/**
 * @class Ext.chart.Navigation
 *
 * Handles panning and zooming capabilities.
 *
 * Used as mixin by Ext.chart.Chart.
 */
Ext.define('Ext.chart.Navigation', {

    constructor: function() {
        this.originalStore = this.store;
    },

    /**
     * Zooms the chart to the specified selection range.
     * Can be used with a selection mask. For example:
     *
     *     items: {
     *         xtype: 'chart',
     *         animate: true,
     *         store: store1,
     *         mask: 'horizontal',
     *         listeners: {
     *             select: {
     *                 fn: function(me, selection) {
     *                     me.setZoom(selection);
     *                     me.mask.hide();
     *                 }
     *             }
     *         }
     *     }
     */
    setZoom: function(zoomConfig) {
        var me = this,
            axes = me.axes,
            axesItems = axes.items,
            i, ln, axis,
            bbox = me.chartBBox,
            xScale = 1 / bbox.width,
            yScale = 1 / bbox.height,
            zoomer = {
                x : zoomConfig.x * xScale,
                y : zoomConfig.y * yScale,
                width : zoomConfig.width * xScale,
                height : zoomConfig.height * yScale
            },
            ends, from, to;
        for (i = 0, ln = axesItems.length; i < ln; i++) {
            axis = axesItems[i];
            ends = axis.calcEnds();
            if (axis.position == 'bottom' || axis.position == 'top') {
                from = (ends.to - ends.from) * zoomer.x + ends.from;
                to = (ends.to - ends.from) * zoomer.width + from;
                axis.minimum = from;
                axis.maximum = to;
            } else {
                to = (ends.to - ends.from) * (1 - zoomer.y) + ends.from;
                from = to - (ends.to - ends.from) * zoomer.height;
                axis.minimum = from;
                axis.maximum = to;
            }
        }
        me.redraw(false);
    },

    /**
     * Restores the zoom to the original value. This can be used to reset
     * the previous zoom state set by `setZoom`. For example:
     *
     *     myChart.restoreZoom();
     */
    restoreZoom: function() {
        if (this.originalStore) {
            this.store = this.substore = this.originalStore;
            this.redraw(true);
        }
    }

});