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 HeaderConverter implements ConverterInterface, ConfigurationAwareInterface

{

    public const STYLE_ATX    = 'atx';

    public const STYLE_SETEXT = 'setext';

    /** @var Configuration */

    protected $config;

    public function setConfig(Configuration $config): void

    {

        $this->config = $config;

    }

    public function convert(ElementInterface $element): string

    {

        $level = (int) \substr($element->getTagName(), 1, 1);

        $style = $this->config->getOption('header_style', self::STYLE_SETEXT);

        if (\strlen($element->getValue()) === 0) {

            return "\n";

        }

        if (($level === 1 || $level === 2) && ! $element->isDescendantOf('blockquote') && $style === self::STYLE_SETEXT) {

            return $this->createSetextHeader($level, $element->getValue());

        }

        return $this->createAtxHeader($level, $element->getValue());

    }

    /**

     * @return string[]

     */

    public function getSupportedTags(): array

    {

        return ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'];

    }

    private function createSetextHeader(int $level, string $content): string

    {

        $length    = \function_exists('mb_strlen') ? \mb_strlen($content, 'utf-8') : \strlen($content);

        $underline = $level === 1 ? '=' : '-';

        return $content . "\n" . \str_repeat($underline, $length) . "\n\n";

    }

    private function createAtxHeader(int $level, string $content): string

    {

        $prefix = \str_repeat('#', $level) . ' ';

        return $prefix . $content . "\n\n";

    }

}