import React from 'react';
import { Button } from '@/components/ui/button';
import { createBrowserRouter, Outlet, useParams, Link } from 'react-router-dom';
import Header from './components/Header';
import BottomNav from './components/BottomNav';
import { useEventData } from './hooks/useEventData';
import { AlertTriangle, Loader2 } from 'lucide-react';
import type { FetchEventErrorCode } from './services/eventApi';
import { EventStatsProvider } from './context/EventStatsContext';
import { GuestIdentityProvider } from './context/GuestIdentityContext';
import LandingPage from './pages/LandingPage';
import ProfileSetupPage from './pages/ProfileSetupPage';
import HomePage from './pages/HomePage';
import TaskPickerPage from './pages/TaskPickerPage';
import TaskDetailPage from './pages/TaskDetailPage';
import UploadPage from './pages/UploadPage';
import UploadQueuePage from './pages/UploadQueuePage';
import GalleryPage from './pages/GalleryPage';
import PhotoLightbox from './pages/PhotoLightbox';
import AchievementsPage from './pages/AchievementsPage';
import SlideshowPage from './pages/SlideshowPage';
import SettingsPage from './pages/SettingsPage';
import LegalPage from './pages/LegalPage';
import NotFoundPage from './pages/NotFoundPage';

function HomeLayout() {
  const { token } = useParams();

  if (!token) {
    return (
      <div className="pb-16">
        <Header title="Event" />
        <div className="px-4 py-3">
          <Outlet />
        </div>
        <BottomNav />
      </div>
    );
  }

  return (
    <GuestIdentityProvider eventKey={token}>
      <EventBoundary token={token} />
    </GuestIdentityProvider>
  );
}

export const router = createBrowserRouter([
  { path: '/event', element: <SimpleLayout title="Event"><LandingPage /></SimpleLayout> },
  {
    path: '/setup/:token',
    element: <SetupLayout />,
    children: [
      { index: true, element: <ProfileSetupPage /> },
    ],
  },
  {
    path: '/e/:token',
    element: <HomeLayout />,
    children: [
      { index: true, element: <HomePage /> },
      { path: 'tasks', element: <TaskPickerPage /> },
      { path: 'tasks/:taskId', element: <TaskDetailPage /> },
      { path: 'upload', element: <UploadPage /> },
      { path: 'queue', element: <UploadQueuePage /> },
      { path: 'gallery', element: <GalleryPage /> },
      { path: 'photo/:photoId', element: <PhotoLightbox /> },
      { path: 'achievements', element: <AchievementsPage /> },
      { path: 'slideshow', element: <SlideshowPage /> },
    ],
  },
  { path: '/settings', element: <SimpleLayout title="Einstellungen"><SettingsPage /></SimpleLayout> },
  { path: '/legal/:page', element: <SimpleLayout title="Rechtliches"><LegalPage /></SimpleLayout> },
  { path: '*', element: <NotFoundPage /> },
]);

function EventBoundary({ token }: { token: string }) {
  const { event, status, error, errorCode } = useEventData();

  if (status === 'loading') {
    return <EventLoadingView />;
  }

  if (status === 'error' || !event) {
    return <EventErrorView code={errorCode} message={error} />;
  }

  return (
    <EventStatsProvider eventKey={token}>
      <div className="pb-16">
        <Header slug={token} />
        <div className="px-4 py-3">
          <Outlet />
        </div>
        <BottomNav />
      </div>
    </EventStatsProvider>
  );
}

function SetupLayout() {
  const { token } = useParams<{ token: string }>();
  if (!token) return null;
  return (
    <GuestIdentityProvider eventKey={token}>
      <EventStatsProvider eventKey={token}>
        <div className="pb-0">
          <Header slug={token} />
          <Outlet />
        </div>
      </EventStatsProvider>
    </GuestIdentityProvider>
  );
}

function EventLoadingView() {
  return (
    <div className="flex min-h-screen flex-col items-center justify-center gap-4 px-6 text-center">
      <Loader2 className="h-10 w-10 animate-spin text-muted-foreground" aria-hidden />
      <div className="space-y-1">
        <p className="text-lg font-semibold text-foreground">Wir prüfen deinen Zugang...</p>
        <p className="text-sm text-muted-foreground">Einen Moment bitte.</p>
      </div>
    </div>
  );
}

interface EventErrorViewProps {
  code: FetchEventErrorCode | null;
  message: string | null;
}

function EventErrorView({ code, message }: EventErrorViewProps) {
  const content = getErrorContent(code, message);

  return (
    <div className="flex min-h-screen flex-col items-center justify-center gap-6 px-6 text-center">
      <div className="flex h-16 w-16 items-center justify-center rounded-full bg-red-100 text-red-600">
        <AlertTriangle className="h-8 w-8" aria-hidden />
      </div>
      <div className="space-y-2">
        <h2 className="text-2xl font-semibold text-foreground">{content.title}</h2>
        <p className="text-sm text-muted-foreground">{content.description}</p>
        {content.hint && (
          <p className="text-xs text-muted-foreground">{content.hint}</p>
        )}
      </div>
      {content.ctaHref && content.ctaLabel && (
        <Button asChild>
          <Link to={content.ctaHref}>{content.ctaLabel}</Link>
        </Button>
      )}
    </div>
  );
}

function getErrorContent(
  code: FetchEventErrorCode | null,
  message: string | null,
) {
  const base = (fallbackTitle: string, fallbackDescription: string, options?: { ctaLabel?: string; ctaHref?: string; hint?: string }) => ({
    title: fallbackTitle,
    description: message ?? fallbackDescription,
    ctaLabel: options?.ctaLabel,
    ctaHref: options?.ctaHref,
    hint: options?.hint ?? null,
  });

  switch (code) {
    case 'invalid_token':
      return base('Zugriffscode ungültig', 'Der eingegebene Code konnte nicht verifiziert werden.', {
        ctaLabel: 'Neuen Code anfordern',
        ctaHref: '/event',
      });
    case 'token_revoked':
      return base('Zugriffscode deaktiviert', 'Dieser Code wurde zurückgezogen. Bitte fordere einen neuen Code an.', {
        ctaLabel: 'Neuen Code anfordern',
        ctaHref: '/event',
      });
    case 'token_expired':
      return base('Zugriffscode abgelaufen', 'Der Code ist nicht mehr gültig. Aktualisiere deinen Code, um fortzufahren.', {
        ctaLabel: 'Code aktualisieren',
        ctaHref: '/event',
      });
    case 'token_rate_limited':
      return base('Zu viele Versuche', 'Es gab zu viele Eingaben in kurzer Zeit. Warte kurz und versuche es erneut.', {
        hint: 'Tipp: Eine erneute Eingabe ist in wenigen Minuten möglich.',
      });
    case 'event_not_public':
      return base('Event nicht öffentlich', 'Dieses Event ist aktuell nicht öffentlich zugänglich.', {
        hint: 'Nimm Kontakt mit den Veranstalter:innen auf, um Zugang zu erhalten.',
      });
    case 'network_error':
      return base('Verbindungsproblem', 'Wir konnten keine Verbindung zum Server herstellen. Prüfe deine Internetverbindung und versuche es erneut.');
    case 'server_error':
      return base('Server nicht erreichbar', 'Der Server reagiert derzeit nicht. Versuche es später erneut.');
    default:
      return base('Event nicht erreichbar', 'Wir konnten dein Event nicht laden. Bitte versuche es erneut.', {
        ctaLabel: 'Zur Code-Eingabe',
        ctaHref: '/event',
      });
  }
}

function SimpleLayout({ title, children }: { title: string; children: React.ReactNode }) {
  return (
    <div className="pb-16">
      <Header title={title} />
      <div className="px-4 py-3">
        {children}
      </div>
      <BottomNav />
    </div>
  );
}