import React from 'react';
import { useNavigate } from 'react-router-dom';
import { CalendarDays, MapPin, Plus, Search, Camera, Users, Sparkles } from 'lucide-react';
import { Card } from '@tamagui/card';
import { YStack, XStack } from '@tamagui/stacks';
import { SizableText as Text } from '@tamagui/text';
import { Pressable } from '@tamagui/react-native-web-lite';
import { ScrollView } from '@tamagui/scroll-view';
import { ToggleGroup } from '@tamagui/toggle-group';
import { Separator } from '@tamagui/separator';
import { useTranslation } from 'react-i18next';
import { MobileShell, HeaderActionButton } from './components/MobileShell';
import { PillBadge, CTAButton, FloatingActionButton, SkeletonCard } from './components/Primitives';
import { MobileInput } from './components/FormControls';
import { getEvents, TenantEvent } from '../api';
import { adminPath } from '../constants';
import { isAuthError } from '../auth/tokens';
import { getApiErrorMessage } from '../lib/apiError';
import { useBackNavigation } from './hooks/useBackNavigation';
import { buildEventStatusCounts, filterEventsByStatus, resolveEventStatusKey, type EventStatusKey } from './lib/eventFilters';
import { buildEventListStats } from './lib/eventListStats';
import { useAdminTheme } from './theme';
import { useAuth } from '../auth/context';

export default function MobileEventsPage() {
  const { t } = useTranslation('management');
  const navigate = useNavigate();
  const { user } = useAuth();
  const isMember = user?.role === 'member';
  const [events, setEvents] = React.useState<TenantEvent[]>([]);
  const [loading, setLoading] = React.useState(true);
  const [error, setError] = React.useState<string | null>(null);
  const [query, setQuery] = React.useState('');
  const [statusFilter, setStatusFilter] = React.useState<EventStatusKey>('all');
  const searchRef = React.useRef<HTMLInputElement>(null);
  const back = useBackNavigation();
  const { text, muted, subtle, border, primary, danger, surface, surfaceMuted, accentSoft, accent, shadow } = useAdminTheme();
  React.useEffect(() => {
    (async () => {
      try {
        setEvents(await getEvents());
      } catch (err) {
        if (!isAuthError(err)) {
          setError(getApiErrorMessage(err, t('events.errors.loadFailed')));
        }
      } finally {
        setLoading(false);
      }
    })();
  }, [t]);

  return (
    <MobileShell
      activeTab="home"
      title={t('events.list.title')}
      onBack={back}
      headerActions={
        <HeaderActionButton
          onPress={() => searchRef.current?.focus()}
          ariaLabel={t('events.detail.pickEvent')}
        >
          <Search size={18} color={text} />
        </HeaderActionButton>
      }
    >
      {error ? (
        <Card
          borderRadius={22}
          borderWidth={2}
          borderColor={border}
          backgroundColor={surface}
          padding="$3"
          shadowColor={shadow}
          shadowOpacity={0.16}
          shadowRadius={16}
          shadowOffset={{ width: 0, height: 10 }}
        >
          <Text fontWeight="700" color={danger}>
            {error}
          </Text>
        </Card>
      ) : null}

      <Card
        borderRadius={22}
        borderWidth={2}
        borderColor={border}
        backgroundColor={surface}
        padding="$3"
        shadowColor={shadow}
        shadowOpacity={0.16}
        shadowRadius={16}
        shadowOffset={{ width: 0, height: 10 }}
      >
        <YStack space="$2.5">
          <XStack
            alignItems="center"
            paddingHorizontal="$3"
            paddingVertical="$1.5"
            borderRadius={999}
            borderWidth={1}
            borderColor={border}
            backgroundColor={surfaceMuted}
          >
            <Text fontSize="$xs" fontWeight="800" color={text}>
              {t('events.list.overview.title')}
            </Text>
          </XStack>
          <MobileInput
            ref={searchRef}
            type="search"
            value={query}
            onChange={(e) => setQuery(e.target.value)}
            placeholder={t('events.detail.pickEvent')}
            compact
          />
          <Text fontSize="$xs" color={muted}>
            {t('events.list.subtitle')}
          </Text>
        </YStack>
      </Card>

      {loading ? (
        <YStack space="$2">
          {Array.from({ length: 3 }).map((_, idx) => (
            <SkeletonCard key={`sk-${idx}`} height={90} />
          ))}
        </YStack>
      ) : events.length === 0 ? (
        <Card
          borderRadius={22}
          borderWidth={2}
          borderColor={border}
          backgroundColor={surface}
          padding="$3"
          shadowColor={shadow}
          shadowOpacity={0.16}
          shadowRadius={16}
          shadowOffset={{ width: 0, height: 10 }}
        >
          <YStack space="$2" alignItems="center">
            <Text fontSize="$md" fontWeight="700">
              {t('events.list.title')}
            </Text>
            <Text fontSize="$sm" color={muted} textAlign="center">
              {t('events.list.overview.empty')}
            </Text>
            {!isMember ? (
              <CTAButton
                label={t('events.list.actions.create')}
                onPress={() => navigate(adminPath('/events/new'))}
              />
            ) : null}
          </YStack>
        </Card>
      ) : (
        <EventsList
          events={events}
          query={query}
          statusFilter={statusFilter}
          onStatusChange={setStatusFilter}
          onOpen={(slug) => navigate(adminPath(`/mobile/events/${slug}`))}
          onEdit={!isMember ? (slug) => navigate(adminPath(`/mobile/events/${slug}/edit`)) : undefined}
        />
      )}

      {!isMember ? (
        <FloatingActionButton
          label={t('events.list.actions.create')}
          icon={Plus}
          onPress={() => navigate(adminPath('/mobile/events/new'))}
        />
      ) : null}
    </MobileShell>
  );
}

function EventsList({
  events,
  query,
  statusFilter,
  onStatusChange,
  onOpen,
  onEdit,
}: {
  events: TenantEvent[];
  query: string;
  statusFilter: EventStatusKey;
  onStatusChange: (value: EventStatusKey) => void;
  onOpen: (slug: string) => void;
  onEdit?: (slug: string) => void;
}) {
  const { t } = useTranslation('management');
  const { text, muted, subtle, border, primary, surface, surfaceMuted, accentSoft, accent, shadow } = useAdminTheme();
  const activeBg = accentSoft;
  const activeBorder = accent;

  const statusCounts = React.useMemo(() => buildEventStatusCounts(events), [events]);
  const filteredByStatus = React.useMemo(
    () => filterEventsByStatus(events, statusFilter),
    [events, statusFilter]
  );
  const filteredEvents = React.useMemo(() => {
    if (!query.trim()) return filteredByStatus;
    const needle = query.toLowerCase();
    return filteredByStatus.filter((event) => {
      const hay = `${event.name ?? ''} ${event.location ?? ''}`.toLowerCase();
      return hay.includes(needle);
    });
  }, [filteredByStatus, query]);

  const filters: Array<{ key: EventStatusKey; label: string; count: number }> = [
    { key: 'all', label: t('events.list.filters.all'), count: statusCounts.all },
    { key: 'upcoming', label: t('events.list.filters.upcoming'), count: statusCounts.upcoming },
    { key: 'draft', label: t('events.list.filters.draft'), count: statusCounts.draft },
    { key: 'past', label: t('events.list.filters.past'), count: statusCounts.past },
  ];

  return (
    <YStack space="$3">
      <Card
        borderRadius={22}
        borderWidth={2}
        borderColor={border}
        backgroundColor={surface}
        padding="$3"
        shadowColor={shadow}
        shadowOpacity={0.14}
        shadowRadius={14}
        shadowOffset={{ width: 0, height: 8 }}
      >
        <YStack space="$2.5">
          <XStack
            alignItems="center"
            paddingHorizontal="$3"
            paddingVertical="$1.5"
            borderRadius={999}
            borderWidth={1}
            borderColor={border}
            backgroundColor={surfaceMuted}
          >
            <Text fontSize="$xs" fontWeight="800" color={text}>
              {t('events.workspace.fields.status')}
            </Text>
          </XStack>
          <ScrollView horizontal showsHorizontalScrollIndicator={false}>
            <ToggleGroup
              type="single"
              value={statusFilter}
              onValueChange={(value) => value && onStatusChange(value as EventStatusKey)}
            >
              <XStack space="$2" paddingVertical="$1">
                {filters.map((filter) => {
                  const active = filter.key === statusFilter;
                  return (
                    <ToggleGroup.Item
                      key={filter.key}
                      value={filter.key}
                      borderRadius={999}
                      borderWidth={1}
                      borderColor={active ? activeBorder : border}
                      backgroundColor={active ? activeBg : surface}
                      paddingVertical="$2"
                      paddingHorizontal="$3"
                    >
                      <XStack alignItems="center" space="$1.5">
                        <Text fontSize="$xs" fontWeight="700" color={active ? primary : muted}>
                          {filter.label}
                        </Text>
                        <PillBadge tone={active ? 'success' : 'muted'}>{filter.count}</PillBadge>
                      </XStack>
                    </ToggleGroup.Item>
                  );
                })}
              </XStack>
            </ToggleGroup>
          </ScrollView>
        </YStack>
      </Card>

      {filteredEvents.length === 0 ? (
        <Card
          borderRadius={22}
          borderWidth={2}
          borderColor={border}
          backgroundColor={surface}
          padding="$3"
          shadowColor={shadow}
          shadowOpacity={0.14}
          shadowRadius={14}
          shadowOffset={{ width: 0, height: 8 }}
        >
          <YStack space="$2" alignItems="center">
            <Text fontSize="$sm" fontWeight="700" color={text}>
              {t('events.list.empty.filtered')}
            </Text>
            <Text fontSize="$xs" color={muted} textAlign="center">
              {t('events.list.empty.filteredHint')}
            </Text>
            <CTAButton
              label={t('events.list.filters.all')}
              tone="ghost"
              fullWidth={false}
              onPress={() => onStatusChange('all')}
            />
          </YStack>
        </Card>
      ) : (
        filteredEvents.map((event) => {
          const statusKey = resolveEventStatusKey(event);
          const statusLabel =
            statusKey === 'draft'
              ? t('events.list.filters.draft')
              : statusKey === 'past'
                ? t('events.list.filters.past')
                : t('events.list.filters.upcoming');
          const statusTone = statusKey === 'draft' ? 'warning' : statusKey === 'past' ? 'muted' : 'success';
          return (
            <EventRow
              key={event.id}
              event={event}
              text={text}
              muted={muted}
              subtle={subtle}
              border={border}
              primary={primary}
              surface={surface}
              shadow={shadow}
              statusLabel={statusLabel}
              statusTone={statusTone}
              onOpen={onOpen}
              onEdit={onEdit}
            />
          );
        })
      )}
    </YStack>
  );
}

function EventRow({
  event,
  text,
  muted,
  subtle,
  border,
  primary,
  surface,
  shadow,
  statusLabel,
  statusTone,
  onOpen,
  onEdit,
}: {
  event: TenantEvent;
  text: string;
  muted: string;
  subtle: string;
  border: string;
  primary: string;
  surface: string;
  shadow: string;
  statusLabel: string;
  statusTone: 'success' | 'warning' | 'muted';
  onOpen: (slug: string) => void;
  onEdit?: (slug: string) => void;
}) {
  const { t, i18n } = useTranslation('management');
  const locale = i18n.language;
  const stats = buildEventListStats(event);
  return (
    <Card
      borderRadius={22}
      borderWidth={2}
      borderColor={border}
      backgroundColor={surface}
      padding="$3"
      shadowColor={shadow}
      shadowOpacity={0.14}
      shadowRadius={14}
      shadowOffset={{ width: 0, height: 8 }}
    >
      <YStack space="$2.5">
        <XStack justifyContent="space-between" alignItems="flex-start" space="$2">
          <YStack space="$1">
            <Text fontSize="$md" fontWeight="800" color={text}>
              {renderName(event.name, t)}
            </Text>
            <XStack alignItems="center" space="$2">
              <CalendarDays size={14} color={subtle} />
              <Text fontSize="$sm" color={muted}>
                {formatDate(event.event_date, t, locale)}
              </Text>
            </XStack>
            <XStack alignItems="center" space="$2">
              <MapPin size={14} color={subtle} />
              <Text fontSize="$sm" color={muted}>
                {resolveLocation(event, t)}
              </Text>
            </XStack>
            <PillBadge tone={statusTone}>{statusLabel}</PillBadge>
          </YStack>
          {onEdit ? (
            <Pressable onPress={() => onEdit(event.slug)}>
              <Text fontSize="$xl" color={muted}>
                ˅
              </Text>
            </Pressable>
          ) : null}
        </XStack>

        <XStack alignItems="center" space="$2" flexWrap="wrap">
          <EventStatChip
            icon={Camera}
            label={t('events.list.stats.photos')}
            value={stats.photos}
            muted={subtle}
          />
          <EventStatChip
            icon={Users}
            label={t('events.list.stats.guests')}
            value={stats.guests}
            muted={subtle}
          />
          <EventStatChip
            icon={Sparkles}
            label={t('events.list.stats.tasks')}
            value={stats.tasks}
            muted={subtle}
          />
        </XStack>

        <Separator borderColor={border} />

        <Pressable onPress={() => onOpen(event.slug)}>
          <XStack alignItems="center" justifyContent="flex-start" space="$2">
            <Plus size={16} color={primary} />
            <Text fontSize="$sm" color={primary} fontWeight="700">
              {t('events.list.actions.open')}
            </Text>
          </XStack>
        </Pressable>
      </YStack>
    </Card>
  );
}

function EventStatChip({
  icon: Icon,
  label,
  value,
  muted,
}: {
  icon: typeof Camera;
  label: string;
  value: number;
  muted: string;
}) {
  return (
    <XStack alignItems="center" space="$1">
      <Icon size={12} color={muted} />
      <Text fontSize="$xs" color={muted}>
        {value} {label}
      </Text>
    </XStack>
  );
}

function renderName(name: TenantEvent['name'], t: (key: string) => string): string {
  if (typeof name === 'string') return name;
  if (name && typeof name === 'object') {
    return name.de ?? name.en ?? Object.values(name)[0] ?? t('events.placeholders.untitled');
  }
  return t('events.placeholders.untitled');
}

function resolveLocation(event: TenantEvent, t: (key: string) => string): string {
  const settings = (event.settings ?? {}) as Record<string, unknown>;
  const candidate =
    (settings.location as string | undefined) ??
    (settings.address as string | undefined) ??
    (settings.city as string | undefined);
  if (candidate && candidate.trim()) {
    return candidate;
  }
  return t('events.detail.locationPlaceholder');
}

function formatDate(iso: string | null, t: (key: string) => string, locale?: string): string {
  const fallback = t('events.detail.dateTbd');
  if (!iso) return fallback;
  const date = new Date(iso);
  if (Number.isNaN(date.getTime())) {
    return fallback;
  }
  return date.toLocaleDateString(locale || undefined, { month: 'short', day: 'numeric', year: 'numeric' });
}
