<?php

declare(strict_types=1);

namespace Evomedien\EvoMegamenuJson\Service;

use Doctrine\DBAL\ParameterType;
use Evomedien\EvoMegamenuJson\Event\BuildCatalogEvent;
use Evomedien\EvoMegamenuJson\Event\BuildSpotlightEvent;
use Psr\EventDispatcher\EventDispatcherInterface;
use TYPO3\CMS\Core\Database\ConnectionPool;
use TYPO3\CMS\Core\Database\Query\QueryBuilder;
use TYPO3\CMS\Core\Database\Query\Restriction\FrontendRestrictionContainer;
use TYPO3\CMS\Core\Domain\Repository\PageRepository;
use TYPO3\CMS\Core\Resource\FileRepository;
use TYPO3\CMS\Core\Service\FlexFormService;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Extbase\Service\ImageService;
use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;

/**
 * Turns one "Megamenu" plugin element into the payload the front end reads.
 *
 * The element carries its entries inline; every entry carries its columns
 * (each with items) and, for the teaser layout, its cards. Presentation
 * settings live in the element's FlexForm and travel with the menu, so the
 * front end takes its behaviour from the payload instead of hard-coding it.
 *
 * Content stages (FlexForm `stage`) decide how much of the editorial detail
 * is emitted: 1 = structure only, 2 = plus images and teaser lines,
 * 3 = plus the featured slot. A front end built for stage 1 keeps working
 * when the stage is raised - later stages only add keys.
 */
final class MenuBuilder
{
    private const TABLE_CONTENT = 'tt_content';
    private const TABLE_ENTRY = 'tx_evomegamenujson_entry';
    private const TABLE_COLUMN = 'tx_evomegamenujson_column';
    private const TABLE_ITEM = 'tx_evomegamenujson_item';
    private const TABLE_TEASER = 'tx_evomegamenujson_teaser';

    /** getMenu() does not filter "hide in menus" by itself. */
    private const NAV_WHERE = 'AND nav_hide = 0';

    private const DEFAULT_SETTINGS = [
        'stage' => 3,
        'pendingBehaviour' => 'fallback',
        'showCounts' => true,
        'showViewAll' => true,
        'viewAllLabel' => 'View all %s',
        'openOn' => 'hover',
        'closeDelay' => 140,
        'columnsPerRow' => 4,
        'panelWidth' => 'container',
    ];

    public function __construct(
        private readonly ConnectionPool $connectionPool,
        private readonly FlexFormService $flexFormService,
        private readonly PageRepository $pageRepository,
        private readonly FileRepository $fileRepository,
        private readonly EventDispatcherInterface $eventDispatcher,
    ) {}

    /**
     * @param array<string,mixed>|null $contentRow pass the row when it is already at hand
     * @return array{settings:array<string,mixed>,entries:array<int,array<string,mixed>>}
     */
    public function build(int $contentUid, ContentObjectRenderer $cObj, ?array $contentRow = null): array
    {
        $row = $contentRow ?? $this->fetchContentRow($contentUid);
        if ($row === null) {
            return ['settings' => self::DEFAULT_SETTINGS, 'entries' => []];
        }

        $settings = $this->settingsOf($row);
        $stage = (int)$settings['stage'];

        $entries = [];
        foreach ($this->children(self::TABLE_ENTRY, (int)$row['uid']) as $entry) {
            $entries[] = $this->buildEntry($entry, $stage, $cObj);
        }

        return ['settings' => $settings, 'entries' => $entries];
    }

    /**
     * @param array<string,mixed> $entry
     * @return array<string,mixed>
     */
    private function buildEntry(array $entry, int $stage, ContentObjectRenderer $cObj): array
    {
        $layout = (string)($entry['layout'] ?? 'columns');
        if (!in_array($layout, ['columns', 'teasers', 'catalog', 'pagetree', 'spotlight'], true)) {
            $layout = 'columns';
        }

        $columns = [];
        foreach ($this->children(self::TABLE_COLUMN, (int)$entry['uid']) as $column) {
            $items = [];
            foreach ($this->children(self::TABLE_ITEM, (int)$column['uid']) as $item) {
                $items[] = $this->buildItem($item, $stage, $cObj);
            }
            $columns[] = [
                'title' => (string)$column['title'],
                'link' => $this->url((string)$column['link'], $cObj),
                'items' => $items,
            ];
        }

        // Page-tree panels (2026-10-23): the columns mirror the live subtree
        // of the page the entry links to - one column per child, its children
        // as the items - so the menu can never age against the page structure
        // again (the stale 9-market panel after the markets realign was the
        // trigger). Curated columns are ignored on this layout; teasers and
        // the featured slot stay editorial.
        if ($layout === 'pagetree') {
            $columns = $this->treeColumns((string)$entry['link'], $stage, $cObj);
        }

        // Spotlight panels (2026-10-27, customer wish "visual menu like
        // rossvideo.com"): a flat left-rail nav built live from the linked
        // page's children (abstract + page media per item, so the front end
        // can swap the visual area on hover) next to live content cards that
        // a site package supplies via BuildSpotlightEvent - this extension
        // does not know the data sources. Curated columns are ignored here
        // like on pagetree; teasers and the featured slot stay editorial.
        if ($layout === 'spotlight') {
            $columns = [];
        }

        $built = [
            'title' => (string)$entry['title'],
            'link' => $this->url((string)$entry['link'], $cObj),
            'layout' => $layout,
            'columns' => $columns,
        ];

        // Page-tree display (2026-11-02): same columns, two presentations -
        // `columns` side by side, or `rail`: the columns as a list on the
        // left, the hovered column's items as image cards on the right
        // (`cardSize` regular|compact). Additive: a front end that does not
        // know `display` keeps rendering columns.
        if ($layout === 'pagetree') {
            $display = (string)($entry['tree_display'] ?? 'columns');
            $built['display'] = str_starts_with($display, 'rail') ? 'rail' : 'columns';
            if ($built['display'] === 'rail') {
                $built['cardSize'] = $display === 'rail-compact' ? 'compact' : 'regular';
            }
        }

        // Catalog panels: the teaser cards serve as the featured tiles (left
        // column), the catalog data itself comes from a listener of
        // BuildCatalogEvent - this extension does not know the data source.
        if ($layout === 'catalog') {
            $event = $this->eventDispatcher->dispatch(new BuildCatalogEvent($entry, $stage));
            $built['catalog'] = $event->getCatalog();
        }

        if ($layout === 'spotlight') {
            $built['nav'] = $this->navItems((string)$entry['link'], $stage, $cObj);
            $spotlightEvent = $this->eventDispatcher->dispatch(new BuildSpotlightEvent($entry, $stage));
            $built['spotlight'] = $spotlightEvent->getSpotlight();
        }

        if ($layout === 'teasers' || $layout === 'catalog') {
            $teasers = [];
            foreach ($this->children(self::TABLE_TEASER, (int)$entry['uid']) as $teaser) {
                $card = [
                    'kicker' => (string)$teaser['kicker'],
                    'title' => (string)$teaser['title'],
                    'link' => $this->url((string)$teaser['link'], $cObj),
                ];
                if ($stage >= 2) {
                    $card['text'] = trim((string)($teaser['teasertext'] ?? ''));
                    $card['image'] = $this->image(self::TABLE_TEASER, 'image', (int)$teaser['uid']);
                }
                $teasers[] = $card;
            }
            $built['teasers'] = $teasers;
        }

        if ($stage >= 3) {
            $built['featured'] = ((int)($entry['featured_enable'] ?? 0) === 1)
                ? [
                    'kicker' => (string)$entry['featured_kicker'],
                    'title' => (string)$entry['featured_title'],
                    'text' => trim((string)($entry['featured_text'] ?? '')),
                    'link' => $this->url((string)$entry['featured_link'], $cObj),
                    'image' => $this->image(self::TABLE_ENTRY, 'featured_image', (int)$entry['uid']),
                ]
                : null;
        }

        return $built;
    }

    /**
     * @param array<string,mixed> $item
     * @return array<string,mixed>
     */
    private function buildItem(array $item, int $stage, ContentObjectRenderer $cObj): array
    {
        $built = [
            'title' => (string)$item['title'],
            'link' => $this->url((string)$item['link'], $cObj),
        ];
        if ((int)($item['pending'] ?? 0) === 1) {
            $built['pending'] = true;
        }
        if ($stage >= 2) {
            $teaser = trim((string)($item['teaser'] ?? ''));
            if ($teaser !== '') {
                $built['teaser'] = $teaser;
            }
            $badge = trim((string)($item['badge'] ?? ''));
            if ($badge !== '') {
                $built['badge'] = $badge;
            }
            $built['image'] = $this->image(self::TABLE_ITEM, 'image', (int)$item['uid']);
        }
        return $built;
    }

    /**
     * Columns from the page tree below the entry's linked page. getMenu()
     * applies the frontend restrictions (hidden, time, fe_group); nav_hide
     * is NOT an enable field and goes through the additional where clause
     * (found 2026-10-27 - the news detail page stayed in the spotlight
     * rail). An editor hides a page and it leaves the menu with the next
     * cache flush.
     *
     * @return array<int,array<string,mixed>>
     */
    private function treeColumns(string $entryLink, int $stage, ContentObjectRenderer $cObj): array
    {
        $rootUid = $this->linkedPageUid($entryLink);
        if ($rootUid <= 0) {
            return [];
        }
        $columns = [];
        foreach ($this->pageRepository->getMenu($rootUid, '*', 'sorting', self::NAV_WHERE) as $child) {
            $items = [];
            foreach ($this->pageRepository->getMenu((int)$child['uid'], '*', 'sorting', self::NAV_WHERE) as $grandchild) {
                $item = [
                    'title' => (string)(($grandchild['nav_title'] ?? '') !== '' ? $grandchild['nav_title'] : $grandchild['title']),
                    'link' => $this->url('t3://page?uid=' . (int)$grandchild['uid'], $cObj),
                ];
                // card data for the `rail` display (2026-11-02), same rules
                // as the spotlight nav: abstract as teaser, page media image
                if ($stage >= 2) {
                    $teaser = trim((string)($grandchild['abstract'] ?? ''));
                    if ($teaser !== '') {
                        $item['teaser'] = $teaser;
                    }
                    $item['image'] = $this->image('pages', 'media', (int)$grandchild['uid']);
                }
                $items[] = $item;
            }
            $column = [
                'title' => (string)(($child['nav_title'] ?? '') !== '' ? $child['nav_title'] : $child['title']),
                'link' => $this->url('t3://page?uid=' . (int)$child['uid'], $cObj),
                'items' => $items,
            ];
            // visual menus (2026-10-27): a page with media gets its first
            // image as the column visual - attach an image in the page
            // properties and the panel turns into image cards by itself
            if ($stage >= 2) {
                $image = $this->image('pages', 'media', (int)$child['uid']);
                if ($image !== null) {
                    $column['image'] = $image;
                }
            }
            $columns[] = $column;
        }
        return $columns;
    }

    /**
     * Flat left-rail nav for the spotlight layout: the linked page's children
     * with abstract and page media, so the front end can render the rail and
     * swap the visual area on hover. Same visibility rules as treeColumns.
     *
     * @return array<int,array<string,mixed>>
     */
    private function navItems(string $entryLink, int $stage, ContentObjectRenderer $cObj): array
    {
        $rootUid = $this->linkedPageUid($entryLink);
        if ($rootUid <= 0) {
            return [];
        }
        $items = [];
        foreach ($this->pageRepository->getMenu($rootUid, '*', 'sorting', self::NAV_WHERE) as $child) {
            $item = [
                'title' => (string)(($child['nav_title'] ?? '') !== '' ? $child['nav_title'] : $child['title']),
                'link' => $this->url('t3://page?uid=' . (int)$child['uid'], $cObj),
            ];
            if ($stage >= 2) {
                $teaser = trim((string)($child['abstract'] ?? ''));
                if ($teaser !== '') {
                    $item['teaser'] = $teaser;
                }
                $item['image'] = $this->image('pages', 'media', (int)$child['uid']);
            }
            $items[] = $item;
        }
        return $items;
    }

    /** Page uid a menu entry links to; 0 when the link is no page link. */
    private function linkedPageUid(string $entryLink): int
    {
        if (preg_match('/t3:\/\/page\?uid=(\d+)/', $entryLink, $matches)) {
            return (int)$matches[1];
        }
        if (ctype_digit(trim($entryLink))) {
            return (int)trim($entryLink);
        }
        return 0;
    }

    // ------------------------------------------------------------ internals

    /** @return array<string,mixed>|null */
    private function fetchContentRow(int $uid): ?array
    {
        if ($uid <= 0) {
            return null;
        }
        $queryBuilder = $this->queryBuilder(self::TABLE_CONTENT);
        $row = $queryBuilder->select('*')->from(self::TABLE_CONTENT)
            ->where($queryBuilder->expr()->eq('uid', $queryBuilder->createNamedParameter($uid, ParameterType::INTEGER)))
            ->executeQuery()->fetchAssociative();
        if ($row === false) {
            return null;
        }
        return $this->overlay(self::TABLE_CONTENT, $row);
    }

    /**
     * Children of one parent record, in backend sorting order, with the
     * frontend restrictions (hidden, time, delete) applied and translations
     * overlaid.
     *
     * @return array<int,array<string,mixed>>
     */
    private function children(string $table, int $parentUid): array
    {
        $queryBuilder = $this->queryBuilder($table);
        $rows = $queryBuilder->select('*')->from($table)
            ->where(
                $queryBuilder->expr()->eq('parentid', $queryBuilder->createNamedParameter($parentUid, ParameterType::INTEGER)),
                $queryBuilder->expr()->in('sys_language_uid', [-1, 0])
            )
            ->orderBy('sorting', 'ASC')
            ->executeQuery()->fetchAllAssociative();

        $overlaid = [];
        foreach ($rows as $row) {
            $translated = $this->overlay($table, $row);
            if ($translated !== null) {
                $overlaid[] = $translated;
            }
        }
        return $overlaid;
    }

    /**
     * @param array<string,mixed> $row
     * @return array<string,mixed>|null null when the translation hides the record
     */
    private function overlay(string $table, array $row): ?array
    {
        try {
            $overlaid = $this->pageRepository->getLanguageOverlay($table, $row);
            return is_array($overlaid) ? $overlaid : null;
        } catch (\Throwable) {
            return $row;
        }
    }

    private function queryBuilder(string $table): QueryBuilder
    {
        $queryBuilder = $this->connectionPool->getQueryBuilderForTable($table);
        $queryBuilder->setRestrictions(GeneralUtility::makeInstance(FrontendRestrictionContainer::class));
        return $queryBuilder;
    }

    /**
     * FlexForm settings merged over the defaults, typed the way the front end
     * expects them.
     *
     * @param array<string,mixed> $row
     * @return array<string,mixed>
     */
    private function settingsOf(array $row): array
    {
        $flex = $this->flexFormService->convertFlexFormContentToArray((string)($row['pi_flexform'] ?? ''));
        $stored = is_array($flex['settings'] ?? null) ? $flex['settings'] : [];
        $settings = array_merge(self::DEFAULT_SETTINGS, array_filter($stored, static fn($v): bool => $v !== '' && $v !== null));

        $settings['stage'] = max(1, min(3, (int)$settings['stage']));
        $settings['closeDelay'] = max(0, (int)$settings['closeDelay']);
        $settings['columnsPerRow'] = max(2, min(6, (int)$settings['columnsPerRow']));
        $settings['showCounts'] = (bool)$settings['showCounts'];
        $settings['showViewAll'] = (bool)$settings['showViewAll'];
        $settings['openOn'] = $settings['openOn'] === 'click' ? 'click' : 'hover';
        $settings['panelWidth'] = $settings['panelWidth'] === 'full' ? 'full' : 'container';
        $settings['pendingBehaviour'] = in_array($settings['pendingBehaviour'], ['fallback', 'mute', 'hide'], true)
            ? $settings['pendingBehaviour'] : 'fallback';
        $settings['viewAllLabel'] = (string)$settings['viewAllLabel'];

        return $settings;
    }

    /** Resolved URL for a link field; '' when empty or unresolvable. */
    private function url(string $link, ContentObjectRenderer $cObj): string
    {
        $link = trim($link);
        if ($link === '') {
            return '';
        }
        try {
            return (string)$cObj->typoLink_URL(['parameter' => $link, 'forceAbsoluteUrl' => false]);
        } catch (\Throwable) {
            return '';
        }
    }

    /**
     * First file reference of a field as a plain object - url plus the
     * metadata a menu needs. Null when nothing is attached.
     *
     * @return array<string,mixed>|null
     */
    private function image(string $table, string $field, int $uid): ?array
    {
        try {
            $references = $this->fileRepository->findByRelation($table, $field, $uid);
        } catch (\Throwable) {
            return null;
        }
        $reference = $references[0] ?? null;
        if ($reference === null) {
            return null;
        }
        try {
            // Menu tiles are small: ship a processed 640px webp instead of the
            // original upload - multi-MB teaser images went over the wire
            // (found 2026-10-23). 640 matches the search-tile convention; the
            // original URL stays the fallback when processing fails, so the
            // menu never loses an image over a converter hiccup.
            try {
                $imageService = GeneralUtility::makeInstance(ImageService::class);
                $processed = $imageService->applyProcessingInstructions(
                    $reference,
                    ['maxWidth' => 640, 'fileExtension' => 'webp']
                );
                return [
                    'url' => $imageService->getImageUri($processed),
                    'alternative' => (string)$reference->getProperty('alternative'),
                    'title' => (string)$reference->getProperty('title'),
                    'width' => (int)$processed->getProperty('width'),
                    'height' => (int)$processed->getProperty('height'),
                ];
            } catch (\Throwable) {
                return [
                    'url' => $reference->getPublicUrl(),
                    'alternative' => (string)$reference->getProperty('alternative'),
                    'title' => (string)$reference->getProperty('title'),
                    'width' => (int)$reference->getProperty('width'),
                    'height' => (int)$reference->getProperty('height'),
                ];
            }
        } catch (\Throwable) {
            return null;
        }
    }
}