<?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\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)
    {
    }

    #[Route('/%kant.admin_path%/menus', name: 'admin_menus', methods: ['GET'])]
    public function index(): Response
    {
        $menus = $this->menus->all();
        $rows = [];
        foreach (MenuRepository::SLOTS as $slot => $label) {
            $rows[$slot] = $this->flatten($menus[$slot]['items'] ?? []);
        }
        $pages = [];
        foreach ($this->pages->listForEditor() as $page) {
            $document = json_decode($page['document'] ?? '{}', true, 512, JSON_THROW_ON_ERROR);
            $pages[] = ['id' => $page['id'], 'path' => $page['path'], 'title' => $document['title'] ?? $page['slug']];
        }

        return $this->render('admin/menus.html.twig', [
            'slots' => MenuRepository::SLOTS,
            'menus' => $menus,
            'rows' => $rows,
            'pages' => $pages,
        ]);
    }

    #[Route('/%kant.admin_path%/menus/{slot}', name: 'admin_menu_save', methods: ['POST'])]
    public function save(Request $request, string $slot): Response
    {
        $this->denyAccessUnlessGranted('ROLE_EDITOR');
        if (!$this->isCsrfTokenValid('menus', $request->request->getString('_csrf_token'))) {
            return $this->back('Deine Sitzung ist abgelaufen. Bitte melde dich erneut an.');
        }
        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 $this->back($e->getMessage());
        }

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

    /**
     * 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' => $item['url'] ?? '',
            ];
            array_push($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) ($row['url'] ?? '')),
                'level' => max(1, min(MenuRepository::MAX_DEPTH, (int) ($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 ('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'): Response
    {
        $this->addFlash($type, $message);

        return $this->redirectToRoute('admin_menus');
    }
}