<?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 League\CommonMark\Block\Element\Paragraph;
use League\CommonMark\Block\Parser\AbstractBlockParser;
use League\CommonMark\ContextInterface;
use League\CommonMark\Cursor;
use Webuni\CommonMark\TableExtension\Table;
use Webuni\CommonMark\TableExtension\TableCell;
use Webuni\CommonMark\TableExtension\TableRow;

/**
 * Convert webtrees 1.x census-assistant markup into tables.
 * Note that webtrees 2.0 generates markdown tables directly.
 *
 * Based on the table parser from webuni/commonmark-table-extension.
 */
class CensusTableParser extends AbstractBlockParser {
	const REGEX_CENSUS_TABLE_HEADER = '/^\.b\.[^.|]+(?:\|\.b\.[^.|]+)*$/';

	/**
	 * Parse a paragraph of text with the following stucture:
	 *
	 * .b.HEADING1|.b.HEADING2|.b.HEADING3
	 * COL1|COL2|COL3
	 * COL1|COL2|COL3
	 *
	 * @param ContextInterface $context
	 * @param Cursor           $cursor
	 *
	 * @return bool
	 */
	public function parse(ContextInterface $context, Cursor $cursor) {
		$container = $context->getContainer();

		// Replace paragraphs with tables
		if (!$container instanceof Paragraph) {
			return false;
		}

		$lines = $container->getStrings();

		$first_line = array_pop($lines);

		if (!preg_match(self::REGEX_CENSUS_TABLE_HEADER, $first_line)) {
			return false;
		}

		$head = $this->parseRow($first_line, TableCell::TYPE_HEAD);

		$table = new Table(function (Cursor $cursor) use (&$table) {
			$row = $this->parseRow($cursor->getLine(), TableCell::TYPE_BODY);
			if ($row === null) {
				return false;
			}
			$table->getBody()->appendChild($row);

			return true;
		});

		$table->getHead()->appendChild($head);
		$context->replaceContainerBlock($table);

		return true;
	}

	/**
	 * @param string $line
	 * @param string $type
	 *
	 * @return TableRow|null
	 */
	private function parseRow($line, $type) {
		if (strpos($line, '|') === false) {
			return null;
		}

		$row = new TableRow;
		foreach (explode('|', $line) as $cell) {
			// Strip leading ".b." from <th> cells
			if ($type === TableCell::TYPE_HEAD && substr_compare($cell, '.b.', 0)) {
				$cell = substr($cell, 3);
			}
			$row->appendChild(new TableCell($cell, $type, null));
		}

		return $row;
	}
}
