Hyde\Framework\Actions\ConvertsMarkdownToPlainText

Complexity

Total Complexity

19

Size/Duplication

Total Lines	121
Duplicated Lines	0 %

Importance

Changes

0

7 Methods

Rating	Name	Duplication	Size	Complexity
A	applyStringTransformations()	0	12	2
A	trimWhitespace()	0	10	5
A	applyRegexTransformations()	0	28	2
A	removeBlockquotes()	0	12	3
A	__construct()	0	3	1
A	execute()	0	3	1
A	removeTables()	0	12	5

<?php

declare(strict_types=1);

namespace Hyde\Framework\Actions;

use function trim;
use function rtrim;
use function is_numeric;
use function str_ends_with;
use function str_starts_with;
use function substr;
use function explode;
use function implode;
use function array_keys;
use function str_replace;
use function array_values;
use function preg_replace;

/**
 * Converts Markdown to plain text.
 */
class ConvertsMarkdownToPlainText
{
    protected const ATX_HEADERS = ['/^(\n)?\s{0,}#{1,6}\s+| {0,}(\n)?\s{0,}#{0,} {0,}(\n)?\s{0,}$/m' => '$1$2$3'];
    protected const SETEXT_HEADERS = ['/\n={2,}/' => "\n"];
    protected const HORIZONTAL_RULES = ['/^(-\s*?|\*\s*?|_\s*?){3,}\s*/m' => ''];
    protected const HTML_TAGS = ['/<[^>]*>/' => ''];
    protected const CODE_BLOCKS = ['/(`{3,})(.*?)\1/m' => '$2'];
    protected const FENCED_CODEBLOCKS = ['/`{3}.*\n/' => '', '/`{3}/' => ''];
    protected const TILDE_FENCED_CODEBLOCKS = ['/~{3}.*\n/' => '', '/~{3}/' => ''];
    protected const INLINE_CODE = ['/`(.+?)`/' => '$1'];
    protected const IMAGES = ['/\!\[(.*?)\][\[\(].*?[\]\)]/' => '$1'];
    protected const INLINE_LINKS = ['/\[(.*?)\][\[\(].*?[\]\)]/' => '$1'];
    protected const REFERENCE_LINKS = ['/^\s{1,2}\[(.*?)\]: (\S+)( ".*?")?\s*$/' => ''];
    protected const STRIKETHROUGH = ['/~~/' => ''];
    protected const BLOCKQUOTES = ['/^\s{0,3}>\s?/' => ''];
    protected const FOOTNOTES = ['/\[\^.+?\](\: .*?$)?/' => ''];
    protected const EMPHASIS = ['/([\*_]{1,3})(\S.*?\S{0,1})\1/' => '$2'];

    /** Emphasis (repeat the line to remove double emphasis) */
    protected const DOUBLE_EMPHASIS = self::EMPHASIS;

    /** Replace two or more newlines with exactly two */
    protected const REPEATED_NEWLINES = ['/\n{2,}/' => "\n\n"];

    protected string $markdown;

    public function __construct(string $markdown)
    {
        $this->markdown = $markdown;
    }

    /**
     * Regex based on https://github.com/stiang/remove-markdown, licensed under MIT.
     */
    public function execute(): string
    {
        return $this->applyStringTransformations($this->applyRegexTransformations($this->markdown));
    }

    protected function applyRegexTransformations(string $markdown): string
    {
        /** @var array<array-key, array<string, string>> $patterns */
        $patterns = [
            static::ATX_HEADERS,
            static::SETEXT_HEADERS,
            static::HORIZONTAL_RULES,
            static::HTML_TAGS,
            static::CODE_BLOCKS,
            static::FENCED_CODEBLOCKS,
            static::TILDE_FENCED_CODEBLOCKS,
            static::INLINE_CODE,
            static::IMAGES,
            static::INLINE_LINKS,
            static::REFERENCE_LINKS,
            static::STRIKETHROUGH,
            static::BLOCKQUOTES,
            static::FOOTNOTES,
            static::EMPHASIS,
            static::DOUBLE_EMPHASIS,
            static::REPEATED_NEWLINES,
        ];

        foreach ($patterns as $pattern) {
            $markdown = preg_replace(array_keys($pattern), array_values($pattern), $markdown) ?? $markdown;
        }

        return $markdown;
    }

    protected function applyStringTransformations(string $markdown): string
    {
        $lines = explode("\n", $markdown);
        foreach ($lines as $line => $contents) {
            $contents = $this->removeTables($contents);
            $contents = $this->removeBlockquotes($contents);
            $contents = $this->trimWhitespace($contents);

            $lines[$line] = $contents;
        }

        return implode("\n", $lines);
    }

    protected function removeTables(string $contents): string
    {
        // Remove dividers
        if (str_starts_with($contents, '|--') && str_ends_with($contents, '--|')) {
            $contents = str_replace(['|', '-'], ['', ''], $contents);
        }
        // Remove cells
        if (str_starts_with($contents, '| ') && str_ends_with($contents, '|')) {
            $contents = rtrim(str_replace(['| ', ' | ', ' |'], ['', '', ''], $contents), ' ');
        }

        return $contents;
    }

    protected function removeBlockquotes(string $contents): string
    {
        // Remove blockquotes
        if (str_starts_with($contents, '> ')) {
            $contents = substr($contents, 2);
        }
        // Remove multiline blockquotes
        if (str_starts_with($contents, '>')) {
            $contents = substr($contents, 1);
        }

        return $contents;
    }

    protected function trimWhitespace(string $contents): string
    {
        // If it is a list, don't trim the whitespace
        $firstCharacter = substr(trim($contents), 0, 1);

        if ($firstCharacter === '-' || $firstCharacter === '*' || $firstCharacter === '+' || is_numeric($firstCharacter)) {
            return $contents;
        }

        return trim($contents);
    }
}