<?php

namespace App\Controller;

use App\Content\CustomCode;
use App\Content\DocumentValidator;
use App\Content\MenuRepository;
use App\Content\PartialRepository;
use App\Content\StyleCompiler;
use App\Content\Theme;
use App\Domain\InvalidDocument;
use App\Domain\InvalidPage;
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;
use Symfony\Component\Security\Csrf\CsrfTokenManagerInterface;

/**
 * Header, footer and reusable sections in the same editor as a page.
 *
 * The editor front end takes its API base from a data attribute, so it works against pages and
 * against areas without a second implementation. Areas have no draft and no publication: they are
 * shared, so a saved change is live. The editor hides the publish button for them.
 */
#[Route('/%kant.admin_path%/partials')]
final class PartialController extends AbstractController
{
    public function __construct(
        private PartialRepository $partials,
        private DocumentValidator $validator,
        private MenuRepository $menus,
        private Theme $theme,
        private StyleCompiler $styles,
        private CustomCode $code,
        private CsrfTokenManagerInterface $csrf,
    ) {
    }

    #[Route('', name: 'admin_partials', methods: ['GET'])]
    public function index(): Response
    {
        $partials = [];
        foreach ($this->partials->all() as $partial) {
            $partial['usedBy'] = 'section' === $partial['kind'] ? $this->partials->usedBy($partial['slug']) : [];
            $partials[] = $partial;
        }

        return $this->render('admin/partials.html.twig', ['partials' => $partials, 'kinds' => PartialRepository::KINDS]);
    }

    #[Route('/new', name: 'admin_partial_create', methods: ['POST'])]
    public function create(Request $request): Response
    {
        $this->denyAccessUnlessGranted('ROLE_EDITOR');
        if (!$this->isCsrfTokenValid('partials', $request->request->getString('_csrf_token'))) {
            return $this->back('Deine Sitzung ist abgelaufen. Bitte melde dich erneut an.');
        }
        $name = trim($request->request->getString('name'));
        try {
            $id = $this->partials->create(
                $request->request->getString('kind', 'section'),
                $request->request->getString('slug') ?: $this->slugify($name),
                $name,
                // A shared area starts with one empty section, so there is something to click on.
                ['schemaVersion' => 11, 'title' => '' === $name ? 'Bereich' : $name, 'description' => 'Wird an jeder Stelle gezeigt, die ihn einbindet.', 'blocks' => [
                    ['id' => 'b_'.bin2hex(random_bytes(8)), 'type' => 'section', 'layout' => ['tone' => 'paper', 'width' => 'normal'], 'children' => []],
                ]],
            );
        } catch (InvalidPage|InvalidDocument $e) {
            return $this->back($e->getMessage());
        }

        return $this->redirectToRoute('admin_partial_editor', ['id' => $id]);
    }

    #[Route('/{id}/delete', name: 'admin_partial_delete', requirements: ['id' => '[a-f0-9]{32}'], methods: ['POST'])]
    public function delete(Request $request, string $id): Response
    {
        $this->denyAccessUnlessGranted('ROLE_EDITOR');
        if (!$this->isCsrfTokenValid('partials', $request->request->getString('_csrf_token'))) {
            return $this->back('Deine Sitzung ist abgelaufen. Bitte melde dich erneut an.');
        }
        try {
            $this->partials->delete($id);
        } catch (InvalidPage $e) {
            return $this->back($e->getMessage());
        }

        return $this->back('Die Sektion wurde entfernt. Seiten, die sie einbinden, zeigen an dieser Stelle nichts mehr.', 'success');
    }

    #[Route('/{id}', name: 'admin_partial_editor', requirements: ['id' => '[a-f0-9]{32}'], methods: ['GET'])]
    public function editor(string $id): Response
    {
        return $this->render('admin/editor.html.twig', ['partial' => $this->partial($id), 'kinds' => PartialRepository::KINDS]);
    }

    #[Route('/{id}/document', name: 'admin_partial_document', requirements: ['id' => '[a-f0-9]{32}'], methods: ['GET'])]
    public function document(string $id): JsonResponse
    {
        return $this->json($this->payload($this->partial($id)));
    }

    #[Route('/{id}/draft', name: 'admin_partial_save', requirements: ['id' => '[a-f0-9]{32}'], methods: ['POST'])]
    #[Route('/{id}/preview', name: 'admin_partial_preview', requirements: ['id' => '[a-f0-9]{32}'], methods: ['POST'])]
    public function write(Request $request, string $id): Response
    {
        $this->denyAccessUnlessGranted('ROLE_EDITOR');
        if (!$this->isCsrfTokenValid('editor', $request->headers->get('X-CSRF-Token'))) {
            return $this->json(['error' => 'Deine Sitzung ist abgelaufen. Bitte melde dich erneut an.'], 403);
        }
        if (strlen($request->getContent()) > 270000) {
            return $this->json(['error' => 'Der Bereich ist zu groß (maximal 256 KiB Inhalt).'], 413);
        }
        $partial = $this->partial($id);
        try {
            $body = json_decode($request->getContent(), true, 64, JSON_THROW_ON_ERROR);
            $document = $body['document'] ?? null;
            if (!is_array($body) || !is_array($document)) {
                throw new \InvalidArgumentException();
            }
            if ('admin_partial_preview' === $request->attributes->get('_route')) {
                $this->validator->validate($document, false);

                return $this->renderPreview($partial, $document);
            }
            if (!isset($body['expectedVersion']) || !is_int($body['expectedVersion'])) {
                throw new \InvalidArgumentException();
            }
            if (!$this->isGranted('ROLE_ADMIN')) {
                $this->code->assertScriptsUnchanged($document, $partial['document']);
            }
            $this->partials->save($id, $document, $body['expectedVersion']);
            $partial['document'] = $document;
            $partial['version'] = $body['expectedVersion'] + 1;

            return $this->json($this->payload($partial));
        } catch (StaleWrite $e) {
            return $this->json(['error' => $e->getMessage(), 'conflict' => true], 409);
        } catch (InvalidDocument|InvalidPage $e) {
            return $this->json(['error' => 'Bitte prüfe die Inhalte: '.$e->getMessage()], 422);
        } catch (\JsonException|\InvalidArgumentException) {
            return $this->json(['error' => 'Die Anfrage enthält kein gültiges Dokument.'], 422);
        }
    }

    /** The area on its own, in the shell of a page, so the editor preview looks like the result. */
    private function renderPreview(array $partial, array $document): Response
    {
        $theme = $this->theme->load();
        $navigation = [];
        foreach ($this->menus->all() as $slot => $menu) {
            $navigation[$slot] = $this->menus->resolve($menu['items'], '');
        }
        $sections = [];
        foreach ($this->partials->referencedSlugs($document) as $slug) {
            $section = $this->partials->resolveSection($slug);
            if (null !== $section) {
                $sections[$slug] = $section['document'];
            }
        }

        return $this->render('page.html.twig', [
            'page' => ['locale' => 'de', 'path' => '', 'type' => 'page', 'slug' => '', 'document' => $document],
            'canonical' => '',
            'editing' => true,
            'navigation' => $navigation,
            'areas' => [],
            'sections' => $sections,
            'postLists' => [],
            'postMeta' => null,
            'needsTabs' => false,
            'forms' => [],
            'pageStyles' => $this->theme->css($theme).$this->styles->compileDocument($document),
            'googleFonts' => $this->theme->googleFontsUrl($theme),
        ]);
    }

    private function partial(string $id): array
    {
        return $this->partials->find($id) ?? throw $this->createNotFoundException('Bereich nicht gefunden.');
    }

    private function payload(array $partial): array
    {
        return [
            'document' => $partial['document'],
            'version' => $partial['version'],
            'revisionId' => null,
            'publishedRevisionId' => null,
            'csrfToken' => $this->csrf->getToken('editor')->getValue(),
        ];
    }

    private function slugify(string $name): string
    {
        $slug = strtr(mb_strtolower($name, 'UTF-8'), ['ä' => 'ae', 'ö' => 'oe', 'ü' => 'ue', 'ß' => 'ss']);

        return substr(trim(preg_replace('/[^a-z0-9]+/', '-', $slug) ?? '', '-'), 0, 80);
    }

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

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