<?php
/**
 * webtrees: online genealogy
 * Copyright (C) 2018 webtrees development team
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
namespace Fisharebest\Webtrees\CommonMark;

use Fisharebest\Webtrees\GedcomRecord;
use Fisharebest\Webtrees\Tree;
use League\CommonMark\Inline\Element\Link;
use League\CommonMark\Inline\Parser\AbstractInlineParser;
use League\CommonMark\InlineParserContext;

/**
 * Convert XREFs within markdown text to links
 */
class XrefParser extends AbstractInlineParser {
	/** @var Tree - match XREFs in this tree */
	private $tree;

	/**
	 * MarkdownXrefParser constructor.
	 *
	 * @param Tree $tree
	 */
	public function __construct(Tree $tree) {
		$this->tree = $tree;
	}

	/**
	 * We are only interested in text that begins with '@'.
	 *
	 * @return array
	 */
	public function getCharacters() {
		return ['@'];
	}

	/**
	 * @param InlineParserContext $context
	 *
	 * @return bool
	 */
	public function parse(InlineParserContext $context) {
		// The cursor should be positioned on the opening '@'.
		$cursor = $context->getcursor();

		// If this isn't the start of an XREF, we'll need to rewind.
		$previous_state = $cursor->saveState();

		$handle = $cursor->match('/@' . WT_REGEX_XREF . '@/');
		if (empty($handle)) {
			// Not an XREF?
			$cursor->restoreState($previous_state);

			return false;
		}

		$xref = trim($handle, '@');

		$record = GedcomRecord::getInstance($xref, $this->tree);

		if ($record === null) {
			// Linked record does not exist?
			$cursor->restoreState($previous_state);

			return false;
		}

		$url   = $record->url();
		$label = $handle;
		$title = strip_tags($record->getFullName());
		$context->getContainer()->appendChild(new Link($url, $label, $title));

		return true;
	}
}