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

/*
 * 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\Core\Utility\GeneralUtility;
use TYPO3\CMS\Fluid\Core\ViewHelper\AbstractTagBasedViewHelper;
use TYPO3\CMS\Fluid\Core\ViewHelper\Exception;
use TYPO3\CMS\Fluid\Core\ViewHelper\TagBuilder;

/**
 * Renders a picture element with different images/sources for specific
 * media breakpoints
 *
 * ### Example
 *
 *     <v:media.picture src="fileadmin/some-image.png" alt="Some Image">
 *         <v:media.source media="(min-width: 1200px)" width="500c" height="500c" />
 *         <v:media.source media="(min-width: 992px)" width="300c" height="300c" />
 *         <v:media.source media="(min-width: 768px)" width="200c" height="200c" />
 *         <v:media.source width="80c" height="80c" />
 *     </v:media.picture>
 *
 * ### Browser Support
 *
 * To have the widest Browser-Support you should consider using a polyfill like:
 * http://scottjehl.github.io/picturefill/
 *
 * @author Marc Neuhaus <mneuhaus@famelo.com>, famelo
 * @package Vhs
 * @subpackage ViewHelpers\Media
 */
class PictureViewHelper extends AbstractTagBasedViewHelper {
	const SCOPE = 'FluidTYPO3\Vhs\ViewHelpers\Media\PictureViewHelper';
	const SCOPE_VARIABLE_SRC = 'src';
	const SCOPE_VARIABLE_DEFAULT_SOURCE = 'default-source';

	/**
	 * name of the tag to be created by this view helper
	 *
	 * @var string
	 * @api
	 */
	protected $tagName = 'picture';

	/**
	 * Initialize arguments.
	 *
	 * @return void
	 * @api
	 */
	public function initializeArguments() {
		parent::initializeArguments();
		$this->registerArgument('src', 'string', 'Path to the image.', TRUE);
		$this->registerArgument('alt', 'string', 'Text for the alt tag.', TRUE);
		$this->registerArgument('title', 'string', 'Text for the alt tag.', FALSE);
	}

	/**
	 * Render method
	 * @return string
	 * @throws Exception
	 */
	public function render() {
		$src = $this->arguments['src'];

		$this->viewHelperVariableContainer->addOrUpdate(self::SCOPE, self::SCOPE_VARIABLE_SRC, $src);
		$content = $this->renderChildren();
		$this->viewHelperVariableContainer->remove(self::SCOPE, self::SCOPE_VARIABLE_SRC);

		if (FALSE === $this->viewHelperVariableContainer->exists(self::SCOPE, self::SCOPE_VARIABLE_DEFAULT_SOURCE)) {
			throw new Exception('Please add a source without a media query as a default.', 1438116616);
		}
		$defaultSource = $this->viewHelperVariableContainer->get(self::SCOPE, self::SCOPE_VARIABLE_DEFAULT_SOURCE);

		$defaultImage = new TagBuilder('img');
		$defaultImage->addAttribute('src', $defaultSource);
		$defaultImage->addAttribute('alt', $this->arguments['alt']);

		if (FALSE === empty($this->arguments['title'])) {
			$defaultImage->addAttribute('title', $this->arguments['alt']);
		}
		$content .= $defaultImage->render();

		$this->tag->setContent($content);
		return $this->tag->render();
	}
}