/**
 * Streamgraph module
 *
 * (c) 2010-2018 Torstein Honsi
 *
 * License: www.highcharts.com/license
 */
'use strict';
import H from '../parts/Globals.js';
import '../parts/AreaSeries.js';

var seriesType = H.seriesType;

/**
 * A streamgraph is a type of stacked area graph which is displaced around a
 * central axis, resulting in a flowing, organic shape.
 *
 * @extends plotOptions.areaspline
 * @product highcharts highstock
 * @sample {highcharts|highstock} highcharts/demo/streamgraph/
 *         Streamgraph
 * @since 6.0.0
 * @optionparent plotOptions.streamgraph
 */
seriesType('streamgraph', 'areaspline', {
    fillOpacity: 1,
    lineWidth: 0,
    marker: {
        enabled: false
    },
    stacking: 'stream'
// Prototype functions
}, {
    negStacks: false,

    /**
     * Modifier function for stream stacks. It simply moves the point up or down
     * in order to center the full stack vertically.
     */
    streamStacker: function (pointExtremes, stack, i) {
        // Y bottom value
        pointExtremes[0] -= stack.total / 2;
        // Y value
        pointExtremes[1] -= stack.total / 2;

        // Record the Y data for use when getting axis extremes
        this.stackedYData[i] = pointExtremes;
    }
});


/**
 * A `streamgraph` series. If the [type](#series.streamgraph.type) option is not
 * specified, it is inherited from [chart.type](#chart.type).
 *
 * @type {Object}
 * @extends series,plotOptions.streamgraph
 * @excluding dataParser,dataURL
 * @product highcharts highstock
 * @apioption series.streamgraph
 */

/**
 * An array of data points for the series. For the `streamgraph` series type,
 * points can be given in the following ways:
 *
 * 1.  An array of numerical values. In this case, the numerical values
 * will be interpreted as `y` options. The `x` values will be automatically
 * calculated, either starting at 0 and incremented by 1, or from `pointStart`
 * and `pointInterval` given in the series options. If the axis has
 * categories, these will be used. Example:
 *
 *  ```js
 *  data: [0, 5, 3, 5]
 *  ```
 *
 * 2.  An array of arrays with 2 values. In this case, the values correspond
 * to `x,y`. If the first value is a string, it is applied as the name
 * of the point, and the `x` value is inferred.
 *
 *  ```js
 *     data: [
 *         [0, 9],
 *         [1, 7],
 *         [2, 6]
 *     ]
 *  ```
 *
 * 3.  An array of objects with named values. The following snippet shows only a
 * few settings, see the complete options set below. If the total number of data
 * points exceeds the series' [turboThreshold](#series.area.turboThreshold),
 * this option is not available.
 *
 *  ```js
 *     data: [{
 *         x: 1,
 *         y: 9,
 *         name: "Point2",
 *         color: "#00FF00"
 *     }, {
 *         x: 1,
 *         y: 6,
 *         name: "Point1",
 *         color: "#FF00FF"
 *     }]
 *  ```
 *
 * @type {Array<Object|Array|Number>}
 * @extends series.line.data
 * @sample {highcharts} highcharts/chart/reflow-true/
 *         Numerical values
 * @sample {highcharts} highcharts/series/data-array-of-arrays/
 *         Arrays of numeric x and y
 * @sample {highcharts} highcharts/series/data-array-of-arrays-datetime/
 *         Arrays of datetime x and y
 * @sample {highcharts} highcharts/series/data-array-of-name-value/
 *         Arrays of point.name and y
 * @sample {highcharts} highcharts/series/data-array-of-objects/
 *         Config objects
 * @product highcharts highstock
 * @apioption series.streamgraph.data
 */