///import core
///commands 撤销和重做
///commandsName  Undo,Redo
///commandsTitle  撤销,重做
/**
* @description 回退
* @author zhanyi
*/

UE.plugins['undo'] = function() {
    var me = this,
        maxUndoCount = me.options.maxUndoCount || 20,
        maxInputCount = me.options.maxInputCount || 20,
        fillchar = new RegExp(domUtils.fillChar + '|<\/hr>','gi'),// ie会产生多余的</hr>
        //在比较时，需要过滤掉这些属性
        specialAttr = /\b(?:href|src|name)="[^"]*?"/gi;

    //场景的range实例
    function sceneRange(rng){
        var me = this;
        me.collapsed = rng.collapsed;
        me.startAddr = getAddr(rng.startContainer,rng.startOffset);
        me.endAddr = rng.collapsed ? me.startAddr : getAddr(rng.endContainer,rng.endOffset)

    }
    sceneRange.prototype ={
        compare : function(obj){
            var me = this;
            if(me.collapsed !== obj.collapsed){
                return 0;
            }
            if(!compareAddr(me.startAddr,obj.startAddr) || !compareAddr(me.endAddr,obj.endAddr)){
                return 0;
            }
            return 1;
        },
        transformRange : function(rng){
            var me = this;
            rng.collapsed = me.collapsed;
            setAddr(rng,'start',me.startAddr);
            rng.collapsed ? rng.collapse(true) : setAddr(rng,'end',me.endAddr)

        }
    };
    function getAddr(node,index){
        for(var i= 0,parentsIndex = [index],ci,
                parents = domUtils.findParents(node,true,function(node){return !domUtils.isBody(node)},true);
            ci=parents[i++];){
            //修正偏移位置
            if(i == 1 && ci.nodeType == 3){

                var tmpNode = ci;
                while(tmpNode = tmpNode.previousSibling){
                    if(tmpNode.nodeType == 3){
//                        console.log(index)
                        index += tmpNode.nodeValue.replace(fillCharReg,'').length;
                    }else{
                        break;
                    }
                }
                parentsIndex[0] = index;
            }

            parentsIndex.push(domUtils.getNodeIndex(ci,true));

        }

        return parentsIndex.reverse();

    }

    function compareAddr(indexA,indexB){
        if(indexA.length != indexB.length)
            return 0;
        for(var i= 0,l=indexA.length;i<l;i++){
            if(indexA[i]!=indexB[i])
                return 0
        }
        return 1;
    }
    function setAddr(range,boundary,addr){

        node = range.document.body;
        for(var i= 0,node,l = addr.length - 1;i<l;i++){
            node = node.childNodes[addr[i]];
        }
        range[boundary+'Container'] = node;
        range[boundary+'Offset'] =  addr[addr.length-1];
    }
    function UndoManager() {

        this.list = [];
        this.index = 0;
        this.hasUndo = false;
        this.hasRedo = false;
        this.undo = function() {

            if ( this.hasUndo ) {
                var currentScene = this.getScene(),
                    lastScene = this.list[this.index];
                if ( lastScene.content.replace(specialAttr,'') != currentScene.content.replace(specialAttr,'') ) {
                    this.save();
                }
                                    if(!this.list[this.index - 1] && this.list.length == 1){
                    this.reset();
                    return;
                }
                while ( this.list[this.index].content == this.list[this.index - 1].content ) {
                    this.index--;
                    if ( this.index == 0 ) {
                        return this.restore( 0 );
                    }
                }
                this.restore( --this.index );
            }
        };
        this.redo = function() {
            if ( this.hasRedo ) {
                while ( this.list[this.index].content == this.list[this.index + 1].content ) {
                    this.index++;
                    if ( this.index == this.list.length - 1 ) {
                        return this.restore( this.index );
                    }
                }
                this.restore( ++this.index );
            }
        };

        this.restore = function() {
            var scene = this.list[this.index];
            //trace:873
            //去掉展位符
            me.document.body.innerHTML = scene.bookcontent.replace(fillchar,'');
            //处理undo后空格不展位的问题
            if(browser.ie){
                for(var i=0,pi,ps = me.document.getElementsByTagName('p');pi = ps[i++];){
                    if(pi.innerHTML == ''){
                        domUtils.fillNode(me.document,pi);
                    }
                }
            }

            var range = new dom.Range( me.document );


            //有可能再save时没有bookmark
            try{
                if(browser.opera || browser.safari){
                    scene.senceRange.transformRange(range)
                }else{
                    range.moveToBookmark( {
                        start : '_baidu_bookmark_start_',
                        end : '_baidu_bookmark_end_',
                        id : true
                        //去掉true 是为了<b>|</b>，回退后还能在b里
                    } );
                }

                //trace:1278 ie9block元素为空，将出现光标定位的问题，必须填充内容
                if(browser.ie && browser.version == 9 && range.collapsed && domUtils.isBlockElm(range.startContainer) && domUtils.isEmptyNode(range.startContainer)){
                    domUtils.fillNode(range.document,range.startContainer);

                }
                range.select(!browser.gecko);
                if(!(browser.opera || browser.safari)){
                    setTimeout(function(){
                        range.scrollToView(me.autoHeightEnabled,me.autoHeightEnabled ? domUtils.getXY(me.iframe).y:0);
                    },200);
                }

            }catch(e){}

            this.update();
            //table的单独处理
            if(me.currentSelectedArr){
                me.currentSelectedArr = [];
                var tds = me.document.getElementsByTagName('td');
                for(var i=0,td;td=tds[i++];){
                    if(td.className == me.options.selectedTdClass){
                         me.currentSelectedArr.push(td);
                    }
                }
            }
            this.clearKey();
            //不能把自己reset了
            me.fireEvent('reset',true);
        };

        this.getScene = function() {
            var range = me.selection.getRange(),
                cont = me.body.innerHTML.replace(fillchar,'');
            //有可能边界落到了<table>|<tbody>这样的位置，所以缩一下位置
            range.shrinkBoundary();
            browser.ie && (cont = cont.replace(/>&nbsp;</g,'><').replace(/\s*</g,'').replace(/>\s*/g,'>'));

            if(browser.opera || browser.safari){
                return {
                    senceRange : new sceneRange(range),
                    content : cont,
                    bookcontent : cont
                }
            }else{
                var bookmark = range.createBookmark( true, true ),
                    bookCont = me.body.innerHTML.replace(fillchar,'');
                bookmark && range.moveToBookmark( bookmark ).select( true );
                return {
                    bookcontent : bookCont,
                    content : cont
                };
            }

        };
        this.save = function(notCompareRange) {

            var currentScene = this.getScene(),
                lastScene = this.list[this.index];
            //内容相同位置相同不存
            if ( lastScene && lastScene.content == currentScene.content &&
                (
                    notCompareRange ? 1 :
                    ( (browser.opera || browser.safari) ? lastScene.senceRange.compare(currentScene.senceRange) : lastScene.bookcontent == currentScene.bookcontent)
                )
            ) {
                return;
            }

            this.list = this.list.slice( 0, this.index + 1 );
            this.list.push( currentScene );
            //如果大于最大数量了，就把最前的剔除
            if ( this.list.length > maxUndoCount ) {
                this.list.shift();
            }
            this.index = this.list.length - 1;
            this.clearKey();
            //跟新undo/redo状态
            this.update();
        };
        this.update = function() {
            this.hasRedo = this.list[this.index + 1] ? true : false;
            this.hasUndo = this.list[this.index - 1] || this.list.length == 1 ? true : false;
        };
        this.reset = function() {
            this.list = [];
            this.index = 0;
            this.hasUndo = false;
            this.hasRedo = false;
            this.clearKey();
        };
        this.clearKey = function(){
            keycont = 0;
            lastKeyCode = null;
            me.fireEvent('contentchange');
        };
    }

    me.undoManger = new UndoManager();
    function saveScene() {
        this.undoManger.save();
    }

    me.addListener( 'beforeexeccommand', saveScene );
    me.addListener( 'afterexeccommand', saveScene );

    me.addListener('reset',function(type,exclude){
        if(!exclude){
            me.undoManger.reset();
        }
    });
    me.commands['redo'] = me.commands['undo'] = {
        execCommand : function( cmdName ) {
            me.undoManger[cmdName]();
        },
        queryCommandState : function( cmdName ) {
            return me.undoManger['has' + (cmdName.toLowerCase() == 'undo' ? 'Undo' : 'Redo')] ? 0 : -1;
        },
        notNeedUndo : 1
    };

    var keys = {
         //  /*Backspace*/ 8:1, /*Delete*/ 46:1,
            /*Shift*/ 16:1, /*Ctrl*/ 17:1, /*Alt*/ 18:1,
            37:1, 38:1, 39:1, 40:1,
            13:1 /*enter*/
        },
        keycont = 0,
        lastKeyCode;

    me.addListener( 'keydown', function( type, evt ) {
        var keyCode = evt.keyCode || evt.which;
        if ( !keys[keyCode] && !evt.ctrlKey && !evt.metaKey && !evt.shiftKey && !evt.altKey ) {
            if ( me.undoManger.list.length == 0 || ((keyCode == 8 ||keyCode == 46) && lastKeyCode != keyCode) ) {
                me.undoManger.save(true);
                lastKeyCode = keyCode;
                return;
            }
            //trace:856
            //修正第一次输入后，回退，再输入要到keycont>maxInputCount才能在回退的问题
            if(me.undoManger.list.length == 2 && me.undoManger.index == 0 && keycont == 0){
                me.undoManger.list.splice(1,1);
                me.undoManger.update();
            }
            lastKeyCode = keyCode;
            keycont++;
            if ( keycont >= maxInputCount ) {
                if(me.selection.getRange().collapsed)
                    me.undoManger.save();
            }
        }
    } );
};
