/**
 *
 *  (c) 2010-2020 Kamil Kulig
 *
 *  License: www.highcharts.com/license
 *
 *  !!!!!!! SOURCE GETS TRANSPILED BY TYPESCRIPT. EDIT TS FILE ONLY. !!!!!!!
 *
 * */
'use strict';
import U from '../../Core/Utilities.js';
var isArray = U.isArray, seriesType = U.seriesType;
/**
 * Linear regression series type.
 *
 * @private
 * @class
 * @name Highcharts.seriesTypes.linearregression
 *
 * @augments Highcharts.Series
 */
seriesType('linearRegression', 'sma', 
/**
 * Linear regression indicator. This series requires `linkedTo` option to be
 * set.
 *
 * @sample {highstock} stock/indicators/linear-regression
 *         Linear regression indicator
 *
 * @extends      plotOptions.sma
 * @since        7.0.0
 * @product      highstock
 * @requires     stock/indicators/indicators
 * @requires     stock/indicators/regressions
 * @optionparent plotOptions.linearregression
 */
{
    params: {
        /**
         * Unit (in milliseconds) for the x axis distances used to compute
         * the regression line paramters (slope & intercept) for every
         * range. In Highstock the x axis values are always represented in
         * milliseconds which may cause that distances between points are
         * "big" integer numbers.
         *
         * Highstock's linear regression algorithm (least squares method)
         * will utilize these "big" integers for finding the slope and the
         * intercept of the regression line for each period. In consequence,
         * this value may be a very "small" decimal number that's hard to
         * interpret by a human.
         *
         * For instance: `xAxisUnit` equealed to `86400000` ms (1 day)
         * forces the algorithm to treat `86400000` as `1` while computing
         * the slope and the intercept. This may enchance the legiblitity of
         * the indicator's values.
         *
         * Default value is the closest distance between two data points.
         *
         * @sample {highstock} stock/plotoptions/linear-regression-xaxisunit
         *         xAxisUnit set to 1 minute
         *
         * @example
         * // In Liniear Regression Slope Indicator series `xAxisUnit` is
         * // `86400000` (1 day) and period is `3`. There're 3 points in the
         * // base series:
         *
         * data: [
         *   [Date.UTC(2020, 0, 1), 1],
         *   [Date.UTC(2020, 0, 2), 3],
         *   [Date.UTC(2020, 0, 3), 5]
         * ]
         *
         * // This will produce one point in the indicator series that has a
         * // `y` value of `2` (slope of the regression line). If we change
         * // the `xAxisUnit` to `1` (ms) the value of the indicator's point
         * // will be `2.3148148148148148e-8` which is harder to interpert
         * // for a human.
         *
         * @type    {number}
         * @product highstock
         */
        xAxisUnit: void 0
    },
    tooltip: {
        valueDecimals: 4
    }
}, 
/**
 * @lends Highcharts.Series#
 */
{
    nameBase: 'Linear Regression Indicator',
    /**
     * Return the slope and intercept of a straight line function.
     * @private
     * @param {Highcharts.LinearRegressionIndicator} this indicator to use
     * @param {Array<number>} xData -  list of all x coordinates in a period
     * @param {Array<number>} yData - list of all y coordinates in a period
     * @return {Highcharts.RegressionLineParametersObject}
     *          object that contains the slope and the intercept
     *          of a straight line function
     */
    getRegressionLineParameters: function (xData, yData) {
        // least squares method
        var yIndex = this.options.params.index, getSingleYValue = function (yValue, yIndex) {
            return isArray(yValue) ? yValue[yIndex] : yValue;
        }, xSum = xData.reduce(function (accX, val) {
            return val + accX;
        }, 0), ySum = yData.reduce(function (accY, val) {
            return getSingleYValue(val, yIndex) + accY;
        }, 0), xMean = xSum / xData.length, yMean = ySum / yData.length, xError, yError, formulaNumerator = 0, formulaDenominator = 0, i, slope;
        for (i = 0; i < xData.length; i++) {
            xError = xData[i] - xMean;
            yError = getSingleYValue(yData[i], yIndex) - yMean;
            formulaNumerator += xError * yError;
            formulaDenominator += Math.pow(xError, 2);
        }
        slope = formulaDenominator ?
            formulaNumerator / formulaDenominator : 0; // don't divide by 0
        return {
            slope: slope,
            intercept: yMean - slope * xMean
        };
    },
    /**
     * Return the y value on a straight line.
     * @private
     * @param {Highcharts.RegressionLineParametersObject} lineParameters
     *          object that contains the slope and the intercept
     *          of a straight line function
     * @param {number} endPointX - x coordinate of the point
     * @return {number} - y value of the point that lies on the line
     */
    getEndPointY: function (lineParameters, endPointX) {
        return lineParameters.slope * endPointX + lineParameters.intercept;
    },
    /**
     * Transform the coordinate system so that x values start at 0 and
     * apply xAxisUnit.
     * @private
     * @param {Array<number>} xData - list of all x coordinates in a period
     * @param {number} xAxisUnit - option (see the API)
     * @return {Array<number>} - array of transformed x data
     */
    transformXData: function (xData, xAxisUnit) {
        var xOffset = xData[0];
        return xData.map(function (xValue) {
            return (xValue - xOffset) / xAxisUnit;
        });
    },
    /**
     * Find the closest distance between points in the base series.
     * @private
     * @param {Array<number>} xData
                list of all x coordinates in the base series
     * @return {number} - closest distance between points in the base series
     */
    findClosestDistance: function (xData) {
        var distance, closestDistance, i;
        for (i = 1; i < xData.length - 1; i++) {
            distance = xData[i] - xData[i - 1];
            if (distance > 0 &&
                (typeof closestDistance === 'undefined' ||
                    distance < closestDistance)) {
                closestDistance = distance;
            }
        }
        return closestDistance;
    },
    // Required to be implemented - starting point for indicator's logic
    getValues: function (baseSeries, regressionSeriesParams) {
        var xData = baseSeries.xData, yData = baseSeries.yData, period = regressionSeriesParams.period, lineParameters, i, periodStart, periodEnd, 
        // format required to be returned
        indicatorData = {
            xData: [],
            yData: [],
            values: []
        }, endPointX, endPointY, periodXData, periodYData, periodTransformedXData, xAxisUnit = this.options.params.xAxisUnit ||
            this.findClosestDistance(xData);
        // Iteration logic: x value of the last point within the period
        // (end point) is used to represent the y value (regression)
        // of the entire period.
        for (i = period - 1; i <= xData.length - 1; i++) {
            periodStart = i - period + 1; // adjusted for slice() function
            periodEnd = i + 1; // (as above)
            endPointX = xData[i];
            periodXData = xData.slice(periodStart, periodEnd);
            periodYData = yData.slice(periodStart, periodEnd);
            periodTransformedXData = this.transformXData(periodXData, xAxisUnit);
            lineParameters = this.getRegressionLineParameters(periodTransformedXData, periodYData);
            endPointY = this.getEndPointY(lineParameters, periodTransformedXData[periodTransformedXData.length - 1]);
            // @todo this is probably not used anywhere
            indicatorData.values.push({
                regressionLineParameters: lineParameters,
                x: endPointX,
                y: endPointY
            });
            indicatorData.xData.push(endPointX);
            indicatorData.yData.push(endPointY);
        }
        return indicatorData;
    }
});
/**
 * A linear regression series. If the [type](#series.linearregression.type)
 * option is not specified, it is inherited from [chart.type](#chart.type).
 *
 * @extends   series,plotOptions.linearregression
 * @since     7.0.0
 * @product   highstock
 * @excluding dataParser,dataURL
 * @requires  stock/indicators/indicators
 * @requires  stock/indicators/regressions
 * @apioption series.linearregression
 */
/* ************************************************************************** */
/**
 * The Linear Regression Slope series type.
 *
 * @private
 * @class
 * @name Highcharts.seriesTypes.linearRegressionSlope
 *
 * @augments Highcharts.Series
 */
seriesType('linearRegressionSlope', 'linearRegression', 
/**
 * Linear regression slope indicator. This series requires `linkedTo`
 * option to be set.
 *
 * @sample {highstock} stock/indicators/linear-regression-slope
 *         Linear regression slope indicator
 *
 * @extends      plotOptions.linearregression
 * @since        7.0.0
 * @product      highstock
 * @requires     stock/indicators/indicators
 * @requires     stock/indicators/regressions
 * @optionparent plotOptions.linearregressionslope
 */
{}, 
/**
 * @lends Highcharts.Series#
 */
{
    nameBase: 'Linear Regression Slope Indicator',
    getEndPointY: function (lineParameters) {
        return lineParameters.slope;
    }
});
/**
 * A linear regression slope series. If the
 * [type](#series.linearregressionslope.type) option is not specified, it is
 * inherited from [chart.type](#chart.type).
 *
 * @extends   series,plotOptions.linearregressionslope
 * @since     7.0.0
 * @product   highstock
 * @excluding dataParser,dataURL
 * @requires  stock/indicators/indicators
 * @requires  stock/indicators/regressions
 * @apioption series.linearregressionslope
 */
/* ************************************************************************** */
/**
 * The Linear Regression Intercept series type.
 *
 * @private
 * @class
 * @name Highcharts.seriesTypes.linearRegressionIntercept
 *
 * @augments Highcharts.Series
 */
seriesType('linearRegressionIntercept', 'linearRegression', 
/**
 * Linear regression intercept indicator. This series requires `linkedTo`
 * option to be set.
 *
 * @sample {highstock} stock/indicators/linear-regression-intercept
 *         Linear intercept slope indicator
 *
 * @extends      plotOptions.linearregression
 * @since        7.0.0
 * @product      highstock
 * @requires     stock/indicators/indicators
 * @requires     stock/indicators/regressions
 * @optionparent plotOptions.linearregressionintercept
 */
{}, 
/**
 * @lends Highcharts.Series#
 */
{
    nameBase: 'Linear Regression Intercept Indicator',
    getEndPointY: function (lineParameters) {
        return lineParameters.intercept;
    }
});
/**
 * A linear regression intercept series. If the
 * [type](#series.linearregressionintercept.type) option is not specified, it is
 * inherited from [chart.type](#chart.type).
 *
 * @extends   series,plotOptions.linearregressionintercept
 * @since     7.0.0
 * @product   highstock
 * @excluding dataParser,dataURL
 * @requires  stock/indicators/indicators
 * @requires  stock/indicators/regressions
 * @apioption series.linearregressionintercept
 */
/* ************************************************************************** */
/**
 * The Linear Regression Angle series type.
 *
 * @private
 * @class
 * @name Highcharts.seriesTypes.linearRegressionAngle
 *
 * @augments Highcharts.Series
 */
seriesType('linearRegressionAngle', 'linearRegression', 
/**
 * Linear regression angle indicator. This series requires `linkedTo`
 * option to be set.
 *
 * @sample {highstock} stock/indicators/linear-regression-angle
 *         Linear intercept angle indicator
 *
 * @extends      plotOptions.linearregression
 * @since        7.0.0
 * @product      highstock
 * @requires     stock/indicators/indicators
 * @requires     stock/indicators/regressions
 * @optionparent plotOptions.linearregressionangle
 */
{
    tooltip: {
        pointFormat: '<span style="color:{point.color}">\u25CF</span>' +
            '{series.name}: <b>{point.y}°</b><br/>'
    }
}, 
/**
 * @lends Highcharts.Series#
 */
{
    nameBase: 'Linear Regression Angle Indicator',
    /**
    * Convert a slope of a line to angle (in degrees) between
    * the line and x axis
    * @private
    * @param {number} slope of the straight line function
    * @return {number} angle in degrees
    */
    slopeToAngle: function (slope) {
        return Math.atan(slope) * (180 / Math.PI); // rad to deg
    },
    getEndPointY: function (lineParameters) {
        return this.slopeToAngle(lineParameters.slope);
    }
});
/**
 * A linear regression intercept series. If the
 * [type](#series.linearregressionangle.type) option is not specified, it is
 * inherited from [chart.type](#chart.type).
 *
 * @extends   series,plotOptions.linearregressionangle
 * @since     7.0.0
 * @product   highstock
 * @excluding dataParser,dataURL
 * @requires  stock/indicators/indicators
 * @requires  stock/indicators/regressions
 * @apioption series.linearregressionangle
 */
''; // to include the above in the js output
