(function() {
    'use strict';
    // CONSTANTS
    var STAGE = 'Stage',
        STRING = 'string',
        PX = 'px',

        MOUSEOUT = 'mouseout',
        MOUSELEAVE = 'mouseleave',
        MOUSEOVER = 'mouseover',
        MOUSEENTER = 'mouseenter',
        MOUSEMOVE = 'mousemove',
        MOUSEDOWN = 'mousedown',
        MOUSEUP = 'mouseup',
        CLICK = 'click',
        DBL_CLICK = 'dblclick',
        TOUCHSTART = 'touchstart',
        TOUCHEND = 'touchend',
        TAP = 'tap',
        DBL_TAP = 'dbltap',
        TOUCHMOVE = 'touchmove',
        DOMMOUSESCROLL = 'DOMMouseScroll',
        MOUSEWHEEL = 'mousewheel',
        WHEEL = 'wheel',

        CONTENT_MOUSEOUT = 'contentMouseout',
        CONTENT_MOUSEOVER = 'contentMouseover',
        CONTENT_MOUSEMOVE = 'contentMousemove',
        CONTENT_MOUSEDOWN = 'contentMousedown',
        CONTENT_MOUSEUP = 'contentMouseup',
        CONTENT_CLICK = 'contentClick',
        CONTENT_DBL_CLICK = 'contentDblclick',
        CONTENT_TOUCHSTART = 'contentTouchstart',
        CONTENT_TOUCHEND = 'contentTouchend',
        CONTENT_DBL_TAP = 'contentDbltap',
        CONTENT_TAP = 'contentTap',
        CONTENT_TOUCHMOVE = 'contentTouchmove',
        CONTENT_WHEEL = 'contentWheel',

        DIV = 'div',
        RELATIVE = 'relative',
        KONVA_CONTENT = 'konvajs-content',
        SPACE = ' ',
        UNDERSCORE = '_',
        CONTAINER = 'container',
        EMPTY_STRING = '',
        EVENTS = [MOUSEDOWN, MOUSEMOVE, MOUSEUP, MOUSEOUT, TOUCHSTART, TOUCHMOVE, TOUCHEND, MOUSEOVER, DOMMOUSESCROLL, MOUSEWHEEL, WHEEL],

        // cached variables
        eventsLength = EVENTS.length;

    function addEvent(ctx, eventName) {
        ctx.content.addEventListener(eventName, function(evt) {
            ctx[UNDERSCORE + eventName](evt);
        }, false);
    }

    /**
     * Stage constructor.  A stage is used to contain multiple layers
     * @constructor
     * @memberof Konva
     * @augments Konva.Container
     * @param {Object} config
     * @param {String|Element} config.container Container selector or DOM element
     * @@nodeParams
     * @example
     * var stage = new Konva.Stage({
         *   width: 500,
         *   height: 800,
         *   container: 'containerId' // or "#containerId" or ".containerClass"
         * });
     */
    Konva.Stage = function(config) {
        this.___init(config);
    };

    Konva.Util.addMethods(Konva.Stage, {
        ___init: function(config) {
            this.nodeType = STAGE;
            // call super constructor
            Konva.Container.call(this, config);
            this._id = Konva.idCounter++;
            this._buildDOM();
            this._bindContentEvents();
            this._enableNestedTransforms = false;
            Konva.stages.push(this);
        },
        _validateAdd: function(child) {
            if (child.getType() !== 'Layer') {
                Konva.Util.throw('You may only add layers to the stage.');
            }
        },
        /**
         * set container dom element which contains the stage wrapper div element
         * @method
         * @memberof Konva.Stage.prototype
         * @param {DomElement} container can pass in a dom element or id string
         */
        setContainer: function (container) {
            if (typeof container === STRING) {
                if (container.charAt(0) === '.') {
                    var className = container.slice(1);
                    container = Konva.document.getElementsByClassName(className)[0];
                } else {
                    var id;
                    if (container.charAt(0) !== '#') {
                        id = container;
                    } else {
                        id = container.slice(1);
                    }
                    container = Konva.document.getElementById(id);
                }
                if (!container) {
                    throw 'Can not find container in document with id ' + id;
                }
            }
            this._setAttr(CONTAINER, container);
            return this;
        },
        shouldDrawHit: function() {
            return true;
        },
        draw: function() {
            Konva.Node.prototype.draw.call(this);
            return this;
        },
        /**
         * draw layer scene graphs
         * @name draw
         * @method
         * @memberof Konva.Stage.prototype
         */

        /**
         * draw layer hit graphs
         * @name drawHit
         * @method
         * @memberof Konva.Stage.prototype
         */

        /**
         * set height
         * @method
         * @memberof Konva.Stage.prototype
         * @param {Number} height
         */
        setHeight: function(height) {
            Konva.Node.prototype.setHeight.call(this, height);
            this._resizeDOM();
            return this;
        },
        /**
         * set width
         * @method
         * @memberof Konva.Stage.prototype
         * @param {Number} width
         */
        setWidth: function(width) {
            Konva.Node.prototype.setWidth.call(this, width);
            this._resizeDOM();
            return this;
        },
        /**
         * clear all layers
         * @method
         * @memberof Konva.Stage.prototype
         */
        clear: function() {
            var layers = this.children,
                len = layers.length,
                n;

            for(n = 0; n < len; n++) {
                layers[n].clear();
            }
            return this;
        },
        clone: function(obj) {
            if (!obj) {
                obj = {};
            }
            obj.container = Konva.document.createElement(DIV);
            return Konva.Container.prototype.clone.call(this, obj);
        },
        /**
         * destroy stage
         * @method
         * @memberof Konva.Stage.prototype
         */
        destroy: function() {
            var content = this.content;
            Konva.Container.prototype.destroy.call(this);

            if(content && Konva.Util._isInDocument(content)) {
                this.getContainer().removeChild(content);
            }
            var index = Konva.stages.indexOf(this);
            if (index > -1) {
                Konva.stages.splice(index, 1);
            }
            return this;
        },
        /**
         * get pointer position which can be a touch position or mouse position
         * @method
         * @memberof Konva.Stage.prototype
         * @returns {Object}
         */
        getPointerPosition: function() {
            return this.pointerPos;
        },
        getStage: function() {
            return this;
        },
        /**
         * get stage content div element which has the
         *  the class name "konvajs-content"
         * @method
         * @memberof Konva.Stage.prototype
         */
        getContent: function() {
            return this.content;
        },
        /**
         * Creates a composite data URL
         * @method
         * @memberof Konva.Stage.prototype
         * @param {Object} config
         * @param {Function} [config.callback] function executed when the composite has completed. Deprecated as method is sync now.
         * @param {String} [config.mimeType] can be "image/png" or "image/jpeg".
         *  "image/png" is the default
         * @param {Number} [config.x] x position of canvas section
         * @param {Number} [config.y] y position of canvas section
         * @param {Number} [config.width] width of canvas section
         * @param {Number} [config.height] height of canvas section
         * @param {Number} [config.quality] jpeg quality.  If using an "image/jpeg" mimeType,
         *  you can specify the quality from 0 to 1, where 0 is very poor quality and 1
         *  is very high quality
         */
        toDataURL: function(config) {
            config = config || {};

            var mimeType = config.mimeType || null,
                quality = config.quality || null,
                x = config.x || 0,
                y = config.y || 0,
                canvas = new Konva.SceneCanvas({
                    width: config.width || this.getWidth(),
                    height: config.height || this.getHeight(),
                    pixelRatio: config.pixelRatio
                }),
                _context = canvas.getContext()._context,
                layers = this.children;

            if(x || y) {
                _context.translate(-1 * x, -1 * y);
            }


            layers.each(function(layer) {
                var width = layer.getCanvas().getWidth();
                var height = layer.getCanvas().getHeight();
                var ratio = layer.getCanvas().getPixelRatio();
                _context.drawImage(layer.getCanvas()._canvas, 0, 0, width / ratio, height / ratio);
            });
            var src = canvas.toDataURL(mimeType, quality);

            if (config.callback) {
                config.callback(src);
            }

            return src;
        },
        /**
         * converts stage into an image.
         * @method
         * @memberof Konva.Stage.prototype
         * @param {Object} config
         * @param {Function} config.callback function executed when the composite has completed
         * @param {String} [config.mimeType] can be "image/png" or "image/jpeg".
         *  "image/png" is the default
         * @param {Number} [config.x] x position of canvas section
         * @param {Number} [config.y] y position of canvas section
         * @param {Number} [config.width] width of canvas section
         * @param {Number} [config.height] height of canvas section
         * @param {Number} [config.quality] jpeg quality.  If using an "image/jpeg" mimeType,
         *  you can specify the quality from 0 to 1, where 0 is very poor quality and 1
         *  is very high quality
         */
        toImage: function(config) {
            var cb = config.callback;

            config.callback = function(dataUrl) {
                Konva.Util._getImage(dataUrl, function(img) {
                    cb(img);
                });
            };
            this.toDataURL(config);
        },
        /**
         * get visible intersection shape. This is the preferred
         *  method for determining if a point intersects a shape or not
         * @method
         * @memberof Konva.Stage.prototype
         * @param {Object} pos
         * @param {Number} pos.x
         * @param {Number} pos.y
         * @param {String} [selector]
         * @returns {Konva.Node}
         * @example
         * var shape = stage.getIntersection({x: 50, y: 50});
         * // or if you interested in shape parent:
         * var group = stage.getIntersection({x: 50, y: 50}, 'Group');
         */
        getIntersection: function(pos, selector) {
            var layers = this.getChildren(),
                len = layers.length,
                end = len - 1,
                n, shape;

            for(n = end; n >= 0; n--) {
                shape = layers[n].getIntersection(pos, selector);
                if (shape) {
                    return shape;
                }
            }

            return null;
        },
        _resizeDOM: function() {
            if(this.content) {
                var width = this.getWidth(),
                    height = this.getHeight(),
                    layers = this.getChildren(),
                    len = layers.length,
                    n, layer;

                // set content dimensions
                this.content.style.width = width + PX;
                this.content.style.height = height + PX;

                this.bufferCanvas.setSize(width, height);
                this.bufferHitCanvas.setSize(width, height);

                // set layer dimensions
                for(n = 0; n < len; n++) {
                    layer = layers[n];
                    layer.setSize(width, height);
                    layer.draw();
                }
            }
        },
        /**
         * add layer or layers to stage
         * @method
         * @memberof Konva.Stage.prototype
         * @param {...Konva.Layer} layer
         * @example
         * stage.add(layer1, layer2, layer3);
         */
        add: function(layer) {
            if (arguments.length > 1) {
                for (var i = 0; i < arguments.length; i++) {
                    this.add(arguments[i]);
                }
                return this;
            }
            Konva.Container.prototype.add.call(this, layer);
            layer._setCanvasSize(this.width(), this.height());

            // draw layer and append canvas to container
            layer.draw();
            this.content.appendChild(layer.canvas._canvas);

            // chainable
            return this;
        },
        getParent: function() {
            return null;
        },
        getLayer: function() {
            return null;
        },
        /**
         * returns a {@link Konva.Collection} of layers
         * @method
         * @memberof Konva.Stage.prototype
         */
        getLayers: function() {
            return this.getChildren();
        },
        _bindContentEvents: function() {
            for (var n = 0; n < eventsLength; n++) {
                addEvent(this, EVENTS[n]);
            }
        },
        _mouseover: function(evt) {
            if (!Konva.UA.mobile) {
                this._setPointerPosition(evt);
                this._fire(CONTENT_MOUSEOVER, {evt: evt});
            }
        },
        _mouseout: function(evt) {
            if (!Konva.UA.mobile) {
                this._setPointerPosition(evt);
                var targetShape = this.targetShape;

                if(targetShape && !Konva.isDragging()) {
                    targetShape._fireAndBubble(MOUSEOUT, {evt: evt});
                    targetShape._fireAndBubble(MOUSELEAVE, {evt: evt});
                    this.targetShape = null;
                }
                this.pointerPos = undefined;

                this._fire(CONTENT_MOUSEOUT, {evt: evt});
            }
        },
        _mousemove: function(evt) {
            // workaround for mobile IE to force touch event when unhandled pointer event elevates into a mouse event
            if (Konva.UA.ieMobile) {
                return this._touchmove(evt);
            }
            // workaround fake mousemove event in chrome browser https://code.google.com/p/chromium/issues/detail?id=161464
            if ((typeof evt.movementX !== 'undefined' || typeof evt.movementY !== 'undefined') && evt.movementY === 0 && evt.movementX === 0) {
                return null;
            }
            if (Konva.UA.mobile) {
                return null;
            }
            this._setPointerPosition(evt);
            var shape;

            if (!Konva.isDragging()) {
                shape = this.getIntersection(this.getPointerPosition());
                if(shape && shape.isListening()) {
                    if(!Konva.isDragging() && (!this.targetShape || this.targetShape._id !== shape._id)) {
                        if(this.targetShape) {
                            this.targetShape._fireAndBubble(MOUSEOUT, {evt: evt}, shape);
                            this.targetShape._fireAndBubble(MOUSELEAVE, {evt: evt}, shape);
                        }
                        shape._fireAndBubble(MOUSEOVER, {evt: evt}, this.targetShape);
                        shape._fireAndBubble(MOUSEENTER, {evt: evt}, this.targetShape);
                        this.targetShape = shape;
                    }
                    else {
                        shape._fireAndBubble(MOUSEMOVE, {evt: evt});
                    }
                }
                /*
                 * if no shape was detected, clear target shape and try
                 * to run mouseout from previous target shape
                 */
                else {
                    if(this.targetShape && !Konva.isDragging()) {
                        this.targetShape._fireAndBubble(MOUSEOUT, {evt: evt});
                        this.targetShape._fireAndBubble(MOUSELEAVE, {evt: evt});
                        this.targetShape = null;
                    }

                }

                // content event
                this._fire(CONTENT_MOUSEMOVE, {evt: evt});
            }

            // always call preventDefault for desktop events because some browsers
            // try to drag and drop the canvas element
            if (evt.preventDefault) {
                evt.preventDefault();
            }
        },
        _mousedown: function(evt) {
            // workaround for mobile IE to force touch event when unhandled pointer event elevates into a mouse event
            if (Konva.UA.ieMobile) {
                return this._touchstart(evt);
            }
            if (!Konva.UA.mobile) {
                this._setPointerPosition(evt);
                var shape = this.getIntersection(this.getPointerPosition());

                Konva.listenClickTap = true;

                if (shape && shape.isListening()) {
                    this.clickStartShape = shape;
                    shape._fireAndBubble(MOUSEDOWN, {evt: evt});
                }

                // content event
                this._fire(CONTENT_MOUSEDOWN, {evt: evt});
            }

            // always call preventDefault for desktop events because some browsers
            // try to drag and drop the canvas element
            if (evt.preventDefault) {
                evt.preventDefault();
            }
        },
        _mouseup: function(evt) {

            // workaround for mobile IE to force touch event when unhandled pointer event elevates into a mouse event
            if (Konva.UA.ieMobile) {
                return this._touchend(evt);
            }
            if (!Konva.UA.mobile) {
                this._setPointerPosition(evt);
                var shape = this.getIntersection(this.getPointerPosition()),
                    clickStartShape = this.clickStartShape,
                    fireDblClick = false,
                    dd = Konva.DD;

                if(Konva.inDblClickWindow) {
                    fireDblClick = true;
                    Konva.inDblClickWindow = false;
                }
                // don't set inDblClickWindow after dragging
                else if (!dd || !dd.justDragged) {
                    Konva.inDblClickWindow = true;
                } else if (dd) {
                    dd.justDragged = false;
                }

                setTimeout(function() {
                    Konva.inDblClickWindow = false;
                }, Konva.dblClickWindow);

                if (shape && shape.isListening()) {
                    shape._fireAndBubble(MOUSEUP, {evt: evt});

                    // detect if click or double click occurred
                    if(Konva.listenClickTap && clickStartShape && clickStartShape._id === shape._id) {
                        shape._fireAndBubble(CLICK, {evt: evt});

                        if(fireDblClick) {
                            shape._fireAndBubble(DBL_CLICK, {evt: evt});
                        }
                    }
                }
                // content events
                this._fire(CONTENT_MOUSEUP, {evt: evt});
                if (Konva.listenClickTap) {
                    this._fire(CONTENT_CLICK, {evt: evt});
                    if(fireDblClick) {
                        this._fire(CONTENT_DBL_CLICK, {evt: evt});
                    }
                }

                Konva.listenClickTap = false;
            }

            // always call preventDefault for desktop events because some browsers
            // try to drag and drop the canvas element
            if (evt.preventDefault) {
                evt.preventDefault();
            }
        },
        _touchstart: function(evt) {
            this._setPointerPosition(evt);
            var shape = this.getIntersection(this.getPointerPosition());

            Konva.listenClickTap = true;

            if (shape && shape.isListening()) {
                this.tapStartShape = shape;
                shape._fireAndBubble(TOUCHSTART, {evt: evt});

                // only call preventDefault if the shape is listening for events
                if (shape.isListening() && shape.preventDefault() && evt.preventDefault) {
                    evt.preventDefault();
                }
            }
            // content event
            this._fire(CONTENT_TOUCHSTART, {evt: evt});
        },
        _touchend: function(evt) {
            this._setPointerPosition(evt);
            var shape = this.getIntersection(this.getPointerPosition()),
                fireDblClick = false;

            if(Konva.inDblClickWindow) {
                fireDblClick = true;
                Konva.inDblClickWindow = false;
            }
            else {
                Konva.inDblClickWindow = true;
            }

            setTimeout(function() {
                Konva.inDblClickWindow = false;
            }, Konva.dblClickWindow);

            if (shape && shape.isListening()) {
                shape._fireAndBubble(TOUCHEND, {evt: evt});

                // detect if tap or double tap occurred
                if(Konva.listenClickTap && this.tapStartShape && shape._id === this.tapStartShape._id) {
                    shape._fireAndBubble(TAP, {evt: evt});

                    if(fireDblClick) {
                        shape._fireAndBubble(DBL_TAP, {evt: evt});
                    }
                }
                // only call preventDefault if the shape is listening for events
                if (shape.isListening() && shape.preventDefault() && evt.preventDefault) {
                    evt.preventDefault();
                }
            }
            // content events
            this._fire(CONTENT_TOUCHEND, {evt: evt});
            if (Konva.listenClickTap) {
                this._fire(CONTENT_TAP, {evt: evt});
                if(fireDblClick) {
                    this._fire(CONTENT_DBL_TAP, {evt: evt});
                }
            }

            Konva.listenClickTap = false;
        },
        _touchmove: function(evt) {
            this._setPointerPosition(evt);
            var dd = Konva.DD,
                shape;
            if (!Konva.isDragging()) {
                shape = this.getIntersection(this.getPointerPosition());
                if (shape && shape.isListening()) {
                    shape._fireAndBubble(TOUCHMOVE, {evt: evt});
                    // only call preventDefault if the shape is listening for events
                    if (shape.isListening() && shape.preventDefault() && evt.preventDefault) {
                        evt.preventDefault();
                    }
                }
                this._fire(CONTENT_TOUCHMOVE, {evt: evt});
            }
            if(dd) {
                if (Konva.isDragging() && Konva.DD.node.preventDefault()) {
                    evt.preventDefault();
                }
            }
        },
        _DOMMouseScroll: function(evt) {
            this._mousewheel(evt);
        },
        _mousewheel: function(evt) {
            this._setPointerPosition(evt);
            var shape = this.getIntersection(this.getPointerPosition());

            if (shape && shape.isListening()) {
                shape._fireAndBubble(WHEEL, {evt: evt});
            }
            this._fire(CONTENT_WHEEL, {evt: evt});
        },
        _wheel: function(evt) {
            this._mousewheel(evt);
        },
        _setPointerPosition: function(evt) {
            var contentPosition = this._getContentPosition(),
                x = null,
                y = null;
            evt = evt ? evt : window.event;

            // touch events
            if(evt.touches !== undefined) {
                // currently, only handle one finger
                if (evt.touches.length > 0) {

                    var touch = evt.touches[0];
                    // get the information for finger #1
                    x = touch.clientX - contentPosition.left;
                    y = touch.clientY - contentPosition.top;
                }
            }
            // mouse events
            else {
                x = evt.clientX - contentPosition.left;
                y = evt.clientY - contentPosition.top;
            }
            if (x !== null && y !== null) {
                this.pointerPos = {
                    x: x,
                    y: y
                };
            }
        },
        _getContentPosition: function() {
            var rect = this.content.getBoundingClientRect ? this.content.getBoundingClientRect() : { top: 0, left: 0 };
            return {
                top: rect.top,
                left: rect.left
            };
        },
        _buildDOM: function() {
            var container = this.getContainer();
            if (!container) {
                if (Konva.Util.isBrowser()) {
                    throw 'Stage has no container. A container is required.';
                } else {
                    // automatically create element for jsdom in nodejs env
                    container = Konva.document.createElement(DIV);
                }
            }
            // clear content inside container
            container.innerHTML = EMPTY_STRING;

            // content
            this.content = Konva.document.createElement(DIV);
            this.content.style.position = RELATIVE;
            this.content.className = KONVA_CONTENT;
            this.content.setAttribute('role', 'presentation');
            container.appendChild(this.content);

            // the buffer canvas pixel ratio must be 1 because it is used as an
            // intermediate canvas before copying the result onto a scene canvas.
            // not setting it to 1 will result in an over compensation
            this.bufferCanvas = new Konva.SceneCanvas();
            this.bufferHitCanvas = new Konva.HitCanvas({pixelRatio: 1});

            this._resizeDOM();
        },
        _onContent: function(typesStr, handler) {
            var types = typesStr.split(SPACE),
                len = types.length,
                n, baseEvent;

            for(n = 0; n < len; n++) {
                baseEvent = types[n];
                this.content.addEventListener(baseEvent, handler, false);
            }
        },
        // currently cache function is now working for stage, because stage has no its own canvas element
        // TODO: may be it is better to cache all children layers?
        cache: function() {
            Konva.Util.warn('Cache function is not allowed for stage. You may use cache only for layers, groups and shapes.');
        },
        clearCache: function() {
        }
    });
    Konva.Util.extend(Konva.Stage, Konva.Container);

    // add getters and setters
    Konva.Factory.addGetter(Konva.Stage, 'container');
    Konva.Factory.addOverloadedGetterSetter(Konva.Stage, 'container');

    /**
     * get container DOM element
     * @name container
     * @method
     * @memberof Konva.Stage.prototype
     * @returns {DomElement} container
     * @example
     * // get container
     * var container = stage.container();
     * // set container
     * var container = document.createElement('div');
     * body.appendChild(container);
     * stage.container(container);
     */

})();