<?php

namespace App\Controller;

use App\Content\MenuRepository;
use App\Content\PageRepository;
use App\Domain\InvalidMenu;
use App\Domain\StaleWrite;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Attribute\Route;

final class MenuController extends AbstractController
{
    public function __construct(private MenuRepository $menus, private PageRepository $pages)
    {
    }

    /**
     * Die Sprungziele einer Seite, fuer die Auswahl im Menue: jeder Baustein mit eigenem Anker,
     * beschriftet mit seiner ersten Ueberschrift. Wer ein Sprungziel setzt, soll es waehlen und
     * nicht wissen muessen, wie es im Editor hiess.
     */
    #[Route('/%kant.admin_path%/api/sprungziele/{id}', name: 'admin_menu_anchors', requirements: ['id' => '[A-Za-z0-9_-]{1,64}'], methods: ['GET'])]
    public function anchors(string $id): JsonResponse
    {
        $this->denyAccessUnlessGranted('ROLE_PUBLISHER');
        $page = $this->pages->findForEditor($id);
        if (null === $page) {
            return $this->json(['items' => []], 404);
        }
        $items = [];
        $heading = static function (array $block) use (&$heading): string {
            if ('heading' === ($block['type'] ?? null)) {
                return trim(html_entity_decode(strip_tags((string) ($block['props']['text'] ?? '')), ENT_QUOTES | ENT_HTML5, 'UTF-8'));
            }
            foreach ($block['children'] ?? [] as $child) {
                $text = $heading($child);
                if ('' !== $text) {
                    return $text;
                }
            }

            return '';
        };
        $walk = static function (array $blocks) use (&$walk, &$items, $heading): void {
            foreach ($blocks as $block) {
                if (is_string($block['anchor'] ?? null) && '' !== $block['anchor']) {
                    $title = $heading($block);
                    $items[] = ['anchor' => $block['anchor'], 'label' => '' === $title ? '#'.$block['anchor'] : mb_strimwidth($title, 0, 70, '…').' (#'.$block['anchor'].')'];
                }
                $walk($block['children'] ?? []);
            }
        };
        $walk($page['document']['blocks'] ?? []);

        return $this->json(['items' => $items]);
    }

    #[Route('/%kant.admin_path%/menus', name: 'admin_menus', methods: ['GET'])]
    public function index(Request $request): Response
    {
        // Ein gespeichertes Menue steht sofort auf der Website - Sache des Veroeffentlichers.
        $this->denyAccessUnlessGranted('ROLE_PUBLISHER');
        $slot = $request->query->getString('slot', 'header');
        $slot = isset(MenuRepository::SLOTS[$slot]) ? $slot : 'header';
        $menu = $this->menus->all()[$slot] ?? null;
        $rows = $this->flatten($menu['items'] ?? []);
        $selected = [];
        foreach ($rows as &$row) {
            if ($row['pageId']) {
                $selected[$row['pageId']] ??= $this->pages->choices(id: $row['pageId'])[0] ?? ['id' => $row['pageId'], 'title' => 'Nicht mehr verfügbar', 'path' => ''];
            }
            $row['page'] = $selected[$row['pageId']] ?? null;
        }
        unset($row);

        return $this->render('admin/menus.html.twig', [
            'slots' => MenuRepository::SLOTS, 'slot' => $slot, 'slotName' => MenuRepository::SLOTS[$slot],
            'menu' => $menu, 'rows' => $rows,
            'menuIcons' => \App\Content\DocumentValidator::ICONS,
        ]);
    }

    #[Route('/%kant.admin_path%/menus/{slot}', name: 'admin_menu_save', methods: ['POST'])]
    public function save(Request $request, string $slot): Response
    {
        $this->denyAccessUnlessGranted('ROLE_PUBLISHER');
        if (!$this->isCsrfTokenValid('menus', $request->request->getString('_csrf_token'))) {
            return 'json' === $request->getPreferredFormat() ? $this->json(['error' => 'Deine Sitzung ist abgelaufen. Bitte erneut anmelden.'], 403) : $this->back('Deine Sitzung ist abgelaufen. Bitte melde dich erneut an.', slot: $slot);
        }
        try {
            $this->menus->save(
                $slot,
                $request->request->getString('name'),
                $this->tree($request->request->all('items')),
                $request->request->getInt('expectedVersion', -1),
            );
        } catch (InvalidMenu|StaleWrite $e) {
            return 'json' === $request->getPreferredFormat() ? $this->json(['error' => $e->getMessage()], $e instanceof StaleWrite ? 409 : 422) : $this->back($e->getMessage(), slot: $slot);
        }

        if ('json' === $request->getPreferredFormat()) {
            return $this->json(['message' => 'Menü gespeichert.', 'version' => $this->menus->all()[$slot]['version']]);
        }

        return $this->back('Das Menü wurde gespeichert.', 'success', $slot);
    }

    /**
     * Turns the stored tree back into the flat rows the form edits.
     *
     * @return list<array{label: string, type: string, pageId: string, anchor: string, url: string, level: int}>
     */
    private function flatten(array $items, int $level = 1): array
    {
        $rows = [];
        foreach ($items as $item) {
            $rows[] = [
                'label' => $item['label'], 'type' => $item['type'], 'level' => $level,
                'pageId' => $item['pageId'] ?? '', 'anchor' => $item['anchor'] ?? '', 'url' => $item['url'] ?? '',
                'newTab' => $item['newTab'] ?? false,
                'icon' => $item['icon'] ?? '', 'iconPosition' => $item['iconPosition'] ?? 'before',
            ];
            array_push($rows, ...$this->flatten($item['children'] ?? [], $level + 1));
        }

        return $rows;
    }

    /**
     * The form posts a flat, numbered list so it works without JavaScript. Order comes from the
     * position field, nesting from the level field: a level-2 row joins the last level-1 row.
     * Rows without a label are treated as removed, which is what the empty "add" row is for.
     */
    private function tree(array $rows): array
    {
        $flat = [];
        foreach ($rows as $row) {
            if (!is_array($row) || '' === trim((string) ($row['label'] ?? ''))) {
                continue;
            }
            $flat[] = [
                'label' => trim((string) $row['label']),
                'type' => (string) ($row['type'] ?? 'page'),
                'pageId' => (string) ($row['pageId'] ?? ''),
                'anchor' => ltrim(trim((string) ($row['anchor'] ?? '')), '#'),
                'url' => trim((string) ($row['url'] ?? '')),
                'newTab' => '1' === (string) ($row['newTab'] ?? ''),
                'icon' => (string) ($row['icon'] ?? ''), 'iconPosition' => (string) ($row['iconPosition'] ?? 'before'),
                'level' => max(1, min(MenuRepository::MAX_DEPTH, (int) ($row['level'] ?? 1))),
                'position' => (int) ($row['position'] ?? 0),
            ];
        }
        usort($flat, static fn (array $a, array $b): int => $a['position'] <=> $b['position']);

        $items = [];
        foreach ($flat as $row) {
            $item = ['label' => $row['label'], 'type' => $row['type'], 'children' => []];
            if ('' !== $row['icon']) {
                $item['icon'] = $row['icon'];
                $item['iconPosition'] = $row['iconPosition'];
            }
            if ($row['newTab']) {
                $item['newTab'] = true;
            }
            if ('url' === $row['type']) {
                $item['url'] = $row['url'];
            } else {
                $item['pageId'] = $row['pageId'];
                $item['anchor'] = $row['anchor'];
            }
            if (1 === $row['level'] || [] === $items) {
                $items[] = $item;
                continue;
            }
            $items[array_key_last($items)]['children'][] = $item;
        }

        return $items;
    }

    private function back(string $message, string $type = 'error', string $slot = 'header'): Response
    {
        $this->addFlash($type, $message);

        return $this->redirectToRoute('admin_menus', 'header' === $slot ? [] : ['slot' => $slot]);
    }
}