/*!
 * headIndex.js - 文章目录生成插件
 * 为 Argon 主题提供文章目录功能
 * 
 * 注意：此文件仅用于后台设置页面预览
 * 前端页面使用的是 argon_js_merged.js 中的压缩版本
 */
;(function($, window) {
    var headIndex = (function() {
        function headIndex(element, options) {
            this.settings = $.extend(true, $.fn.headIndex.default, options || {});
            this.element = element;
            this.init();
        }
        
        headIndex.prototype = {
            init: function() {
                this.articleWrap = $(this.settings.articleWrapSelector);
                this.headerList = this.articleWrap.find(':header');
                this.indexBox = $(this.settings.indexBoxSelector);
                this.indexScrollBox = $(this.settings.indexScrollBoxSelector);
                this.scrollBody = $(this.settings.scrollSelector);
                this.scrollWrap = $(this.settings.scrollWrap);
                this.manual = false;
                this.mouseHovered = false;
                
                if (this.indexBox.length === 0 || this.headerList.length === 0) {
                    return null;
                }
                
                this.initHeader();
                this.event();
            },
            
            initHeader: function() {
                for (var i = 0; i < this.headerList.length; i++, this.autoId++) {
                    this.headerList[i].id = this.headerList[i].id || "header-id-" + this.autoId;
                    this.headerList[i].topHeight = this.offsetTop(this.headerList[i]);
                    this.headerList[i].h = Number(this.headerList[i].tagName.charAt(1));
                }
                
                this.tempHtml = [];
                this.buildHtml(this.buildTree());
                var res = '<ul>' + this.tempHtml.join('') + '</ul>';
                this.indexBox.html(res);
            },
            
            event: function() {
                var that = this;
                var manualValTimer = null;
                
                this.indexBox.on('click.headindex', function(event) {
                    var target = $(event.target);
                    if (target.hasClass(that.settings.linkClass)) {
                        event.preventDefault();
                        var indexItem = target.parent('.' + that.settings.itemClass);
                        that.manual = true;
                        if (manualValTimer) {
                            clearTimeout(manualValTimer);
                            manualValTimer = null;
                        }
                        manualValTimer = setTimeout(function() {
                            that.manual = false;
                        }, 400);
                        that.current(indexItem);
                        that.scrollTo(event.target.getAttribute('href'));
                    }
                });
                
                this.indexScrollBox.on('mouseover', function(event) {
                    that.mouseHovered = true;
                });
                
                this.indexScrollBox.on('mouseleave', function(event) {
                    that.mouseHovered = false;
                });
                
                $(this.scrollWrap).scroll(function() {
                    if (that.manual) return;
                    that.updateCurrent();
                });
                
                that.updateCurrent();
            },
            
            updateTopHeight: function() {
                var length = this.headerList.length;
                var i;
                if (length === 0) return;
                
                if (this.headerList[0].topHeight === this.offsetTop(this.headerList[0]) && 
                    this.headerList[length - 1].topHeight === this.offsetTop(this.headerList[length - 1])) {
                    return;
                }
                
                if ((this.headerList[0].topHeight - this.offsetTop(this.headerList[0])) === 
                    (this.headerList[length - 1].topHeight - this.offsetTop(this.headerList[length - 1]))) {
                    var hx = this.offsetTop(this.headerList[0]) - this.headerList[0].topHeight;
                    for (i = 0; i < this.headerList.length; i++, this.autoId++) {
                        this.headerList[i].topHeight += hx;
                    }
                    return;
                }
                
                for (i = 0; i < this.headerList.length; i++, this.autoId++) {
                    this.headerList[i].topHeight = this.offsetTop(this.headerList[i]);
                }
            },
            
            current: function(indexItem) {
                var subBox, currentClass = 'current';
                if (indexItem.length === 0 || indexItem.hasClass(currentClass)) {
                    return;
                }
                
                var otherCurrent = this.indexBox.find('li.' + currentClass);
                if (otherCurrent.length > 0) {
                    otherCurrent.removeClass(currentClass);
                }
                
                // 如果设置了默认展开，则不折叠其他项
                if (!this.settings.defaultExpanded) {
                    this.indexBox.find('ul.open').removeClass('open');
                }
                
                subBox = indexItem.children('.' + this.settings.subItemBoxClass);
                if (subBox.length > 0) {
                    subBox.addClass('open').slideDown();
                }
                
                var parentsBox = indexItem.parents('ul.' + this.settings.subItemBoxClass);
                if (parentsBox.length > 0) {
                    parentsBox.addClass('open').slideDown();
                }
                
                // 如果设置了默认展开，则不折叠其他子项
                if (!this.settings.defaultExpanded) {
                    subBox = this.indexBox.find('ul.' + this.settings.subItemBoxClass).not('.open');
                    if (subBox.length > 0) {
                        subBox.slideUp();
                    }
                }
                
                indexItem.addClass(currentClass);
                
                // 自动滚动目录容器，让当前项保持在可视区域
                
                if (this.mouseHovered) {
                    return;
                }
                
                var relativeOffsetTopToWrapper = indexItem.position().top;
                var indexScrollBoxScrollTop = this.indexScrollBox.scrollTop();
                var indexScrollBoxHeight = this.indexScrollBox.height();
                
                if (relativeOffsetTopToWrapper < 20 + indexItem.height()) {
                    var target = indexScrollBoxScrollTop + relativeOffsetTopToWrapper - 20 - indexItem.height();
                    if (target < 30) {
                        target = 0;
                    }
                    this.indexScrollBox.stop().animate({scrollTop: target}, 'normal', 'easeOutExpo');
                }
                
                if (relativeOffsetTopToWrapper > indexScrollBoxHeight - 10) {
                    this.indexScrollBox.stop().animate({
                        scrollTop: indexScrollBoxScrollTop + relativeOffsetTopToWrapper - indexScrollBoxHeight + 10 + indexItem.height()
                    }, 'normal', 'easeOutExpo');
                }
            },
            
            buildHtml: function(tree) {
                if (tree === undefined || tree.length === 0) return;
                
                for (var i = 0; i < tree.length; i++) {
                    this.tempHtml.push("<li class='" + this.settings.itemClass + "'><a no-pjax class='" + this.settings.linkClass + "' href='#" + tree[i].item.id + "'>" + tree[i].item.innerText + "</a>");
                    if (tree[i].children.length !== 0) {
                        this.tempHtml.push("<ul class='" + this.settings.subItemBoxClass + "'>");
                        this.buildHtml(tree[i].children);
                        this.tempHtml.push("</ul>");
                    }
                    this.tempHtml.push("</li>");
                }
            },
            
            buildTree: function() {
                var current = null, tempCur, indexTree = [];
                
                for (var i = 0; i < this.headerList.length; i++) {
                    if (current == null) {
                        current = {
                            item: this.headerList[i],
                            parent: null,
                            children: []
                        };
                        indexTree.push(current);
                        continue;
                    }
                    
                    if (current.item.h < this.headerList[i].h) {
                        tempCur = {
                            item: this.headerList[i],
                            parent: current,
                            children: []
                        };
                        current.children.push(tempCur);
                        current = tempCur;
                        continue;
                    }
                    
                    if (current.item.h === this.headerList[i].h) {
                        tempCur = {
                            item: this.headerList[i],
                            parent: current.parent,
                            children: []
                        };
                        ((current.parent && current.parent.children) || indexTree).push(tempCur);
                        current = tempCur;
                        continue;
                    }
                    
                    while (current != null && current.item.h > this.headerList[i].h) {
                        current = current.parent;
                    }
                    
                    if (current == null) {
                        current = {
                            item: this.headerList[i],
                            parent: null,
                            children: []
                        };
                        indexTree.push(current);
                        continue;
                    }
                    i--;
                }
                
                return indexTree;
            },
            
            search: function(start, end, findValue) {
                if (this.headerList.length === 0) return null;
                
                if (end - start <= 1) {
                    if (this.headerList[end].topHeight < findValue) {
                        return this.headerList[end];
                    }
                    return this.headerList[start];
                }
                
                if (start < end) {
                    var middleIndex = parseInt((start + end) / 2);
                    var middleValue = this.headerList[middleIndex].topHeight;
                    
                    if (findValue < middleValue) {
                        end = middleIndex;
                    } else if (findValue > middleValue) {
                        start = middleIndex;
                    } else {
                        return this.headerList[middleIndex];
                    }
                    return this.search(start, end, findValue);
                }
            },
            
            offsetTop: function(elem) {
                return $(elem).offset().top - this.settings.offset;
            },
            
            scrollTo: function(eid) {
                this.scrollBody.stop().animate({
                    scrollTop: this.offsetTop(document.getElementById(eid.substr(1))) + 8
                }, 'normal', 'easeOutExpo');
            },
            
            updateCurrent: function() {
                var scrollTop = this.scrollBody.scrollTop();
                this.updateTopHeight();
                var find = this.search(0, this.headerList.length - 1, scrollTop);
                if (!find) {
                    return;
                }
                var indexItem = this.indexBox.find('a[href="#' + find.id + '"]').parent('li.' + this.settings.itemClass);
                this.current(indexItem);
            },
            
            clean: function() {
                if (this.element) {
                    this.element.data("headIndex", null);
                }
            },
            
            ignoreScrollEvent: function(ignore) {
                if (ignore) {
                    this.manual = true;
                } else {
                    this.manual = false;
                    this.updateCurrent();
                }
            }
        };
        
        headIndex.prototype.autoId = 1;
        
        return headIndex;
    })();
    
    $.fn.headIndex = function(options) {
        return this.each(function() {
            var $this = $(this),
                instance = $this.data("headIndex");
            instance = new headIndex($this, options);
            $this.data("headIndex", instance);
            if ($.type(options) === "string") return instance[options]();
        });
    };
    
    $.fn.headIndex.default = {
        articleWrapSelector: ".article-wrap",
        indexBoxSelector: ".index-box",
        indexScrollBoxSelector: "#leftbar_part2_inner",
        scrollSelector: 'body,html',
        scrollWrap: window,
        subItemBoxClass: "index-subItem-box",
        itemClass: "index-item",
        linkClass: "index-link",
        offset: 0,
        defaultExpanded: false
    };
    
})(jQuery, window);