'use client';

import { useState, useRef, useCallback } from 'react';
import {
  Trophy,
  Users,
  Globe,
  Award,
  Search,
  Plus,
  ChevronLeft,
  ChevronRight,
  Sparkles,
  Flag,
  Filter,
  Flame,
  Clock,
  Target,
  Timer,
} from 'lucide-react';
import { LeagueCard } from '@/ui/LeagueCardWrapper';
import { Button } from '@/ui/Button';
import { Card } from '@/ui/Card';
import { Input } from '@/ui/Input';
import { Heading } from '@/ui/Heading';
import { Container } from '@/ui/Container';
import { Box } from '@/ui/Box';
import { Stack } from '@/ui/Stack';
import { Text } from '@/ui/Text';
import { Grid } from '@/ui/Grid';
import { GridItem } from '@/ui/GridItem';
import { PageHero } from '@/ui/PageHero';
import type { LeaguesViewData } from '@/lib/view-data/LeaguesViewData';
import type { LeagueSummaryViewModel } from '@/lib/view-models/LeagueSummaryViewModel';

// ============================================================================
// 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: LeaguesViewData['leagues'][number]) => boolean;
  color?: string;
}

interface LeagueSliderProps {
  title: string;
  icon: React.ElementType;
  description: string;
  leagues: LeaguesViewData['leagues'];
  autoScroll?: boolean;
  iconColor?: string;
  scrollSpeedMultiplier?: number;
  scrollDirection?: 'left' | 'right';
}

interface LeaguesTemplateProps {
  viewData: LeaguesViewData;
}

// ============================================================================
// 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
// ============================================================================

function LeagueSlider({
  title,
  icon: Icon,
  description,
  leagues,
  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
  const initializeScroll = useCallback(() => {
    if (scrollDirection === 'left' && scrollRef.current) {
      const { scrollWidth, clientWidth } = scrollRef.current;
      scrollPositionRef.current = scrollWidth - clientWidth;
      scrollRef.current.scrollLeft = scrollPositionRef.current;
    }
  }, [scrollDirection]);

  // Smooth continuous auto-scroll using requestAnimationFrame with variable speed and direction
  const setupAutoScroll = useCallback(() => {
    // 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
  const setupManualScroll = useCallback(() => {
    const scrollContainer = scrollRef.current;
    if (!scrollContainer) return;

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

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

  // Initialize effects
  useState(() => {
    initializeScroll();
  });

  // Setup auto-scroll effect
  useState(() => {
    setupAutoScroll();
  });

  // Setup manual scroll effect
  useState(() => {
    setupManualScroll();
  });

  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) => {
            // Convert ViewData to ViewModel for LeagueCard
            const viewModel: LeagueSummaryViewModel = {
              id: league.id,
              name: league.name,
              description: league.description ?? '',
              logoUrl: league.logoUrl,
              ownerId: league.ownerId,
              createdAt: league.createdAt,
              maxDrivers: league.maxDrivers,
              usedDriverSlots: league.usedDriverSlots,
              maxTeams: league.maxTeams ?? 0,
              usedTeamSlots: league.usedTeamSlots ?? 0,
              structureSummary: league.structureSummary,
              timingSummary: league.timingSummary,
              category: league.category ?? undefined,
              scoring: league.scoring ? {
                ...league.scoring,
                primaryChampionshipType: league.scoring.primaryChampionshipType as 'driver' | 'team' | 'nations' | 'trophy',
              } : undefined,
            };
            
            return (
              <div key={league.id} className="flex-shrink-0 w-[320px] h-full">
                <a href={`/leagues/${league.id}`} className="block h-full">
                  <LeagueCard league={viewModel} />
                </a>
              </div>
            );
          })}
        </div>
      </div>
    </div>
  );
}

// ============================================================================
// MAIN TEMPLATE COMPONENT
// ============================================================================

export function LeaguesClient({
  viewData,
}: LeaguesTemplateProps) {
  const [searchQuery, setSearchQuery] = useState('');
  const [activeCategory, setActiveCategory] = useState<CategoryId>('all');
  const [showFilters, setShowFilters] = useState(false);

  // Filter by search query
  const searchFilteredLeagues = viewData.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) => {
      // First try to use the dedicated category field, fall back to scoring-based filtering
      acc[category.id] = searchFilteredLeagues.filter((league) => {
        // If league has a category field, use it directly
        if (league.category) {
          return league.category === category.id;
        }
        // Otherwise fall back to the existing scoring-based filter
        return category.filter(league);
      });
      return acc;
    },
    {} as Record<CategoryId, LeaguesViewData['leagues']>,
  );

  // 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' },
  ];

  return (
    <Container size="lg" pb={12}>
      {/* Hero Section */}
      <PageHero
        title="Find Your Grid"
        description="From casual sprints to epic endurance battles — discover the perfect league for your racing style."
        icon={Trophy}
        stats={[
          { value: viewData.leagues.length, label: 'active leagues', color: 'bg-performance-green', animate: true },
          { value: leaguesByCategory.new.length, label: 'new this week', color: 'bg-primary-blue' },
          { value: leaguesByCategory.openSlots.length, label: 'with open slots', color: 'bg-neon-aqua' },
        ]}
        actions={[
          {
            label: 'Create League',
            onClick: () => { window.location.href = '/leagues/create'; },
            icon: Plus,
            description: 'Set up your own racing series'
          }
        ]}
      />

      {/* Search and Filter Bar */}
      <Box mb={6}>
        <Stack direction="row" gap={4} wrap>
          {/* Search */}
          <Box display="flex" position="relative" style={{ flex: 1 }}>
            <Box position="absolute" style={{ left: '0.75rem', top: '50%', transform: 'translateY(-50%)', zIndex: 10 }}>
              <Search className="w-5 h-5 text-gray-500" />
            </Box>
            <Input
              type="text"
              placeholder="Search leagues by name, description, or game..."
              value={searchQuery}
              onChange={(e: React.ChangeEvent<HTMLInputElement>) => setSearchQuery(e.target.value)}
              className="pl-11"
            />
          </Box>

          {/* Filter toggle (mobile) */}
          <Box display="none" className="lg:hidden">
            <Button
              type="button"
              variant="secondary"
              onClick={() => setShowFilters(!showFilters)}
              className="flex items-center gap-2"
            >
              <Filter className="w-4 h-4" />
              Filters
            </Button>
          </Box>
        </Stack>

        {/* Category Tabs */}
        <Box mt={4} display={showFilters ? 'block' : 'none'} className="lg:block">
          <Stack direction="row" gap={2} wrap>
            {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>
              );
            })}
          </Stack>
        </Box>
      </Box>

      {/* Content */}
      {viewData.leagues.length === 0 ? (
        /* Empty State */
        <Card className="text-center py-16">
          <Box maxWidth="28rem" mx="auto">
            <Box display="flex" center mb={6} rounded="2xl" p={4} className="bg-primary-blue/10 border border-primary-blue/20 mx-auto w-16 h-16">
              <Trophy className="w-8 h-8 text-primary-blue" />
            </Box>
            <Heading level={2} className="text-2xl mb-3">
              No leagues yet
            </Heading>
            <Text color="text-gray-400" mb={8} block>
              Be the first to create a racing series. Start your own league and invite drivers to compete for glory.
            </Text>
            <Button
              onClick={() => { window.location.href = '/leagues/create'; }}
              className="inline-flex items-center gap-2 px-6 py-3 bg-primary-blue text-white rounded-lg hover:bg-blue-600 transition-colors"
            >
              <Sparkles className="w-4 h-4" />
              Create Your First League
            </Button>
          </Box>
        </Card>
      ) : activeCategory === 'all' && !searchQuery ? (
        /* Slider View - Show featured categories with sliders at different speeds and directions */
        <Box>
          {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]}
                autoScroll={true}
                iconColor={category.color || 'text-primary-blue'}
                scrollSpeedMultiplier={speed}
                scrollDirection={direction}
              />
            ))}
        </Box>
      ) : (
        /* Grid View - Filtered by category or search */
        <Box>
          {categoryFilteredLeagues.length > 0 ? (
            <>
              <Box display="flex" align="center" justify="between" mb={6}>
                <Text size="sm" color="text-gray-400">
                  Showing <Text color="text-white" weight="medium">{categoryFilteredLeagues.length}</Text>{' '}
                  {categoryFilteredLeagues.length === 1 ? 'league' : 'leagues'}
                  {searchQuery && (
                    <span>
                      {' '}
                      for "<Text color="text-primary-blue">{searchQuery}</Text>"
                    </span>
                  )}
                </Text>
              </Box>
              <Grid cols={1} mdCols={2} lgCols={3} gap={6}>
                {categoryFilteredLeagues.map((league) => {
                  // Convert ViewData to ViewModel for LeagueCard
                  const viewModel: LeagueSummaryViewModel = {
                    id: league.id,
                    name: league.name,
                    description: league.description ?? '',
                    logoUrl: league.logoUrl,
                    ownerId: league.ownerId,
                    createdAt: league.createdAt,
                    maxDrivers: league.maxDrivers,
                    usedDriverSlots: league.usedDriverSlots,
                    maxTeams: league.maxTeams ?? 0,
                    usedTeamSlots: league.usedTeamSlots ?? 0,
                    structureSummary: league.structureSummary,
                    timingSummary: league.timingSummary,
                    category: league.category ?? undefined,
                    scoring: league.scoring ? {
                      ...league.scoring,
                      primaryChampionshipType: league.scoring.primaryChampionshipType as 'driver' | 'team' | 'nations' | 'trophy',
                    } : undefined,
                  };
                  
                  return (
                    <GridItem key={league.id}>
                      <a href={`/leagues/${league.id}`} className="block h-full">
                        <LeagueCard league={viewModel} />
                      </a>
                    </GridItem>
                  );
                })}
              </Grid>
            </>
          ) : (
            <Card className="text-center py-12">
              <Stack align="center" gap={4}>
                <Search className="w-10 h-10 text-gray-600" />
                <Text color="text-gray-400">
                  No leagues found{searchQuery ? ` matching "${searchQuery}"` : ' in this category'}
                </Text>
                <Button
                  variant="secondary"
                  onClick={() => {
                    setSearchQuery('');
                    setActiveCategory('all');
                  }}
                >
                  Clear filters
                </Button>
              </Stack>
            </Card>
          )}
        </Box>
      )}
    </Container>
  );
}