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

/*
 * 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.
 */

use TYPO3\CMS\Extbase\Reflection\ObjectAccess;
use TYPO3\CMS\Fluid\Core\ViewHelper\AbstractViewHelper;

/**
 * ### Variable: Get
 *
 * ViewHelper used to read the value of a current template
 * variable. Can be used with dynamic indices in arrays:
 *
 *     <v:variable.get name="array.{dynamicIndex}" />
 *     <v:variable.get name="array.{v:variable.get(name: 'arrayOfSelectedKeys.{indexInArray}')}" />
 *     <f:for each="{v:variable.get(name: 'object.arrayProperty.{dynamicIndex}')}" as="nestedObject">
 *         ...
 *     </f:for>
 *
 * Or to read names of variables which contain dynamic parts:
 *
 *     <!-- if {variableName} is "Name", outputs value of {dynamicName} -->
 *     {v:variable.get(name: 'dynamic{variableName}')}
 *
 * If your target object is an array with unsequential yet
 * numeric indices (e.g. {123: 'value1', 513: 'value2'},
 * commonly seen in reindexed UID map arrays) use
 * `useRawIndex="TRUE"` to indicate you do not want your
 * array/QueryResult/Iterator to be accessed by locating
 * the Nth element - which is the default behavior.
 *
 * ```warning
 * Do not try `useRawKeys="TRUE"` on QueryResult or
 * ObjectStorage unless you are fully aware what you are
 * doing. These particular types require an unpredictable
 * index value - the SPL object hash value - when accessing
 * members directly. This SPL indexing and the very common
 * occurrences of QueryResult and ObjectStorage variables
 * in templates is the very reason why `useRawKeys` by
 * default is set to `FALSE`.
 * ```
 *
 * @author Claus Due <claus@namelesscoder.net>
 * @package Vhs
 * @subpackage ViewHelpers\Var
 */
class GetViewHelper extends AbstractViewHelper {

	/**
	 * @param string $name
	 * @param boolean $useRawKeys
	 * @return mixed
	 */
	public function render($name, $useRawKeys = FALSE) {
		if (FALSE === strpos($name, '.')) {
			if (TRUE === $this->templateVariableContainer->exists($name)) {
				return $this->templateVariableContainer->get($name);
			}
		} else {
			$segments = explode('.', $name);
			$lastSegment = array_shift($segments);
			$templateVariableRootName = $lastSegment;
			if (TRUE === $this->templateVariableContainer->exists($templateVariableRootName)) {
				$templateVariableRoot = $this->templateVariableContainer->get($templateVariableRootName);
				if (TRUE === $useRawKeys) {
					return ObjectAccess::getPropertyPath($templateVariableRoot, implode('.', $segments));
				}
				try {
					$value = $templateVariableRoot;
					foreach ($segments as $segment) {
						if (TRUE === ctype_digit($segment)) {
							$segment = intval($segment);
							$index = 0;
								// Note: this loop approach is not a stupid solution. If you doubt this,
								// attempt to feth a number at a numeric index from ObjectStorage ;)
							foreach ($value as $possibleValue) {
								if ($index === $segment) {
									$value = $possibleValue;
									break;
								}
								++ $index;
							}
							continue;
						}
						$value = ObjectAccess::getProperty($value, $segment);
					}
					return $value;
				} catch (\Exception $e) {
					return NULL;
				}
			}
		}
		return NULL;
	}

}