/*
 * The variable used in DisqusJS
 *
 * DisqusJS Mode
 * @param {string} disqusjs.mode = dsqjs | disqus - Set which mode to use, should store and get in localStorage
 *
 * DisqusJS Config
 * @param {string} disqusjs.config.shortname - The disqus shortname
 * @param {string} disqusjs.config.siteName - The Forum Name
 * @param {string} disqusjs.config.identifier - The identifier of the page
 * @param {string} disqusjs.config.url - The url of the page
 * @param {string} disqusjs.config.api - Where to get data
 * @param {string} disqusjs.config.apikey - The apikey used to request Disqus API
 * @param {string} disqusjs.config.admin - The disqus forum admin username
 * @param {string} disqusjs.config.adminLabel - The disqus moderator badge text
 *
 * DisqusJS Info
 * @param {string} disqusjs.page.id = The thread id, used at next API call
 * @param {boolean} disqusjs.page.isClosed - Whether the comment is closed
 * @param {number} disqusjs.page.length - How many comment in the thread
 */

function DisqusJS(config) {
    /*
     * get - 封装 XHR GET
     *
     * @param {string} url
     * @param {string} timeout
     * @param {boolean} async
     * @param {function} success
     * @param {function} error
     *
     * Example:
        get({
            'http://localhost:3000/getData',
            4000,
            true,
            (res) => {
                console.log(res)
            },
            () => {}
        })
     */
    const get = (url, success, error) => {
        let xhr = new XMLHttpRequest()
        xhr.open('GET', encodeURI(url), true);
        xhr.onload = () => {
            if (xhr.status >= 200 && xhr.status < 300 || xhr.status === 304) {
                let res = JSON.parse(xhr.responseText)
                success(res)
            } else {
                loadError();
            }
        }
        xhr.timeout = 4500;
        xhr.ontimeout = (e) => {
            error(e);
        };
        xhr.onerror = (e) => {
            error(e);
        };
        xhr.send();
    }

    // localstorage 操作类
    // 用于持久化某些数据（如 newComment 的评论者的相关信息）

    /*
     * setLS(kwy, value) - 设置 localStorage
     *
     * @param {string} key
     * @param {string} value
     */
    const setLS = (key, value) => {
        try {
            localStorage.setItem(key, value);
        } catch (e) {
        }
    }

    /*
     * getLS(key) - 从 localStorage 条目
     *
     * @param {string} key
     * @return {string} - 返回条目 value 内容
     */
    const getLS = (key) => {
        return localStorage.getItem(key);
    }

    /*
     * dateFormat(date) - 解析 date 为 yyyy-MM-dd hh:mm:ss
     *
     * @param {string} date - 传入评论创建日期（XML 格式）
     * @return {string} - 格式化后的日期
     */
    const dateFormat = (date) => {
        // 将传入的 date 转化为时间戳
        date = Date.parse(new Date(date));

        // Disqus API 返回的是 UTC 时间，所以在时间戳上加 28800000 毫秒补上 8 小时时差
        date = new Date(date + 28800000);
        let y = date.getFullYear();
        let m = date.getMonth() + 1;
        // 如果不足两位则补 0
        m = m < 10 ? `0${m}` : m;
        let d = date.getDate();
        d = d < 10 ? `0${d}` : d;
        let h = date.getHours();
        h = h < 10 ? `0${h}` : h;
        let minute = date.getMinutes();
        minute = minute < 10 ? (`0${minute}`) : minute;

        return `${y}-${m}-${d} ${h}:${minute}`;
    }

    /*
     * loadDisqus() - 加载 Disqus
     */
    function loadDisqus() {
        let d = document;
        let s = d.createElement('script');

        // 显示提示信息
        // Disqus 加载成功以后会把 #disqus_thread 内的内容全部覆盖
        d.getElementById('disqus_thread').innerHTML = '<div id="dsqjs"><section><div id="dsqjs-msg">评论完整模式加载中...如果长时间无法加载，请针对 disq.us | disquscdn.com | disqus.com 启用代理，或使用 <a id="dsqjs-force-dsqjs" class="dsqjs-msg-btn">评论基础模式</a></div></section><footer><p class="dsqjs-footer">Powered by <a class="dsqjs-disqus-logo" href="https://disqus.com" rel="nofollow noopener noreferrer" target="_blank"></a>&nbsp;&amp;&nbsp;<a href="https://github.com/SukkaW/DisqusJS" target="_blank">DisqusJS</a></p></footer>'
        d.getElementById('dsqjs-force-dsqjs').addEventListener('click', forceDsqjs);

        s.src = 'https://' + disqusjs.config.shortname + '.disqus.com/embed.js';
        s.setAttribute('data-timestamp', + new Date());
        (d.head || d.body).appendChild(s);
    }

    function checkDisqus() {
        // 测试 Disqus 的域名
        // *.disquscdn.com 没有被墙所以不做检查
        let domain = ['disqus.com', `${disqusjs.config.shortname}.disqus.com`],
            test = 0,
            success = 0;

        let checker = () => {
            // 测试域名数量 ==== 测试次数 === 成功次数
            // 如果 truw 则认定可以 Disqus 可以连通
            if ((domain.length === test) && (test === success)) {
                forceDisqus()
                // 否则认为 Disqus 无法连通
            } else if (domain.length === test) {
                forceDsqjs()
            }
            // 如果测试域名数量不等于测试次数则说明测试还没有完成，不执行任何操作
        }

        for (let i of domain) {
            ((i) => {
                let img = new Image;
                // 处理加载超时
                let timeout = setTimeout(() => {
                    img.onerror = img.onload = null;
                    test++;
                    checker()
                }, 3000);

                img.onerror = () => {
                    clearTimeout(timeout);
                    test++;
                    checker()
                }

                img.onload = () => {
                    clearTimeout(timeout);
                    test++;
                    success++;
                    checker()
                }

                img.src = `https://${i}/favicon.ico?${+(new Date)}`
            })(i);
        }
    }

    function loadDsqjs() {
        (() => {
            // 在 #disqus_thread 中填充 DisqusJS Container
            /*
            <div id="dsqjs">
            <section>
                 <div id="dsqjs-msg"></div>
            </section>
            <header class="dsqjs-header dsqjs-hide" id="dsqjs-header">
                <nav class="dsqjs-nav dsqjs-clearfix">
                    <ul>
                        <li class="dsqjs-nav-tab dsqjs-tab-active">
                            <span><span id="dsqjs-comment-num"></span> Comments</span>
                        </li>
                        <li class="dsqjs-nav-tab">
                            <span id="dsqjs-site-name"></span>
                        </li>
                    </ul>
                </nav>
            </header>
            <section class="dsqjs-post-container">
                <ul class="dsqjs-post-list" id="dsqjs-post-container"></ul>
                <a id="dsqjs-load-more" class="dsqjs-load-more dsqjs-hide">加载更多评论</a>
            </section>
            <footer>
                <p class="dsqjs-footer">
                    Powered by <a class="dsqjs-disqus-logo" href="https://disqus.com" rel="nofollow noopener noreferrer" target="_blank"></a>&nbsp;&amp;&nbsp;<a href="https://github.com/SukkaW/DisqusJS" target="_blank">DisqusJS</a>
                </p>
            </footer>
            </div>
            */

            let d = document;
            d.getElementById('disqus_thread').innerHTML = `<div id="dsqjs"><section><div id="dsqjs-msg"></div></section><header class="dsqjs-header dsqjs-hide" id="dsqjs-header"><nav class="dsqjs-nav dsqjs-clearfix"><ul><li class="dsqjs-nav-tab dsqjs-tab-active"><span><span id="dsqjs-comment-num"></span> Comments</span></li><li class="dsqjs-nav-tab"><span id="dsqjs-site-name"></span></li></ul></nav></header><section class="dsqjs-post-container"><ul class="dsqjs-post-list" id="dsqjs-post-container"></ul><a id="dsqjs-load-more" class="dsqjs-load-more dsqjs-hide">加载更多评论</a></section><footer><p class="dsqjs-footer">Powered by <a class="dsqjs-disqus-logo" href="https://disqus.com" rel="nofollow noopener noreferrer" target="_blank"></a>&nbsp;&amp;&nbsp;<a href="https://github.com/SukkaW/DisqusJS" target="_blank">DisqusJS</a></p></footer></div>`;
            // DisqusJS 加载中信息
            d.getElementById('dsqjs-msg').innerHTML = `评论基础模式加载中。如需完整体验请针对 disq.us | disquscdn.com | disqus.com 启用代理并 <a id="dsqjs-reload-disqus" class="dsqjs-msg-btn">尝试完整 Disqus 模式</a> | <a id="dsqjs-force-disqus" class="dsqjs-msg-btn">强制完整 Disqus 模式</a>。`
            d.getElementById('dsqjs-reload-disqus').addEventListener('click', checkDisqus);
            d.getElementById('dsqjs-force-disqus').addEventListener('click', forceDisqus);

            /*
             * 获取 Thread 信息
             * Disqus API 只支持通过 Thread ID 获取评论列表，所以必须先通过 identifier 获取当前页面 Thread ID
             *
             * API Docs: https://disqus.com/api/docs/threads/list/
             * API URI: /3.0/threads/list.json?forum=[disqus_shortname]&thread=ident:[identifier]&api_key=[apikey]
             */
            let url = `${disqusjs.config.api}3.0/threads/list.json?forum=${disqusjs.config.shortname}&thread=ident:${disqusjs.config.identifier}&api_key=${disqusjs.config.apikey}`;

            get(url, (res) => {
                var d = document;
                // 如果只返回一条则找到了对应 thread，否则是当前 identifier 不能找到唯一的 thread
                // 如果 thread 不唯一则需要进行初始化
                if (res.code === 0 && res.response.length === 1) {
                    var resp = res.response[0];
                    disqusjs.page = {
                        id: resp.id,
                        title: resp.title,
                        isClosed: resp.isClosed,
                        length: resp.posts
                    };

                    // 填充站点名称和评论数目
                    d.getElementById('dsqjs-comment-num').innerHTML = disqusjs.page.length

                    if (disqusjs.config.siteName) {
                        d.getElementById('dsqjs-site-name').innerHTML = disqusjs.config.siteName
                    }

                    // 获取评论列表
                    getComment()
                } else if (res.code === 0 && res.response.length !== 1) {
                    // 当前页面可能还未初始化（需要创建 thread）
                    // Disqus API 的 threads/create 需要在服务端发起请求，不支持 AJAX Call
                    d.getElementById('dsqjs-msg').innerHTML = `该 Thread 并没有初始化，是否 <a id="dsqjs-force-disqus" class="dsqjs-msg-btn">切换到完整 Disqus 模式</a> 进行初始化？`
                    d.getElementById('dsqjs-force-disqus').addEventListener('click', forceDisqus);
                } else {
                    // 评论列表加载错误
                    loadError()
                }
            }, (e) => {
                // 评论列表加载错误
                loadError()
            })
        })()

        /*
         * getComment(cursor) - 获取评论列表
         *
         * @param {string} cursor - 传入 cursor 用于加载下一页的评论
         */
        let getComment = (cursor) => {
            // 处理传入的 cursor
            if (!cursor) {
                cursor = '';
            } else {
                cursor = `&cursor=${cursor}`;
            }
            /*
             * 获取评论列表
             *
             * API Docs: https://disqus.com/api/docs/posts/list/
             * API URI: /3.0/posts/list.json?forum=[shortname]&thread=[thread id]&api_key=[apikey]
             *
             * https://github.com/SukkaW/DisqusJS/issues/6
             * 可以使用 include=deleted 来获得已被删除评论列表
             */
            let url = `${disqusjs.config.api}3.0/posts/list.json?forum=${disqusjs.config.shortname}&thread=${disqusjs.page.id}${cursor}&include=approved&include=deleted&api_key=${disqusjs.config.apikey}`;
            get(url, (res) => {
                if (res.code === 0 && res.response.length > 0) {
                    // 已获得评论列表，进行渲染
                    renderComment(res.response)

                    var $loadMoreBtn = document.getElementById('dsqjs-load-more');
                    if (res.cursor.hasNext) {
                        // 显示 加载更多评论 按钮
                        $loadMoreBtn.classList.remove('dsqjs-hide');
                        $loadMoreBtn.addEventListener('click', () => {
                            // 递归调用 getComment，传入 cursor 参数
                            getComment(res.cursor.next)
                        });
                    } else {
                        // 没有更多评论了，确保按钮隐藏
                        $loadMoreBtn.classList.add('dsqjs-hide');
                    }
                } else if (res.code === 0 && res.response.length === 0) {
                    // 当前没有评论，显示提示信息
                    let d = document;
                    d.getElementById('dsqjs-msg').innerHTML = '你可能无法访问 Disqus，已启用评论基础模式。如需完整体验请针对 disq.us | disquscdn.com | disqus.com 启用代理并 <a id="dsqjs-reload-disqus" class="dsqjs-msg-btn">尝试完整 Disqus 模式</a> | <a id="dsqjs-force-disqus" class="dsqjs-msg-btn">强制完整 Disqus 模式</a>。'
                    d.getElementById('dsqjs-header').classList.remove('dsqjs-hide')
                    d.getElementById('dsqjs-post-container').innerHTML = '<div class="dsqjs-no-comment">这里冷冷清清的，一条评论都没有</div>'
                    d.getElementById('dsqjs-reload-disqus').addEventListener('click', checkDisqus);
                    d.getElementById('dsqjs-force-disqus').addEventListener('click', forceDisqus);
                } else {
                    // 评DisqusJS 加载错误
                    loadError()
                }
            }, (e) => {
                // 评论列表加载错误
                loadError()
            })
        }

        /*
         * parseCommentData(data) - 解析评论列表
         *
         * @param {Array} data - 评论列表 JSON
         * @return {Array} - 解析后的评论列表数据
         */
        let parseCommentData = (data) => {
            var topLevelComments = [],
                childComments = [];

            let getChildren = (id) => {
                // 如果没有子评论，就不需要解析子评论了
                if (childComments.length === 0) {
                    return null;
                }

                var list = [];
                for (let comment of childComments) {
                    if (comment.parent === id) {
                        list.unshift({
                            comment,
                            author: comment.author.name,
                            // 如果不设置 admin 会返回 undefined，所以需要嘴一个判断
                            isPrimary: (disqusjs.config.admin ? (comment.author.username === disqusjs.config.admin) : false),
                            children: getChildren(+comment.id)
                        });
                    }
                }

                if (list.length) {
                    return list;
                } else {
                    return null;
                }
            }

            data.forEach((comment) => {
                // 如果没有 comment.parent 说明是第一级评论
                (comment.parent ? childComments : topLevelComments)['push'](comment);
            });

            let commentLists = topLevelComments.map((comment) => {
                return {
                    comment,
                    author: comment.author.name,
                    isPrimary: (disqusjs.config.admin ? (comment.author.username === disqusjs.config.admin) : false),
                    children: getChildren(+comment.id)
                };
            });

            return commentLists;
        }

        /*
         * renderCommentData(data) - 渲染评论列表
         *
         * @param {Array} data - 从 getComment() 获取到的 JSON
         */
        let renderComment = (data) => {
            /*
             * processData(data) - 处理评论列表
             *
             * @param {Array} data - 解析后的评论列表 JSON
             */
            let processData = (data) => {
                // 处理 Disqus Profile URL
                if (data.comment.author.profileUrl) {
                    /*
                    Avatar Element
                    <a href="${data.comment.author.profileUrl}">
                        <img src="${data.comment.author.avatar.cache}">
                    </a>

                    Author Element
                    <span class="dsqjs-post-author">
                        <a href="${data.comment.author.profileUrl}" target="_blank" rel="nofollow noopener noreferrer">${data.comment.author.name}</a>
                    </span>
                    */
                    data.comment.avatarEl = `<a href="${data.comment.author.profileUrl}"><img src="${data.comment.author.avatar.cache}"></a>`
                    data.comment.authorEl = `<span class="dsqjs-post-author"><a href="${data.comment.author.profileUrl}" target="_blank" rel="nofollow noopener noreferrer">${data.comment.author.name}</a></span>`
                } else {
                    data.comment.avatarEl = `<img src="${data.comment.author.avatar.cache}">`
                    data.comment.authorEl = `<span class="dsqjs-post-author">${data.comment.author.name}</span>`
                }

                // 处理 Admin Label
                // 需要同时设置 isPrimary 和 adminLabel；admin 已经在 processData() 中做过判断了
                if (disqusjs.config.adminLabel && data.isPrimary) {
                    data.comment.authorEl += `<span class="dsqjs-admin-badge">${disqusjs.config.adminLabel}</span>`;
                }

                return data;
            }

            /*
             * removeDisqUs(msg) - 将 comment 中的短链接 disq.us 去除
             * @param {string} msg - 评论信息
             * @return {string} msg - 经过处理的评论信息
             */
            let removeDisqUs = (msg) => {
                // aMatcher - 只处理 Disqus 短链接
                var aMatcher = new RegExp(/<a.+?href=\"https:\/\/disq.us(.+?)\".*>/gi),
                    hrefMatcher = new RegExp(/href=\"(.+?)\"/gi)
                let link = (msg.match(aMatcher) || [])
                link.map((link) => {
                    // (.*) 是贪婪处理，会一致匹配到最后，可以用于匹配最后一次
                    link = link.match(hrefMatcher)[0].replace(/href=\"https:\/\/disq.us\/url\?url=/g, '').replace(/(.*)"/, '$1');
                    link = decodeURIComponent(link).replace(/(.*):(.*)/, '$1')
                    msg = msg.replace(aMatcher, `<a href="${link}" rel="nofollow noopener noreferrer">${link}</a>`)
                })

                // 在最后添加 target="_blank" 可以生效到全局链接（包括 Disqus CDN 直链）
                return msg.replace(/href=/g, 'target="_blank" href=')
            }

            let renderPostItem = (s) => {
                console.log(s.isDeleted)
                if (s.isDeleted) {
                    var authorEl = ``,
                        message = `<small>此评论已被删除</small>`;
                } else {
                    var authorEl = `${s.authorEl}<span class="dsqjs-bullet"></span>`,
                        message = s.message;
                }
                /*
                    <div class="dsqjs-post-item dsqjs-clearfix">
                        <div class="dsqjs-post-avatar">
                            ${s.avatarEl}
                        </div>
                        <div class="dsqjs-post-body">
                            <div class="dsqjs-post-header">
                                ${authorEl}
                                <span class="dsqjs-meta"><time>${dateFormat(s.createdAt)}</time></span>
                            </div>
                            <div class="dsqjs-post-content">
                                ${message}
                            </div>
                        </div>
                    </div>
                */
                var html = `<div class="dsqjs-post-item dsqjs-clearfix"><div class="dsqjs-post-avatar">${s.avatarEl}</div><div class="dsqjs-post-body"><div class="dsqjs-post-header">${authorEl}<span class="dsqjs-meta"><time>${dateFormat(s.createdAt)}</time></span></div><div class="dsqjs-post-content">${removeDisqUs(message)}</div></div></div>`

                return html;
            }

            let childrenComments = (data) => {
                var nesting = data.nesting,
                    children = (data.children || []);

                if (!children) {
                    return;
                }

                let html = (() => {
                    // 如果当前评论嵌套数大于 4 则不再右移
                    if (nesting < 4) {
                        return '<ul class="dsqjs-post-list dsqjs-children">';
                    } else {
                        return '<ul class="dsqjs-post-list">';
                    }
                })();

                html += children.map((comment) => {
                    comment = processData(comment);
                    comment.nesting = nesting + 1;
                    return `<li data-id="comment-${comment.comment.id}">${renderPostItem(comment.comment)}${childrenComments(comment)}</li>`;
                });

                html += '</ul>';

                if (html.length !== 0) {
                    return html;
                } else {
                    return;
                }
            }

            var html = ''

            data = parseCommentData(data);

            data.map((comment) => {
                // 如果有子评论，设置当前评论前套数为 1
                if (comment.children) {
                    comment.nesting = 1;
                }
                comment = processData(comment);
                html += `<li data-id="comment-${comment.comment.id}">${renderPostItem(comment.comment)}${childrenComments(comment)}</li>`;
            });

            let d = document;
            d.getElementById('dsqjs-header').classList.remove('dsqjs-hide')
            // 增加提示信息
            d.getElementById('dsqjs-msg').innerHTML = '你可能无法访问 Disqus，已启用评论基础模式。如需完整体验请针对 disq.us | disquscdn.com | disqus.com 启用代理并 <a id="dsqjs-reload-disqus" class="dsqjs-msg-btn">尝试完整 Disqus 模式</a> | <a id="dsqjs-force-disqus" class="dsqjs-msg-btn">强制完整 Disqus 模式</a>。'

            // 使用 append，当有评论翻页的时候可以无限在尾部添加
            d.getElementById('dsqjs-post-container').insertAdjacentHTML('beforeend', html);
            d.getElementById('dsqjs-reload-disqus').addEventListener('click', checkDisqus);
            d.getElementById('dsqjs-force-disqus').addEventListener('click', forceDisqus);
        }
    }

    /*
     * loadError() - 评论基础模式加载出现错误
     */
    function loadError() {
        let d = document;
        d.getElementById('dsqjs-msg').innerHTML = '评论基础模式加载失败，是否 <a id="dsqjs-reload-dsqjs" class="dsqjs-msg-btn">重载</a> 或 <a id="dsqjs-reload-disqus" class="dsqjs-msg-btn">尝试完整 Disqus 模式</a> ？'
        d.getElementById('dsqjs-reload-dsqjs').addEventListener('click', loadDsqjs);
        d.getElementById('dsqjs-reload-disqus').addEventListener('click', checkDisqus);
    }


    /*
     * forceDsqjs() - 强制使用 DisqusJS
     * forceDisqus() - 强制使用 Disqus
     */
    function forceDsqjs() {
        setLS('dsqjs_mode', 'dsqjs')
        loadDsqjs()
    }

    function forceDisqus() {
        setLS('dsqjs_mode', 'disqus')
        loadDisqus()
    }

    var disqusjs = [];

    // 将传入的 config 参数赋给 disqusjs.config
    disqusjs.config = config
    // 使用 https://disqus.skk.moe/disqus/ 作为备选反代服务器
    disqusjs.config.api = (disqusjs.config.api || 'https://disqus.skk.moe/disqus/')
    // 使用 document.location.origin + document.location.pathname + document.location.search 为默认 URL 和 identifier
    // Google Analytics Measurement Protocol 也使用这个参数作为 URL
    disqusjs.config.identifier = (disqusjs.config.identifier || document.location.origin + document.location.pathname + document.location.search)
    disqusjs.config.url = (disqusjs.config.url || document.location.origin + document.location.pathname + document.location.search)

    // 定义 disqusjs.page，之后会填充 thread id、title 等数据
    disqusjs.page = [];

    /*
     * window.disqus_config - 从 disqusjs.config 获取 Disqus 所需的配置
     */
    window.disqus_config = function () {
        this.page.url = disqusjs.config.url;
        this.page.identifier = disqusjs.config.identifier;
    };


    disqusjs.mode = getLS('dsqjs_mode');

    if (disqusjs.mode === 'disqus') {
        loadDisqus();
    } else if (disqusjs.mode === 'dsqjs') {
        loadDsqjs();
    } else {
        // 没有在 localStorage 中找到 disqusjs_mode 相关内容，开始检查访客的 Disqus 可用性
        // 也作为不支持 localStorage 的浏览器的 fallback
        checkDisqus();
    }
}