(function() {
    'use strict';
    // constants
    var ATTR_CHANGE_LIST = ['fontFamily', 'fontSize', 'fontStyle', 'padding', 'lineHeight', 'text'],
        CHANGE_KONVA = 'Change.konva',
        NONE = 'none',
        UP = 'up',
        RIGHT = 'right',
        DOWN = 'down',
        LEFT = 'left',
        LABEL = 'Label',

     // cached variables
     attrChangeListLen = ATTR_CHANGE_LIST.length;

    /**
     * Label constructor.  Labels are groups that contain a Text and Tag shape
     * @constructor
     * @memberof Konva
     * @param {Object} config
     * @@nodeParams
     * @example
     * // create label
     * var label = new Konva.Label({
     *   x: 100,
     *   y: 100,
     *   draggable: true
     * });
     *
     * // add a tag to the label
     * label.add(new Konva.Tag({
     *   fill: '#bbb',
     *   stroke: '#333',
     *   shadowColor: 'black',
     *   shadowBlur: 10,
     *   shadowOffset: [10, 10],
     *   shadowOpacity: 0.2,
     *   lineJoin: 'round',
     *   pointerDirection: 'up',
     *   pointerWidth: 20,
     *   pointerHeight: 20,
     *   cornerRadius: 5
     * }));
     *
     * // add text to the label
     * label.add(new Konva.Text({
     *   text: 'Hello World!',
     *   fontSize: 50,
     *   lineHeight: 1.2,
     *   padding: 10,
     *   fill: 'green'
     *  }));
     */
    Konva.Label = function(config) {
        this.____init(config);
    };

    Konva.Label.prototype = {
        ____init: function(config) {
            var that = this;

            Konva.Group.call(this, config);
            this.className = LABEL;

            this.on('add.konva', function(evt) {
                that._addListeners(evt.child);
                that._sync();
            });
        },
        /**
         * get Text shape for the label.  You need to access the Text shape in order to update
         * the text properties
         * @name getText
         * @method
         * @memberof Konva.Label.prototype
         */
        getText: function() {
            return this.find('Text')[0];
        },
        /**
         * get Tag shape for the label.  You need to access the Tag shape in order to update
         * the pointer properties and the corner radius
         * @name getTag
         * @method
         * @memberof Konva.Label.prototype
         */
        getTag: function() {
            return this.find('Tag')[0];
        },
        _addListeners: function(text) {
            var that = this,
                n;
            var func = function(){
                    that._sync();
                };

            // update text data for certain attr changes
            for(n = 0; n < attrChangeListLen; n++) {
                text.on(ATTR_CHANGE_LIST[n] + CHANGE_KONVA, func);
            }
        },
        getWidth: function() {
            return this.getText().getWidth();
        },
        getHeight: function() {
            return this.getText().getHeight();
        },
        _sync: function() {
            var text = this.getText(),
                tag = this.getTag(),
                width, height, pointerDirection, pointerWidth, x, y, pointerHeight;

            if (text && tag) {
                width = text.getWidth();
                height = text.getHeight();
                pointerDirection = tag.getPointerDirection();
                pointerWidth = tag.getPointerWidth();
                pointerHeight = tag.getPointerHeight();
                x = 0;
                y = 0;

                switch(pointerDirection) {
                    case UP:
                        x = width / 2;
                        y = -1 * pointerHeight;
                        break;
                    case RIGHT:
                        x = width + pointerWidth;
                        y = height / 2;
                        break;
                    case DOWN:
                        x = width / 2;
                        y = height + pointerHeight;
                        break;
                    case LEFT:
                        x = -1 * pointerWidth;
                        y = height / 2;
                        break;
                }

                tag.setAttrs({
                    x: -1 * x,
                    y: -1 * y,
                    width: width,
                    height: height
                });

                text.setAttrs({
                    x: -1 * x,
                    y: -1 * y
                });
            }
        }
    };

    Konva.Util.extend(Konva.Label, Konva.Group);

    Konva.Collection.mapMethods(Konva.Label);

    /**
     * Tag constructor.&nbsp; A Tag can be configured
     *  to have a pointer element that points up, right, down, or left
     * @constructor
     * @memberof Konva
     * @param {Object} config
     * @param {String} [config.pointerDirection] can be up, right, down, left, or none; the default
     *  is none.  When a pointer is present, the positioning of the label is relative to the tip of the pointer.
     * @param {Number} [config.pointerWidth]
     * @param {Number} [config.pointerHeight]
     * @param {Number} [config.cornerRadius]
     */
    Konva.Tag = function(config) {
        this.___init(config);
    };

    Konva.Tag.prototype = {
        ___init: function(config) {
            Konva.Shape.call(this, config);
            this.className = 'Tag';
            this.sceneFunc(this._sceneFunc);
        },
        _sceneFunc: function(context) {
            var width = this.getWidth(),
                height = this.getHeight(),
                pointerDirection = this.getPointerDirection(),
                pointerWidth = this.getPointerWidth(),
                pointerHeight = this.getPointerHeight(),
                cornerRadius = Math.min(this.getCornerRadius(), width / 2, height / 2);

            context.beginPath();
            if (!cornerRadius) {
                context.moveTo(0, 0);
            } else {
                context.moveTo(cornerRadius, 0);
            }

            if (pointerDirection === UP) {
                context.lineTo((width - pointerWidth) / 2, 0);
                context.lineTo(width / 2, -1 * pointerHeight);
                context.lineTo((width + pointerWidth) / 2, 0);
            }

            if(!cornerRadius) {
                context.lineTo(width, 0);
            } else {
                context.lineTo(width - cornerRadius, 0);
                context.arc(width - cornerRadius, cornerRadius, cornerRadius, Math.PI * 3 / 2, 0, false);
            }

            if (pointerDirection === RIGHT) {
                context.lineTo(width, (height - pointerHeight) / 2);
                context.lineTo(width + pointerWidth, height / 2);
                context.lineTo(width, (height + pointerHeight) / 2);
            }

            if(!cornerRadius) {
                context.lineTo(width, height);
            } else {
                context.lineTo(width, height - cornerRadius);
                context.arc(width - cornerRadius, height - cornerRadius, cornerRadius, 0, Math.PI / 2, false);
            }

            if (pointerDirection === DOWN) {
                context.lineTo((width + pointerWidth) / 2, height);
                context.lineTo(width / 2, height + pointerHeight);
                context.lineTo((width - pointerWidth) / 2, height);
            }

            if(!cornerRadius) {
                context.lineTo(0, height);
            } else {
                context.lineTo(cornerRadius, height);
                context.arc(cornerRadius, height - cornerRadius, cornerRadius, Math.PI / 2, Math.PI, false);
            }

            if (pointerDirection === LEFT) {
                context.lineTo(0, (height + pointerHeight) / 2);
                context.lineTo(-1 * pointerWidth, height / 2);
                context.lineTo(0, (height - pointerHeight) / 2);
            }

            if(cornerRadius) {
                context.lineTo(0, cornerRadius);
                context.arc(cornerRadius, cornerRadius, cornerRadius, Math.PI, Math.PI * 3 / 2, false);
            }

            context.closePath();
            context.fillStrokeShape(this);
        },
        getSelfRect: function() {
            var x = 0,
                y = 0,
                pointerWidth = this.getPointerWidth(),
                pointerHeight = this.getPointerHeight(),
                direction = this.pointerDirection(),
                width = this.getWidth(),
                height = this.getHeight();

            if (direction === UP) {
                y -= pointerHeight;
                height += pointerHeight;
            } else if (direction === DOWN) {
                height += pointerHeight;
            } else if (direction === LEFT) {
                // ARGH!!! I have no idea why should I used magic 1.5!!!!!!!!!
                x -= pointerWidth * 1.5;
                width += pointerWidth;
            } else if (direction === RIGHT) {
                width += pointerWidth * 1.5;
            }
            return {
                x: x,
                y: y,
                width: width,
                height: height
            };
        }
    };

    Konva.Util.extend(Konva.Tag, Konva.Shape);
    Konva.Factory.addGetterSetter(Konva.Tag, 'pointerDirection', NONE);

    /**
     * set pointer Direction
     * @name setPointerDirection
     * @method
     * @memberof Konva.Tag.prototype
     * @param {String} pointerDirection can be up, right, down, left, or none.  The
     *  default is none
     */

     /**
     * get pointer Direction
     * @name getPointerDirection
     * @method
     * @memberof Konva.Tag.prototype
     */

    Konva.Factory.addGetterSetter(Konva.Tag, 'pointerWidth', 0);

    /**
     * set pointer width
     * @name setPointerWidth
     * @method
     * @memberof Konva.Tag.prototype
     * @param {Number} pointerWidth
     */

     /**
     * get pointer width
     * @name getPointerWidth
     * @method
     * @memberof Konva.Tag.prototype
     */

    Konva.Factory.addGetterSetter(Konva.Tag, 'pointerHeight', 0);

    /**
     * set pointer height
     * @name setPointerHeight
     * @method
     * @memberof Konva.Tag.prototype
     * @param {Number} pointerHeight
     */

     /**
     * get pointer height
     * @name getPointerHeight
     * @method
     * @memberof Konva.Tag.prototype
     */

    Konva.Factory.addGetterSetter(Konva.Tag, 'cornerRadius', 0);

    /**
     * set corner radius
     * @name setCornerRadius
     * @method
     * @memberof Konva.Tag.prototype
     * @param {Number} corner radius
     */

    /**
     * get corner radius
     * @name getCornerRadius
     * @method
     * @memberof Konva.Tag.prototype
     */

    Konva.Collection.mapMethods(Konva.Tag);
})();