'use strict';

/**
 * Licensed Materials - Property of IBM
 * IBM Cognos Products: BI Cloud (C) Copyright IBM Corp. 2016, 2017
 * US Government Users Restricted Rights - Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
 */
define(['../../lib/@waca/core-client/js/core-client/ui/core/Class'], function (Class) {

	var ScaleUtil = {};

	/**
  * Functions used to handle calculation of scale options for infographic display functionality
  *
  */
	ScaleUtil = Class.extend({
		// Constants that handles conversion between numeric and text values. Used for readability, as numbers are used for scale slider min/max but they interpret as text values
		SCALE_VALUE_FEW: 0,
		SCALE_VALUE_DEFAULT: 1,
		SCALE_VALUE_MANY: 2,

		PERCENT_OPTIMAL_VALUE: 0.1,
		PERCENT_SCALE_OPTIONS: [0.01, 0.1, 1],

		/**
   * Calculates the default scale value for a given input number
   * @param rawNum - Input number to be infographically displayed
   * @param isPercent - If the raw number is used to represent a percentage infographic
   * @returns The default scale value to be used
   */
		calcOptimalValue: function calcOptimalValue(rawNum, isPercent) {

			// If rawNum is null (i.e. no value provided, treat same as zero case to avoid returning errors later on
			if (rawNum === null) {
				rawNum = 0;
			}

			// Null if not a number
			if (typeof rawNum !== 'number') {
				return null;
			}

			if (isPercent) {
				return this.PERCENT_OPTIMAL_VALUE;
			}

			// Take abs to handle negative numbers
			var absNum = Math.abs(rawNum);
			var sign = this.getSign(rawNum) || 1;

			var numLen = Math.ceil(Math.log(absNum + 1) / Math.LN10);

			// Default optimal value is 1.
			var optimalValue = 1;

			// If the number of digits is greater than 2 than calculate the optimal value
			if (numLen > 2) {
				optimalValue = Math.pow(10, numLen - 2);
			}

			return optimalValue * sign;
		},

		/**
   * Gets an object containing a list of scale options as well as the default for a given number
   * @param rawNum - Input number to be infographically displayed
   * @param isPercent - If the raw number is used to represent a percentage infographic
   * @returns An object containing an array of scaling options to be used, as well as the default scale to be shown
   */
		getScalingProperties: function getScalingProperties(rawNum, isPercent) {

			// If rawNum is null (i.e. no value provided, treat same as zero case to avoid returning errors later on
			if (rawNum === null) {
				rawNum = 0;
			}

			// Null if not a number
			if (typeof rawNum !== 'number') {
				return null;
			}

			if (isPercent) {
				return {
					availableScales: this.PERCENT_SCALE_OPTIONS,
					optimalScale: this.PERCENT_OPTIMAL_VALUE,
					scalingOptions: [this.SCALE_VALUE_FEW, this.SCALE_VALUE_DEFAULT, this.SCALE_VALUE_MANY]
				};
			}

			// get the absolute number
			var absNum = Math.abs(rawNum);
			// get the sign of the number to help handle negative numbers
			var sign = this.getSign(rawNum) || 1;

			// Get the ideal scale for the given number
			var optimalValue = this.calcOptimalValue(absNum);
			var availableScales = [optimalValue * sign];

			// Only add lower scale option if the default is greater than one
			if (optimalValue > 1) {
				availableScales.unshift(optimalValue / 10 * sign);
			}

			// Check if potential high value is valid scale option for input number
			var potentialHigh = optimalValue * 10;
			if (absNum / potentialHigh >= 1) {
				availableScales.push(potentialHigh * sign);
			}

			// Assemble both parts of final product to be returned to user
			var result = {
				availableScales: availableScales,
				optimalScale: optimalValue * sign
			};
			result.scalingOptions = this._getScaleOptions(result, isPercent);

			return result;
		},

		/**
   * Returns the corresponding min/max values for slider which user utilizes to select preferred scale option
   * @param {Number} rawNum - Raw input number which is being used to determine the scale
   * @param isPercent - If the raw number is used to represent a percentage infographic
   * @returns result object containing min and max value for slider
   */
		getMinMax: function getMinMax(rawNum, isPercent) {

			// If rawNum is null (i.e. no value provided, treat same as zero case to avoid returning errors later on
			if (rawNum === null) {
				rawNum = 0;
			}

			var scales = this.getScalingProperties(rawNum, isPercent);
			return {
				min: scales.scalingOptions[0],
				max: scales.scalingOptions[scales.scalingOptions.length - 1]
			};
		},

		/**
   * Given a corresponding value and scale to use, calculate the number of shapes and partial shapes to return to the user
   * @param value - The value we are calculating the number off of
   * @param scale - The scale that will be used
   * @param isPercent - If the raw number is used to represent a percentage infographic
   * @returns An object that contains the number of shapes and partial shapes to be displayed in the infographic summary
   */
		getScaleComponents: function getScaleComponents(value, scale, isPercent) {

			// If rawNum is null (i.e. no value provided, treat same as zero case to avoid returning errors later on
			if (value === null) {
				value = 0;
			}

			/**
    * Used to divide a number by a floating point decimal, which can sometimes lead to repeating decimal values using the normal '/' operator
    * @param numerator - Numerator of division expression
    * @param denominator - Denominator of division expression
    * @returns Result of numerator divided by denominator
    */
			function _division(numerator, denominator) {
				while (denominator < 1 && denominator > 0) {
					denominator *= 10;
					numerator *= 10;
				}
				return numerator / denominator;
			}

			/**
    * Used to find the remainder of a number by a floating point decimal, which can sometimes lead to repeating decimal values using the normal '%' operator
    * @param numerator - Numerator of remainder expression
    * @param denominator - Denominator of remainder expression
    * @returns remainder of expression
    */
			function _remainder(numerator, denominator) {
				return numerator - denominator * Math.floor(_division(numerator, denominator));
			}

			value = Math.abs(value);
			scale = Math.abs(scale);
			var numShapes = Math.floor(_division(value, scale));
			var partialValue = _division(_remainder(value, scale), scale);
			partialValue = parseFloat(partialValue.toFixed(2));

			var numGreyedShapes;
			if (isPercent) {
				numGreyedShapes = _division(1, scale) - numShapes - Math.ceil(partialValue);
			} else {
				numGreyedShapes = 0;
			}

			return {
				numShapes: numShapes,
				partialValue: partialValue,
				numGreyedShapes: numGreyedShapes
			};
		},

		_getScaleOptions: function _getScaleOptions(scaleData) {
			var numOfScales = scaleData.availableScales.length;
			var result;

			if (numOfScales === 3) {
				result = [this.SCALE_VALUE_FEW, this.SCALE_VALUE_DEFAULT, this.SCALE_VALUE_MANY];
			} else if (numOfScales === 1) {
				result = [this.SCALE_VALUE_DEFAULT];
			} else if (scaleData.availableScales.indexOf(scaleData.optimalScale) === 0) {
				result = [this.SCALE_VALUE_FEW, this.SCALE_VALUE_DEFAULT];
			} else if (scaleData.availableScales.indexOf(scaleData.optimalScale) === 1) {
				result = [this.SCALE_VALUE_DEFAULT, this.SCALE_VALUE_MANY];
			}
			return result;
		},

		getSign: function getSign(x) {
			x = +x; // convert to a number
			if (isNaN(x)) {
				return NaN;
			}
			return x >= 0 ? 1 : -1;
		}
	});

	return new ScaleUtil();
});
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