<?php

declare(strict_types=1);

/*
 * This file is part of the league/commonmark package.
 *
 * (c) Colin O'Dell <colinodell@gmail.com>
 *
 * Original code based on the CommonMark JS reference parser (http://bitly.com/commonmark-js)
 *  - (c) John MacFarlane
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace League\CommonMark\Extension\SmartPunct;

use League\CommonMark\Node\Inline\Text;
use League\CommonMark\Parser\Inline\InlineParserInterface;
use League\CommonMark\Parser\Inline\InlineParserMatch;
use League\CommonMark\Parser\InlineParserContext;

final class DashParser implements InlineParserInterface
{
    private const EN_DASH = '–';
    private const EM_DASH = '—';

    public function getMatchDefinition(): InlineParserMatch
    {
        return InlineParserMatch::regex('(?<!-)(-{2,})');
    }

    public function parse(InlineParserContext $inlineContext): bool
    {
        $count = $inlineContext->getFullMatchLength();
        $inlineContext->getCursor()->advanceBy($count);

        $enCount = 0;
        $emCount = 0;
        if ($count % 3 === 0) { // If divisible by 3, use all em dashes
            $emCount = (int) ($count / 3);
        } elseif ($count % 2 === 0) { // If divisible by 2, use all en dashes
            $enCount = (int) ($count / 2);
        } elseif ($count % 3 === 2) { // If 2 extra dashes, use en dash for last 2; em dashes for rest
            $emCount = (int) (($count - 2) / 3);
            $enCount = 1;
        } else { // Use en dashes for last 4 hyphens; em dashes for rest
            $emCount = (int) (($count - 4) / 3);
            $enCount = 2;
        }

        $inlineContext->getContainer()->appendChild(new Text(
            \str_repeat(self::EM_DASH, $emCount) . \str_repeat(self::EN_DASH, $enCount)
        ));

        return true;
    }
}