// ==UserScript==
// @name         让链接可点击
// @namespace    https://viayoo.com/
// @version      2.0
// @description  不用再复制链接打开这么麻烦了，自动将文本中的URL转换为可点击的链接
// @author       谷花泰
// @homepageURL  https://app.viayoo.com/addons/31
// @match        *://*/*
// @exclude      *://example.com/*
// @run-at       document-start
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    /* 判断是否该执行 */
    const key = encodeURIComponent('谷花泰:让链接可点击:执行判断');
    if (window[key]) return;
    window[key] = true;

    class ClickLink {
        constructor() {
            this.init();
        }
        
        init() {
            console.log('嘿嘿嘿');
            this.url_regexp = /((https?:\/\/|www\.)[\x21-\x7e]+[\w\/=]|\w([\w._-])+@\w[\w\._-]+\.(com|cn|org|net|info|tv|cc|gov|edu)|(\w[\w._-]+\.(com|cn|org|net|info|tv|cc|gov|edu))(\/[\x21-\x7e]*[\w\/])?|ed2k:\/\/[\x21-\x7e]+\|\/|thunder:\/\/[\x21-\x7e]+=)/gi;
            this.urlPrefixes = ['http://', 'https://', 'ftp://', 'thunder://', 'ed2k://', 'mailto://', 'file://'];
            document.addEventListener("mouseover", this.clearLink.bind(this));
            this.excludedTags = "a,svg,canvas,applet,input,button,area,pre,embed,frame,frameset,head,iframe,img,option,map,meta,noscript,object,script,style,textarea,code".split(",");
            this.xPath = "//text()[not(ancestor::" + this.excludedTags.join(') and not(ancestor::') + ")]";
            this.startObserve();
            setTimeout(this.linkMixInit.bind(this), 100);
        }
        
        clearLink(event) {
            let link = event.originalTarget || event.target;
            if (!(link && link.localName === "a" && link.className && link.className.indexOf("textToLink") !== -1)) {
                return;
            }
            
            let url = link.getAttribute("href");
            for (let prefix of this.urlPrefixes) {
                if (url.indexOf(prefix) === 0) {
                    return;
                }
            }
            
            if (url.indexOf('@') !== -1) {
                link.setAttribute("href", "mailto://" + url);
            } else {
                link.setAttribute("href", "http://" + url);
            }
        }
        
        setLink(candidate) {
            if (!candidate || 
                (candidate.parentNode && 
                 candidate.parentNode.className && 
                 typeof candidate.parentNode.className.indexOf === "function" && 
                 candidate.parentNode.className.indexOf("textToLink") !== -1) || 
                candidate.nodeName === "#cdata-section") {
                return;
            }
            
            let text = candidate.textContent.replace(this.url_regexp, '<a href="$1" target="_blank" class="textToLink">$1</a>');
            if (candidate.textContent && candidate.textContent.length === text.length) {
                return;
            }
            
            let span = document.createElement("span");
            span.innerHTML = text;
            candidate.parentNode.replaceChild(span, candidate);
        }
        
        linkPack(result, start) {
            let startTime = Date.now();
            while (start + 10000 < result.snapshotLength) {
                for (let i = start; i <= start + 10000; i++) {
                    this.setLink(result.snapshotItem(i));
                }
                start += 10000;
                if (Date.now() - startTime > 2500) return;
            }
            
            for (let i = start; i < result.snapshotLength; i++) {
                this.setLink(result.snapshotItem(i));
            }
        }
        
        linkify(node) {
            let result = document.evaluate(this.xPath, node, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);
            this.linkPack(result, 0);
        }
        
        linkFilter(node) {
            for (let tag of this.excludedTags) {
                if (tag === node.parentNode.localName.toLowerCase()) {
                    return NodeFilter.FILTER_REJECT;
                }
            }
            return NodeFilter.FILTER_ACCEPT;
        }
        
        observePage(root) {
            const tW = document.createTreeWalker(root, NodeFilter.SHOW_TEXT, {
                acceptNode: this.linkFilter.bind(this)
            }, false);
            
            while (tW.nextNode()) {
                this.setLink(tW.currentNode);
            }
        }
        
        startObserve() {
            this.observer = new MutationObserver(mutations => {
                for (let mutation of mutations) {
                    if (mutation.type === "childList") {
                        for (let node of mutation.addedNodes) {
                            this.observePage(node);
                        }
                    }
                }
            });
        }
        
        linkMixInit() {
            if (window !== window.top || window.document.title === "") return;
            this.linkify(document.body);
            this.observer.observe(document.body, {
                childList: true,
                subtree: true
            });
        }
    }

    try {
        new ClickLink();
    } catch (err) {
        console.log('via插件：让链接可点击：加载失败', err);
    }
})();