/* eslint-disable @next/next/no-img-element -- External or generated image URLs; next/image migration is out of scope. */
import { useState, useEffect } from 'react';
import { useRouter } from 'next/router';
import Link from 'next/link';
import Layout from '../../components/Layout';
import { ManaCost, ColorIdentity } from '../../components/ManaSymbols';
import { useAuth } from '../../lib/use-auth';
import { getColorIdentity } from '../../lib/mana-symbols';

export default function DeckDetail() {
  const { user } = useAuth();
  const router = useRouter();
  const { id: deckId } = router.query;
  
  const [deck, setDeck] = useState(null);
  const [loading, setLoading] = useState(true);
  const [groupBy, setGroupBy] = useState('type');

  const fetchDeck = async () => {
    try {
      const token = localStorage.getItem('auth_token');
      const headers = token ? { 'Authorization': `Bearer ${token}` } : {};
      
      const response = await fetch(`/api/decks/${deckId}`, { headers });

      if (response.ok) {
        const data = await response.json();
        setDeck(data);
      } else {
        console.error('Failed to fetch deck');
        router.push('/decks');
      }
    } catch (error) {
      console.error('Error fetching deck:', error);
      router.push('/decks');
    } finally {
      setLoading(false);
    }
  }

  useEffect(() => {
    if (deckId) {
      // eslint-disable-next-line react-hooks/set-state-in-effect -- load deck when route id changes
      fetchDeck();
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps -- refetch when route deck id changes
  }, [deckId]);

;

  const getDeckStats = () => {
    if (!deck?.cards) return { totalCards: 0, avgCmc: 0, colorCounts: {}, typeCounts: {} };
    
    const totalCards = deck.cards.reduce((sum, card) => sum + card.quantity, 0);
    const avgCmc = deck.cards.length > 0 
      ? (deck.cards.reduce((sum, card) => sum + (card.cmc || 0) * card.quantity, 0) / totalCards).toFixed(1)
      : 0;
    
    const colorCounts = deck.cards.reduce((counts, card) => {
      if (card.colors) {
        try {
          const colors = JSON.parse(card.colors);
          colors.forEach(color => {
            counts[color] = (counts[color] || 0) + card.quantity;
          });
        } catch (e) {
          // Handle non-JSON color format
        }
      }
      return counts;
    }, {});

    const typeCounts = deck.cards.reduce((counts, card) => {
      if (card.card_type) {
        const types = card.card_type.split(' — ')[0].split(' ');
        types.forEach(type => {
          counts[type] = (counts[type] || 0) + card.quantity;
        });
      }
      return counts;
    }, {});

    return { totalCards, avgCmc, colorCounts, typeCounts };
  };

  const getGroupedCards = () => {
    if (!deck?.cards) return {};
    
    return deck.cards.reduce((groups, card) => {
      let key;
      
      switch (groupBy) {
        case 'type':
          key = card.card_type ? card.card_type.split(' — ')[0] : 'Unknown';
          break;
        case 'cmc':
          key = `${card.cmc || 0} Mana`;
          break;
        case 'color':
          try {
            const colors = card.colors ? JSON.parse(card.colors) : [];
            key = colors.length === 0 ? 'Colorless' : colors.map(c => c).join('');
          } catch (e) {
            key = 'Colorless';
          }
          break;
        case 'rarity':
          key = card.rarity || 'Unknown';
          break;
        default:
          key = 'All Cards';
      }
      
      if (!groups[key]) groups[key] = [];
      groups[key].push(card);
      return groups;
    }, {});
  };

  const getFormatIcon = (format) => {
    switch (format) {
      case 'Commander':
        return '⚔️';
      case 'Standard':
        return '🏆';
      case 'Modern':
        return '🔥';
      case 'Legacy':
        return '💎';
      default:
        return '🃏';
    }
  };

  if (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 border-accent-ember"></div>
        </div>
      </Layout>
    );
  }

  if (!deck) {
    return (
      <Layout user={user}>
        <div className="flex items-center justify-center min-h-screen">
          <div className="text-center">
            <h1 className="text-2xl font-bold mb-4">Deck not found</h1>
            <Link href="/decks" className="text-accent-ember hover:underline">
              Back to Decks
            </Link>
          </div>
        </div>
      </Layout>
    );
  }

  const stats = getDeckStats();
  const groupedCards = getGroupedCards();
  const isOwner = user && deck.user_id === user.userId;

  return (
    <Layout user={user}>
      <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8">
        {/* Header */}
        <div className="flex justify-between items-start mb-8">
          <div>
            <div className="flex items-center space-x-3 mb-2">
              <Link href="/decks" className="text-accent-ember hover:underline">
                ← Back to Decks
              </Link>
            </div>
            <div className="flex items-center space-x-3 mb-2">
              <span className="text-3xl">{getFormatIcon(deck.format)}</span>
              <h1 className="text-3xl font-bold text-text-primary">{deck.name}</h1>
              {deck.is_public && (
                <span className="bg-green-100 text-green-800 px-2 py-1 rounded-full text-xs font-medium">
                  Public
                </span>
              )}
            </div>
            <p className="text-text-secondary mb-2">
              by {deck.creator_username} • {deck.format} • {stats.totalCards} cards
            </p>
            {deck.description && (
              <p className="text-text-secondary max-w-2xl">{deck.description}</p>
            )}
          </div>
          
          {isOwner && (
            <div className="flex space-x-3">
              <Link
                href={`/deck-builder?deck=${deck.id}`}
                className="bg-accent-ember text-white px-4 py-2 rounded-lg hover:bg-accent-ember-dark transition-colors"
              >
                Edit Deck
              </Link>
            </div>
          )}
        </div>

        <div className="grid grid-cols-1 lg:grid-cols-4 gap-6">
          {/* Stats Sidebar */}
          <div className="lg:col-span-1">
            <div className="bg-bg-secondary rounded-lg p-6 mb-6">
              <h3 className="text-lg font-semibold text-text-primary mb-4">Statistics</h3>
              
              <div className="space-y-3">
                <div className="flex justify-between">
                  <span className="text-text-secondary">Total Cards:</span>
                  <span className="text-text-primary font-medium">{stats.totalCards}</span>
                </div>
                <div className="flex justify-between">
                  <span className="text-text-secondary">Avg. CMC:</span>
                  <span className="text-text-primary font-medium">{stats.avgCmc}</span>
                </div>
                <div className="flex justify-between">
                  <span className="text-text-secondary">Format:</span>
                  <span className="text-text-primary font-medium">{deck.format}</span>
                </div>
              </div>

              {/* Color Distribution */}
              {Object.keys(stats.colorCounts).length > 0 && (
                <div className="mt-6">
                  <h4 className="text-text-secondary text-sm font-medium mb-3">Color Distribution</h4>
                  <div className="space-y-2">
                    {Object.entries(stats.colorCounts)
                      .sort(([,a], [,b]) => b - a)
                      .map(([color, count]) => (
                        <div key={color} className="flex justify-between items-center">
                          <div className="flex items-center space-x-2">
                            <span className="text-lg">{color}</span>
                            <span className="text-text-secondary text-sm">{color}</span>
                          </div>
                          <span className="text-text-primary font-medium">{count}</span>
                        </div>
                      ))}
                  </div>
                </div>
              )}

              {/* Type Distribution */}
              {Object.keys(stats.typeCounts).length > 0 && (
                <div className="mt-6">
                  <h4 className="text-text-secondary text-sm font-medium mb-3">Card Types</h4>
                  <div className="space-y-2">
                    {Object.entries(stats.typeCounts)
                      .sort(([,a], [,b]) => b - a)
                      .slice(0, 8)
                      .map(([type, count]) => (
                        <div key={type} className="flex justify-between">
                          <span className="text-text-secondary text-sm">{type}</span>
                          <span className="text-text-primary font-medium">{count}</span>
                        </div>
                      ))}
                  </div>
                </div>
              )}
            </div>

            {/* Group By Controls */}
            <div className="bg-bg-secondary rounded-lg p-6">
              <h3 className="text-lg font-semibold text-text-primary mb-4">Group Cards By</h3>
              <div className="space-y-2">
                {[
                  { value: 'type', label: 'Card Type' },
                  { value: 'cmc', label: 'Mana Cost' },
                  { value: 'color', label: 'Color' },
                  { value: 'rarity', label: 'Rarity' }
                ].map(option => (
                  <button
                    key={option.value}
                    onClick={() => setGroupBy(option.value)}
                    className={`w-full text-left px-3 py-2 rounded-lg transition-colors ${
                      groupBy === option.value
                        ? 'bg-accent-ember text-white'
                        : 'text-text-secondary hover:bg-bg-tertiary'
                    }`}
                  >
                    {option.label}
                  </button>
                ))}
              </div>
            </div>
          </div>

          {/* Card List */}
          <div className="lg:col-span-3">
            <div className="bg-bg-secondary rounded-lg p-6">
              {deck.cards && deck.cards.length === 0 ? (
                <div className="text-center py-12">
                  <div className="text-6xl mb-4">🃏</div>
                  <h3 className="text-xl font-semibold text-text-primary mb-2">Empty Deck</h3>
                  <p className="text-text-secondary">This deck doesn&apos;t have any cards yet</p>
                </div>
              ) : (
                <div className="space-y-6">
                  {Object.entries(groupedCards)
                    .sort(([a], [b]) => a.localeCompare(b))
                    .map(([group, cards]) => (
                      <div key={group}>
                        <h3 className="text-lg font-semibold text-text-primary mb-3 border-b border-border pb-2">
                          {group} ({cards.reduce((sum, card) => sum + card.quantity, 0)})
                        </h3>
                        <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
                          {cards
                            .sort((a, b) => a.name.localeCompare(b.name))
                            .map((card) => (
                              <div key={`${card.card_id}-${card.id}`} className="flex items-center space-x-3 p-3 bg-bg-primary rounded-lg hover:bg-bg-tertiary transition-colors">
                                {card.image_url && (
                                  <img
                                    src={card.image_url}
                                    alt={card.name}
                                    className="w-12 h-16 object-cover rounded"
                                  />
                                )}
                                <div className="flex-1 min-w-0">
                                  <div className="flex items-center justify-between">
                                    <h4 className="font-medium text-text-primary truncate">{card.name}</h4>
                                    <span className="text-text-primary font-medium ml-2">{card.quantity}x</span>
                                  </div>
                                  <p className="text-text-secondary text-sm">{card.set_name}</p>
                                  <div className="flex items-center space-x-2 text-xs text-text-secondary">
                                    {card.mana_cost && (
                                      <ManaCost cost={card.mana_cost} size="xs" />
                                    )}
                                    {card.rarity && <span className="capitalize">{card.rarity}</span>}
                                  </div>
                                </div>
                              </div>
                            ))}
                        </div>
                      </div>
                    ))}
                </div>
              )}
            </div>
          </div>
        </div>
      </div>
    </Layout>
  );
}