/**
 * Defines a mask for a chart's series.
 * The 'chart' member must be set prior to rendering.
 *
 * A Mask can be used to select a certain region in a chart.
 * When enabled, the `select` event will be triggered when a
 * region is selected by the mask, allowing the user to perform
 * other tasks like zooming on that region, etc.
 *
 * In order to use the mask one has to set the Chart `mask` option to
 * `true`, `vertical` or `horizontal`. Then a possible configuration for the
 * listener could be:
 *
 *     items: {
 *         xtype: 'chart',
 *         animate: true,
 *         store: store1,
 *         mask: 'horizontal',
 *         listeners: {
 *             select: {
 *                 fn: function(me, selection) {
 *                     me.setZoom(selection);
 *                     me.mask.hide();
 *                 }
 *             }
 *         }
 *     }
 *
 * In this example we zoom the chart to that particular region. You can also get
 * a handle to a mask instance from the chart object. The `chart.mask` element is a
 * `Ext.Panel`.
 * 
 */
Ext.define('Ext.chart.Mask', {
    mixinId: 'mask',

    requires: [
        'Ext.chart.MaskLayer'
    ],
    
    /**
     * @cfg {Boolean/String} mask
     * Enables selecting a region on chart. True to enable any selection,
     * 'horizontal' or 'vertical' to restrict the selection to X or Y axis.
     *
     * The mask in itself will do nothing but fire 'select' event.
     * See {@link Ext.chart.Mask} for example.
     */

    /**
     * Creates new Mask.
     * @param {Object} [config] Config object.
     */
    constructor: function(config) {
        var me = this;

        if (config) {
            Ext.apply(me, config);
        }
        if (me.enableMask) {
            me.on('afterrender', function() {
                //create a mask layer component
                var comp = new Ext.chart.MaskLayer({
                    renderTo: me.el,
                    hidden: true
                });
                comp.el.on({
                    'mousemove': function(e) {
                        me.onMouseMove(e);
                    },
                    'mouseup': function(e) {
                        me.onMouseUp(e);
                    }
                });
                comp.initDraggable();
                me.maskType = me.mask;
                me.mask = comp;
                me.maskSprite = me.surface.add({
                    type: 'path',
                    path: ['M', 0, 0],
                    zIndex: 1001,
                    opacity: 0.6,
                    hidden: true,
                    stroke: '#00f',
                    cursor: 'crosshair'
                });
            }, me, { single: true });
        }
    },

    onMouseUp: function(e) {
        var me = this,
            bbox = me.bbox || me.chartBBox,
            sel;
        me.maskMouseDown = false;
        me.mouseDown = false;
        if (me.mouseMoved) {
            me.handleMouseEvent(e);
            me.mouseMoved = false;
            sel = me.maskSelection;
            me.fireEvent('select', me, {
                x: sel.x - bbox.x,
                y: sel.y - bbox.y,
                width: sel.width,
                height: sel.height
            });
        }
    },

    onMouseDown: function(e) {
        this.handleMouseEvent(e);
    },

    onMouseMove: function(e) {
        this.handleMouseEvent(e);
    },

    handleMouseEvent: function(e) {
        var me = this,
            mask = me.maskType,
            bbox = me.bbox || me.chartBBox,
            x = bbox.x,
            y = bbox.y,
            math = Math,
            floor = math.floor,
            abs = math.abs,
            min = math.min,
            max = math.max,
            height = floor(y + bbox.height),
            width = floor(x + bbox.width),
            staticX = e.getPageX() - me.el.getX(),
            staticY = e.getPageY() - me.el.getY(),
            maskMouseDown = me.maskMouseDown,
            path;

        staticX = max(staticX, x);
        staticY = max(staticY, y);
        staticX = min(staticX, width);
        staticY = min(staticY, height);

        if (e.type === 'mousedown') {
            // remember the cursor location
            me.mouseDown = true;
            me.mouseMoved = false;
            me.maskMouseDown = {
                x: staticX,
                y: staticY
            };
        }
        else {
            // mousedown or mouseup:
            // track the cursor to display the selection
            me.mouseMoved = me.mouseDown;
            if (maskMouseDown && me.mouseDown) {
                if (mask == 'horizontal') {
                    staticY = y;
                    maskMouseDown.y = height;
                }
                else if (mask == 'vertical') {
                    staticX = x;
                    maskMouseDown.x = width;
                }
                width = maskMouseDown.x - staticX;
                height = maskMouseDown.y - staticY;
                path = ['M', staticX, staticY, 'l', width, 0, 0, height, -width, 0, 'z'];
                me.maskSelection = {
                    x: (width > 0 ? staticX : staticX + width) + me.el.getX(),
                    y: (height > 0 ? staticY : staticY + height) + me.el.getY(),
                    width: abs(width),
                    height: abs(height)
                };
                me.mask.updateBox(me.maskSelection);
                me.mask.show();
                me.maskSprite.setAttributes({
                    hidden: true    
                }, true);
            }
            else {
                if (mask == 'horizontal') {
                    path = ['M', staticX, y, 'L', staticX, height];
                }
                else if (mask == 'vertical') {
                    path = ['M', x, staticY, 'L', width, staticY];
                }
                else {
                    path = ['M', staticX, y, 'L', staticX, height, 'M', x, staticY, 'L', width, staticY];
                }
                me.maskSprite.setAttributes({
                    path: path,
                    'stroke-width': mask === true ? 1 : 1,
                    hidden: false
                }, true);
            }
        }

    },

    onMouseLeave: function(e) {
        var me = this;
        me.mouseMoved = false;
        me.mouseDown = false;
        me.maskMouseDown = false;
        me.mask.hide();
        me.maskSprite.hide(true);
    }
});