'use strict';

var helpers = require('./helpers.core');

/**
 * @alias Chart.helpers.math
 * @namespace
 */
var exports = {
	/**
	 * Returns an array of factors sorted from 1 to sqrt(value)
	 * @private
	 */
	_factorize: function(value) {
		var result = [];
		var sqrt = Math.sqrt(value);
		var i;

		for (i = 1; i < sqrt; i++) {
			if (value % i === 0) {
				result.push(i);
				result.push(value / i);
			}
		}
		if (sqrt === (sqrt | 0)) { // if value is a square number
			result.push(sqrt);
		}

		result.sort(function(a, b) {
			return a - b;
		}).pop();
		return result;
	},

	log10: Math.log10 || function(x) {
		var exponent = Math.log(x) * Math.LOG10E; // Math.LOG10E = 1 / Math.LN10.
		// Check for whole powers of 10,
		// which due to floating point rounding error should be corrected.
		var powerOf10 = Math.round(exponent);
		var isPowerOf10 = x === Math.pow(10, powerOf10);

		return isPowerOf10 ? powerOf10 : exponent;
	}
};

module.exports = exports;

// DEPRECATIONS

/**
 * Provided for backward compatibility, use Chart.helpers.math.log10 instead.
 * @namespace Chart.helpers.log10
 * @deprecated since version 2.9.0
 * @todo remove at version 3
 * @private
 */
helpers.log10 = exports.log10;