'use client';

import { useState, useEffect, useRef, useCallback } from 'react';
import { useRouter } from 'next/navigation';
import {
  Trophy,
  Users,
  Globe,
  Award,
  Search,
  Plus,
  ChevronLeft,
  ChevronRight,
  Sparkles,
  Flag,
  Filter,
  Gamepad2,
  Flame,
  Clock,
  Zap,
  Target,
  Star,
  TrendingUp,
  Calendar,
  Timer,
  Car,
} from 'lucide-react';
import LeagueCard from '@/components/leagues/LeagueCard';
import Button from '@/components/ui/Button';
import Card from '@/components/ui/Card';
import Input from '@/components/ui/Input';
import Heading from '@/components/ui/Heading';
import type { LeagueSummaryDTO } from '@gridpilot/racing/application/dto/LeagueSummaryDTO';
import { getGetAllLeaguesWithCapacityAndScoringUseCase } from '@/lib/di-container';

// ============================================================================
// TYPES
// ============================================================================

type CategoryId =
  | 'all'
  | 'driver'
  | 'team'
  | 'nations'
  | 'trophy'
  | 'new'
  | 'popular'
  | 'iracing'
  | 'acc'
  | 'f1'
  | 'endurance'
  | 'sprint'
  | 'openSlots';

interface Category {
  id: CategoryId;
  label: string;
  icon: React.ElementType;
  description: string;
  filter: (league: LeagueSummaryDTO) => boolean;
  color?: string;
}

// ============================================================================
// DEMO LEAGUES DATA
// ============================================================================

// ============================================================================
// CATEGORIES
// ============================================================================

const CATEGORIES: Category[] = [
  {
    id: 'all',
    label: 'All',
    icon: Globe,
    description: 'Browse all available leagues',
    filter: () => true,
  },
  {
    id: 'popular',
    label: 'Popular',
    icon: Flame,
    description: 'Most active leagues right now',
    filter: (league) => {
      const fillRate = (league.usedDriverSlots ?? 0) / (league.maxDrivers ?? 1);
      return fillRate > 0.7;
    },
    color: 'text-orange-400',
  },
  {
    id: 'new',
    label: 'New',
    icon: Sparkles,
    description: 'Fresh leagues looking for members',
    filter: (league) => {
      const oneWeekAgo = new Date();
      oneWeekAgo.setDate(oneWeekAgo.getDate() - 7);
      return new Date(league.createdAt) > oneWeekAgo;
    },
    color: 'text-performance-green',
  },
  {
    id: 'openSlots',
    label: 'Open Slots',
    icon: Target,
    description: 'Leagues with available spots',
    filter: (league) => {
      // Check for team slots if it's a team league
      if (league.maxTeams && league.maxTeams > 0) {
        const usedTeams = league.usedTeamSlots ?? 0;
        return usedTeams < league.maxTeams;
      }
      // Otherwise check driver slots
      const used = league.usedDriverSlots ?? 0;
      const max = league.maxDrivers ?? 0;
      return max > 0 && used < max;
    },
    color: 'text-neon-aqua',
  },
  {
    id: 'driver',
    label: 'Driver',
    icon: Trophy,
    description: 'Compete as an individual',
    filter: (league) => league.scoring?.primaryChampionshipType === 'driver',
  },
  {
    id: 'team',
    label: 'Team',
    icon: Users,
    description: 'Race together as a team',
    filter: (league) => league.scoring?.primaryChampionshipType === 'team',
  },
  {
    id: 'nations',
    label: 'Nations',
    icon: Flag,
    description: 'Represent your country',
    filter: (league) => league.scoring?.primaryChampionshipType === 'nations',
  },
  {
    id: 'trophy',
    label: 'Trophy',
    icon: Award,
    description: 'Special championship events',
    filter: (league) => league.scoring?.primaryChampionshipType === 'trophy',
  },
  {
    id: 'endurance',
    label: 'Endurance',
    icon: Timer,
    description: 'Long-distance racing',
    filter: (league) =>
      league.scoring?.scoringPresetId?.includes('endurance') ??
      league.timingSummary?.includes('h Race') ??
      false,
  },
  {
    id: 'sprint',
    label: 'Sprint',
    icon: Clock,
    description: 'Quick, intense races',
    filter: (league) =>
      (league.scoring?.scoringPresetId?.includes('sprint') ?? false) &&
      !(league.scoring?.scoringPresetId?.includes('endurance') ?? false),
  },
];

// ============================================================================
// LEAGUE SLIDER COMPONENT
// ============================================================================

interface LeagueSliderProps {
  title: string;
  icon: React.ElementType;
  description: string;
  leagues: LeagueSummaryDTO[];
  onLeagueClick: (id: string) => void;
  autoScroll?: boolean;
  iconColor?: string;
  scrollSpeedMultiplier?: number;
  scrollDirection?: 'left' | 'right';
}

function LeagueSlider({
  title,
  icon: Icon,
  description,
  leagues,
  onLeagueClick,
  autoScroll = true,
  iconColor = 'text-primary-blue',
  scrollSpeedMultiplier = 1,
  scrollDirection = 'right',
}: LeagueSliderProps) {
  const scrollRef = useRef<HTMLDivElement>(null);
  const [canScrollLeft, setCanScrollLeft] = useState(false);
  const [canScrollRight, setCanScrollRight] = useState(true);
  const [isHovering, setIsHovering] = useState(false);
  const animationRef = useRef<number | null>(null);
  const scrollPositionRef = useRef(0);

  const checkScrollButtons = useCallback(() => {
    if (scrollRef.current) {
      const { scrollLeft, scrollWidth, clientWidth } = scrollRef.current;
      setCanScrollLeft(scrollLeft > 0);
      setCanScrollRight(scrollLeft < scrollWidth - clientWidth - 10);
    }
  }, []);

  const scroll = useCallback((direction: 'left' | 'right') => {
    if (scrollRef.current) {
      const cardWidth = 340;
      const scrollAmount = direction === 'left' ? -cardWidth : cardWidth;
      // Update the ref so auto-scroll continues from new position
      scrollPositionRef.current = scrollRef.current.scrollLeft + scrollAmount;
      scrollRef.current.scrollBy({ left: scrollAmount, behavior: 'smooth' });
    }
  }, []);

  // Initialize scroll position for left-scrolling sliders
  useEffect(() => {
    if (scrollDirection === 'left' && scrollRef.current) {
      const { scrollWidth, clientWidth } = scrollRef.current;
      scrollPositionRef.current = scrollWidth - clientWidth;
      scrollRef.current.scrollLeft = scrollPositionRef.current;
    }
  }, [scrollDirection, leagues.length]);

  // Smooth continuous auto-scroll using requestAnimationFrame with variable speed and direction
  useEffect(() => {
    // Allow scroll even with just 2 leagues (minimum threshold = 1)
    if (!autoScroll || leagues.length <= 1) return;

    const scrollContainer = scrollRef.current;
    if (!scrollContainer) return;

    let lastTimestamp = 0;
    // Base speed with multiplier for variation between sliders
    const baseSpeed = 0.025;
    const scrollSpeed = baseSpeed * scrollSpeedMultiplier;
    const directionMultiplier = scrollDirection === 'left' ? -1 : 1;

    const animate = (timestamp: number) => {
      if (!isHovering && scrollContainer) {
        const delta = lastTimestamp ? timestamp - lastTimestamp : 0;
        lastTimestamp = timestamp;

        scrollPositionRef.current += scrollSpeed * delta * directionMultiplier;

        const { scrollWidth, clientWidth } = scrollContainer;
        const maxScroll = scrollWidth - clientWidth;

        // Handle wrap-around for both directions
        if (scrollDirection === 'right' && scrollPositionRef.current >= maxScroll) {
          scrollPositionRef.current = 0;
        } else if (scrollDirection === 'left' && scrollPositionRef.current <= 0) {
          scrollPositionRef.current = maxScroll;
        }

        scrollContainer.scrollLeft = scrollPositionRef.current;
      } else {
        lastTimestamp = timestamp;
      }

      animationRef.current = requestAnimationFrame(animate);
    };

    animationRef.current = requestAnimationFrame(animate);

    return () => {
      if (animationRef.current) {
        cancelAnimationFrame(animationRef.current);
      }
    };
  }, [autoScroll, leagues.length, isHovering, scrollSpeedMultiplier, scrollDirection]);

  // Sync scroll position when user manually scrolls
  useEffect(() => {
    const scrollContainer = scrollRef.current;
    if (!scrollContainer) return;

    const handleScroll = () => {
      scrollPositionRef.current = scrollContainer.scrollLeft;
      checkScrollButtons();
    };

    scrollContainer.addEventListener('scroll', handleScroll);
    return () => scrollContainer.removeEventListener('scroll', handleScroll);
  }, [checkScrollButtons]);

  if (leagues.length === 0) return null;

  return (
    <div className="mb-10">
      {/* Section header */}
      <div className="flex items-center justify-between mb-4">
        <div className="flex items-center gap-3">
          <div className={`flex h-10 w-10 items-center justify-center rounded-xl bg-iron-gray border border-charcoal-outline`}>
            <Icon className={`w-5 h-5 ${iconColor}`} />
          </div>
          <div>
            <h2 className="text-lg font-semibold text-white">{title}</h2>
            <p className="text-xs text-gray-500">{description}</p>
          </div>
          <span className="ml-2 px-2 py-0.5 rounded-full text-xs bg-charcoal-outline/50 text-gray-400">
            {leagues.length}
          </span>
        </div>

        {/* Navigation arrows */}
        <div className="flex items-center gap-2">
          <button
            type="button"
            onClick={() => scroll('left')}
            disabled={!canScrollLeft}
            className={`flex h-8 w-8 items-center justify-center rounded-lg transition-all ${
              canScrollLeft
                ? 'bg-iron-gray border border-charcoal-outline text-white hover:border-primary-blue hover:text-primary-blue'
                : 'bg-iron-gray/30 border border-charcoal-outline/30 text-gray-600 cursor-not-allowed'
            }`}
          >
            <ChevronLeft className="w-4 h-4" />
          </button>
          <button
            type="button"
            onClick={() => scroll('right')}
            disabled={!canScrollRight}
            className={`flex h-8 w-8 items-center justify-center rounded-lg transition-all ${
              canScrollRight
                ? 'bg-iron-gray border border-charcoal-outline text-white hover:border-primary-blue hover:text-primary-blue'
                : 'bg-iron-gray/30 border border-charcoal-outline/30 text-gray-600 cursor-not-allowed'
            }`}
          >
            <ChevronRight className="w-4 h-4" />
          </button>
        </div>
      </div>

      {/* Scrollable container with fade edges */}
      <div className="relative">
        {/* Left fade gradient */}
        <div className="absolute left-0 top-0 bottom-4 w-12 bg-gradient-to-r from-deep-graphite to-transparent z-10 pointer-events-none" />
        {/* Right fade gradient */}
        <div className="absolute right-0 top-0 bottom-4 w-12 bg-gradient-to-l from-deep-graphite to-transparent z-10 pointer-events-none" />
        
        <div
          ref={scrollRef}
          onMouseEnter={() => setIsHovering(true)}
          onMouseLeave={() => setIsHovering(false)}
          className="flex gap-4 overflow-x-auto pb-4 px-4"
          style={{
            scrollbarWidth: 'none',
            msOverflowStyle: 'none',
          }}
        >
          <style jsx>{`
            div::-webkit-scrollbar {
              display: none;
            }
          `}</style>
          {leagues.map((league) => (
            <div key={league.id} className="flex-shrink-0 w-[320px] h-full">
              <LeagueCard league={league} onClick={() => onLeagueClick(league.id)} />
            </div>
          ))}
        </div>
      </div>
    </div>
  );
}

// ============================================================================
// MAIN PAGE COMPONENT
// ============================================================================

export default function LeaguesPage() {
  const router = useRouter();
  const [realLeagues, setRealLeagues] = useState<LeagueSummaryDTO[]>([]);
  const [loading, setLoading] = useState(true);
  const [searchQuery, setSearchQuery] = useState('');
  const [activeCategory, setActiveCategory] = useState<CategoryId>('all');
  const [showFilters, setShowFilters] = useState(false);

  useEffect(() => {
    loadLeagues();
  }, []);

  const loadLeagues = async () => {
    try {
      const useCase = getGetAllLeaguesWithCapacityAndScoringUseCase();
      await useCase.execute();
      const presenter = useCase.presenter as unknown as {
        getViewModel(): { leagues: LeagueSummaryDTO[] };
      };
      const viewModel = presenter.getViewModel();
      setRealLeagues(viewModel.leagues);
    } catch (error) {
      console.error('Failed to load leagues:', error);
    } finally {
      setLoading(false);
    }
  };

  // Use only real leagues from repository
  const leagues = realLeagues;

  const handleLeagueClick = (leagueId: string) => {
    // Navigate to league - all leagues are clickable
    router.push(`/leagues/${leagueId}`);
  };

  // Filter by search query
  const searchFilteredLeagues = leagues.filter((league) => {
    if (!searchQuery) return true;
    const query = searchQuery.toLowerCase();
    return (
      league.name.toLowerCase().includes(query) ||
      (league.description ?? '').toLowerCase().includes(query) ||
      (league.scoring?.gameName ?? '').toLowerCase().includes(query)
    );
  });

  // Get leagues for active category
  const activeCategoryData = CATEGORIES.find((c) => c.id === activeCategory);
  const categoryFilteredLeagues = activeCategoryData
    ? searchFilteredLeagues.filter(activeCategoryData.filter)
    : searchFilteredLeagues;

  // Group leagues by category for slider view
  const leaguesByCategory = CATEGORIES.reduce(
    (acc, category) => {
      acc[category.id] = searchFilteredLeagues.filter(category.filter);
      return acc;
    },
    {} as Record<CategoryId, LeagueSummaryDTO[]>,
  );

  // Featured categories to show as sliders with different scroll speeds and alternating directions
  const featuredCategoriesWithSpeed: { id: CategoryId; speed: number; direction: 'left' | 'right' }[] = [
    { id: 'popular', speed: 1.0, direction: 'right' },
    { id: 'new', speed: 1.3, direction: 'left' },
    { id: 'driver', speed: 0.8, direction: 'right' },
    { id: 'team', speed: 1.1, direction: 'left' },
    { id: 'nations', speed: 0.9, direction: 'right' },
    { id: 'endurance', speed: 0.7, direction: 'left' },
    { id: 'sprint', speed: 1.2, direction: 'right' },
  ];

  if (loading) {
    return (
      <div className="max-w-7xl mx-auto px-4">
        <div className="flex items-center justify-center min-h-[400px]">
          <div className="flex flex-col items-center gap-4">
            <div className="w-10 h-10 border-2 border-primary-blue border-t-transparent rounded-full animate-spin" />
            <p className="text-gray-400">Loading leagues...</p>
          </div>
        </div>
      </div>
    );
  }

  return (
    <div className="max-w-7xl mx-auto px-4 pb-12">
      {/* Hero Section */}
      <div className="relative mb-10 py-10 px-8 rounded-2xl bg-gradient-to-br from-iron-gray/80 via-deep-graphite to-iron-gray/60 border border-charcoal-outline/50 overflow-hidden">
        {/* Background decoration */}
        <div className="absolute top-0 right-0 w-96 h-96 bg-primary-blue/5 rounded-full blur-3xl" />
        <div className="absolute bottom-0 left-0 w-64 h-64 bg-neon-aqua/5 rounded-full blur-3xl" />

        <div className="relative z-10 flex flex-col lg:flex-row lg:items-center lg:justify-between gap-8">
          <div className="max-w-2xl">
            <div className="flex items-center gap-3 mb-4">
              <div className="flex h-12 w-12 items-center justify-center rounded-xl bg-gradient-to-br from-primary-blue/20 to-primary-blue/5 border border-primary-blue/20">
                <Trophy className="w-6 h-6 text-primary-blue" />
              </div>
              <Heading level={1} className="text-3xl lg:text-4xl">
                Find Your Grid
              </Heading>
            </div>
            <p className="text-gray-400 text-lg leading-relaxed mb-6">
              From casual sprints to epic endurance battles — discover the perfect league for your racing style.
            </p>

            {/* Stats */}
            <div className="flex flex-wrap gap-6">
              <div className="flex items-center gap-2">
                <div className="w-2 h-2 rounded-full bg-performance-green animate-pulse" />
                <span className="text-sm text-gray-400">
                  <span className="text-white font-semibold">{leagues.length}</span> active leagues
                </span>
              </div>
              <div className="flex items-center gap-2">
                <div className="w-2 h-2 rounded-full bg-primary-blue" />
                <span className="text-sm text-gray-400">
                  <span className="text-white font-semibold">{leaguesByCategory.new.length}</span> new this week
                </span>
              </div>
              <div className="flex items-center gap-2">
                <div className="w-2 h-2 rounded-full bg-neon-aqua" />
                <span className="text-sm text-gray-400">
                  <span className="text-white font-semibold">{leaguesByCategory.openSlots.length}</span> with open slots
                </span>
              </div>
            </div>
          </div>

          {/* CTA */}
          <div className="flex flex-col gap-4">
            <Button
              variant="primary"
              onClick={() => router.push('/leagues/create')}
              className="flex items-center gap-2 px-6 py-3"
            >
              <Plus className="w-5 h-5" />
              <span>Create League</span>
            </Button>
            <p className="text-xs text-gray-500 text-center">Set up your own racing series</p>
          </div>
        </div>
      </div>

      {/* Search and Filter Bar */}
      <div className="mb-6">
        <div className="flex flex-col lg:flex-row gap-4">
          {/* Search */}
          <div className="flex-1 relative">
            <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-5 h-5 text-gray-500" />
            <Input
              type="text"
              placeholder="Search leagues by name, description, or game..."
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
              className="pl-11"
            />
          </div>

          {/* Filter toggle (mobile) */}
          <Button
            type="button"
            variant="secondary"
            onClick={() => setShowFilters(!showFilters)}
            className="lg:hidden flex items-center gap-2"
          >
            <Filter className="w-4 h-4" />
            Filters
          </Button>
        </div>

        {/* Category Tabs */}
        <div className={`mt-4 ${showFilters ? 'block' : 'hidden lg:block'}`}>
          <div className="flex flex-wrap gap-2">
            {CATEGORIES.map((category) => {
              const Icon = category.icon;
              const count = leaguesByCategory[category.id].length;
              const isActive = activeCategory === category.id;

              return (
                <button
                  key={category.id}
                  type="button"
                  onClick={() => setActiveCategory(category.id)}
                  className={`flex items-center gap-1.5 px-3 py-1.5 rounded-full text-xs font-medium transition-all duration-200 ${
                    isActive
                      ? 'bg-primary-blue text-white shadow-[0_0_15px_rgba(25,140,255,0.3)]'
                      : 'bg-iron-gray/60 text-gray-400 border border-charcoal-outline hover:border-gray-500 hover:text-white'
                  }`}
                >
                  <Icon className={`w-3.5 h-3.5 ${!isActive && category.color ? category.color : ''}`} />
                  <span>{category.label}</span>
                  {count > 0 && (
                    <span className={`px-1.5 py-0.5 rounded-full text-[10px] ${isActive ? 'bg-white/20' : 'bg-charcoal-outline/50'}`}>
                      {count}
                    </span>
                  )}
                </button>
              );
            })}
          </div>
        </div>
      </div>

      {/* Content */}
      {leagues.length === 0 ? (
        /* Empty State */
        <Card className="text-center py-16">
          <div className="max-w-md mx-auto">
            <div className="flex h-16 w-16 mx-auto items-center justify-center rounded-2xl bg-primary-blue/10 border border-primary-blue/20 mb-6">
              <Trophy className="w-8 h-8 text-primary-blue" />
            </div>
            <Heading level={2} className="text-2xl mb-3">
              No leagues yet
            </Heading>
            <p className="text-gray-400 mb-8">
              Be the first to create a racing series. Start your own league and invite drivers to compete for glory.
            </p>
            <Button
              variant="primary"
              onClick={() => router.push('/leagues/create')}
              className="flex items-center gap-2 mx-auto"
            >
              <Sparkles className="w-4 h-4" />
              Create Your First League
            </Button>
          </div>
        </Card>
      ) : activeCategory === 'all' && !searchQuery ? (
        /* Slider View - Show featured categories with sliders at different speeds and directions */
        <div>
          {featuredCategoriesWithSpeed
            .map(({ id, speed, direction }) => {
              const category = CATEGORIES.find((c) => c.id === id)!;
              return { category, speed, direction };
            })
            .filter(({ category }) => leaguesByCategory[category.id].length > 0)
            .map(({ category, speed, direction }) => (
              <LeagueSlider
                key={category.id}
                title={category.label}
                icon={category.icon}
                description={category.description}
                leagues={leaguesByCategory[category.id]}
                onLeagueClick={handleLeagueClick}
                autoScroll={true}
                iconColor={category.color || 'text-primary-blue'}
                scrollSpeedMultiplier={speed}
                scrollDirection={direction}
              />
            ))}
        </div>
      ) : (
        /* Grid View - Filtered by category or search */
        <div>
          {categoryFilteredLeagues.length > 0 ? (
            <>
              <div className="flex items-center justify-between mb-6">
                <p className="text-sm text-gray-400">
                  Showing <span className="text-white font-medium">{categoryFilteredLeagues.length}</span>{' '}
                  {categoryFilteredLeagues.length === 1 ? 'league' : 'leagues'}
                  {searchQuery && (
                    <span>
                      {' '}
                      for "<span className="text-primary-blue">{searchQuery}</span>"
                    </span>
                  )}
                </p>
              </div>
              <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
                {categoryFilteredLeagues.map((league) => (
                  <LeagueCard key={league.id} league={league} onClick={() => handleLeagueClick(league.id)} />
                ))}
              </div>
            </>
          ) : (
            <Card className="text-center py-12">
              <div className="flex flex-col items-center gap-4">
                <Search className="w-10 h-10 text-gray-600" />
                <p className="text-gray-400">
                  No leagues found{searchQuery ? ` matching "${searchQuery}"` : ' in this category'}
                </p>
                <Button
                  variant="secondary"
                  onClick={() => {
                    setSearchQuery('');
                    setActiveCategory('all');
                  }}
                >
                  Clear filters
                </Button>
              </div>
            </Card>
          )}
        </div>
      )}
    </div>
  );
}