<?php

namespace App\Controller;

use App\Domain\InvalidPage;
use App\Ops\Installation;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Cookie;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
use Symfony\Component\Routing\Attribute\Route;

/**
 * Six screens from an empty webspace to a website, without a console.
 *
 * Every screen answers only while the installation is unfinished, and every one of them writes its
 * result straight away, so a reload continues where it stopped instead of starting over. The order
 * is fixed and enforced here, not only suggested by links: a step whose requirement is missing
 * sends you back to the step that produces it.
 *
 * After the first account exists, every route in this file answers 404 - not because a file was
 * deleted, but because the database says there is an installation.
 *
 * Vorher öffnet sich kein Schritt ohne den Installationsschlüssel (ADR 116): Er steht auf der
 * Abschlussseite von install.php bzw. in var/install.key. Einmal eingegeben, bleibt im Browser
 * ein Cookie mit einem Nachweis darüber, nur für /install.
 */
final class InstallController extends AbstractController
{
    public function __construct(private Installation $installation)
    {
    }

    /** Der Name des Cookies, das den Installationsschlüssel nachweist. */
    public const KEY_COOKIE = 'kant_install';

    #[Route('/install/schluessel', name: 'install_key', methods: ['GET', 'POST'], priority: 11)]
    public function key(Request $request): Response
    {
        if ($this->installation->isInstalled()) {
            throw new NotFoundHttpException('Diese Installation ist abgeschlossen.');
        }
        $error = null;
        try {
            $this->installation->installKey();
            $given = $request->isMethod('POST') ? $request->request->getString('schluessel') : $request->query->getString('schluessel');
            if ('' !== $given) {
                if ($this->installation->acceptsKey($given)) {
                    // Weiter ohne den Schlüssel in der Adresse: er soll weder im Verlauf noch in
                    // einem Serverprotokoll als Verweis stehen bleiben.
                    $response = $this->redirectToRoute('install');
                    $response->headers->setCookie(Cookie::create(self::KEY_COOKIE, $this->installation->keyProof(), 0, '/install', null, $request->isSecure(), true, false, Cookie::SAMESITE_STRICT));

                    return $response;
                }
                $error = 'Dieser Schlüssel passt nicht.';
            }
        } catch (\RuntimeException $e) {
            $error = $e->getMessage();
        }

        $response = $this->render('install/key.html.twig', ['step' => 1, 'error' => $error, 'keyFile' => Installation::KEY_FILE]);
        $response->headers->set('Referrer-Policy', 'no-referrer');

        return $response;
    }

    #[Route('/install', name: 'install', methods: ['GET'], priority: 10)]
    public function check(Request $request): Response
    {
        if ($blocked = $this->guard($request)) {
            return $blocked;
        }
        $checks = $this->installation->checks();

        return $this->render('install/check.html.twig', [
            'step' => 1,
            'checks' => $checks,
            'ready' => $this->installation->ready($checks),
        ]);
    }

    #[Route('/install/datenbank', name: 'install_database', methods: ['GET', 'POST'], priority: 10)]
    public function database(Request $request): Response
    {
        if ($blocked = $this->guard($request)) {
            return $blocked;
        }
        $error = null;
        $driver = $request->request->getString('driver', 'sqlite');
        if ($request->isMethod('POST') && $this->signed($request, 'datenbank')) {
            $input = [
                'host' => $request->request->getString('host', '127.0.0.1'),
                'port' => $request->request->getString('port', '3306'),
                'name' => $request->request->getString('name', 'cms'),
                'user' => $request->request->getString('user'),
                'password' => $request->request->getString('password'),
            ];
            $result = $this->installation->testDatabase('mysql' === $driver ? 'mysql' : 'sqlite', $input);
            $error = $result['error'];
            if (null === $error) {
                try {
                    $this->installation->writeEnvironment(['APP_ENV' => 'prod', 'APP_DEBUG' => '0', 'DATABASE_URL' => $result['url']]);

                    // The new connection only exists in the next request, because the environment
                    // file is read while booting. That is also why this is a redirect and not a
                    // rendered page: the migration screen has to talk to the new database.
                    return $this->redirectToRoute('install_migration');
                } catch (\RuntimeException $e) {
                    $error = $e->getMessage();
                }
            }
        }

        return $this->render('install/database.html.twig', [
            'step' => 2,
            'driver' => $driver,
            'error' => $error,
            'values' => $request->request->all(),
            'mysql' => \extension_loaded('pdo_mysql'),
            // SQLite nur, wenn die Fassung die Tabellenfunktionen kennt, mit denen Doctrine das
            // Schema liest - sonst scheitert erst der naechste Schritt, und zwar unverstaendlich.
            'sqlite' => \extension_loaded('pdo_sqlite') && null !== $this->installation->sqliteVersion()
                && version_compare((string) $this->installation->sqliteVersion(), Installation::MIN_SQLITE, '>='),
            'sqliteVersion' => $this->installation->sqliteVersion(),
            'minSqlite' => Installation::MIN_SQLITE,
            ...$this->token('datenbank'),
        ]);
    }

    #[Route('/install/migration', name: 'install_migration', methods: ['GET', 'POST'], priority: 10)]
    public function migration(Request $request): Response
    {
        if ($blocked = $this->guard($request)) {
            return $blocked;
        }
        if (!$this->installation->environmentWritten()) {
            return $this->redirectToRoute('install_database');
        }
        $error = null;
        $applied = null;
        if ($request->isMethod('POST') && $this->signed($request, 'migration')) {
            @set_time_limit(0);
            try {
                $applied = $this->installation->migrate();

                return $this->redirectToRoute('install_website');
            } catch (\Throwable $e) {
                $error = $e->getMessage();
            }
        }

        return $this->render('install/migration.html.twig', [
            'step' => 3,
            'pending' => $error ? [] : $this->pending(),
            'applied' => $applied,
            'error' => $error,
            ...$this->token('migration'),
        ]);
    }

    #[Route('/install/website', name: 'install_website', methods: ['GET', 'POST'], priority: 10)]
    public function website(Request $request): Response
    {
        if ($blocked = $this->guard($request)) {
            return $blocked;
        }
        if (!$this->installation->schemaReady()) {
            return $this->redirectToRoute('install_migration');
        }
        $error = null;
        if ($request->isMethod('POST') && $this->signed($request, 'website')) {
            try {
                $this->installation->createSite(
                    $request->request->getString('name'),
                    $request->request->getString('origin'),
                    $request->request->getString('locale', 'de'),
                );

                return $this->redirectToRoute('install_account');
            } catch (InvalidPage|\RuntimeException $e) {
                $error = $e->getMessage();
            }
        }

        return $this->render('install/website.html.twig', [
            'step' => 4,
            'error' => $error,
            'values' => $request->request->all(),
            // The address the browser is on is almost always the right one, so it is prefilled.
            'origin' => $request->getSchemeAndHttpHost(),
            ...$this->token('website'),
        ]);
    }

    #[Route('/install/konto', name: 'install_account', methods: ['GET', 'POST'], priority: 10)]
    public function account(Request $request): Response
    {
        if ($blocked = $this->guard($request)) {
            return $blocked;
        }
        if (!$this->installation->siteReady()) {
            return $this->redirectToRoute('install_website');
        }
        $error = null;
        if ($request->isMethod('POST') && $this->signed($request, 'konto')) {
            try {
                $this->installation->createAdmin(
                    $request->request->getString('username'),
                    $request->request->getString('password'),
                    $request->request->getString('repeat'),
                );

                // The last screen is rendered here, not after a redirect: one request later this
                // route is gone, because the account it just created ends the installation.
                return $this->render('install/done.html.twig', [
                    'step' => 6,
                    'username' => strtolower(trim($request->request->getString('username'))),
                ]);
            } catch (InvalidPage $e) {
                $error = $e->getMessage();
            }
        }

        return $this->render('install/account.html.twig', [
            'step' => 5,
            'error' => $error,
            'username' => $request->request->getString('username'),
            ...$this->token('konto'),
        ]);
    }

    /** Reading the pending list must never be the reason the screen cannot be shown. */
    private function pending(): array
    {
        try {
            return $this->installation->pendingMigrations();
        } catch (\Throwable) {
            return [];
        }
    }

    /** 404 nach der Installation; davor ohne Schlüsselnachweis zurück zur Eingabe des Schlüssels. */
    private function guard(Request $request): ?Response
    {
        if ($this->installation->isInstalled()) {
            throw new NotFoundHttpException('Diese Installation ist abgeschlossen.');
        }
        try {
            if ($this->installation->acceptsProof($request->cookies->getString(self::KEY_COOKIE))) {
                return null;
            }
        } catch (\RuntimeException) {
            // Kein Schlüssel lesbar oder schreibbar: die Eingabeseite sagt, woran es liegt.
        }

        return new RedirectResponse($this->generateUrl('install_key'));
    }

    private function token(string $step): array
    {
        $issued = time();

        return ['issued' => $issued, 'signature' => $this->installation->sign($step, $issued)];
    }

    private function signed(Request $request, string $step): bool
    {
        return $this->installation->verify($step, $request->request->getInt('issued'), $request->request->getString('signature'));
    }
}