<?php
namespace FluidTYPO3\Vhs\Traits;

/*
 * 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.
 */

/**
 * This trait can be used by viewhelpers that generate image tags
 * to add srcsets based to the imagetag for better responsiveness
 */
trait ConditionViewHelperTrait {
	/**
	 * renders <f:then> child if $condition is true, otherwise renders <f:else> child.
	 *
	 * @return string the rendered string
	 * @api
	 */
	public function render() {
		if (static::evaluateCondition($this->arguments)) {
			return $this->renderThenChild();
		} else {
			return $this->renderElseChild();
		}
	}

	/**
	 * Default implementation for use in compiled templates
	 *
	 * TODO: remove at some point, because this is only here for legacy reasons.
	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
	 * method. 7.2+ on the other hand provides basically exactly this method here
	 * luckily it's backwards compatible out of the box.
	 * tl;dr -> remove after expiration of support for anything below 7.2
	 *
	 * @param array $arguments
	 * @param \Closure $renderChildrenClosure
	 * @param \TYPO3\CMS\Fluid\Core\Rendering\RenderingContextInterface $renderingContext
	 * @return mixed
	 */
	static public function renderStatic(array $arguments, \Closure $renderChildrenClosure, \TYPO3\CMS\Fluid\Core\Rendering\RenderingContextInterface $renderingContext) {
		$hasEvaluated = TRUE;
		if (static::evaluateCondition($arguments)) {
			$result = static::renderStaticThenChild($arguments, $hasEvaluated);
			if ($hasEvaluated) {
				return $result;
			}

			return $renderChildrenClosure();
		} else {
			$result = static::renderStaticElseChild($arguments, $hasEvaluated);
			if ($hasEvaluated) {
				return $result;
			}
		}

		return '';
	}

	/**
	 * Statically evalute "then" children.
	 * The "$hasEvaluated" argument is there to distinguish the case that "then" returned NULL or was not evaluated.
	 *
	 * TODO: remove at some point, because this is only here for legacy reasons.
	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
	 * method. 7.2+ on the other hand provides basically exactly this method here
	 * luckily it's backwards compatible out of the box.
	 * tl;dr -> remove after expiration of support for anything below 7.2
	 *
	 * @param array $arguments ViewHelper arguments
	 * @param bool $hasEvaluated Can be used to check if the "then" child was actually evaluated by this method.
	 * @return string
	 */
	static protected function renderStaticThenChild($arguments, &$hasEvaluated) {
		if (isset($arguments['then'])) {
			return $arguments['then'];
		}
		if (isset($arguments['__thenClosure'])) {
			$thenClosure = $arguments['__thenClosure'];
			return $thenClosure();
		} elseif (isset($arguments['__elseClosure'])) {
			return '';
		}

		$hasEvaluated = FALSE;
	}

	/**
	 * Statically evalute "else" children.
	 * The "$hasEvaluated" argument is there to distinguish the case that "else" returned NULL or was not evaluated.
	 *
	 * TODO: remove at some point, because this is only here for legacy reasons.
	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
	 * method. 7.2+ on the other hand provides basically exactly this method here
	 * luckily it's backwards compatible out of the box.
	 * tl;dr -> remove after expiration of support for anything below 7.2
	 *
	 * @param array $arguments ViewHelper arguments
	 * @param bool $hasEvaluated Can be used to check if the "else" child was actually evaluated by this method.
	 * @return string
	 */
	static protected function renderStaticElseChild($arguments, &$hasEvaluated) {
		if (isset($arguments['else'])) {
			return $arguments['else'];
		}
		if (isset($arguments['__elseClosure'])) {
			$elseClosure = $arguments['__elseClosure'];
			return $elseClosure();
		}

		$hasEvaluated = FALSE;
	}

	/**
	 * This method decides if the condition is TRUE or FALSE. It can be overriden in extending viewhelpers to adjust functionality.
	 *
	 * TODO: remove at some point, because this is only here for legacy reasons.
	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
	 * method. 7.2+ on the other hand provides basically exactly this method here
	 * luckily it's backwards compatible out of the box.
	 * tl;dr -> remove after expiration of support for anything below 7.2
	 *
	 * @param array $arguments ViewHelper arguments to evaluate the condition for this ViewHelper, allows for flexiblity in overriding this method.
	 * @return bool
	 */
	static protected function evaluateCondition($arguments = NULL) {
		return (isset($arguments['condition']) && $arguments['condition']);
	}
}