<?php

declare(strict_types=1);

namespace Evomedien\Vitec\UserFunc;

use Doctrine\DBAL\ParameterType;
use TYPO3\CMS\Core\Attribute\AsAllowedCallable;
use TYPO3\CMS\Core\Database\ConnectionPool;
use TYPO3\CMS\Core\Database\Query\Restriction\FrontendRestrictionContainer;
use TYPO3\CMS\Core\Service\FlexFormService;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;

/**
 * Data source for the product filter: the product category hierarchy, and
 * nothing else.
 *
 * The editor places ONE `vitec_productfinder` element above the product
 * lists on the products page. It renders no product cards - the React front
 * end builds the filter selects from this payload and filters the products
 * the `vitec_productlist` elements already delivered, client side, via URL
 * parameters (?cat=58&subcat=66). No change to the list plugin was needed.
 *
 * Emitted shape:
 *
 *   content.productfinder.categories[] = { uid, title, subcategories[] }
 *   subcategories[]                    = { uid, title }
 *
 * Level 1 below the configured root becomes the main categories, their
 * direct children the subcategories - the same tree the product records
 * hang on, so a filter value maps straight onto `product.categories[].uid`.
 *
 * TYPO3 v14 hands the ContentObjectRenderer in through the setter; without
 * it $this->cObj stays null and the element cannot read its own FlexForm.
 */
final class ProductFinderJsonRenderer
{
    private const CATEGORY_TABLE = 'sys_category';

    /** Fallback when no root is configured: the category tree the products use. */
    private const DEFAULT_ROOT_TITLE = 'Product';

    protected ?ContentObjectRenderer $cObj = null;

    public function setContentObjectRenderer(ContentObjectRenderer $cObj): void
    {
        $this->cObj = $cObj;
    }

    #[AsAllowedCallable]
    public function render(string $content, array $conf): string
    {
        try {
            $settings = $this->settings();

            $root = (int)($settings['categoryRoot'] ?? 0);
            if ($root <= 0) {
                $root = $this->rootByTitle(self::DEFAULT_ROOT_TITLE);
            }
            if ($root <= 0) {
                return (string)json_encode(['categories' => []]);
            }

            $order = (string)($settings['sorting'] ?? 'sorting');
            $categories = [];
            foreach ($this->childrenOf($root, $order) as $main) {
                $categories[] = [
                    'uid' => (int)$main['uid'],
                    'title' => (string)$main['title'],
                    'subcategories' => array_map(
                        static fn(array $sub): array => [
                            'uid' => (int)$sub['uid'],
                            'title' => (string)$sub['title'],
                        ],
                        $this->childrenOf((int)$main['uid'], $order)
                    ),
                ];
            }

            return (string)json_encode(['categories' => $categories], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
        } catch (\Throwable) {
            // A broken filter must never take the page payload down with it.
            return (string)json_encode(['categories' => []]);
        }
    }

    /**
     * FlexForm settings of the element being rendered.
     *
     * @return array<string,mixed>
     */
    private function settings(): array
    {
        $flexform = (string)($this->cObj->data['pi_flexform'] ?? '');
        if ($flexform === '') {
            return [];
        }
        $parsed = GeneralUtility::makeInstance(FlexFormService::class)
            ->convertFlexFormContentToArray($flexform);

        return is_array($parsed['settings'] ?? null) ? $parsed['settings'] : [];
    }

    /**
     * Direct children of a category, honouring the frontend restrictions
     * (hidden, start/end time, deleted).
     *
     * @return array<int,array<string,mixed>>
     */
    private function childrenOf(int $parent, string $order): array
    {
        $queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)
            ->getQueryBuilderForTable(self::CATEGORY_TABLE);
        $queryBuilder->setRestrictions(GeneralUtility::makeInstance(FrontendRestrictionContainer::class));

        $query = $queryBuilder->select('uid', 'title', 'sorting')
            ->from(self::CATEGORY_TABLE)
            ->where(
                $queryBuilder->expr()->eq('parent', $queryBuilder->createNamedParameter($parent, ParameterType::INTEGER)),
                $queryBuilder->expr()->in('sys_language_uid', [-1, 0])
            );

        match ($order) {
            'title' => $query->orderBy('title', 'ASC'),
            'uid' => $query->orderBy('uid', 'ASC'),
            default => $query->orderBy('sorting', 'ASC')->addOrderBy('title', 'ASC'),
        };

        return $query->executeQuery()->fetchAllAssociative();
    }

    /** Uid of a root-level category by title, 0 when it does not exist. */
    private function rootByTitle(string $title): int
    {
        $queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)
            ->getQueryBuilderForTable(self::CATEGORY_TABLE);
        $queryBuilder->setRestrictions(GeneralUtility::makeInstance(FrontendRestrictionContainer::class));

        $uid = $queryBuilder->select('uid')->from(self::CATEGORY_TABLE)
            ->where(
                $queryBuilder->expr()->eq('parent', 0),
                $queryBuilder->expr()->eq('title', $queryBuilder->createNamedParameter($title))
            )
            ->setMaxResults(1)
            ->executeQuery()->fetchOne();

        return is_numeric($uid) ? (int)$uid : 0;
    }
}