<?php

/*                                                                        *
 * This script belongs to the FLOW3 package "Fluid".                      *
 *                                                                        *
 * It is free software; you can redistribute it and/or modify it under    *
 * the terms of the GNU Lesser General Public License as published by the *
 * Free Software Foundation, either version 3 of the License, or (at your *
 * option) any later version.                                             *
 *                                                                        *
 * This script is distributed in the hope that it will be useful, but     *
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN-    *
 * TABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser       *
 * General Public License for more details.                               *
 *                                                                        *
 * You should have received a copy of the GNU Lesser General Public       *
 * License along with the script.                                         *
 * If not, see http://www.gnu.org/licenses/lgpl.html                      *
 *                                                                        *
 * The TYPO3 project - inspiring people to share!                         *
 *                                                                        */

/**
 * This view helper is an abstract ViewHelper which implements an if/else condition.
 * @see Tx_Fluid_Core_Parser_SyntaxTree_ViewHelperNode::convertArgumentValue() to find see how boolean arguments are evaluated
 *
 * = Usage =
 *
 * To create a custom Condition ViewHelper, you need to subclass this class, and
 * implement your own render() method. Inside there, you should call $this->renderThenChild()
 * if the condition evaluated to TRUE, and $this->renderElseChild() if the condition evaluated
 * to FALSE.
 *
 * Every Condition ViewHelper has a "then" and "else" argument, so it can be used like:
 * <[aConditionViewHelperName] .... then="condition true" else="condition false" />,
 * or as well use the "then" and "else" child nodes.
 *
 * @see Tx_Fluid_ViewHelpers_IfViewHelper for a more detailed explanation and a simple usage example.
 * Make sure to NOT OVERRIDE the constructor.
 *
 * @license http://www.gnu.org/licenses/lgpl.html GNU Lesser General Public License, version 3 or later
 * @api
 */
abstract class Tx_Fluid_Core_ViewHelper_AbstractConditionViewHelper extends Tx_Fluid_Core_ViewHelper_AbstractViewHelper implements Tx_Fluid_Core_ViewHelper_Facets_ChildNodeAccessInterface, Tx_Fluid_Core_ViewHelper_Facets_CompilableInterface {

	/**
	 * An array of Tx_Fluid_Core_Parser_SyntaxTree_AbstractNode
	 * @var array
	 */
	private $childNodes = array();

	/**
	 * Setter for ChildNodes - as defined in ChildNodeAccessInterface
	 *
	 * @param array $childNodes Child nodes of this syntax tree node
	 * @return void
	 * @author Sebastian Kurfürst <sebastian@typo3.org>
	 */
	public function setChildNodes(array $childNodes) {
		$this->childNodes = $childNodes;
	}

	/**
	 * Initializes the "then" and "else" arguments
	 *
	 * @author Sebastian Kurfürst <sebastian@typo3.org>
	 */
	public function __construct() {
		$this->registerArgument('then', 'mixed', 'Value to be returned if the condition if met.', FALSE);
		$this->registerArgument('else', 'mixed', 'Value to be returned if the condition if not met.', FALSE);
	}

	/**
	 * Returns value of "then" attribute.
	 * If then attribute is not set, iterates through child nodes and renders ThenViewHelper.
	 * If then attribute is not set and no ThenViewHelper and no ElseViewHelper is found, all child nodes are rendered
	 *
	 * @return string rendered ThenViewHelper or contents of <f:if> if no ThenViewHelper was found
	 * @author Sebastian Kurfürst <sebastian@typo3.org>
	 * @author Bastian Waidelich <bastian@typo3.org>
	 * @api
	 */
	protected function renderThenChild() {
		if ($this->hasArgument('then')) {
			return $this->arguments['then'];
		}
		if ($this->hasArgument('__thenClosure')) {
			$thenClosure = $this->arguments['__thenClosure'];
			return $thenClosure();
		} elseif ($this->hasArgument('__elseClosure') || $this->hasArgument('else')) {
			return '';
		}

		$elseViewHelperEncountered = FALSE;
		foreach ($this->childNodes as $childNode) {
			if ($childNode instanceof Tx_Fluid_Core_Parser_SyntaxTree_ViewHelperNode
				&& $childNode->getViewHelperClassName() === 'Tx_Fluid_ViewHelpers_ThenViewHelper') {
				$data = $childNode->evaluate($this->renderingContext);
				return $data;
			}
			if ($childNode instanceof Tx_Fluid_Core_Parser_SyntaxTree_ViewHelperNode
				&& $childNode->getViewHelperClassName() === 'Tx_Fluid_ViewHelpers_ElseViewHelper') {
				$elseViewHelperEncountered = TRUE;
			}
		}

		if ($elseViewHelperEncountered) {
			return '';
		} else {
			return $this->renderChildren();
		}
	}

	/**
	 * Returns value of "else" attribute.
	 * If else attribute is not set, iterates through child nodes and renders ElseViewHelper.
	 * If else attribute is not set and no ElseViewHelper is found, an empty string will be returned.
	 *
	 * @return string rendered ElseViewHelper or an empty string if no ThenViewHelper was found
	 * @author Sebastian Kurfürst <sebastian@typo3.org>
	 * @author Bastian Waidelich <bastian@typo3.org>
	 * @api
	 */
	protected function renderElseChild() {
		if ($this->hasArgument('else')) {
			return $this->arguments['else'];
		}
		if ($this->hasArgument('__elseClosure')) {
			$elseClosure = $this->arguments['__elseClosure'];
			return $elseClosure();
		}
		foreach ($this->childNodes as $childNode) {
			if ($childNode instanceof Tx_Fluid_Core_Parser_SyntaxTree_ViewHelperNode
				&& $childNode->getViewHelperClassName() === 'Tx_Fluid_ViewHelpers_ElseViewHelper') {
				return $childNode->evaluate($this->renderingContext);
			}
		}

		return '';
	}

	/**
	 * The compiled ViewHelper adds two new ViewHelper arguments: __thenClosure and __elseClosure.
	 * These contain closures which are be executed to render the then(), respectively else() case.
	 *
	 * @param string $argumentsVariableName
	 * @param string $renderChildrenClosureVariableName
	 * @param string $initializationPhpCode
	 * @param Tx_Fluid_Core_Parser_SyntaxTree_AbstractNode $syntaxTreeNode
	 * @param Tx_Fluid_Core_Compiler_TemplateCompiler $templateCompiler
	 * @return string
	 * @internal
	 */
	public function compile($argumentsVariableName, $renderChildrenClosureVariableName, &$initializationPhpCode, Tx_Fluid_Core_Parser_SyntaxTree_AbstractNode $syntaxTreeNode, Tx_Fluid_Core_Compiler_TemplateCompiler $templateCompiler) {
		foreach ($syntaxTreeNode->getChildNodes() as $childNode) {
			if ($childNode instanceof Tx_Fluid_Core_Parser_SyntaxTree_ViewHelperNode
				&& $childNode->getViewHelperClassName() === 'Tx_Fluid_ViewHelpers_ThenViewHelper') {

				$childNodesAsClosure = $templateCompiler->wrapChildNodesInClosure($childNode);
				$initializationPhpCode .= sprintf('%s[\'__thenClosure\'] = %s;', $argumentsVariableName, $childNodesAsClosure) . chr(10);
			}
			if ($childNode instanceof Tx_Fluid_Core_Parser_SyntaxTree_ViewHelperNode
				&& $childNode->getViewHelperClassName() === 'Tx_Fluid_ViewHelpers_ElseViewHelper') {

				$childNodesAsClosure = $templateCompiler->wrapChildNodesInClosure($childNode);
				$initializationPhpCode .= sprintf('%s[\'__elseClosure\'] = %s;', $argumentsVariableName, $childNodesAsClosure) . chr(10);
			}
		}
		return Tx_Fluid_Core_Compiler_TemplateCompiler::SHOULD_GENERATE_VIEWHELPER_INVOCATION;
	}
}

?>