// ==UserScript==
// @name        Douban Book Bar
// @namespace   DoubanBookBar
// @license		MIT License
// @author      ElvisKang<elviskang@foxmail.com>
// @description 以最优惠的价格买到最心仪的书
// @include     *://www.amazon.cn/*
// @include     *://item.jd.com/*
// @include     *://product.dangdang.com/*
// @include     *://product.china-pub.com/*
// @include     *://product.suning.com/*
// @include     *://www.suning.com/emall/*
// @include     *://www.duokan.com/book/*
// @include     *://www.winxuan.com/product/*
// @include     *://www.ituring.com.cn/*
// @version     ver 1.2.15
// @grant       GM_xmlhttpRequest
// @grant       GM_addStyle
// @downloadURL none
// ==/UserScript==

//用于解决greasemonkey在iframe中运行的问题,避免脚本多次运行
if ( window.top === window.self ) {
    (function () {
        "use strict";

        //全局变量(构造函数)声明区

        //包含支持的网站列表以及当前网站对象
        var sitesContainer = {

            //以下划线开头的属性为访问器属性
            _siteList     : [],    //插件支持的网页
            _curSite      : null,  //当前网页
            _siteNameList : [],
            addSites      : function (sitesArray) {
                if ( Array.isArray ( sitesArray ) ) {
                    this._siteList = this.list.concat ( sitesArray );
                    var that = this;
                    sitesArray.forEach ( function (value) {
                        that.nameList.push ( value.name );
                    } );
                }
            },
            get list () {
                return this._siteList;
            },
            get nameList () {
                return this._siteNameList;
            },
            get curSite () {
                return this._curSite;
            },
            set curSite (href) {
                //通过对象中的checker属性匹配网站
                var i,
                    len = this.list.length;
                for ( i = 0 ; i < len ; i++ ) {
                    var checker = this.list[i].checker;
                    if ( checker.test && checker.test ( href ) ) {
                        this._curSite = this.list[i];
                    }
                }
            }
        };

        function SupportSite (siteInfo) {
            if ( typeof siteInfo === "object" ) {
                for ( var props in siteInfo ) {
                    if ( siteInfo.hasOwnProperty ( props ) ) {
                        this[props] = siteInfo[props];
                    }
                }
            }
        }

        SupportSite.prototype.createDoubanBar = function (bookInfo, priceList) {
            var insertPosition = document.querySelector ( this.insertPosition );
            if ( !insertPosition ) {
                log ( "-Error: 网页发生变动，插入位置没有找到" );
                return;
            }
            var infoRowContainer  = createInfoRowContainer (),
                priceRowContainer = createPriceRowContainer ();
            var scoreSpan         = createScoreSpan ( bookInfo ),
                contrastPriceInfo = createContrastPriceInfo ( priceList );
            priceRowContainer.appendChild ( contrastPriceInfo );
            infoRowContainer.appendChild ( scoreSpan );
            setBaseCss ();
            var bar = createBar ( infoRowContainer, priceRowContainer );
            insertBar ( bar, insertPosition );
        };

        var Amazon = new SupportSite ( {

            name : "亚马逊",

            checker : /(https?:\/\/)?(www)?\.amazon\.(com|cn)\/.*/,

            logo : "http://www.amazon.cn/favicon.ico",

            getISBN        : function () {
                var contents = document.querySelectorAll ( "div.content b" );
                for ( var i = 0 ; i <= contents.length ; i++ ) {
                    var info = contents[i];
                    if ( info && info.textContent === "ISBN:" ) {
                        return info.nextSibling.data.split ( "," )[0].substring ( 1 );
                    }
                }
            },
            insertPosition : "#tmmSwatches"
        } );

        var JD = new SupportSite ( {
            name : "京东商城",

            checker : /(https?:\/\/)?(www|item)?\.jd\.com\/.*/,

            logo : "http://www.jd.com/favicon.ico",

            getISBN        : function () {
                var liContent = document.querySelector ( "#parameter2 > li:nth-child(2)" ).innerHTML;
                if(liContent.match(/^ISBN/) !== null) {
                    return liContent.split ( "：" )[1];
                }
                return null;
            },
            insertPosition : "#summary-price"
        } );

        var Dangdang = new SupportSite ( {

            name : "当当网",

            checker : /(https?:\/\/)?(www|product)?\.dangdang\.com\/.*/,

            logo : "http://www.dangdang.com/favicon.ico",

            getISBN        : function () {
                var scanItems = document.querySelectorAll ( "#detail_describe li" );
                for ( var i = 0 ; i < scanItems.length ; i++ ) {
                    var splitResult = scanItems[i].innerText.split('ISBN：');
                    if ( splitResult.length === 2 ) {
                        return splitResult[1];
                    }
                }
            },
            insertPosition : ".messbox_info"
        } );

        var Chinapub = new SupportSite ( {

            name : "China-pub",

            checker : /(https?:\/\/)?(product|www)\.china\-pub\.com\/.*/,

            logo : "http://www.china-pub.com/favicon.ico",

            getISBN        : function () {
                var list = document.querySelectorAll ( "#con_a_1 li" );
                for ( var i = 0 ; i < list.length ; i++ ) {
                    if ( list[i].innerHTML.split ( "：" )[0] === "ISBN" ) {
                        return list[i].innerHTML.split ( "：" )[1].replace ( /<.*?>/g, "" ).match ( /[0-9]*/g ).join ( "" );
                    }
                }
            },
            insertPosition : ".pro_buy_star"
        } );

        var Suning = new SupportSite ( {

            name : "苏宁易购",

            checker : /(https?:\/\/)?(product)\.suning\.com\/.*/,

            logo : "http://www.suning.com/favicon.ico",

            getISBN        : function () {
                var isbn = document.querySelector ( "#bookParameterField > dl:nth-child(4) > dd:nth-child(2)" );
                return isbn.innerHTML;
            },
            insertPosition : "#existPrice"
        } );
        //苏宁第三方(文轩等)
        var SuningThird = new SupportSite ( {

            name : "苏宁易购第三方",

            checker : /(https?:\/\/)?(www)?\.suning\.com\/emall\/.*/,

            logo : "http://www.suning.com/favicon.ico",

            getISBN        : function () {
                var isbn = document.querySelector ( "li.li-b:nth-child(11) > span:nth-child(2)" );
                return isbn.innerHTML;
            },
            insertPosition : "#productInfoUl"
        } );

        var WinXuan = new SupportSite ( {
            name           : "文轩网",
            checker        : /(https?:\/\/)?(www)\.winxuan\.com\/.*/,
            logo           : "http://www.winxuan.com/favicon.ico",
            insertPosition : "div.name:nth-child(1)",
            getISBN        : function () {
                var contents = document.querySelectorAll ( ".list-text-3>li" );
                //目前文轩网的ISBN位于列表的最后一项，考虑到以后的位置可能发生改变，所以从后往前遍历列表
                var i = contents.length ;
                for ( ; i-- ; ) {
                    var text = contents[i].textContent;
                    var textChecker = /^I S B N：/;
                    if ( text && textChecker.test(text) ) {
                        return text.split ( "：" )[1];
                    }
                }
            }
        } );
        var DuoKan = new SupportSite ( {

            name : "多看阅读",

            isEBook : true,

            checker : /(https?:\/\/)?(www)\.duokan\.com\/.*/,

            logo : "http://www.duokan.com/favicon.ico",

            getISBN        : function () {
                    var isbn = document.querySelector ( "span.isbn" );
                    return isbn.innerHTML;
            },
            insertPosition : "div[itemprop=aggregateRating]"
        } );

        var ituring = new SupportSite ( {
            name : "图灵社区",

            checker : /(http?:\/\/)?(www)?\.ituring\.com\.cn\/book\/.*/,

            logo : "http://www.ituring.com.cn/favicon.ico",

            getISBN        : function () {
                var tlContent = document.querySelectorAll ( "#info table td" );
                var patt = new RegExp(/^(\d+-){3,4}(?:\d+|X)$/);
                for ( var i = 0 ; i < tlContent.length ; i++ ) {
                    if ( patt.test(tlContent[i].textContent) ) {
                        return tlContent[i].innerHTML.replace(new RegExp(/(-)/g),'');
                    }
                }
                return null;
            },
            insertPosition : "#ckepop"
        } );

        //全局函数声明区

        function log (msg) {
            console.log ( "DoubanBookBar: " + msg );
        }

        //调用API设置比价栏的CSS属性
        function setBaseCss () {
            var baseCSS = [
                "#bookbar-container a {color:#228A31 !important;text-decoration:none;font-size: 13px;}",
                "#bookbar-container .bookbar-title {font-size: 14px;width:70px;}",
                "#bookbar-container span {margin-right: 5px;display: inline-block;font-size: 13px;font-weight: bold;}",
                "#bookbar-container ul {padding-left: 0;margin: 4px 0;}",
                "#bookbar-container li {list-style: none none outside; display: inline;padding: 0 4px;}",
                "#bookbar-container img{ height:16px; width:16px;}",
                "#avgScore {color:#DC0000 !important;}"
            ].join ( "" );
            GM_addStyle ( baseCSS );
        }

        // create* ----生成比价栏相关的函数
        //创建比价栏的调用控制函数在SupportSite对象的原型链中
        //星级信息
        function createStarSpan (score) {
            var starSpan = document.createElement ( "span" );
            starSpan.id = "bookbar-star";
            var bgPosition = "0 " + (-15) * (10 - Math.floor ( parseFloat ( score ) + 0.8 )) + "px";
            var starSpanCSS = [
                "#bookbar-star { ",
                "background :url(https://img3.doubanio.com/f/shire/680a4bc4c384199245b080c7104da5be8ed717d3/pics/rating_icons/ic_rating_m.png) no-repeat scroll " + bgPosition + " ; ",
                "width:75px; height: 15px; position: relative; top: 1px;}"
            ].join ( "" );
            GM_addStyle ( starSpanCSS );
            return starSpan;
        }

        //得分与评价信息
        function createScoreSpan (bookInfo) {
            var bookID       = bookInfo.id,
                bookRating   = bookInfo.rating || {},
                numRaters    = bookRating.numRaters,
                averageScore = bookRating.average;
            var scoreSpan    = document.createElement ( "span" ),
                infoUl       = document.createElement ( "ul" ),
                commentsLink = document.createElement ( "li" ),
                bookInfoLink = document.createElement ( "li" );
            if ( numRaters === 0 ) {
                commentsLink.innerHTML = "<span>没有人评价这本书</span>";
            } else if ( numRaters < 10 ) {
                commentsLink.innerHTML = "<span>少于10人评价这本书</span>";
            } else if ( numRaters >= 10 ) {
                commentsLink.innerHTML = '<a  href="http://book.douban.com/subject/' + bookID + '/collections" target="_blank">(共' + numRaters + '人评价)</a>';
            } else {
                //获取信息出现错误
                commentsLink.innerHTML = "";
            }
            if ( commentsLink.innerHTML !== "" ) {
                var avgLi    = document.createElement ( "li" ),
                    starLi   = document.createElement ( "li" ),
                    starSpan = createStarSpan ( averageScore );
                avgLi.innerHTML = '<span>' + averageScore + '</span>';
                avgLi.id = "avgScore";
                starLi.appendChild ( starSpan );
                infoUl.appendChild ( avgLi );
                bookInfoLink.innerHTML = '<a href="http://book.douban.com/subject/' + bookID + '/" target="_blank" >(去豆瓣看这本书)</a>';
                infoUl.appendChild ( starLi );
                infoUl.appendChild ( commentsLink );
            } else {
                bookInfoLink.innerHTML = '<a href="http://book.douban.com" target="_blank">没在豆瓣找到这本书,去豆瓣逛逛?</a>';
            }
            infoUl.appendChild ( bookInfoLink );
            scoreSpan.appendChild ( infoUl );
            return scoreSpan;
        }

        //由 createContrastPriceInfo 函数调用
        //生成每一个价格<li>标签
        function createPriceLi (iconLink, priceData, sitePrice) {
            var priceLi = document.createElement ( "li" ),
                link    = document.createElement ( "a" ),
                img     = document.createElement ( "img" );
            img.src = iconLink;
            link.href = priceData.href || "#";
            link.target = "_blank";
            if ( priceData.price === undefined ) {
                link.textContent = "[没找到]";
            } else {
                link.textContent = "￥" + priceData.price;
                if ( sitePrice !== -1 ) {
                    var difference = parseFloat ( priceData.price ) - parseFloat ( sitePrice );
                    var sgn = difference > 0 ? "+" : "";
                    link.textContent += "( " + sgn + difference.toFixed ( 2 ) + " )";
                }
            }
            priceLi.appendChild ( img );
            priceLi.appendChild ( link );
            return priceLi;
        }

        //价格(其他网站)信息
        function createContrastPriceInfo (priceList) {
            var contrastPriceInfo = document.createElement ( "span" ),
                infoContainer     = document.createElement ( "ul" );
            if ( priceList.length === 0 ) {
                contrastPriceInfo.innerHTML = "<span>豆瓣上没有购买信息</span>";
            } else {
                for ( var i = 0, len = priceList.length ; i < len ; i++ ) {
                    var matchIndex = sitesContainer.nameList.indexOf ( priceList[i].name );
                    var priceLi = createPriceLi ( sitesContainer.list[matchIndex].logo, priceList[i], priceList.curSitePrice );
                    infoContainer.appendChild ( priceLi );
                }
            }
            contrastPriceInfo.appendChild ( infoContainer );
            return contrastPriceInfo;
        }

        function createBar (infoRow, priceRow) {
            var bar = document.createElement ( "div" );
            bar.id = "bookbar-container";
            bar.appendChild ( infoRow );
            bar.appendChild ( priceRow );
            return bar;

        }

        function createPriceRowContainer () {
            var container = document.createElement ( "div" ),
                label     = document.createElement ( "span" );
            container.id = "bookbar-priceInfo";
            label.innerHTML = "比价:";
            label.className = "bookbar-title";
            container.appendChild ( label );
            return container;
        }

        function createInfoRowContainer () {
            var container = document.createElement ( "div" ),
                label     = document.createElement ( "span" );
            container.id = "bookbar-doubanInfo";
            label.className = "bookbar-title";
            label.innerHTML = "豆瓣评分:";
            container.appendChild ( label );
            return container;
        }

        function insertBar (bar, position) {
            var parent = position.parentNode;
            if ( parent.lastChild === position ) {
                parent.appendChild ( bar );
            }
            else {
                parent.insertBefore ( bar, position.nextSibling );
            }
        }

        // 获取书籍信息
        function getBookInfo (isbn) {
            if ( !isbn ) {
                return null;
            }
            GM_xmlhttpRequest ( {
                method  : "get",
                url     : "https://api.douban.com/v2/book/isbn/" + isbn,
                onload  : function (result) {
                    var bookInfo = JSON.parse ( result.responseText );
                    getBookPrice ( bookInfo );
                },
                onerror : function (result) {
                    log ( "-Error:获取书籍信息失败" );
                }
            } );
        }

        function getBookPrice (bookInfo) {
            var doubanID = bookInfo.id || null;
            var doubanLink = "http://book.douban.com/subject/" + doubanID + "/buylinks";
            var priceList = [];
            GM_xmlhttpRequest ( {
                method  : "get",
                url     : doubanLink,
                onload  : function (result) {
                    var container = document.createElement ( "div" );
                    container.innerHTML = result.responseText;
                    var list = document.evaluate ( '//table[@id="buylink-table"]/tbody/tr', container, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null );
                    var priceChecker = /[0-9]+(\.[0-9]+)?/;
                    var curSitePrice = -1;
                    for ( var i = 1, len = list.snapshotLength ; i < len ; i++ ) {
                        var part = list.snapshotItem ( i );
                        var link_info = part.querySelectorAll ( "td.pl2" );
                        var siteName = link_info[0].textContent.trim ();
                        if ( sitesContainer.nameList.indexOf ( siteName ) !== -1 ) {
                            if ( siteName === sitesContainer.curSite.name ) {
                                curSitePrice = priceChecker.exec ( link_info[1].textContent.trim () )[0];
                            } else {
                                var priceInfo = {
                                    "name"  : siteName,
                                    "href"  : link_info[0].getElementsByTagName ( "a" )[0].href,
                                    "price" : priceChecker.exec ( link_info[1].textContent.trim () )[0]
                                };
                                priceList.push ( priceInfo );
                            }
                            priceList.curSitePrice = curSitePrice; // 如果为-1，则说明没有获得当前网页的书本价格
                        }
                    }
                    sitesContainer.curSite.createDoubanBar ( bookInfo, priceList );
                },
                onerror : function (result) {
                    log ( "-Error:获取书籍价格失败" );
                }
            } );

        }

        function run () {
            sitesContainer.addSites ( [Amazon, JD, Dangdang, Chinapub, Suning, SuningThird, DuoKan, WinXuan, ituring] );
            sitesContainer.curSite = location.href;
            if ( !sitesContainer.curSite ) {
                log ( "-Error: 不支持当前的页面" );
                return;
            }
            var isbn = sitesContainer.curSite.getISBN ();
            if ( !isbn ) {
                log ( "-Error: 无法获取ISBN" );
                return;
            } else {
                log ( "-Success: 成功获取ISBN" );

                //异步调用的Ajax ,所以之后需要调用的函数都封装到ajax当中
                getBookInfo ( isbn );
            }
        }

        //代码执行区
        run ();
    }) ();
}