import { useMemo } from 'react';
import { useSeoMeta } from '@unhead/react';
import { Link } from 'react-router-dom';
import { ErrorState } from '@/components/ErrorState';
import { Card, CardContent } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import { Avatar, AvatarImage, AvatarFallback } from '@/components/ui/avatar';
import { Skeleton } from '@/components/ui/skeleton';
import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useTranslation } from '@/contexts/language';
import { useAuthor } from '@/hooks/useAuthor';
import { useSkateShops } from '@/hooks/useSkateShops';
import { useSkateSpots } from '@/hooks/useSkateSpots';
import { genUserName } from '@/lib/genUserName';
import { nip19 } from 'nostr-tools';
import { Trophy, Medal, Crown, Store, MapPin, Zap, Camera, FileText, Users, Sparkles } from 'lucide-react';
import { cn } from '@/lib/utils';

// Leaderboard entry component
function LeaderboardEntry({ 
  rank, 
  pubkey, 
  count, 
  type,
  isCurrentUser 
}: { 
  rank: number; 
  pubkey: string; 
  count: number;
  type: 'shops' | 'spots' | 'total';
  isCurrentUser: boolean;
}) {
  const { t } = useTranslation();
  const author = useAuthor(pubkey);
  const metadata = author.data?.metadata;
  const displayName = metadata?.name ?? genUserName(pubkey);
  const avatar = metadata?.picture;

  // Rank styling
  const getRankIcon = () => {
    if (rank === 1) return <Crown className="h-5 w-5 text-yellow-400" />;
    if (rank === 2) return <Medal className="h-5 w-5 text-gray-300" />;
    if (rank === 3) return <Medal className="h-5 w-5 text-amber-600" />;
    return <span className="text-sm font-bold text-gray-500">#{rank}</span>;
  };

  const getRankBg = () => {
    if (rank === 1) return 'bg-gradient-to-r from-yellow-950/50 to-orange-950/30 border-yellow-500/50';
    if (rank === 2) return 'bg-gradient-to-r from-gray-900/50 to-gray-800/30 border-gray-500/50';
    if (rank === 3) return 'bg-gradient-to-r from-amber-950/50 to-orange-950/30 border-amber-600/50';
    return 'bg-black/30 border-gray-800';
  };

  const getTypeLabel = () => {
    if (type === 'shops') return t('walletUi.leaderboard.shopsLower');
    if (type === 'spots') return t('walletUi.leaderboard.spotsLower');
    return t('walletUi.leaderboard.contributions');
  };

  return (
    <Link to={`/${nip19.npubEncode(pubkey)}`}>
      <div className={cn(
        'flex items-center gap-3 p-3 sm:p-4 rounded-xl border-2 transition-all hover:scale-[1.01]',
        getRankBg(),
        isCurrentUser && 'ring-2 ring-[#ff0040] ring-offset-2 ring-offset-black'
      )}>
        {/* Rank */}
        <div className="w-8 h-8 flex items-center justify-center flex-shrink-0">
          {getRankIcon()}
        </div>

        {/* Avatar */}
        <Avatar className="h-10 w-10 sm:h-12 sm:w-12 border-2 border-gray-700 flex-shrink-0">
          <AvatarImage src={avatar} alt={displayName} />
          <AvatarFallback className="bg-[#ff0040]/20 text-[#ff0040] text-xs sm:text-sm font-bold">
            {displayName.slice(0, 2).toUpperCase()}
          </AvatarFallback>
        </Avatar>

        {/* Info */}
        <div className="flex-1 min-w-0">
          <div className="flex items-center gap-2">
            <p className="font-bold text-white truncate text-sm sm:text-base">
              {displayName}
            </p>
            {isCurrentUser && (
              <Badge className="bg-[#ff0040] text-white text-[10px] px-1.5 py-0">{t('walletUi.leaderboard.you')}</Badge>
            )}
          </div>
          <p className="text-xs text-gray-500 capitalize">
            {getTypeLabel()}
          </p>
        </div>

        {/* Count */}
        <div className="text-right flex-shrink-0">
          <p className="text-lg sm:text-xl font-black text-[#ccff00]">{count}</p>
        </div>
      </div>
    </Link>
  );
}

function LeaderboardSkeleton() {
  return (
    <div className="space-y-3">
      {Array.from({ length: 10 }).map((_, i) => (
        <div key={i} className="flex items-center gap-3 p-4 rounded-xl bg-black/30 border border-gray-800">
          <Skeleton className="w-8 h-8 rounded-full" />
          <Skeleton className="h-12 w-12 rounded-full" />
          <div className="flex-1 space-y-2">
            <Skeleton className="h-4 w-32" />
            <Skeleton className="h-3 w-20" />
          </div>
          <Skeleton className="h-6 w-12" />
        </div>
      ))}
    </div>
  );
}

export default function BountyLeaderboardPage() {
  const { t } = useTranslation();
  useSeoMeta({
    title: t('seoUi.bountyLeaderboardTitle'),
    description: t('seoUi.bountyLeaderboardDesc'),
  });

  const { user } = useCurrentUser();
  const { data: shops, isLoading: shopsLoading, isError: shopsError, refetch: refetchShops } = useSkateShops(500);
  const { data: spots, isLoading: spotsLoading, isError: spotsError, refetch: refetchSpots } = useSkateSpots(500);

  // Calculate shop leaderboard
  const shopLeaderboard = useMemo(() => {
    if (!shops) return [];
    
    const countByPubkey: Record<string, number> = {};
    shops.forEach(shop => {
      countByPubkey[shop.pubkey] = (countByPubkey[shop.pubkey] || 0) + 1;
    });

    return Object.entries(countByPubkey)
      .map(([pubkey, count]) => ({ pubkey, count }))
      .sort((a, b) => b.count - a.count);
  }, [shops]);

  // Calculate spot leaderboard
  const spotLeaderboard = useMemo(() => {
    if (!spots) return [];
    
    const countByPubkey: Record<string, number> = {};
    spots.forEach(spot => {
      countByPubkey[spot.pubkey] = (countByPubkey[spot.pubkey] || 0) + 1;
    });

    return Object.entries(countByPubkey)
      .map(([pubkey, count]) => ({ pubkey, count }))
      .sort((a, b) => b.count - a.count);
  }, [spots]);

  // Combined leaderboard (total contributions)
  const combinedLeaderboard = useMemo(() => {
    const combined: Record<string, { shops: number; spots: number; total: number }> = {};
    
    shops?.forEach(shop => {
      if (!combined[shop.pubkey]) combined[shop.pubkey] = { shops: 0, spots: 0, total: 0 };
      combined[shop.pubkey].shops++;
      combined[shop.pubkey].total++;
    });
    
    spots?.forEach(spot => {
      if (!combined[spot.pubkey]) combined[spot.pubkey] = { shops: 0, spots: 0, total: 0 };
      combined[spot.pubkey].spots++;
      combined[spot.pubkey].total++;
    });

    return Object.entries(combined)
      .map(([pubkey, data]) => ({ pubkey, ...data }))
      .sort((a, b) => b.total - a.total);
  }, [shops, spots]);

  // Find user's rank
  const userCombinedRank = combinedLeaderboard.findIndex(e => e.pubkey === user?.pubkey) + 1;
  const userContributions = combinedLeaderboard.find(e => e.pubkey === user?.pubkey);

  // Stats
  const totalShops = shops?.length || 0;
  const totalSpots = spots?.length || 0;
  const totalMappers = combinedLeaderboard.length;

  if (shopsError || spotsError) {
    return (
      <>
        <div className="container mx-auto max-w-3xl px-4 py-8">
          <ErrorState onRetry={() => { refetchShops(); refetchSpots(); }} />
        </div>
      </>
    );
  }

  return (
    <>
      <div className="container px-4 py-6 sm:py-8 max-w-4xl">
        {/* Header */}
        <div className="text-center mb-8">
          <div className="inline-flex items-center gap-2 px-4 py-2 rounded-full bg-[#ccff00]/10 border border-[#ccff00]/30 mb-4">
            <Zap className="h-5 w-5 text-[#ccff00]" />
            <span className="text-[#ccff00] font-bold uppercase text-sm">{t('walletUi.leaderboard.mapEarn')}</span>
          </div>
          <h1 className="text-3xl sm:text-4xl font-black uppercase mb-3">
            <span className="neon-lime">{t('walletUi.leaderboard.helpMap')}</span>
          </h1>
          <p className="text-gray-400 max-w-lg mx-auto">
            {t('walletUi.leaderboard.intro')}
          </p>
        </div>

        {/* How It Works */}
        <Card className="mb-8 bg-gradient-to-br from-[#ccff00]/5 to-[#ff0040]/5 border-2 border-[#ccff00]/20">
          <CardContent className="p-6">
            <h2 className="text-lg font-black uppercase mb-4 flex items-center gap-2">
              <Sparkles className="h-5 w-5 text-[#ccff00]" />
              {t('walletUi.leaderboard.howItWorks')}
            </h2>
            <div className="grid grid-cols-1 sm:grid-cols-3 gap-4">
              <div className="p-4 rounded-xl bg-black/40 border border-gray-800">
                <div className="w-10 h-10 rounded-lg bg-[#ff0040]/20 flex items-center justify-center mb-3">
                  <MapPin className="h-5 w-5 text-[#ff0040]" />
                </div>
                <h3 className="font-bold text-white mb-1">{t('walletUi.leaderboard.step1Title')}</h3>
                <p className="text-xs text-gray-400">
                  {t('walletUi.leaderboard.step1Desc')}
                </p>
              </div>
              <div className="p-4 rounded-xl bg-black/40 border border-gray-800">
                <div className="w-10 h-10 rounded-lg bg-[#ccff00]/20 flex items-center justify-center mb-3">
                  <Zap className="h-5 w-5 text-[#ccff00]" />
                </div>
                <h3 className="font-bold text-white mb-1">{t('walletUi.leaderboard.step2Title')}</h3>
                <p className="text-xs text-gray-400">
                  {t('walletUi.leaderboard.step2Desc')}
                </p>
              </div>
              <div className="p-4 rounded-xl bg-black/40 border border-gray-800">
                <div className="w-10 h-10 rounded-lg bg-orange-500/20 flex items-center justify-center mb-3">
                  <Trophy className="h-5 w-5 text-orange-400" />
                </div>
                <h3 className="font-bold text-white mb-1">{t('walletUi.leaderboard.step3Title')}</h3>
                <p className="text-xs text-gray-400">
                  {t('walletUi.leaderboard.step3Desc')}
                </p>
              </div>
            </div>

            {/* Quality Tips */}
            <div className="mt-4 p-4 rounded-xl bg-black/40 border border-[#ccff00]/20">
              <p className="text-sm font-bold text-[#ccff00] mb-2">{t('walletUi.leaderboard.proTips')}</p>
              <div className="flex flex-wrap gap-3 text-xs text-gray-400">
                <span className="flex items-center gap-1">
                  <Camera className="h-3 w-3" />
                  {t('walletUi.leaderboard.tipPhotos')}
                </span>
                <span className="flex items-center gap-1">
                  <FileText className="h-3 w-3" />
                  {t('walletUi.leaderboard.tipDescriptions')}
                </span>
                <span className="flex items-center gap-1">
                  <MapPin className="h-3 w-3" />
                  {t('walletUi.leaderboard.tipLocation')}
                </span>
              </div>
            </div>
          </CardContent>
        </Card>

        {/* Quick Actions */}
        <div className="grid grid-cols-2 gap-3 mb-8">
          <Link to="/create-shop">
            <Card className="h-full bg-[#ccff00]/10 border-2 border-[#ccff00]/30 hover:border-[#ccff00]/60 transition-all hover:scale-[1.02] cursor-pointer">
              <CardContent className="p-4 sm:p-6 text-center">
                <Store className="h-8 w-8 mx-auto mb-2 text-[#ccff00]" />
                <h3 className="font-black uppercase text-sm sm:text-base mb-1">{t('walletUi.leaderboard.mapShop')}</h3>
                <p className="text-xs text-gray-400 hidden sm:block">{t('walletUi.leaderboard.mapShopDesc')}</p>
              </CardContent>
            </Card>
          </Link>
          <Link to="/create-spot">
            <Card className="h-full bg-[#ff0040]/10 border-2 border-[#ff0040]/30 hover:border-[#ff0040]/60 transition-all hover:scale-[1.02] cursor-pointer">
              <CardContent className="p-4 sm:p-6 text-center">
                <MapPin className="h-8 w-8 mx-auto mb-2 text-[#ff0040]" />
                <h3 className="font-black uppercase text-sm sm:text-base mb-1">{t('walletUi.leaderboard.mapSpot')}</h3>
                <p className="text-xs text-gray-400 hidden sm:block">{t('walletUi.leaderboard.mapSpotDesc')}</p>
              </CardContent>
            </Card>
          </Link>
        </div>

        {/* Stats */}
        <div className="grid grid-cols-3 gap-3 mb-6">
          <Card className="bg-[#ccff00]/10 border-[#ccff00]/30">
            <CardContent className="p-3 sm:p-4 text-center">
              <Store className="h-5 w-5 mx-auto mb-1 text-[#ccff00]" />
              <p className="text-xl sm:text-2xl font-black text-white">{totalShops}</p>
              <p className="text-[10px] sm:text-xs text-gray-400 uppercase">{t('walletUi.leaderboard.shops')}</p>
            </CardContent>
          </Card>
          <Card className="bg-[#ff0040]/10 border-[#ff0040]/30">
            <CardContent className="p-3 sm:p-4 text-center">
              <MapPin className="h-5 w-5 mx-auto mb-1 text-[#ff0040]" />
              <p className="text-xl sm:text-2xl font-black text-white">{totalSpots}</p>
              <p className="text-[10px] sm:text-xs text-gray-400 uppercase">{t('walletUi.stats.spots')}</p>
            </CardContent>
          </Card>
          <Card className="bg-orange-500/10 border-orange-500/30">
            <CardContent className="p-3 sm:p-4 text-center">
              <Users className="h-5 w-5 mx-auto mb-1 text-orange-400" />
              <p className="text-xl sm:text-2xl font-black text-white">{totalMappers}</p>
              <p className="text-[10px] sm:text-xs text-gray-400 uppercase">{t('walletUi.stats.mappers')}</p>
            </CardContent>
          </Card>
        </div>

        {/* User's position (if logged in and has contributions) */}
        {user && userCombinedRank > 0 && userContributions && (
          <Card className="mb-6 bg-gradient-to-r from-[#ff0040]/20 to-[#ccff00]/10 border-2 border-[#ff0040]/50">
            <CardContent className="p-4">
              <div className="flex items-center justify-between">
                <div className="flex items-center gap-3">
                  <div className="w-12 h-12 rounded-full bg-[#ff0040]/20 flex items-center justify-center">
                    <span className="text-lg font-black text-[#ff0040]">#{userCombinedRank}</span>
                  </div>
                  <div>
                    <p className="font-bold text-white">{t('walletUi.leaderboard.yourRanking')}</p>
                    <p className="text-sm text-gray-400">
                      {t('walletUi.leaderboard.spotsShops', { spots: userContributions.spots, shops: userContributions.shops })}
                    </p>
                  </div>
                </div>
                <div className="text-right">
                  <p className="text-2xl font-black text-[#ccff00]">{userContributions.total}</p>
                  <p className="text-xs text-gray-500">{t('walletUi.leaderboard.totalLower')}</p>
                </div>
              </div>
            </CardContent>
          </Card>
        )}

        {/* Leaderboard */}
        <div className="mb-4">
          <h2 className="text-xl font-black uppercase flex items-center gap-2">
            <Trophy className="h-5 w-5 text-yellow-400" />
            {t('walletUi.stats.topMappers')}
          </h2>
        </div>

        <Tabs defaultValue="combined" className="space-y-4">
          <TabsList className="grid w-full grid-cols-3 bg-black/50 border border-gray-800">
            <TabsTrigger value="combined" className="gap-1.5 text-xs sm:text-sm">
              <Trophy className="h-4 w-4" />
              <span className="hidden sm:inline">{t('walletUi.leaderboard.overall')}</span>
            </TabsTrigger>
            <TabsTrigger value="shops" className="gap-1.5 text-xs sm:text-sm">
              <Store className="h-4 w-4" />
              {t('walletUi.leaderboard.shops')}
            </TabsTrigger>
            <TabsTrigger value="spots" className="gap-1.5 text-xs sm:text-sm">
              <MapPin className="h-4 w-4" />
              {t('walletUi.stats.spots')}
            </TabsTrigger>
          </TabsList>

          <TabsContent value="combined">
            {shopsLoading || spotsLoading ? (
              <LeaderboardSkeleton />
            ) : combinedLeaderboard.length > 0 ? (
              <div className="space-y-2">
                {combinedLeaderboard.slice(0, 20).map((entry, i) => (
                  <LeaderboardEntry
                    key={entry.pubkey}
                    rank={i + 1}
                    pubkey={entry.pubkey}
                    count={entry.total}
                    type="total"
                    isCurrentUser={entry.pubkey === user?.pubkey}
                  />
                ))}
              </div>
            ) : (
              <Card className="border-dashed border-2 border-gray-700">
                <CardContent className="py-12 text-center">
                  <Trophy className="h-12 w-12 mx-auto mb-4 text-gray-600" />
                  <p className="text-gray-400 mb-4">{t('walletUi.leaderboard.noContributions')}</p>
                  <Link to="/create-spot">
                    <Button className="bg-[#ff0040] hover:bg-[#ff0040]/90 text-white font-bold">
                      {t('walletUi.leaderboard.addFirstSpot')}
                    </Button>
                  </Link>
                </CardContent>
              </Card>
            )}
          </TabsContent>

          <TabsContent value="shops">
            {shopsLoading ? (
              <LeaderboardSkeleton />
            ) : shopLeaderboard.length > 0 ? (
              <div className="space-y-2">
                {shopLeaderboard.slice(0, 20).map((entry, i) => (
                  <LeaderboardEntry
                    key={entry.pubkey}
                    rank={i + 1}
                    pubkey={entry.pubkey}
                    count={entry.count}
                    type="shops"
                    isCurrentUser={entry.pubkey === user?.pubkey}
                  />
                ))}
              </div>
            ) : (
              <Card className="border-dashed border-2 border-gray-700">
                <CardContent className="py-12 text-center">
                  <Store className="h-12 w-12 mx-auto mb-4 text-gray-600" />
                  <p className="text-gray-400 mb-4">{t('walletUi.leaderboard.noShops')}</p>
                  <Link to="/create-shop">
                    <Button className="bg-[#ccff00] text-black hover:bg-[#ccff00]/90 font-bold">
                      {t('walletUi.leaderboard.addFirstShop')}
                    </Button>
                  </Link>
                </CardContent>
              </Card>
            )}
          </TabsContent>

          <TabsContent value="spots">
            {spotsLoading ? (
              <LeaderboardSkeleton />
            ) : spotLeaderboard.length > 0 ? (
              <div className="space-y-2">
                {spotLeaderboard.slice(0, 20).map((entry, i) => (
                  <LeaderboardEntry
                    key={entry.pubkey}
                    rank={i + 1}
                    pubkey={entry.pubkey}
                    count={entry.count}
                    type="spots"
                    isCurrentUser={entry.pubkey === user?.pubkey}
                  />
                ))}
              </div>
            ) : (
              <Card className="border-dashed border-2 border-gray-700">
                <CardContent className="py-12 text-center">
                  <MapPin className="h-12 w-12 mx-auto mb-4 text-gray-600" />
                  <p className="text-gray-400 mb-4">{t('walletUi.leaderboard.noSpots')}</p>
                  <Link to="/create-spot">
                    <Button className="bg-[#ff0040] hover:bg-[#ff0040]/90 text-white font-bold">
                      {t('walletUi.leaderboard.addFirstSpot')}
                    </Button>
                  </Link>
                </CardContent>
              </Card>
            )}
          </TabsContent>
        </Tabs>

        {/* Community Note */}
        <Card className="mt-8 bg-gray-900/50 border-gray-800">
          <CardContent className="p-4 sm:p-6 text-center">
            <Zap className="h-8 w-8 mx-auto mb-3 text-yellow-400" />
            <h3 className="font-bold text-white mb-2">{t('walletUi.leaderboard.poweredBy')}</h3>
            <p className="text-sm text-gray-400 max-w-md mx-auto">
              {t('walletUi.leaderboard.poweredByDesc')}
            </p>
          </CardContent>
        </Card>
      </div>
    </>
  );
}