import { useState, useEffect } from 'react';
import { useRouter } from 'next/router';
import Link from 'next/link';
import Layout from '../../components/Layout';
import PermissionIndicator from '../../components/PermissionIndicator';
import { useAuth } from '../../lib/use-auth';

export default function CommunityCollections() {
  const router = useRouter();
  const { user, loading: authLoading } = useAuth();
  
  const [collections, setCollections] = useState([]);
  const [loading, setLoading] = useState(true);
  const [searchQuery, setSearchQuery] = useState('');
  const [sortBy, setSortBy] = useState('name');

  // Redirect to login if not authenticated
  useEffect(() => {
    if (!authLoading && !user) {
      router.push('/login');
    }
  }, [authLoading, user, router]);

  useEffect(() => {
    if (user) {
      fetchPublicCollections();
    }
  }, [user]);

  const fetchPublicCollections = async () => {
    try {
      const token = localStorage.getItem('auth_token');
      const headers = {
        'Content-Type': 'application/json',
      };
      
      if (token) {
        headers.Authorization = `Bearer ${token}`;
      }
      
      const response = await fetch('/api/community/collections', { headers });
      
      if (response.ok) {
        const data = await response.json();
        
        // Fetch thumbnails for each collection
        const collectionsWithThumbnails = await Promise.all(
          data.map(async (collection) => {
            try {
              const identifier = collection.slug || collection.id;
              const thumbnailResponse = await fetch(`/api/collections/${identifier}/thumbnails`, { headers });
              if (thumbnailResponse.ok) {
                const thumbnailData = await thumbnailResponse.json();
                return { ...collection, thumbnails: thumbnailData.thumbnails };
              }
              return { ...collection, thumbnails: [] };
            } catch (error) {
              console.error(`Error fetching thumbnails for collection ${collection.id}:`, error);
              return { ...collection, thumbnails: [] };
            }
          })
        );
        
        setCollections(collectionsWithThumbnails);
      } else {
        console.error('Failed to fetch public collections');
      }
    } catch (error) {
      console.error('Error fetching public collections:', error);
    } finally {
      setLoading(false);
    }
  };

  const sortOptions = [
    { value: 'name', label: 'Name (A-Z)' },
    { value: 'value', label: 'Value (High to Low)' },
    { value: 'cardCount', label: 'Card Count (High to Low)' },
    { value: 'createdAt', label: 'Recently Created' }
  ];

  const sortCollections = (collections, sortBy) => {
    return [...collections].sort((a, b) => {
      switch (sortBy) {
        case 'name':
          return a.name.localeCompare(b.name);
        case 'value':
          return (b.value || 0) - (a.value || 0);
        case 'cardCount':
          return (b.cardCount || 0) - (a.cardCount || 0);
        case 'createdAt':
          return new Date(b.createdAt) - new Date(a.createdAt);
        default:
          return 0;
      }
    });
  };

  const filteredCollections = collections.filter(collection => {
    const matchesSearch = collection.name.toLowerCase().includes(searchQuery.toLowerCase()) ||
                         collection.description.toLowerCase().includes(searchQuery.toLowerCase());
    return matchesSearch;
  });

  const sortedCollections = sortCollections(filteredCollections, sortBy);

  const formatCurrency = (amount) => {
    return new Intl.NumberFormat('en-US', {
      style: 'currency',
      currency: 'USD'
    }).format(amount);
  };

  const formatDate = (dateString) => {
    return new Date(dateString).toLocaleDateString();
  };

  // Collection thumbnail component (same as in regular collections)
  const CollectionThumbnail = ({ collection }) => {
    const { thumbnails = [], image } = collection;

    // If collection has a custom hero image, use it
    if (image) {
      return (
        <div className="w-full h-48 rounded-xl overflow-hidden mb-4">
          <img 
            src={image} 
            alt={collection.name}
            className="w-full h-full object-cover"
          />
        </div>
      );
    }

    // If no thumbnails available, show placeholder
    if (!thumbnails || thumbnails.length === 0) {
      return (
        <div className="w-full h-48 rounded-xl mb-4 flex items-center justify-center" style={{ backgroundColor: 'var(--bg-tertiary)' }}>
          <div className="text-center">
            <div className="text-4xl mb-2">📦</div>
            <p className="text-sm" style={{ color: 'var(--text-secondary)' }}>No cards yet</p>
          </div>
        </div>
      );
    }

    // Show main card (rarest) and grid of 4 others
    const mainCard = thumbnails[0]; // Rarest card
    const gridCards = thumbnails.slice(1, 5); // Next 4 cards

    return (
      <div className="w-full h-48 rounded-xl overflow-hidden mb-4 flex gap-2">
        {/* Main card (rarest) - takes up 2/3 of the space */}
        <div className="flex-2 h-full relative group">
          {mainCard ? (
            <div className="w-full h-full relative">
              <img 
                src={mainCard.image_url || mainCard.stock_image_url} 
                alt={mainCard.name}
                className="w-full h-full object-cover"
              />
              {/* Rarity glow effect */}
              <div className={`absolute inset-0 rarity-glow-${mainCard.rarity?.toLowerCase()}`}></div>
              {/* Card name overlay */}
              <div className="absolute bottom-0 left-0 right-0 bg-gradient-to-t from-black/80 to-transparent p-2">
                <p className="text-white text-xs font-medium truncate">{mainCard.name}</p>
              </div>
            </div>
          ) : (
            <div className="w-full h-full flex items-center justify-center" style={{ backgroundColor: 'var(--bg-tertiary)' }}>
              <div className="text-2xl">🃏</div>
            </div>
          )}
        </div>

        {/* Grid of 4 other cards - takes up 1/3 of the space */}
        <div className="flex-1 h-full">
          <div className="grid grid-cols-2 gap-1 h-full">
            {Array.from({ length: 4 }).map((_, index) => {
              const card = gridCards[index];
              return (
                <div key={index} className="relative">
                  {card ? (
                    <div className="w-full h-full relative">
                      <img 
                        src={card.image_url || card.stock_image_url} 
                        alt={card.name}
                        className="w-full h-full object-cover rounded"
                      />
                      {/* Subtle rarity glow */}
                      <div className={`absolute inset-0 rarity-glow-${card.rarity?.toLowerCase()} opacity-50 rounded`}></div>
                    </div>
                  ) : (
                    <div className="w-full h-full flex items-center justify-center rounded" style={{ backgroundColor: 'var(--bg-tertiary)' }}>
                      <div className="text-lg opacity-50">🃏</div>
                    </div>
                  )}
                </div>
              );
            })}
          </div>
        </div>
      </div>
    );
  };

  // Show loading spinner while auth is loading or data is loading
  if (authLoading || loading) {
    return (
      <Layout user={user}>
        <div className="flex items-center justify-center min-h-screen">
          <div className="animate-spin rounded-full h-32 w-32 border-b-2" style={{ borderColor: 'var(--accent-ember)' }}></div>
        </div>
      </Layout>
    );
  }

  // Redirect to login if not authenticated (handled by useEffect, but this is a fallback)
  if (!user) {
    return null;
  }

  return (
    <Layout user={user}>
      {/* Header */}
      <div className="p-6" style={{ backgroundColor: 'var(--bg-secondary)', borderBottom: '1px solid var(--border)' }}>
        <div className="flex items-center justify-between">
          <div>
            <h1 className="text-3xl font-bold" style={{ color: 'var(--text-primary)' }}>
              Community Collections
            </h1>
            <p className="mt-2" style={{ color: 'var(--text-secondary)' }}>
              Discover public collections shared by the community
            </p>
          </div>
        </div>
        
        {/* Search and Sort */}
        <div className="flex items-center justify-between mt-6">
          <div className="flex-1 max-w-md">
            <input
              type="text"
              placeholder="Search collections..."
              className="input-field w-full"
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
            />
          </div>
          <div className="flex gap-4">
            <select
              value={sortBy}
              onChange={(e) => setSortBy(e.target.value)}
              className="input-field w-48"
            >
              {sortOptions.map(option => (
                <option key={option.value} value={option.value}>
                  {option.label}
                </option>
              ))}
            </select>
          </div>
        </div>
      </div>

      {/* Collections Grid */}
      <div className="p-6">
        {sortedCollections.length === 0 ? (
          <div className="text-center py-12">
            <div className="text-6xl mb-4">🌍</div>
            <h3 className="text-xl font-semibold mb-2" style={{ color: 'var(--text-primary)' }}>
              {searchQuery ? 'No collections found' : 'No public collections yet'}
            </h3>
            <p className="text-sm mb-6" style={{ color: 'var(--text-secondary)' }}>
              {searchQuery 
                ? 'Try adjusting your search terms'
                : 'Be the first to share a public collection with the community!'
              }
            </p>
            {!searchQuery && (
              <Link href="/collections">
                <button className="px-6 py-3 rounded-xl font-medium transition-all duration-200 hover:shadow-md"
                  style={{ 
                    backgroundColor: 'var(--accent-ember)',
                    color: 'white'
                  }}
                >
                  Go to My Collections
                </button>
              </Link>
            )}
          </div>
        ) : (
          <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-6">
            {sortedCollections.map(collection => (
              <Link key={collection.id} href={`/collection/${collection.slug || collection.id}`}>
                <div className="card group cursor-pointer hover:shadow-lg transition-all duration-200">
                  <CollectionThumbnail collection={collection} />
                  
                  <div className="space-y-3">
                    <div className="flex items-start justify-between">
                      <div className="flex-1 min-w-0">
                        <h3 className="font-semibold text-lg truncate" style={{ color: 'var(--text-primary)' }}>
                          {collection.name}
                        </h3>
                        {collection.description && (
                          <p className="text-sm mt-1 line-clamp-2" style={{ color: 'var(--text-secondary)' }}>
                            {collection.description}
                          </p>
                        )}
                        <p className="text-xs mt-1" style={{ color: 'var(--text-secondary)' }}>
                          by {collection.creator}
                        </p>
                      </div>
                      <div className="flex items-center space-x-1 ml-2">
                        <PermissionIndicator 
                          userRole={collection.userRole} 
                          isPublic={collection.isPublic}
                          showTooltip={false}
                        />
                      </div>
                    </div>
                    
                    {/* Compact Stats */}
                    <div className="flex items-center justify-between text-sm" style={{ color: 'var(--text-secondary)' }}>
                      <div className="flex items-center space-x-4">
                        <span className="font-medium" style={{ color: 'var(--text-primary)' }}>
                          {collection.cardCount} cards
                        </span>
                        <span className="font-medium" style={{ color: 'var(--accent-ember)' }}>
                          {formatCurrency(collection.value)}
                        </span>
                      </div>
                      <span className="text-xs">
                        {formatDate(collection.createdAt)}
                      </span>
                    </div>
                    
                    {/* Tags */}
                    {collection.tags && collection.tags.length > 0 && (
                      <div className="flex flex-wrap gap-1">
                        {collection.tags.slice(0, 2).map((tag, index) => (
                          <span
                            key={index}
                            className="px-2 py-1 rounded-md text-xs font-medium"
                            style={{ 
                              backgroundColor: 'var(--bg-tertiary)', 
                              color: 'var(--text-secondary)' 
                            }}
                          >
                            {tag}
                          </span>
                        ))}
                        {collection.tags.length > 2 && (
                          <span
                            className="px-2 py-1 rounded-md text-xs font-medium"
                            style={{ 
                              backgroundColor: 'var(--bg-tertiary)', 
                              color: 'var(--text-secondary)' 
                            }}
                          >
                            +{collection.tags.length - 2}
                          </span>
                        )}
                      </div>
                    )}
                  </div>
                </div>
              </Link>
            ))}
          </div>
        )}
      </div>
    </Layout>
  );
}