thephpleague / html-to-markdown

<?php

declare(strict_types=1);

namespace League\HTMLToMarkdown\Converter;

use League\HTMLToMarkdown\Configuration;

use League\HTMLToMarkdown\ConfigurationAwareInterface;

use League\HTMLToMarkdown\ElementInterface;

class EmphasisConverter implements ConverterInterface, ConfigurationAwareInterface

{

    /** @var Configuration */

    protected $config;

    protected function getNormTag(?ElementInterface $element): string

    {

        if ($element !== null && ! $element->isText()) {

            $tag = $element->getTagName();

            if ($tag === 'i' || $tag === 'em') {

                return 'em';

            }

            if ($tag === 'b' || $tag === 'strong') {

                return 'strong';

            }

        }

        return '';

    }

    public function setConfig(Configuration $config): void

    {

        $this->config = $config;

    }

    public function convert(ElementInterface $element): string

    {

        $tag   = $this->getNormTag($element);

        $value = $element->getValue();

        if (! \trim($value)) {

            return $value;

        }

        if ($tag === 'em') {

            $style = $this->config->getOption('italic_style');

        } else {

            $style = $this->config->getOption('bold_style');

        }

        $prefix = \ltrim($value) !== $value ? ' ' : '';

        $suffix = \rtrim($value) !== $value ? ' ' : '';

        /* If this node is immediately preceded or followed by one of the same type don't emit

         * the start or end $style, respectively. This prevents <em>foo</em><em>bar</em> from

         * being converted to *foo**bar* which is incorrect. We want *foobar* instead.

         */

        $preStyle  = $this->getNormTag($element->getPreviousSibling()) === $tag ? '' : $style;

        $postStyle = $this->getNormTag($element->getNextSibling()) === $tag ? '' : $style;

        return $prefix . $preStyle . \trim($value) . $postStyle . $suffix;

    }

    /**

     * @return string[]

     */

    public function getSupportedTags(): array

    {

        return ['em', 'i', 'strong', 'b'];

    }

}