import { useState, useMemo } from 'react';
import { useSeoMeta } from '@unhead/react';
import { Link } from 'react-router-dom';
import { Layout } from '@/components/Layout';
import { EventCard, EventCardSkeleton } from '@/components/EventCard';
import { TourCard, TourCardSkeleton } from '@/components/TourCard';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Badge } from '@/components/ui/badge';
import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
import { ScrollArea, ScrollBar } from '@/components/ui/scroll-area';
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
import { TrustFilter, type TrustFilterLevel, filterByTrustLevel } from '@/components/TrustFilter';
import { SortDropdown, type SortOption } from '@/components/SortDropdown';
import { useSkateEvents } from '@/hooks/useSkateEvents';
import { useTours } from '@/hooks/useTours';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useFollowing } from '@/hooks/useFollowing';
import { useBatchTrustScores } from '@/hooks/useBatchTrustScores';
import { useComments } from '@/hooks/useComments';
import { useTranslation } from '@/contexts/LanguageContext';
import { EVENT_TYPE_LABELS, TOUR_CATEGORIES, TOUR_SKILL_LEVELS, type TourCategory, type SkateTour } from '@/lib/types';
import {
  Search,
  Plus,
  Calendar,
  X,
  Route,
} from 'lucide-react';
import { cn } from '@/lib/utils';

export default function EventsPage() {
  const { t } = useTranslation();
  
  useSeoMeta({
    title: 'Skate Events & Tours - SkateSpots',
    description: 'Discover skateboarding events, competitions, tours, and sessions near you.',
  });

  const { user } = useCurrentUser();
  const { data: followingList } = useFollowing(user?.pubkey);
  const followCount = followingList?.length ?? 0;
  const smartDefault: TrustFilterLevel = (user && followCount >= 5) ? 'trusted' : 'all';
  const { data: events, isLoading: eventsLoading } = useSkateEvents(100);
  const { data: tours, isLoading: toursLoading } = useTours(100);

  // Main view: events or tours
  const [mainView, setMainView] = useState<'events' | 'tours'>('events');
  
  // Event filters
  const [searchQuery, setSearchQuery] = useState('');
  const [selectedTypes, setSelectedTypes] = useState<string[]>([]);
  const [activeTab, setActiveTab] = useState<'upcoming' | 'past'>('upcoming');
  const [trustFilter, setTrustFilter] = useState<TrustFilterLevel>(smartDefault);
  const [sortBy, setSortBy] = useState<SortOption>('recent');
  
  // Tour filters
  const [tourSearchQuery, setTourSearchQuery] = useState('');
  const [tourCategory, setTourCategory] = useState<TourCategory | 'all'>('all');
  const [tourSkillLevel, setTourSkillLevel] = useState<string>('all');
  const [tourVerifiedOnly, setTourVerifiedOnly] = useState(false);
  const [tourTrustFilter, setTourTrustFilter] = useState<TrustFilterLevel>(smartDefault);
  const [tourSortBy, setTourSortBy] = useState<SortOption>('recent');

  const now = Math.floor(Date.now() / 1000);

  // Fetch trust scores for all event organizers and tour guides
  const allPubkeys = useMemo(() => {
    const eventPubkeys = events?.map((e) => e.pubkey) || [];
    const tourPubkeys = tours?.map((t) => t.pubkey) || [];
    return [...new Set([...eventPubkeys, ...tourPubkeys])];
  }, [events, tours]);
  const { data: trustScores } = useBatchTrustScores(allPubkeys);

  const getTrustScore = (pubkey: string) => trustScores?.get(pubkey);

  // Fetch comment counts for popularity sorting
  const allEventIds = useMemo(() => {
    const eventIds = events?.map((e) => e.event.id) || [];
    const tourIds = tours?.map((t) => t.event.id) || [];
    return [...eventIds, ...tourIds];
  }, [events, tours]);
  const { data: allComments } = useComments(allEventIds);

  const getCommentCount = (eventId: string) => {
    return allComments?.filter((c) => {
      const eTag = c.tags.find(([tag]) => tag === 'e')?.[1];
      return eTag === eventId;
    }).length || 0;
  };

  // Filter and sort tours
  const filteredTours = useMemo(() => {
    if (!tours) return [];

    let filtered = tours.filter((tour) => {
      // Search filter
      if (tourSearchQuery) {
        const query = tourSearchQuery.toLowerCase();
        const matchesTitle = tour.title.toLowerCase().includes(query);
        const matchesLocation = tour.location?.toLowerCase().includes(query);
        const matchesDescription = tour.description?.toLowerCase().includes(query);
        const matchesCities = tour.cities?.some(c => c.toLowerCase().includes(query));
        const matchesCountries = tour.countries?.some(c => c.toLowerCase().includes(query));
        if (!matchesTitle && !matchesLocation && !matchesDescription && !matchesCities && !matchesCountries) {
          return false;
        }
      }

      // Category filter
      if (tourCategory !== 'all' && tour.category !== tourCategory) {
        return false;
      }

      // Skill level filter
      if (tourSkillLevel !== 'all' && tour.skillLevel !== tourSkillLevel) {
        return false;
      }

      return true;
    });

    // Apply trust filter (soft for 'trusted', strict for 'verified'/'following')
    if (trustScores && tourTrustFilter !== 'all') {
      if (tourTrustFilter === 'trusted') {
        filtered.sort((a, b) => {
          const tA = (getTrustScore(a.pubkey) ?? -1) >= 60 ? 1 : 0;
          const tB = (getTrustScore(b.pubkey) ?? -1) >= 60 ? 1 : 0;
          return tB - tA;
        });
      } else {
        filtered = filterByTrustLevel(filtered, tourTrustFilter, getTrustScore);
      }
    }

    // Apply sorting
    filtered.sort((a, b) => {
      switch (tourSortBy) {
        case 'trust': {
          const scoreA = getTrustScore(a.pubkey) || 0;
          const scoreB = getTrustScore(b.pubkey) || 0;
          if (scoreB !== scoreA) return scoreB - scoreA;
          return b.createdAt - a.createdAt;
        }
        case 'popular': {
          const popA = getCommentCount(a.event.id);
          const popB = getCommentCount(b.event.id);
          if (popB !== popA) return popB - popA;
          return b.createdAt - a.createdAt;
        }
        case 'recent':
        default:
          return b.createdAt - a.createdAt;
      }
    });

    return filtered;
  }, [tours, tourSearchQuery, tourCategory, tourSkillLevel, tourTrustFilter, trustScores, tourSortBy]);

  // Filter and sort events
  const filteredEvents = useMemo(() => {
    if (!events) return { upcoming: [], past: [] };

    let filtered = events.filter((event) => {
      // Search filter
      if (searchQuery) {
        const query = searchQuery.toLowerCase();
        const matchesTitle = event.title.toLowerCase().includes(query);
        const matchesLocation = event.location?.toLowerCase().includes(query);
        const matchesDescription = event.description?.toLowerCase().includes(query);
        if (!matchesTitle && !matchesLocation && !matchesDescription) {
          return false;
        }
      }

      // Type filter
      if (selectedTypes.length > 0) {
        const hasMatchingType = event.types.some((type) =>
          selectedTypes.includes(type)
        );
        if (!hasMatchingType) return false;
      }

      return true;
    });

    // Apply trust filter (soft for 'trusted', strict for 'verified'/'following')
    if (trustScores && trustFilter !== 'all') {
      if (trustFilter === 'trusted') {
        filtered.sort((a, b) => {
          const tA = (getTrustScore(a.pubkey) ?? -1) >= 60 ? 1 : 0;
          const tB = (getTrustScore(b.pubkey) ?? -1) >= 60 ? 1 : 0;
          return tB - tA;
        });
      } else {
        filtered = filterByTrustLevel(filtered, trustFilter, getTrustScore);
      }
    }

    // Split into upcoming and past
    let upcoming = filtered.filter((e) => e.start >= now);
    let past = filtered.filter((e) => e.start < now);

    // Apply sorting
    const sortFn = (a: typeof events[0], b: typeof events[0]) => {
      switch (sortBy) {
        case 'trust': {
          const scoreA = getTrustScore(a.pubkey) || 0;
          const scoreB = getTrustScore(b.pubkey) || 0;
          if (scoreB !== scoreA) return scoreB - scoreA; // Highest first
          return a.start - b.start; // Then by time
        }
        case 'popular': {
          const popA = getCommentCount(a.event.id);
          const popB = getCommentCount(b.event.id);
          if (popB !== popA) return popB - popA; // Most popular first
          return a.start - b.start;
        }
        case 'recent':
        default:
          return 0; // Keep time-based sorting
      }
    };

    // Sort upcoming by start time (ascending) + secondary sort
    upcoming.sort((a, b) => {
      if (sortBy === 'recent') return a.start - b.start;
      return sortFn(a, b);
    });

    // Sort past by start time (descending) + secondary sort  
    past.sort((a, b) => {
      if (sortBy === 'recent') return b.start - a.start;
      return sortFn(a, b);
    });

    return { upcoming, past };
  }, [events, searchQuery, selectedTypes, trustFilter, trustScores, sortBy, now, allComments]);

  const toggleType = (type: string) => {
    setSelectedTypes((prev) =>
      prev.includes(type)
        ? prev.filter((t) => t !== type)
        : [...prev, type]
    );
  };

  const clearFilters = () => {
    setSearchQuery('');
    setSelectedTypes([]);
    setTrustFilter('all');
    setSortBy('recent');
  };

  const clearTourFilters = () => {
    setTourSearchQuery('');
    setTourCategory('all');
    setTourSkillLevel('all');
    setTourVerifiedOnly(false);
    setTourTrustFilter('all');
    setTourSortBy('recent');
  };

  const hasActiveFilters = searchQuery || selectedTypes.length > 0 || trustFilter !== 'all' || sortBy !== 'recent';
  const hasActiveTourFilters = tourSearchQuery || tourCategory !== 'all' || tourSkillLevel !== 'all' || tourVerifiedOnly || tourTrustFilter !== 'all' || tourSortBy !== 'recent';
  
  const isLoading = mainView === 'events' ? eventsLoading : toursLoading;

  return (
    <Layout>
      <div className="container px-4 py-8">
        {/* Header */}
        <div className="flex flex-col sm:flex-row items-start sm:items-center justify-between gap-4 mb-6">
          <div>
            <h1 className="text-3xl font-black uppercase neon-lime" style={{
              fontFamily: 'Impact, "Arial Black", sans-serif'
            }}>
              {mainView === 'events' ? t('events.title') : 'Skate Tours'}
            </h1>
            <p className="text-gray-400 mt-1">
              {mainView === 'events' 
                ? t('events.findEvents')
                : 'Discover local guides, national road trips, and world destruction competitions'}
            </p>
          </div>
          {user ? (
            <Link to={mainView === 'events' ? '/create-event' : '/create-tour'}>
              <Button className="gap-2 bg-[#ccff00] text-black hover:bg-[#ccff00]/90 font-bold uppercase">
                <Plus className="h-4 w-4" />
                {mainView === 'events' ? t('events.createEvent') : 'Create Tour'}
              </Button>
            </Link>
          ) : (
            <Badge variant="outline" className="border-yellow-500/50 text-yellow-400 px-3 py-1">
              🔒 {t('events.loginToCreate')}
            </Badge>
          )}
        </div>

        {/* Main View Toggle: Events / Tours */}
        <div className="flex gap-2 mb-6">
          <Button
            variant={mainView === 'events' ? 'default' : 'outline'}
            onClick={() => setMainView('events')}
            className={cn(
              'gap-2 font-bold uppercase',
              mainView === 'events' 
                ? 'bg-[#ccff00] text-black hover:bg-[#ccff00]/90' 
                : 'border-[#ccff00]/30 text-[#ccff00] hover:bg-[#ccff00]/10'
            )}
          >
            <Calendar className="h-4 w-4" />
            Events
            {events && events.length > 0 && (
              <Badge variant="secondary" className={cn(
                'ml-1',
                mainView === 'events' ? 'bg-black/20 text-black' : 'bg-[#ccff00]/20 text-[#ccff00]'
              )}>
                {events.length}
              </Badge>
            )}
          </Button>
          <Button
            variant={mainView === 'tours' ? 'default' : 'outline'}
            onClick={() => setMainView('tours')}
            className={cn(
              'gap-2 font-bold uppercase',
              mainView === 'tours' 
                ? 'bg-cyan-500 text-white hover:bg-cyan-500/90' 
                : 'border-cyan-500/30 text-cyan-400 hover:bg-cyan-500/10'
            )}
          >
            <Route className="h-4 w-4" />
            Tours
            {tours && tours.length > 0 && (
              <Badge variant="secondary" className={cn(
                'ml-1',
                mainView === 'tours' ? 'bg-white/20 text-white' : 'bg-cyan-500/20 text-cyan-400'
              )}>
                {tours.length}
              </Badge>
            )}
          </Button>
        </div>

        {/* Events View */}
        {mainView === 'events' && (
          <>
            {/* Filters */}
            <div className="space-y-4 mb-8">
              {/* Search, Trust Filter, and Sort */}
              <div className="flex flex-col sm:flex-row gap-3">
                <div className="relative flex-1 max-w-md">
                  <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
                  <Input
                    placeholder={t('events.searchPlaceholder')}
                    value={searchQuery}
                    onChange={(e) => setSearchQuery(e.target.value)}
                    className="pl-9"
                  />
                </div>
                <div className="flex gap-2">
                  <SortDropdown
                    value={sortBy}
                    onChange={setSortBy}
                    contentType="events"
                  />
                  <TrustFilter
                    value={trustFilter}
                    onChange={setTrustFilter}
                    compact
                  />
                </div>
              </div>

              {/* Type filters */}
              <ScrollArea className="w-full whitespace-nowrap">
                <div className="flex gap-2 pb-2">
                  {Object.entries(EVENT_TYPE_LABELS).map(([type, label]) => (
                    <Badge
                      key={type}
                      variant={selectedTypes.includes(type) ? 'default' : 'outline'}
                      className={cn(
                        'cursor-pointer transition-colors',
                        selectedTypes.includes(type)
                          ? 'bg-primary hover:bg-primary/90'
                          : 'hover:bg-muted'
                      )}
                      onClick={() => toggleType(type)}
                    >
                      {label}
                    </Badge>
                  ))}
                  {hasActiveFilters && (
                    <Badge
                      variant="destructive"
                      className="cursor-pointer gap-1"
                      onClick={clearFilters}
                    >
                      <X className="h-3 w-3" />
                      {t('common.clearAll')}
                    </Badge>
                  )}
                </div>
                <ScrollBar orientation="horizontal" />
              </ScrollArea>
            </div>

            {/* Tabs */}
            <Tabs value={activeTab} onValueChange={(v) => setActiveTab(v as 'upcoming' | 'past')}>
              <TabsList className="mb-6">
                <TabsTrigger value="upcoming" className="gap-2">
                  {t('events.upcomingEvents')}
                  {filteredEvents.upcoming.length > 0 && (
                    <Badge variant="secondary" className="ml-1">
                      {filteredEvents.upcoming.length}
                    </Badge>
                  )}
                </TabsTrigger>
                <TabsTrigger value="past" className="gap-2">
                  {t('events.pastEvents')}
                  {filteredEvents.past.length > 0 && (
                    <Badge variant="secondary" className="ml-1">
                      {filteredEvents.past.length}
                    </Badge>
                  )}
                </TabsTrigger>
              </TabsList>

              <TabsContent value="upcoming">
                {eventsLoading ? (
                  <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 stagger-children">
                    {Array.from({ length: 6 }).map((_, i) => (
                      <EventCardSkeleton key={i} />
                    ))}
                  </div>
                ) : filteredEvents.upcoming.length > 0 ? (
                  <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 stagger-children">
                    {filteredEvents.upcoming.map((event) => (
                      <EventCard key={event.id} event={event} />
                    ))}
                  </div>
                ) : (
                  <div className="text-center py-12">
                    <Calendar className="h-12 w-12 mx-auto mb-4 text-muted-foreground/50" />
                    <p className="text-muted-foreground mb-4">
                      {hasActiveFilters
                        ? t('events.noEventsMatch')
                        : t('events.noUpcoming')}
                    </p>
                    {hasActiveFilters ? (
                      <Button variant="outline" onClick={clearFilters}>
                        {t('common.clearFilters')}
                      </Button>
                    ) : (
                      user && (
                        <Link to="/create-event">
                          <Button className="gap-2">
                            <Plus className="h-4 w-4" />
                            {t('events.createEvent')}
                          </Button>
                        </Link>
                      )
                    )}
                  </div>
                )}
              </TabsContent>

              <TabsContent value="past">
                {eventsLoading ? (
                  <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 stagger-children">
                    {Array.from({ length: 6 }).map((_, i) => (
                      <EventCardSkeleton key={i} />
                    ))}
                  </div>
                ) : filteredEvents.past.length > 0 ? (
                  <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 stagger-children">
                    {filteredEvents.past.map((event) => (
                      <EventCard key={event.id} event={event} />
                    ))}
                  </div>
                ) : (
                  <div className="text-center py-12">
                    <Calendar className="h-12 w-12 mx-auto mb-4 text-muted-foreground/50" />
                    <p className="text-muted-foreground">
                      {t('events.noPast')}
                    </p>
                  </div>
                )}
              </TabsContent>
            </Tabs>
          </>
        )}

        {/* Tours View */}
        {mainView === 'tours' && (
          <>
            {/* Tour Filters */}
            <div className="space-y-4 mb-8">
              {/* Search, Category, Skill Level, Sort, Trust */}
              <div className="flex flex-col sm:flex-row gap-3">
                <div className="relative flex-1 max-w-md">
                  <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
                  <Input
                    placeholder="Search tours by name, location, or country..."
                    value={tourSearchQuery}
                    onChange={(e) => setTourSearchQuery(e.target.value)}
                    className="pl-9"
                  />
                </div>
                <div className="flex gap-2 flex-wrap">
                  <Select value={tourCategory} onValueChange={(v) => setTourCategory(v as TourCategory | 'all')}>
                    <SelectTrigger className="w-[140px]">
                      <SelectValue placeholder="Category" />
                    </SelectTrigger>
                    <SelectContent>
                      <SelectItem value="all">All Categories</SelectItem>
                      {Object.entries(TOUR_CATEGORIES).map(([key, info]) => (
                        <SelectItem key={key} value={key}>
                          {info.emoji} {info.label}
                        </SelectItem>
                      ))}
                    </SelectContent>
                  </Select>
                  
                  <Select value={tourSkillLevel} onValueChange={setTourSkillLevel}>
                    <SelectTrigger className="w-[130px]">
                      <SelectValue placeholder="Skill Level" />
                    </SelectTrigger>
                    <SelectContent>
                      <SelectItem value="all">All Levels</SelectItem>
                      {Object.entries(TOUR_SKILL_LEVELS).map(([key, info]) => (
                        <SelectItem key={key} value={key}>
                          {info.emoji} {info.label}
                        </SelectItem>
                      ))}
                    </SelectContent>
                  </Select>
                  
                  <SortDropdown
                    value={tourSortBy}
                    onChange={setTourSortBy}
                    contentType="tours"
                  />
                  <TrustFilter
                    value={tourTrustFilter}
                    onChange={setTourTrustFilter}
                    compact
                  />
                </div>
              </div>

              {/* Tour Category Quick Filters */}
              <ScrollArea className="w-full whitespace-nowrap">
                <div className="flex gap-2 pb-2">
                  {Object.entries(TOUR_CATEGORIES).map(([key, info]) => (
                    <Badge
                      key={key}
                      variant={tourCategory === key ? 'default' : 'outline'}
                      className={cn(
                        'cursor-pointer transition-colors',
                        tourCategory === key
                          ? 'text-white'
                          : 'hover:bg-muted'
                      )}
                      style={{
                        backgroundColor: tourCategory === key ? info.color : 'transparent',
                        borderColor: `${info.color}60`,
                        color: tourCategory === key ? (info.color === '#ccff00' ? 'black' : 'white') : info.color,
                      }}
                      onClick={() => setTourCategory(tourCategory === key ? 'all' : key as TourCategory)}
                    >
                      {info.emoji} {info.label}
                    </Badge>
                  ))}
                  {hasActiveTourFilters && (
                    <Badge
                      variant="destructive"
                      className="cursor-pointer gap-1"
                      onClick={clearTourFilters}
                    >
                      <X className="h-3 w-3" />
                      Clear All
                    </Badge>
                  )}
                </div>
                <ScrollBar orientation="horizontal" />
              </ScrollArea>
            </div>

            {/* Tours Grid */}
            {toursLoading ? (
              <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 stagger-children">
                {Array.from({ length: 6 }).map((_, i) => (
                  <TourCardSkeleton key={i} />
                ))}
              </div>
            ) : filteredTours.length > 0 ? (
              <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6 stagger-children">
                {filteredTours.map((tour) => (
                  <TourCard key={tour.id} tour={tour} />
                ))}
              </div>
            ) : (
              <div className="text-center py-12">
                <Route className="h-12 w-12 mx-auto mb-4 text-muted-foreground/50" />
                <p className="text-muted-foreground mb-4">
                  {hasActiveTourFilters
                    ? 'No tours match your filters'
                    : 'No tours available yet'}
                </p>
                {hasActiveTourFilters ? (
                  <Button variant="outline" onClick={clearTourFilters}>
                    Clear Filters
                  </Button>
                ) : (
                  user && (
                    <Link to="/create-tour">
                      <Button className="gap-2 bg-cyan-500 hover:bg-cyan-600">
                        <Plus className="h-4 w-4" />
                        Create Tour
                      </Button>
                    </Link>
                  )
                )}
              </div>
            )}
          </>
        )}
      </div>
    </Layout>
  );
}