1<?php
2
3declare(strict_types=1);
4
5/*
6 * This file is part of the league/commonmark package.
7 *
8 * (c) Colin O'Dell <colinodell@gmail.com>
9 *
10 * For the full copyright and license information, please view the LICENSE
11 * file that was distributed with this source code.
12 */
13
14namespace League\CommonMark\Extension\TableOfContents;
15
16use League\CommonMark\Event\DocumentParsedEvent;
17use League\CommonMark\Extension\CommonMark\Node\Block\Heading;
18use League\CommonMark\Extension\HeadingPermalink\HeadingPermalink;
19use League\CommonMark\Extension\TableOfContents\Node\TableOfContents;
20use League\CommonMark\Extension\TableOfContents\Node\TableOfContentsPlaceholder;
21use League\CommonMark\Node\Block\Document;
22use League\CommonMark\Node\NodeIterator;
23use League\Config\ConfigurationAwareInterface;
24use League\Config\ConfigurationInterface;
25use League\Config\Exception\InvalidConfigurationException;
26
27final class TableOfContentsBuilder implements ConfigurationAwareInterface
28{
29    public const POSITION_TOP             = 'top';
30    public const POSITION_BEFORE_HEADINGS = 'before-headings';
31    public const POSITION_PLACEHOLDER     = 'placeholder';
32
33    /** @psalm-readonly-allow-private-mutation */
34    private ConfigurationInterface $config;
35
36    public function onDocumentParsed(DocumentParsedEvent $event): void
37    {
38        $document = $event->getDocument();
39
40        $generator = new TableOfContentsGenerator(
41            (string) $this->config->get('table_of_contents/style'),
42            (string) $this->config->get('table_of_contents/normalize'),
43            (int) $this->config->get('table_of_contents/min_heading_level'),
44            (int) $this->config->get('table_of_contents/max_heading_level'),
45            (string) $this->config->get('heading_permalink/fragment_prefix'),
46        );
47
48        $toc = $generator->generate($document);
49        if ($toc === null) {
50            // No linkable headers exist, so no TOC could be generated
51            return;
52        }
53
54        // Add custom CSS class(es), if defined
55        $class = $this->config->get('table_of_contents/html_class');
56        if ($class !== null) {
57            $toc->data->append('attributes/class', $class);
58        }
59
60        // Add the TOC to the Document
61        $position = $this->config->get('table_of_contents/position');
62        if ($position === self::POSITION_TOP) {
63            $document->prependChild($toc);
64        } elseif ($position === self::POSITION_BEFORE_HEADINGS) {
65            $this->insertBeforeFirstLinkedHeading($document, $toc);
66        } elseif ($position === self::POSITION_PLACEHOLDER) {
67            $this->replacePlaceholders($document, $toc);
68        } else {
69            throw InvalidConfigurationException::forConfigOption('table_of_contents/position', $position);
70        }
71    }
72
73    private function insertBeforeFirstLinkedHeading(Document $document, TableOfContents $toc): void
74    {
75        foreach ($document->iterator(NodeIterator::FLAG_BLOCKS_ONLY) as $node) {
76            if (! $node instanceof Heading) {
77                continue;
78            }
79
80            foreach ($node->children() as $child) {
81                if ($child instanceof HeadingPermalink) {
82                    $node->insertBefore($toc);
83
84                    return;
85                }
86            }
87        }
88    }
89
90    private function replacePlaceholders(Document $document, TableOfContents $toc): void
91    {
92        foreach ($document->iterator(NodeIterator::FLAG_BLOCKS_ONLY) as $node) {
93            // Add the block once we find a placeholder
94            if (! $node instanceof TableOfContentsPlaceholder) {
95                continue;
96            }
97
98            $node->replaceWith(clone $toc);
99        }
100    }
101
102    public function setConfiguration(ConfigurationInterface $configuration): void
103    {
104        $this->config = $configuration;
105    }
106}
107