/** @module random */

/**
 * Random generator for double values.
 * 
 * ### Example ###
 * 
 *     let value1 = RandomDouble.nextDouble(5, 10);     // Possible result: 7.3
 *     let value2 = RandomDouble.nextDouble(10);        // Possible result: 3.7
 *     let value3 = RandomDouble.updateDouble(10, 3);   // Possible result: 9.2
 */
export class RandomDouble {

    /**
     * Generates a random double value in the range ['minYear', 'maxYear'].
     * 
     * @param min   (optional) minimum range value
     * @param max   max range value
     * @returns     a random double value.
     */
    public static nextDouble(min: number, max: number = null): number {
        if (max == null) {
            max = min;
            min = 0;
        }

    	if (max - min <= 0)
    		return min;
    	
        return min + Math.random() * (max - min);
    }

    /**
     * Updates (drifts) a double value within specified range defined
     * 
     * @param value     a double value to drift.
     * @param range     (optional) a range. Default: 10% of the value
     */
	public static updateDouble(value: number, range: number = null): number {		
        if (range == null) range = 0;
        range = range == 0 ? 0.1 * value : range;
        let minValue = value - range;
        let maxValue = value + range;
        return RandomDouble.nextDouble(minValue, maxValue);
    }    
}