            addRssLink(guessedUrl);
        });

        if (window.location.hostname === 'github.com') {
            const pathParts = window.location.pathname.split('/').filter(Boolean);
            if (pathParts.length >= 2) {
                const [user, repo] = pathParts;
                addRssLink(`https://github.com/${user}.atom`);
                addRssLink(`https://github.com/${user}/${repo}/commits.atom`);
                addRssLink(`https://github.com/${user}/${repo}/releases.atom`);
            }
        }

        if (window.location.hostname === "twitter.com" && window.location.pathname.startsWith('/')) {
            const userName = window.location.pathname.slice(1);
            if (userName) {
                addRssLink(`https://news.google.com/rss/search?q=site:twitter.com/${userName}+when:7d`);
            }
        }

        const rssSubscribeLinks = document.querySelectorAll('a.rss-subscribe');
        rssSubscribeLinks.forEach(link => {
            if (link.href) {
                addRssLink(link.href);
            }
        });
    }

    addStyle();
    window.onload = findRssLinks;
})();