'use client';

import { useMemo, useState } from 'react';
import Link from 'next/link';
import {
  CalendarIcon,
  ClockIcon,
  MapPinIcon,
  ArrowTopRightOnSquareIcon,
  TicketIcon,
  UserPlusIcon,
  QrCodeIcon,
} from '@heroicons/react/24/outline';
import toast from 'react-hot-toast';
import Card from '@/components/ui/Card';
import Button from '@/components/ui/Button';
import type { UserTicket, NextEventInfo } from '@/lib/api';
import { useLanguage } from '@/context/LanguageContext';
import { formatDateLong, formatTime, parseDate } from '@/lib/utils';
import { StatusPill, deriveTicketStatus } from './_shared/status';
import {
  groupByBooking,
  isUnpaid,
  isAwaitingApproval,
  isOnHold,
  isActionableAttention,
  ticketAmount,
  shareTicket,
  isToday,
  type BookingGroup,
} from './_shared/helpers';
import PayActions from './_shared/PayActions';
import AttentionBanner from './_shared/AttentionBanner';
import QrTicketModal from './_shared/QrTicketModal';

interface OverviewTabProps {
  nextEvent: NextEventInfo | null;
  tickets: UserTicket[];
  locale: string;
  userName: string;
  onChange: () => void;
}

export default function OverviewTab({
  nextEvent,
  tickets,
  locale,
  userName,
  onChange,
}: OverviewTabProps) {
  const [qrTickets, setQrTickets] = useState<UserTicket[] | null>(null);

  const activeTickets = useMemo(
    () => tickets.filter((t) => t.status !== 'cancelled'),
    [tickets]
  );

  // Banner: the single booking that most needs attention (unpaid first, then
  // awaiting approval), ordered by soonest event.
  const attentionTicket = useMemo(() => {
    const candidates = activeTickets.filter(
      (t) =>
        isActionableAttention(t) &&
        (isUnpaid(t) || isOnHold(t) || isAwaitingApproval(t))
    );
    const priority = (t: UserTicket) => (isUnpaid(t) ? 0 : isOnHold(t) ? 1 : 2);
    candidates.sort((a, b) => {
      const aUnpaid = priority(a);
      const bUnpaid = priority(b);
      if (aUnpaid !== bUnpaid) return aUnpaid - bUnpaid;
      const aStart = a.event?.startDatetime
        ? parseDate(a.event.startDatetime).getTime()
        : Infinity;
      const bStart = b.event?.startDatetime
        ? parseDate(b.event.startDatetime).getTime()
        : Infinity;
      return aStart - bStart;
    });
    return candidates[0] || null;
  }, [activeTickets]);

  // Hero: full tickets for the next event's booking.
  const heroGroup = useMemo<BookingGroup | null>(() => {
    if (!nextEvent) return null;
    const primary =
      activeTickets.find((t) => t.id === nextEvent.ticket.id) || null;
    if (!primary) return null;
    const groupTickets = primary.bookingId
      ? activeTickets.filter((t) => t.bookingId === primary.bookingId)
      : [primary];
    return { bookingId: primary.bookingId || primary.id, tickets: groupTickets };
  }, [nextEvent, activeTickets]);

  // "Also coming up": upcoming booking groups other than the hero.
  const upcomingGroups = useMemo<BookingGroup[]>(() => {
    const now = Date.now();
    const groups = groupByBooking(
      activeTickets.filter(
        (t) => t.event && parseDate(t.event.startDatetime).getTime() > now
      )
    );
    return groups.filter((g) => g.bookingId !== heroGroup?.bookingId);
  }, [activeTickets, heroGroup]);

  const handleShare = async (ticket: UserTicket) => {
    const title =
      (locale === 'es' && ticket.event?.titleEs
        ? ticket.event.titleEs
        : ticket.event?.title) || 'Event';
    const result = await shareTicket(ticket.id, title, locale);
    if (result === 'copied')
      toast.success(locale === 'es' ? 'Enlace copiado' : 'Link copied');
    else if (result === 'failed')
      toast.error(locale === 'es' ? 'No se pudo compartir' : 'Could not share');
  };

  // Empty state.
  if (activeTickets.length === 0) {
    return (
      <Card className="p-8 text-center">
        <div className="mx-auto mb-4 flex h-14 w-14 items-center justify-center rounded-full bg-primary-yellow/15">
          <TicketIcon className="h-7 w-7 text-primary-yellow" />
        </div>
        <h2 className="mb-1 text-xl font-semibold">
          {locale === 'es' ? `¡Hola, ${userName}!` : `Welcome, ${userName}!`}
        </h2>
        <p className="mx-auto mb-6 max-w-sm text-gray-600">
          {locale === 'es'
            ? 'Todavía no tienes reservas. Encuentra tu primer evento de intercambio de idiomas.'
            : "You have no bookings yet. Find your first language exchange event."}
        </p>
        <Link href="/events">
          <Button size="lg">
            {locale === 'es' ? 'Explorar eventos' : 'Browse events'}
          </Button>
        </Link>
      </Card>
    );
  }

  return (
    <div className="space-y-6">
      {/* 1 — Attention banner (only when money is owed / awaiting). */}
      {attentionTicket && (
        <AttentionBanner
          ticket={attentionTicket}
          locale={locale}
          onChange={onChange}
        />
      )}

      {/* 2 — Next event hero. */}
      {heroGroup && heroGroup.tickets[0].event && (
        <HeroCard
          group={heroGroup}
          locale={locale}
          onChange={onChange}
          onShowQr={() => setQrTickets(heroGroup.tickets)}
          onShare={handleShare}
        />
      )}

      {/* 3 — Also coming up. */}
      {upcomingGroups.length > 0 && (
        <Card className="p-6">
          <h3 className="mb-4 text-lg font-semibold">
            {locale === 'es' ? 'También se viene' : 'Also coming up'}
          </h3>
          <div className="space-y-3">
            {upcomingGroups.map((group) => {
              const t = group.tickets[0];
              const status = deriveTicketStatus(t.status, t.payment?.status);
              const title =
                (locale === 'es' && t.event?.titleEs
                  ? t.event.titleEs
                  : t.event?.title) || 'Event';
              const { amount, currency } = ticketAmount(t);
              return (
                <div
                  key={group.bookingId}
                  className="flex flex-col gap-3 rounded-card bg-secondary-gray p-4 sm:flex-row sm:items-center sm:justify-between"
                >
                  <div className="min-w-0">
                    <div className="flex items-center gap-2">
                      <p className="truncate font-medium">{title}</p>
                      {group.tickets.length > 1 && (
                        <span className="text-xs text-gray-500">
                          ×{group.tickets.length}
                        </span>
                      )}
                    </div>
                    <p className="mt-0.5 text-sm text-gray-600">
                      {t.event && formatDateLong(t.event.startDatetime, locale as 'en' | 'es')}
                    </p>
                  </div>
                  <div className="flex items-center gap-3">
                    <StatusPill status={status} locale={locale} />
                    {isOnHold(t) ? (
                      <PayActions
                        ticketId={t.id}
                        amount={amount}
                        currency={currency}
                        destination={title}
                        locale={locale}
                        onPaid={onChange}
                        layout="inline"
                        size="sm"
                        onHold
                      />
                    ) : isUnpaid(t) ? (
                      <PayActions
                        ticketId={t.id}
                        amount={amount}
                        currency={currency}
                        destination={title}
                        locale={locale}
                        onPaid={onChange}
                        layout="inline"
                        size="sm"
                      />
                    ) : (
                      (status === 'confirmed' || status === 'attended') && (
                        <Button
                          variant="outline"
                          size="sm"
                          onClick={() => setQrTickets(group.tickets)}
                        >
                          {locale === 'es' ? 'Ver entrada' : 'View ticket'}
                        </Button>
                      )
                    )}
                  </div>
                </div>
              );
            })}
          </div>
        </Card>
      )}

      {/* 6 — Browse events. */}
      <div className="flex justify-center pt-2">
        <Link href="/events">
          <Button variant="outline" size="lg">
            {locale === 'es' ? 'Explorar eventos' : 'Browse events'}
          </Button>
        </Link>
      </div>

      {qrTickets && (
        <QrTicketModal
          tickets={qrTickets}
          locale={locale}
          onClose={() => setQrTickets(null)}
        />
      )}
    </div>
  );
}

function HeroCard({
  group,
  locale,
  onChange,
  onShowQr,
  onShare,
}: {
  group: BookingGroup;
  locale: string;
  onChange: () => void;
  onShowQr: () => void;
  onShare: (ticket: UserTicket) => void;
}) {
  const { t } = useLanguage();
  const ticket = group.tickets[0];
  const event = ticket.event!;
  const title =
    (locale === 'es' && event.titleEs ? event.titleEs : event.title) || 'Event';
  const status = deriveTicketStatus(ticket.status, ticket.payment?.status);
  const { amount, currency } = ticketAmount(ticket);
  const multi = group.tickets.length > 1;
  const today = isToday(event.startDatetime);
  const showQrReady = status === 'confirmed' || status === 'attended';

  return (
    <Card className="overflow-hidden">
      {/* Image with status pill + today badge overlay. */}
      <div className="relative h-44 w-full bg-secondary-gray sm:h-56">
        {event.bannerUrl ? (
          <img
            src={event.bannerUrl}
            alt={title}
            className="h-full w-full object-cover"
          />
        ) : (
          <div className="flex h-full w-full items-center justify-center">
            <TicketIcon className="h-12 w-12 text-gray-300" />
          </div>
        )}
        <div className="absolute right-3 top-3 flex items-center gap-2">
          {today && (
            <span className="rounded-full bg-primary-yellow px-3 py-1 text-xs font-semibold text-primary-dark shadow-sm">
              {locale === 'es' ? 'Hoy' : 'Today'}
            </span>
          )}
          <StatusPill status={status} locale={locale} className="shadow-sm" />
        </div>
      </div>

      <div className="p-6">
        <p className="mb-1 text-xs font-semibold uppercase tracking-wider text-primary-yellow">
          {locale === 'es' ? 'Tu próximo evento' : 'Your next event'}
        </p>
        <div className="mb-4 flex items-start justify-between gap-3">
          <h3 className="text-2xl font-bold leading-tight">{title}</h3>
          {multi && (
            <span className="whitespace-nowrap rounded-full bg-secondary-gray px-3 py-1 text-sm font-medium text-gray-700">
              {locale === 'es'
                ? `${group.tickets.length} entradas`
                : `${group.tickets.length} tickets`}
            </span>
          )}
        </div>

        <div className="mb-5 space-y-2 text-gray-600">
          <p className="flex items-center gap-3">
            <CalendarIcon className="h-5 w-5 text-primary-yellow" />
            {formatDateLong(event.startDatetime, locale as 'en' | 'es')}
          </p>
          <p className="flex items-center gap-3">
            <ClockIcon className="h-5 w-5 text-primary-yellow" />
            {formatTime(event.startDatetime, locale as 'en' | 'es')}
          </p>
          <p className="flex items-center gap-3">
            <MapPinIcon className="h-5 w-5 text-primary-yellow" />
            <span className="flex-1">{event.location}</span>
            {event.locationUrl && (
              <a
                href={event.locationUrl}
                target="_blank"
                rel="noopener noreferrer"
                className="inline-flex items-center gap-1 whitespace-nowrap text-sm font-medium text-secondary-blue hover:underline"
              >
                {locale === 'es' ? 'Cómo llegar' : 'Get directions'}
                <ArrowTopRightOnSquareIcon className="h-4 w-4" />
              </a>
            )}
          </p>
        </div>

        {/* Today + ready → show the QR prominently for check-in. */}
        {today && showQrReady && (
          <div className="mb-4 rounded-card bg-primary-yellow/10 p-4 text-center">
            <p className="mb-3 text-sm font-medium text-primary-dark">
              {locale === 'es'
                ? 'Muestra este código en la entrada'
                : 'Show this code at the door'}
            </p>
            <Button onClick={onShowQr} size="lg" className="w-full sm:w-auto">
              <QrCodeIcon className="mr-2 h-5 w-5" />
              {locale === 'es' ? 'Mostrar código QR' : 'Show QR code'}
            </Button>
          </div>
        )}

        {/* Smart primary action. */}
        {isOnHold(ticket) ? (
          <PayActions
            ticketId={ticket.id}
            amount={amount}
            currency={currency}
            destination={title}
            locale={locale}
            onPaid={onChange}
            layout="inline"
            size="md"
            onHold
          />
        ) : isUnpaid(ticket) ? (
          <PayActions
            ticketId={ticket.id}
            amount={amount}
            currency={currency}
            destination={title}
            locale={locale}
            onPaid={onChange}
            layout="inline"
            size="md"
          />
        ) : isAwaitingApproval(ticket) ? (
          <p className="rounded-card bg-amber-50 px-4 py-3 text-sm text-amber-800">
            {t('dashboard.payment.receivedConfirmShortly')}
          </p>
        ) : (
          !today && (
            <Button onClick={onShowQr} size="md">
              <TicketIcon className="mr-2 h-5 w-5" />
              {locale === 'es' ? 'Ver entrada' : 'View ticket'}
            </Button>
          )
        )}

        {/* Multi-ticket guest reminder. */}
        {multi && showQrReady && (
          <div className="mt-4 flex flex-col gap-2 rounded-card border border-secondary-light-gray p-3 sm:flex-row sm:items-center sm:justify-between">
            <p className="text-sm text-gray-600">
              {locale === 'es'
                ? 'Tienes una entrada de más para un invitado.'
                : 'You have a spare ticket for a guest.'}
            </p>
            <Button
              variant="outline"
              size="sm"
              onClick={() => onShare(group.tickets[1])}
            >
              <UserPlusIcon className="mr-2 h-4 w-4" />
              {locale === 'es' ? 'Compartir con un invitado' : 'Share with a guest'}
            </Button>
          </div>
        )}
      </div>
    </Card>
  );
}