<?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.
 */

use TYPO3\CMS\Core\Utility\GeneralUtility;

/**
 * Class SlideViewHelperTrait
 *
 * Trait implemented by ViewHelpers that wants some kind of
 * records to be optionally looked up and/or collected from
 * the current page and pages up the rootline. ViewHelpers must
 * implement the getSlideRecordsFromPage method which looks up
 * resources for a single page.
 *
 * Has the following main responsibilities:
 * - register arguments common for sliding
 * - method to get records with sliding according
 *   to the ViewHelper arguments
 */
trait SlideViewHelperTrait {

	/**
	 * Default initialisation of arguments - will be used
	 * if the implementing ViewHelper does not itself define
	 * this method.
	 *
	 * @return void
	 */
	public function initializeArguments() {
		$this->registerSlideArguments();
	}

	/**
	 * Register the "limit", "slide", "slideCollect" and "slideCollectReverse"
	 * arguments which are consumed by getSlideRecords.
	 * Should be used inside registerArguments().
	 *
	 * @return void
	 * @api
	 */
	protected function registerSlideArguments() {
		$this->registerArgument('limit', 'integer', 'Optional limit to the total number of records to render');
		$this->registerArgument('slide', 'integer', 'Enables Record Sliding - amount of levels which shall get walked up the rootline, including the current page. For infinite sliding (till the rootpage) set to -1. Only the first PID which has at minimum one record is used', FALSE, 0);
		$this->registerArgument('slideCollect', 'integer', 'If TRUE, content is collected up the root line. If FALSE, only the first PID which has content is used. If greater than zero, this value overrides $slide.', FALSE, 0);
		$this->registerArgument('slideCollectReverse', 'boolean', 'Normally when collecting records the elements from the actual page get shown on the top and those from the parent pages below those. You can invert this behaviour (actual page elements at bottom) by setting this flag))', FALSE, 0);
	}

	/**
	 * @return \FluidTYPO3\Vhs\Service\PageSelectService
	 */
	protected function getPageSelectService() {
		$objectManager = GeneralUtility::makeInstance('TYPO3\\CMS\\Extbase\\Object\\ObjectManager');
		return $objectManager->get('FluidTYPO3\\Vhs\\Service\\PageSelectService');
	}

	/**
	 * Get a number of records from a page for sliding
	 *
	 * @param integer $pageUid PID to get the records from
	 * @param integer $limit number of records to get at maximum
	 */
	abstract protected function getSlideRecordsFromPage($pageUid, $limit);

	/**
	 * Get records, optionally sliding up the page rootline
	 *
	 * @param integer $pageUid
	 * @param integer $limit
	 * @return array
	 * @api
	 */
	protected function getSlideRecords($pageUid, $limit = NULL) {
		if (NULL === $limit && FALSE === empty($this->arguments['limit'])) {
			$limit = (integer) $this->arguments['limit'];
		}

		$slide = (integer) $this->arguments['slide'];
		$slideCollectReverse = (boolean) $this->arguments['slideCollectReverse'];
		$slideCollect = (integer) $this->arguments['slideCollect'];

		if (0 < $slideCollect) {
			$slide = $slideCollect;
		}

		// find out which storage page UIDs to read from, respecting slide depth
		$storagePageUids = array();
		if (0 === $slide) {
			$storagePageUids[] = $pageUid;
		} else {
			$reverse = FALSE;
			if (TRUE === $slideCollectReverse && 0 !== $slideCollect) {
				$reverse = TRUE;
			}
			$rootLine = $this->getPageSelectService()->getRootLine($pageUid, NULL, $reverse);
			if (-1 !== $slide) {
				if (TRUE === $reverse) {
					$rootLine = array_slice($rootLine, - $slide);
				} else {
					$rootLine = array_slice($rootLine, 0, $slide);
				}
			}
			foreach ($rootLine as $page) {
				$storagePageUids[] = (integer) $page['uid'];
			}
		}
		// select records, respecting slide and slideCollect.
		$records = array();
		do {
			$storagePageUid = array_shift($storagePageUids);
			$limitRemaining = NULL;
			if (NULL !== $limit) {
				$limitRemaining = $limit - count($records);
				if (0 >= $limitRemaining) {
					break;
				}
			}
			$recordsFromPageUid = $this->getSlideRecordsFromPage($storagePageUid, $limitRemaining);
			if (0 < count($recordsFromPageUid)) {
				$records = array_merge($records, $recordsFromPageUid);
				if (0 === $slideCollect) {
					// stop collecting because argument said so and we've gotten at least one record now.
					break;
				}
			}
		} while (FALSE === empty($storagePageUids));

		return $records;
	}

}