<?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: Average
 *
 * Performs average across an array. If $a is an array and
 * $b is an array, each member of $a is averaged against the
 * same member in $b. If $a is an array and $b is a number,
 * each member of $a is averaged agained $b. If $a is an array
 * this array is averaged to one number. If $a is a number and
 * $b is not provided or NULL, $a is gracefully returned as an
 * average value of itself.
 *
 * @author Claus Due <claus@namelesscoder.net>
 * @package Vhs
 * @subpackage ViewHelpers\Math
 */
class AverageViewHelper extends AbstractMultipleMathViewHelper {

	/**
	 * @return void
	 */
	public function initializeArguments() {
		parent::initializeArguments();
		$this->overrideArgument('b', 'mixed', 'Optional: Second number or Iterator/Traversable/Array for calculation', FALSE, NULL);
	}

	/**
	 * @return mixed
	 * @throw Exception
	 */
	public function render() {
		$a = $this->getInlineArgument();
		$b = $this->arguments['b'];
		$aIsIterable = $this->assertIsArrayOrIterator($a);
		$bIsIterable = $this->assertIsArrayOrIterator($b);
		if (TRUE === $aIsIterable && NULL === $b) {
			$a = $this->arrayFromArrayOrTraversableOrCSV($a);
			$sum = array_sum($a);
			$distribution = count($a);
			return $sum / $distribution;
		} elseif (TRUE === $aIsIterable && FALSE === $bIsIterable) {
			$a = $this->arrayFromArrayOrTraversableOrCSV($a);
			foreach ($a as $index => $value) {
				$a[$index] = $this->calculateAction($value, $b);
			}
			return $a;
		} elseif (TRUE === isset($a) && NULL === $b) {
			return $a;
		}
		return $this->calculate($a, $b);
	}

	/**
	 * @param mixed $a
	 * @param $b
	 * @return mixed
	 */
	protected function calculateAction($a, $b) {
		return ($a + $b) / 2;
	}

}