(function($, window, document, undefined) {
    var $window = $(window);
    var webp = false;

    function check_webp_feature(feature, callback) {
        var kTestImages = {
            lossy: "UklGRiIAAABXRUJQVlA4IBYAAAAwAQCdASoBAAEADsD+JaQAA3AAAAAA",
            lossless: "UklGRhoAAABXRUJQVlA4TA0AAAAvAAAAEAcQERGIiP4HAA==",
            alpha: "UklGRkoAAABXRUJQVlA4WAoAAAAQAAAAAAAAAAAAQUxQSAwAAAARBxAR/Q9ERP8DAABWUDggGAAAABQBAJ0BKgEAAQAAAP4AAA3AAP7mtQAAAA==",
            animation: "UklGRlIAAABXRUJQVlA4WAoAAAASAAAAAAAAAAAAQU5JTQYAAAD/////AABBTk1GJgAAAAAAAAAAAAAAAAAAAGQAAABWUDhMDQAAAC8AAAAQBxAREYiI/gcA"
        };
        var img = new Image();
        img.onload = function () {
            var result = (img.width > 0) && (img.height > 0);
            callback(feature, result);
        };
        img.onerror = function () {
            callback(feature, false);
        };
        img.src = "data:image/webp;base64," + kTestImages[feature];
    }

    setTimeout(function(){
        check_webp_feature('lossy', function(feature, result) {
            webp = result;
        });
    }, 50);

    function img_url_format(imgUrl, opts) {
        if (!imgUrl) {
            return imgUrl;
        }
        var splits = imgUrl.split('?');
        var url = splits[0];
        var query = splits[1] || '';

        if (query.indexOf('imageView2') === 0) {
            if (query.indexOf('/q/') < 0 && !!opts.q) {
                query += '/q/' + opts.q;
            }
            if (query.indexOf('/format/') < 0 && !!opts.format) {
                query += '/format/' + opts.format;
            }
            return imgUrl + '?' + query;
        } else if (query.indexOf('imageMogr2') === 0) {
            if (query.indexOf('/quality/') < 0 && !!opts.q) {
                query += '/quality/' + opts.q;
            }
            if (query.indexOf('/format/') < 0 && !!opts.format) {
                query += '/format/' + opts.format;
            }
            return imgUrl + '?' + query;
        } else if (query === '') {
            var imageUrl = 'imageView2/2/interlace/1/q/' + opts.q;

            if (opts.format) {
                imageUrl += '/format/' + opts.format;
            }
            return url + '?' +imageUrl;
        } else {
            return imgUrl;
        }
    }

    $.fn.lazyload = function(options) {
        var elements = this;
        var $container;
        var settings = {
            threshold       : 0,
            failure_limit   : 0,
            event           : "scroll",
            effect          : "show",
            container       : window,
            data_attribute  : "original",
            skip_invisible  : true,
            appear          : null,
            load            : null,
            yasPath: '/web/',
            yasImgDomain: 'http://analytics.yhurl.com/yas.gif',
            placeholder     : "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC",
            try_again_css: null 
 
        };

        function update() {
            var counter = 0;

            elements.each(function() {
                var $this = $(this);
                if (settings.skip_invisible && !$this.is(":visible")) {
                    return;
                }
                if ($.abovethetop(this, settings) ||
                    $.leftofbegin(this, settings)) {
                        /* Nothing. */
                } else if (!$.belowthefold(this, settings) &&
                    !$.rightoffold(this, settings)) {
                        $this.trigger("appear");
                        /* if we found an image we'll load, reset the counter */
                        counter = 0;
                } else {
                    if (++counter > settings.failure_limit) {
                        return false;
                    }
                }
            });

        };

        //add by jp, 发送图片方式跨域发送消息
        function crossSend(param, callback) {
            var image = new Image(1, 1);
            image.src = settings.yasImgDomain + settings.yasPath + '?' + param;
            image.onload = function() {
                image.onload = null;
                if (callback) {
                    callback();
                }
            };
        };
        
        if(options) {
            /* Maintain BC for a couple of versions. */
            if (undefined !== options.failurelimit) {
                options.failure_limit = options.failurelimit;
                delete options.failurelimit;
            }
            if (undefined !== options.effectspeed) {
                options.effect_speed = options.effectspeed;
                delete options.effectspeed;
            }

            $.extend(settings, options);
        }

        /* Cache container as jQuery as object. */
        $container = (settings.container === undefined ||
                      settings.container === window) ? $window : $(settings.container);

        /* Fire one scroll event per scroll. Not one scroll event per image. */
        if (0 === settings.event.indexOf("scroll")) {
            $container.bind(settings.event, function() {
                return update();
            });
        }

        this.each(function() {
            var self = this;
            var $self = $(self);
            var original = $self.attr("data-" + settings.data_attribute);

            original = img_url_format(original, {q: 75, format: (webp ? 'webp': '')});
            setTimeout(function(){
                var preImg = new Image();
                preImg.src = original;
            }, 100);

            self.loaded = false;

            /* If no src attribute given use data:uri. */
            if ($self.attr("src") === undefined || $self.attr("src") === false || $self.attr("src") === '') {
                if ($self.is("img")) {
                    $self.attr("src", settings.placeholder);
                }
            }

            /* When appear is triggered load original image. */
            $self.one("appear", function() {
                
                //add by jp
                if($self.timerid) clearTimeout($self.timerid);
                //console.log("img appear, this.loaded:" + this.loaded + ", id:" + $self.attr("id"));
                
                if (!this.loaded) {
                    if (settings.appear) {
                        var elements_left = elements.length;
                        settings.appear.call(self, elements_left, settings);
                    }
                    $("<img />")
                        //add by jp
                        .bind("error abort", function(){
                                $self.attr("src",settings.placeholder);
                                loadfail({info:'error'});
                        })                  
                        .bind("load", function() {

                            //add by jp, 加载超时后，不再进行加载，通过传统方式设置src，边下载边渲染
                            if($self.loadtimeout){
                                return;
                            }
                        
                            //add by jp, 清理检测图片下载超时定时器
                            clearTimeout($self.timerid);
                            
                            //add by jp, 上报图片加载成功事件
                            if( $self.attr("pfmrpt") ){
                                //crossImgSend('success');
                            }
                            
                            $self.hide();
                            if ($self.is("img")) {
                                $self.attr("src", original);
                            } else {
                                $self.css("background-image", "url('" + original + "')");
                            }
                            $self[settings.effect](settings.effect_speed);

                            self.loaded = true;

                            /* Remove image from array so it is not looped next time. */
                            var temp = $.grep(elements, function(element) {
                                return !element.loaded;
                            });
                            elements = $(temp);

                            if (settings.load) {
                                var elements_left = elements.length;
                                settings.load.call(self, elements_left, settings);
                            }
                        })
                        .attr("src", $self.attr("data-" + settings.data_attribute));
                        
                        //add by jp , 临时保存图片url
                        $self.src = $self.attr("data-" + settings.data_attribute);
                        
                        //add by jp , 上报图片开始加载事件
                        if( $self.attr("pfmrpt") && _yas && _yas.add){
                            //crossImgSend(,'start');
                        }
                        
                        //add by jp, 图片加载失败或超时的处理
                        var loadtimeout = function(options){
                      
                            //记录标识图片加载超时
                            $self.loadtimeout = true;
                            
                            //上报图片加载超时事件
                            if( $self.attr("pfmrpt") && _yas && _yas.add){
                                options.info ; //error or timeout
                                //crossImgSend(settings.yasImgDomain,settings.yasPath,'fail');
                            }
                        
                            //清除图片src取值，便于图片边下载边渲染
                            $self.attr("src","");
            
                            setTimeout(function(){
                                $self.attr("src",$self.src);
                            },50);
        
                        };
                      
                      //add by jp, 图片加载失败或超时的处理
                      var loadfail = function(options){
                      
                      //记录标识图片加载超时
                      $self.loadtimeout = true;
                      
                      //上报图片加载失败事件
                      if( $self.attr("pfmrpt") && _yas && _yas.add){
                          options.info ; //error or timeout
                      //crossImgSend(settings.yasImgDomain,settings.yasPath,'fail');
                      }
                      
                      var width = $self.width();
                      var height = $self.height();
                      
                      var $tryagain = $("<div class="+settings.try_again_css+" style='background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC) ;text-align: center;position:relative;width:"+width+"px;height:"+height+"px; line-height:"+height+"px'>图片打开失败,点击重新加载</div>");
                     // $tryagain.css("background-image",settings.placeholder);
                      $self.replaceWith($tryagain);
                      $tryagain.bind("click", function(e){
                            e.preventDefault();
                            $tryagain.replaceWith($self);
                            //清除图片src取值，便于图片边下载边渲染
                            $self.attr("src","");
                            setTimeout(function(){
                                       $self.attr("src",$self.src);
                                       },50);
                            });
                      };
                      
                      
                        //图片下载超时检测
                        $self.timerid = setTimeout(loadtimeout,5000);
                        
                        
                }
            });

            /* When wanted event is triggered load original image */
            /* by triggering appear.                              */
            if (0 !== settings.event.indexOf("scroll")) {
                $self.bind(settings.event, function() {
                    if (!self.loaded) {
                        $self.trigger("appear");
                    }
                });
            }
        });

        /* Check if something appears when window is resized. */
        $window.bind("resize", function() {
            update();
        });

        /* With IOS5 force loading images when navigating with back button. */
        /* Non optimal workaround. */
        if ((/(?:iphone|ipod|ipad).*os 5/gi).test(navigator.appVersion)) {
            $window.bind("pageshow", function(event) {
                if (event.originalEvent && event.originalEvent.persisted) {
                    elements.each(function() {
                        $(this).trigger("appear");
                    });
                }
            });
        }

        /* Force initial check if images should appear. */
        $(document).ready(function() {
            update();
        });

        return this;
    };


    
    /* Convenience methods in jQuery namespace.           */
    /* Use as  $.belowthefold(element, {threshold : 100, container : window}) */

    $.belowthefold = function(element, settings) {
        var fold;

        if (settings.container === undefined || settings.container === window) {
            fold = (window.innerHeight ? window.innerHeight : $window.height()) + $window.scrollTop();
        } else {
            fold = $(settings.container).offset().top + $(settings.container).height();
        }

        return fold <= $(element).offset().top - settings.threshold;
    };

    $.rightoffold = function(element, settings) {
        var fold;

        if (settings.container === undefined || settings.container === window) {
            fold = $window.width() + $window.scrollLeft();
        } else {
            fold = $(settings.container).offset().left + $(settings.container).width();
        }

        return fold <= $(element).offset().left - settings.threshold;
    };

    $.abovethetop = function(element, settings) {
        var fold;

        if (settings.container === undefined || settings.container === window) {
            fold = $window.scrollTop();
        } else {
            fold = $(settings.container).offset().top;
        }

        return fold >= $(element).offset().top + settings.threshold  + $(element).height();
    };

    $.leftofbegin = function(element, settings) {
        var fold;

        if (settings.container === undefined || settings.container === window) {
            fold = $window.scrollLeft();
        } else {
            fold = $(settings.container).offset().left;
        }

        return fold >= $(element).offset().left + settings.threshold + $(element).width();
    };

    $.inviewport = function(element, settings) {
         return !$.rightoffold(element, settings) && !$.leftofbegin(element, settings) &&
                !$.belowthefold(element, settings) && !$.abovethetop(element, settings);
     };

})($, window, document);