/**
 * Object that is used to undo actions when the property editor is used
 * @this {ShapeChangePropertyCommand} 
 * @constructor
 * @param figureId {Numeric} -  the id of the object
 * @param property {String} - property name that is being edited on the figure
 * @param newValue {Object} - the value to set the property to
 * @param [previousValue] {Object} - the previous value of property
 * @author Alex, Artyom
 */
function ShapeChangePropertyCommand(figureId, property, newValue, previousValue){
    this.figureId = figureId;
    this.property = property;    
    this.newValue = newValue;
    this.previousValue = typeof(previousValue) !== 'undefined' ? previousValue : this._getValue(figureId, property);
    this.firstExecute = true;

    // check if property corresponds to a Text primitive
    // isTextPrimitiveProperty property used for calling TextEditorPopup callback on property change
    this.textPrimitiveId = this._getTextPrimitiveId();
    this.isTextPrimitiveProperty = this.textPrimitiveId !== -1;
    
    this.oType = "ShapeChangePropertyCommand";
}

ShapeChangePropertyCommand.prototype = {
    
    /**This method got called every time the Command must execute*/
    execute : function(){
        if (this.firstExecute) {
            this._setValue(this.figureId, this.property, this.newValue);
            this.firstExecute = false; 
            //setUpEditPanel(STACK.figureGetById(this.figureId));

            // if property change of Text primitive executed
            // then state must be equal to text editing
            // and we call it's setProperty method to provide WYSIWYG functionality
            if (this.isTextPrimitiveProperty) {
                if (state == STATE_TEXT_EDITING) {
                    currentTextEditor.setProperty(this.property, this.newValue);
//                } else {
//                    throw "ShapeChangePropertyCommand:execute() - this should never happen";
                }
            }
        }
        else{
            throw "Redo not implemented.";
        }
    },
    
    
    /**This method should be called every time the Command should be undone*/
    undo : function(){
        this._setValue(this.figureId, this.property, this.previousValue);
        
        var shape = this.__getShape(this.figureId);
        
        setUpEditPanel(shape);

        // if property of Text primitive is changing back
        // then we need to set this change on TextEditorPopup
        // to provide WYSIWYG functionality
        if (this.isTextPrimitiveProperty) {

            // if we already in text editing state
            if (state == STATE_TEXT_EDITING) {
                // if currentTextEditor refers to another shape/primitive
                // then we destroy current and create new TextEditorPopup
                if (!currentTextEditor.refersTo(shape, this.textPrimitiveId)) {
                    currentTextEditor.destroy();
                    setUpTextEditorPopup(shape, this.textPrimitiveId);
                    // and we call setProperty of currentTextEditor method to provide WYSIWYG functionality
                    currentTextEditor.setProperty(this.property, this.previousValue);
                }
            }
        }
    },
    
    
    /**As 
     *@param id {Numeric} the id of the shape (Figure, Connector, Container)
     **/
    __getShape : function(id){
        var shape = STACK.figureGetById(id);
        if(shape == null){
            shape = CONNECTOR_MANAGER.connectorGetById(id);
        }
        
        if(shape == null){
            shape = STACK.containerGetById(id);
        }
        
        return shape;
    },
    
    
    /**Get */
    _getValue : function(figureId, property){
        //gel old value
        var shape = this.__getShape(this.figureId);

        var propertyObject = shape;
        var propertyAccessors = property.split(".");
        for(var i = 0; i<propertyAccessors.length-1; i++){
            propertyObject = propertyObject[propertyAccessors[i]];
        }

        if(propertyObject[propertyAccessors[propertyAccessors.length -1]] === undefined){
            /*if something is complicated enough to need a function, 
             *likelyhood is it will need access to its parent figure*/
            return propertyObject["get"+propertyAccessors[propertyAccessors.length -1]];
        }
        else{
            return propertyObject[propertyAccessors[propertyAccessors.length -1]];
        }  
    },
    
    /**Set */
    _setValue : function(figureId, property, value){
        //gel old value
        var shape = this.__getShape(this.figureId);

        var propertyObject = shape;
        var propertyAccessors = property.split(".");
        for(var i = 0; i<propertyAccessors.length-1; i++){
            propertyObject = propertyObject[propertyAccessors[i]];
        }

        if(propertyObject[propertyAccessors[propertyAccessors.length -1]] === undefined){
            /*if something is complicated enough to need a function, 
             *likelyhood is it will need access to its parent figure*/
            propertyObject["set"+propertyAccessors[propertyAccessors.length -1]](value);
        }
        else{
            propertyObject[propertyAccessors[propertyAccessors.length -1]] = value;                
        }  
    },

    /**
     * Checks if property applied to Text primitive
     * @return -1 if property didn't apply to Text primitive or id of the corresponding Text primitive otherwise
    **/
    _getTextPrimitiveId : function() {
        var textPrimitiveId = -1;

        // check by RegExp - is property applying to a Text primitive
        // typical examples: "primitives.3.size", "primitives.1.str", "primitives.5.font" and "middleText.str" for a Connector
        if (/(primitives\.\d+|middleText)\.(str|size|font|align|underlined|style\.fillStyle)/g.test(this.property)) {
            // according to RegExp this (between first and second dots) part is a number
            var id = this.property.split('.')[1];

            textPrimitiveId = parseInt(id, 10);
        }
        return textPrimitiveId;
    }
}