WP-LIT-MCP/src/Integrations/Divi/BlockTree/LibraryContent.php

<?php

declare(strict_types=1);

namespace LIT\MCP\Integrations\Divi\BlockTree;

defined('ABSPATH') || exit;

/**
 * post_content of Divi Library entries (F4, fixtures stage3): the nodes sit in a divi/placeholder
 * frame; a section/row/module entry has exactly one root, a layout entry sections. Pure PHP.
 */
final class LibraryContent
{
    public const WRAPPER = 'divi/placeholder';

    /**
     * Parses library content for copying and unifies its line breaks (Container::unifyLineBreaks()).
     * Never used for the content a tool edits in place – that keeps its bytes.
     *
     * @throws MalformedMarkup
     */
    public static function load(Parser $parser, string $content): Document
    {
        $document = $parser->parse($content);
        $document->unifyLineBreaks();

        return $document;
    }

    /** post_content of a library entry holding $node, framed like the builder's "add to library". */
    public static function wrap(Block $node): string
    {
        return '<!-- wp:' . self::WRAPPER . ' -->' . Serializer::block($node) . '<!-- /wp:' . self::WRAPPER . ' -->';
    }

    /** @return list<Block> Top-level nodes: the children of the first divi/placeholder, else of the document. */
    public static function roots(Document $document): array
    {
        foreach ($document->children() as $block) {
            if ($block->isPlaceholder()) {
                return $block->children();
            }
        }

        return $document->children();
    }

    /** Whether $block is or contains a global module. */
    public static function containsGlobal(Block $block): bool
    {
        if ($block->isGlobal()) {
            return true;
        }

        foreach ($block->children() as $child) {
            if (self::containsGlobal($child)) {
                return true;
            }
        }

        return false;
    }

    /**
     * Why the roots $after may not replace $before, or null. Instances on pages expect their
     * entry's root type (blockName), so a section/row/module entry keeps exactly one root of the
     * same type; a layout entry (or one with several roots) holds sections only. A global entry
     * contains no global modules (F10: Divi forbids nesting).
     *
     * @param list<Block> $before
     * @param list<Block> $after
     */
    public static function shapeViolation(array $before, array $after, ?string $layoutType, bool $global): ?string
    {
        if ($after === []) {
            return 'Der Bibliothekseintrag darf nicht leer werden.';
        }

        if ($layoutType === 'layout' || count($before) !== 1) {
            foreach ($after as $root) {
                if (GlobalInstance::effectiveName($root) !== 'divi/section') {
                    return 'Ein Layout-Eintrag der Bibliothek enthält nur Abschnitte.';
                }
            }
        } else {
            $expected = GlobalInstance::effectiveName($before[0]);
            if (count($after) !== 1 || GlobalInstance::effectiveName($after[0]) !== $expected) {
                return sprintf(
                    'Der Bibliothekseintrag muss genau ein %s bleiben (Instanzen auf den Seiten erwarten diesen Typ).',
                    $expected
                );
            }
        }

        if ($global) {
            foreach ($after as $root) {
                if (self::containsGlobal($root)) {
                    return 'Ein globaler Bibliothekseintrag darf keine globalen Module enthalten (Divi erlaubt keine '
                        . 'Verschachtelung).';
                }
            }
        }

        return null;
    }
}