WP-LIT-MCP/src/Integrations/WordPress/Schema/MetaFieldSource.php

<?php

declare(strict_types=1);

namespace LIT\MCP\Integrations\WordPress\Schema;

/**
 * Shared read/write via the post meta API.
 */
abstract class MetaFieldSource implements FieldSource
{
    public function read(int $postId, FieldDefinition $field): mixed
    {
        return get_post_meta($postId, $field->key, ! $field->multiple);
    }

    public function write(int $postId, string $postType, array $values, array $definitions): void
    {
        foreach ($values as $key => $value) {
            $key = (string) $key;
            if ($value === null) {
                delete_post_meta($postId, $key);
                continue;
            }

            $field = $definitions[$key] ?? null;
            if ($field !== null && $field->multiple && is_array($value) && array_is_list($value)) {
                delete_post_meta($postId, $key);
                foreach ($value as $item) {
                    add_post_meta($postId, $key, wp_slash($item));
                }
                continue;
            }

            update_post_meta($postId, $key, wp_slash($value));
        }
    }
}