import React from 'react';
import {
  ArrowRight,
  Camera,
  Clock3,
  Heart,
  MessageCircle,
  Moon,
  QrCode,
  ShieldCheck,
  Sparkles,
  SunMedium,
  Wand2,
} from 'lucide-react';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import { cn } from '@/lib/utils';
import { LanguageSwitcher } from '../components/LanguageSwitcher';
import { FrostedSurface } from '../components/tenant';
import { ADMIN_DEFAULT_AFTER_LOGIN_PATH, ADMIN_LOGIN_PATH } from '../constants';
import { encodeReturnTo, resolveReturnTarget } from '../lib/returnTo';
import { navigateToHref } from '../lib/navigation';

const heroStats = [
  { label: 'Events begleitet', value: '2.100+' },
  { label: 'Fotos kuratiert', value: '680k' },
  { label: 'Mission Cards live', value: '120+' },
];

const featureCards = [
  {
    icon: Sparkles,
    badge: 'Welcome Flow',
    title: 'Geführte Einrichtung',
    description:
      'Ein roter Faden von eurer ersten Mission bis zum Event-Branding. Alles läuft dort, wo ihr später auch Events steuert.',
  },
  {
    icon: QrCode,
    badge: 'Gäste einladen',
    title: 'Links & QR-Cards teilen',
    description:
      'Mit einem Fingertipp entstehen Einladungslinks, QR-Codes und TWA-Links für Android & iOS – ganz ohne App Store Hürden.',
  },
  {
    icon: Camera,
    badge: 'Live Galerie',
    title: 'Moderieren wie im Dashboard',
    description:
      'Markiert Highlights, ordnet Emotions oder sperrt Fotos – exakt die Tools aus dem Event Admin, nur mit Willkommens-Glow.',
  },
];

const timelineSteps = [
  {
    title: 'Mission Cards wählen',
    description: 'Kuratiert Aufgaben, die eure Gäste ins Erzählen bringen. Jeder Schritt speichert automatisch.',
  },
  {
    title: 'Event Branding festlegen',
    description: 'Farben, Story, Cover – alles in einer Ansicht. Vorschau zeigt sofort, wie der Gastzugang wirkt.',
  },
  {
    title: 'Link teilen & feiern',
    description: 'QR-Code oder Link verschicken, fertig. Gäste landen direkt in eurer Galerie und können ohne Login starten.',
  },
];

const supportHighlights = [
  {
    icon: ShieldCheck,
    title: 'Datenschutz-ready',
    description: 'Keine versteckten Tracker, DSGVO-konformes Hosting und Kontrolle, wer Fotos sieht.',
  },
  {
    icon: Clock3,
    title: 'Offline nutzbar',
    description: 'Uploads puffern automatisch, falls das WLAN in der Location aussetzt.',
  },
  {
    icon: MessageCircle,
    title: 'Crew an eurer Seite',
    description: 'Direkter Chat zum Fotospiel-Team – aus der App heraus oder via hallo@fotospiel.de.',
  },
];

export default function WelcomeTeaserPage() {
  const [isRedirecting, setIsRedirecting] = React.useState(false);
  const [mode, setMode] = React.useState<'dark' | 'light'>('dark');
  const isLightMode = mode === 'light';
  const flowSectionRef = React.useRef<HTMLDivElement | null>(null);

  React.useEffect(() => {
    document.body.classList.add('tenant-admin-theme', 'tenant-admin-welcome-theme');

    return () => {
      document.body.classList.remove('tenant-admin-theme', 'tenant-admin-welcome-theme');
    };
  }, []);

  React.useEffect(() => {
    document.body.classList.toggle('tenant-admin-welcome-light', isLightMode);
    document.body.classList.toggle('tenant-admin-welcome-dark', !isLightMode);
  }, [isLightMode]);

  const theme = React.useMemo(
    () => ({
      rootBackground: isLightMode
        ? 'bg-gradient-to-br from-rose-50 via-white to-sky-50 text-slate-900'
        : 'bg-slate-950 text-white',
      aurora: isLightMode
        ? 'bg-[radial-gradient(ellipse_at_top,_rgba(255,179,205,0.55),_transparent_55%),radial-gradient(ellipse_at_bottom,_rgba(148,187,233,0.45),_transparent_60%)]'
        : 'bg-[radial-gradient(ellipse_at_top,_rgba(255,137,170,0.25),_transparent_60%),radial-gradient(ellipse_at_bottom,_rgba(99,102,241,0.25),_transparent_62%)]',
      overlay: isLightMode
        ? 'bg-gradient-to-br from-white/85 via-rose-50/70 to-sky-50/70'
        : 'bg-gradient-to-br from-slate-950/95 via-slate-950/80 to-[#150b1f]/90',
      headerBadge: isLightMode ? 'border-rose-100 bg-white text-rose-500' : 'border-white/30 bg-white/5 text-white',
      headerSubtitle: isLightMode ? 'text-slate-600' : 'text-white/70',
      heroEyebrow: isLightMode ? 'text-rose-500' : 'text-rose-200',
      heroTitle: isLightMode ? 'text-slate-900' : 'text-white',
      heroBody: isLightMode ? 'text-slate-600' : 'text-white/75',
      ghostButton: isLightMode ? 'text-slate-700 hover:bg-slate-100' : 'text-white/80 hover:bg-white/10',
      statCard: isLightMode
        ? 'border-rose-100/70 bg-white/90 text-slate-900 shadow-rose-100/50'
        : 'border-white/15 bg-white/10 text-white shadow-rose-500/30',
      featureCard: isLightMode
        ? 'border-rose-100 bg-white text-slate-900 shadow-rose-100/40'
        : 'border-white/15 bg-white/10 text-white shadow-slate-900/40',
      timelineCard: isLightMode ? 'border-slate-200 bg-white text-slate-900' : 'border-white/15 bg-white/5 text-white',
      timelineDescription: isLightMode ? 'text-slate-600' : 'text-white/70',
      supportCard: isLightMode ? 'border-slate-200 bg-white text-slate-900' : 'border-white/15 bg-white/10 text-white',
      supportDescription: isLightMode ? 'text-slate-600' : 'text-white/70',
      ctaSurface: isLightMode ? 'border-slate-200 bg-white text-slate-900' : 'border-white/15 bg-white/10 text-white',
      ctaDetail: isLightMode ? 'text-slate-600' : 'text-white/70',
      footer: isLightMode
        ? 'border-t border-slate-200/80 bg-white/70 text-slate-500'
        : 'border-t border-white/10 bg-black/20 text-white/60',
    }),
    [isLightMode]
  );

  const toggleMode = React.useCallback(() => {
    setMode((prev) => (prev === 'dark' ? 'light' : 'dark'));
  }, []);

  const handleLoginRedirect = React.useCallback(() => {
    if (isRedirecting) {
      return;
    }

    setIsRedirecting(true);

    const params = new URLSearchParams(window.location.search);
    const rawReturnTo = params.get('return_to');
    const { finalTarget, encodedFinal } = resolveReturnTarget(rawReturnTo, ADMIN_DEFAULT_AFTER_LOGIN_PATH);
    const target = new URL(ADMIN_LOGIN_PATH, window.location.origin);
    target.searchParams.set('return_to', encodedFinal ?? encodeReturnTo(finalTarget));
    const nextHref = `${target.pathname}${target.search}`;
    navigateToHref(nextHref);
  }, [isRedirecting]);

  const handleScrollToFlow = React.useCallback(() => {
    flowSectionRef.current?.scrollIntoView({ behavior: 'smooth', block: 'start' });
  }, []);

  return (
    <div className={cn('relative min-h-svh overflow-hidden transition-colors duration-500', theme.rootBackground)}>
      <div
        aria-hidden
        className={cn(
          'pointer-events-none absolute inset-0 motion-safe:animate-[aurora_24s_ease-in-out_infinite]',
          theme.aurora
        )}
      />
      <div aria-hidden className={cn('absolute inset-0 transition-colors duration-500', theme.overlay)} />

      <div className="relative z-10 flex min-h-svh flex-col">
        <header className="mx-auto flex w-full max-w-6xl flex-wrap items-center justify-between gap-4 px-6 pb-4 pt-8">
          <div className="space-y-1">
            <Badge
              variant="outline"
              className={cn(
                'border text-[11px] font-semibold uppercase tracking-[0.4em] transition-colors duration-300',
                theme.headerBadge
              )}
            >
              Event Admin · Fotospiel
            </Badge>
            <p className={cn('text-sm transition-colors duration-300', theme.headerSubtitle)}>
              Euer mobiles Kontrollzentrum für Events, Workshops und Feiern
            </p>
          </div>
          <div className="flex flex-wrap items-center gap-3">
            <LanguageSwitcher />
            <Button
              type="button"
              variant="outline"
              className={cn(
                'items-center gap-2 border text-xs font-semibold uppercase tracking-wide',
                isLightMode
                  ? 'border-slate-200 text-slate-700 hover:bg-slate-100'
                  : 'border-white/30 text-white hover:bg-white/10'
              )}
              onClick={toggleMode}
            >
              {isLightMode ? (
                <>
                  <Moon className="h-4 w-4" />
                  Dark Mode
                </>
              ) : (
                <>
                  <SunMedium className="h-4 w-4" />
                  Light Mode
                </>
              )}
            </Button>
            <Button
              type="button"
              variant="outline"
              className={cn(
                'border text-sm font-semibold transition-colors duration-300',
                isLightMode ? 'border-slate-200 text-slate-700 hover:bg-slate-100' : 'border-white/30 text-white hover:bg-white/10'
              )}
              onClick={handleLoginRedirect}
              disabled={isRedirecting}
            >
              {isRedirecting ? 'Weiterleitung …' : 'Login öffnen'}
            </Button>
          </div>
        </header>

        <main className="mx-auto flex w-full max-w-6xl flex-1 flex-col gap-12 px-6 pb-16 pt-4">
          <section className="grid gap-10 lg:grid-cols-[1.1fr_0.9fr]">
            <div className="space-y-8">
              <div className="space-y-4">
                <p
                  className={cn(
                    'text-sm font-semibold uppercase tracking-[0.4em] transition-colors duration-300',
                    theme.heroEyebrow
                  )}
                >
                  Willkommen im Event-Kontrollzentrum
                </p>
                <h1
                  className={cn(
                    'font-display text-4xl font-semibold leading-tight transition-colors duration-300 md:text-5xl',
                    theme.heroTitle
                  )}
                >
                  Alles für eure Gästegeschichte in einer App
                </h1>
                <p
                  className={cn(
                    'text-base leading-relaxed transition-colors duration-300 md:text-lg',
                    theme.heroBody
                  )}
                >
                  Der neue Startscreen begrüßt euch wie eine mobile App, führt euch in den Welcome Flow und lässt euch
                  jederzeit zurück ins Dashboard springen, sobald ihr bereit seid.
                </p>
              </div>

              <div className="flex flex-col gap-3 sm:flex-row">
                <Button type="button" size="lg" onClick={handleLoginRedirect} disabled={isRedirecting}>
                  {isRedirecting ? 'Weiterleitung …' : 'Event Admin öffnen'}
                  <ArrowRight className="h-4 w-4" />
                </Button>
                <Button
                  type="button"
                  size="lg"
                  variant="ghost"
                  className={cn('transition-colors duration-300', theme.ghostButton)}
                  onClick={handleScrollToFlow}
                >
                  Geführten Ablauf ansehen
                  <Heart className="h-4 w-4" />
                </Button>
              </div>

              <div className="grid gap-4 sm:grid-cols-3">
                {heroStats.map((stat) => (
                  <FrostedSurface
                    key={stat.label}
                    className={cn(
                      'rounded-3xl border px-5 py-4 shadow-2xl backdrop-blur transition-colors duration-300',
                      theme.statCard
                    )}
                  >
                    <p className={cn('text-2xl font-semibold', isLightMode ? 'text-slate-900' : 'text-white')}>{stat.value}</p>
                    <p
                      className={cn(
                        'text-xs font-semibold uppercase tracking-wide',
                        isLightMode ? 'text-slate-500' : 'text-white/70'
                      )}
                    >
                      {stat.label}
                    </p>
                  </FrostedSurface>
                ))}
              </div>
            </div>

            <div className="relative">
              <div className="pointer-events-none absolute inset-0 -z-10 translate-y-6 scale-105 rounded-[40px] bg-gradient-to-br from-rose-500/40 via-white/5 to-sky-500/30 blur-3xl" />
              <div className="relative rounded-[40px] border border-white/15 bg-white/95 p-6 text-slate-900 shadow-[0_40px_90px_rgba(15,23,42,0.55)]">
                <div className="flex items-center justify-between text-xs font-semibold text-slate-500">
                  <span>Fotospiel</span>
                  <span>Event Admin</span>
                </div>
                <div className="mt-4 rounded-3xl bg-slate-900/5 p-4">
                  <div className="flex items-center justify-between text-xs font-semibold text-slate-500">
                    <span>Heute</span>
                    <span>Live</span>
                  </div>
                  <div className="mt-4 space-y-3">
                    {['Mission Pack auswählen', 'Event Branding finalisieren', 'Einladungslink teilen'].map((item) => (
                      <div key={item} className="flex items-center justify-between rounded-2xl bg-white p-3 text-sm shadow">
                        <div>
                          <p className="font-semibold text-slate-900">{item}</p>
                          <p className="text-xs text-slate-500">Welcome Flow</p>
                        </div>
                        <Wand2 className="h-5 w-5 text-rose-500" />
                      </div>
                    ))}
                  </div>
                </div>
                <div className="mt-6 rounded-3xl bg-slate-900 text-white">
                  <div className="flex items-center justify-between border-b border-white/10 px-5 py-3 text-xs uppercase tracking-[0.3em] text-white/70">
                    <span>Live Moments</span>
                    <span>+28</span>
                  </div>
                  <div className="space-y-4 px-5 py-6">
                    {[
                      { title: 'Anna lädt 6 Fotos hoch', subtitle: 'Event · Gartenpalast' },
                      { title: 'Max reagiert auf Mission „Emotionen“', subtitle: 'Tasks · Emotion Board' },
                      { title: 'QR-Link 124x gescannt', subtitle: 'Einladungen · Photobooth' },
                    ].map((entry) => (
                      <div key={entry.title} className="space-y-1">
                        <p className="text-sm font-semibold">{entry.title}</p>
                        <p className="text-xs text-white/70">{entry.subtitle}</p>
                      </div>
                    ))}
                  </div>
                </div>
              </div>
            </div>
          </section>

          <section className="grid gap-6 lg:grid-cols-3">
            {featureCards.map((feature) => (
              <FrostedSurface
                key={feature.title}
                className={cn(
                  'flex flex-col gap-4 rounded-3xl border p-6 shadow-lg backdrop-blur transition-colors duration-300',
                  theme.featureCard
                )}
              >
                <div
                  className={cn('flex items-center gap-3 text-sm', isLightMode ? 'text-rose-600' : 'text-white/80')}
                >
                  <feature.icon className={cn('h-5 w-5', isLightMode ? 'text-rose-400' : 'text-rose-200')} />
                  <span>{feature.badge}</span>
                </div>
                <h2 className={cn('text-2xl font-semibold', isLightMode ? 'text-slate-900' : 'text-white')}>
                  {feature.title}
                </h2>
                <p
                  className={cn('text-sm leading-relaxed', isLightMode ? 'text-slate-600' : 'text-white/75')}
                >
                  {feature.description}
                </p>
              </FrostedSurface>
            ))}
          </section>

          <section ref={flowSectionRef} className="grid gap-8 lg:grid-cols-[0.95fr_1.05fr]">
            <FrostedSurface
              className={cn('rounded-3xl border p-6 transition-colors duration-300', theme.timelineCard)}
            >
              <p
                className={cn(
                  'text-xs font-semibold uppercase tracking-[0.4em]',
                  isLightMode ? 'text-rose-500' : 'text-rose-200'
                )}
              >
                Guided Journey
              </p>
              <h3 className={cn('mt-3 text-3xl font-semibold', isLightMode ? 'text-slate-900' : 'text-white')}>
                So leitet euch der Welcome Flow
              </h3>
              <div className="mt-6 space-y-4">
                {timelineSteps.map((step, index) => (
                  <div
                    key={step.title}
                    className={cn(
                      'flex gap-4 rounded-2xl border p-4 transition-colors duration-300',
                      isLightMode ? 'border-slate-200 bg-white' : 'border-white/15 bg-white/5'
                    )}
                  >
                    <div
                      className={cn(
                        'flex h-10 w-10 items-center justify-center rounded-2xl text-lg font-semibold',
                        isLightMode ? 'bg-rose-100 text-rose-600' : 'bg-rose-500/15 text-white'
                      )}
                    >
                      {index + 1}
                    </div>
                    <div>
                      <p className={cn('font-semibold', isLightMode ? 'text-slate-900' : 'text-white')}>
                        {step.title}
                      </p>
                      <p className={cn('text-sm', theme.timelineDescription)}>{step.description}</p>
                    </div>
                  </div>
                ))}
              </div>
            </FrostedSurface>

            <div className="space-y-6">
              <FrostedSurface className="flex flex-col gap-4 rounded-3xl border-white/15 bg-white/95 p-6 text-slate-900 shadow-2xl">
                <div className="flex items-center justify-between text-xs font-semibold uppercase tracking-[0.3em] text-slate-500">
                  <span>Mobile Greeting</span>
                  <span>Neu</span>
                </div>
                <p className="text-2xl font-semibold text-slate-900">Fühlt sich an wie eine native App</p>
                <p className="text-sm text-slate-600">
                  Mit großen Touch-Flächen, Animationen und frosted Cards wirkt der Startscreen wie die mobile Version
                  des Event Admins – perfekt für TWA und Capacitor Builds.
                </p>
                <div className="mt-2 grid gap-3 sm:grid-cols-2">
                  <div className="rounded-2xl bg-slate-900/5 p-4">
                    <p className="text-xs text-slate-500">CTA</p>
                    <p className="text-lg font-semibold text-slate-900">Event Admin öffnen</p>
                    <p className="text-sm text-slate-600">Leitet direkt zum OAuth Login</p>
                  </div>
                  <div className="rounded-2xl bg-slate-900/5 p-4">
                    <p className="text-xs text-slate-500">Scroll Action</p>
                    <p className="text-lg font-semibold text-slate-900">Journey ansehen</p>
                    <p className="text-sm text-slate-600">Smooth Scroll bis zur Timeline</p>
                  </div>
                </div>
              </FrostedSurface>

              <div className="grid gap-4 sm:grid-cols-3">
                {supportHighlights.map((support) => (
                  <FrostedSurface
                    key={support.title}
                    className={cn(
                      'flex flex-col gap-2 rounded-2xl border p-4 transition-colors duration-300',
                      theme.supportCard
                    )}
                  >
                    <support.icon className={cn('h-5 w-5', isLightMode ? 'text-rose-500' : 'text-rose-200')} />
                    <p className={cn('font-semibold', isLightMode ? 'text-slate-900' : 'text-white')}>
                      {support.title}
                    </p>
                    <p className={cn('text-sm', theme.supportDescription)}>{support.description}</p>
                  </FrostedSurface>
                ))}
              </div>
            </div>
          </section>

          <FrostedSurface
            className={cn(
              'flex flex-col gap-4 rounded-3xl border px-6 py-5 transition-colors duration-300 md:flex-row md:items-center md:justify-between',
              theme.ctaSurface
            )}
          >
            <div>
              <p className={cn('text-sm uppercase tracking-[0.4em]', theme.ctaDetail)}>Bereit?</p>
              <h3 className={cn('text-2xl font-semibold', isLightMode ? 'text-slate-900' : 'text-white')}>
                Wechselt ins Dashboard, sobald euer Flow steht.
              </h3>
              <p className={cn('text-sm', theme.ctaDetail)}>
                Alle Schritte lassen sich später direkt aus dem Event Admin wieder öffnen.
              </p>
            </div>
            <Button type="button" size="lg" className="self-start md:self-auto" onClick={handleLoginRedirect} disabled={isRedirecting}>
              {isRedirecting ? 'Weiterleitung …' : 'Zum Login'}
              <ArrowRight className="h-4 w-4" />
            </Button>
          </FrostedSurface>
        </main>

        <footer className={cn('py-6 text-center text-xs transition-colors duration-300', theme.footer)}>
          Fotospiel · Eure Gäste gestalten eure Lieblingsmomente
        </footer>
      </div>
    </div>
  );
}