<?php
namespace FluidTYPO3\Vhs\ViewHelpers\Math;

/*
 * This file is part of the FluidTYPO3/Vhs project under GPLv2 or later.
 *
 * For the full copyright and license information, please read the
 * LICENSE.md file that was distributed with this source code.
 */

/**
 * Math: Median
 *
 * Gets the median value from an array of numbers. If there
 * is an odd number of numbers the middle value is returned.
 * If there is an even number of numbers an average of the
 * two middle numbers is returned.
 *
 * @author Claus Due <claus@namelesscoder.net>
 * @package Vhs
 * @subpackage ViewHelpers\Math
 */
class MedianViewHelper extends AbstractSingleMathViewHelper {

	/**
	 * @return mixed
	 * @throw Exception
	 */
	public function render() {
		$a = $this->getInlineArgument();
		$aIsIterable = $this->assertIsArrayOrIterator($a);
		if (TRUE === $aIsIterable) {
			$a = $this->arrayFromArrayOrTraversableOrCSV($a);
			sort($a, SORT_NUMERIC);
			$size = count($a);
			$midpoint = $size / 2;
			if (1 === $size % 2) {
				/*
				 * Array indexes of float are truncated to integers,
				 * not everybody knows, let's make it explicit for everybody
				 * wondering.
				 */
				return $a[(integer) $midpoint];
			}
			$candidates = array_slice($a, floor($midpoint) - 1, 2);
			return array_sum($candidates) / 2;
		}
		return $a;
	}

}