import ManaCore
import SwiftUI

/// Explore-Tab: Featured + Trending Sections, plus Browse-Link.
struct ExploreView: View {
    @Binding var deepLinkSlug: String?

    @Environment(AuthClient.self) private var auth
    @State private var store: MarketplaceStore?
    @State private var path: [MarketplaceRoute] = []

    init(deepLinkSlug: Binding<String?> = .constant(nil)) {
        _deepLinkSlug = deepLinkSlug
    }

    var body: some View {
        NavigationStack(path: $path) {
            ZStack {
                CardsTheme.background.ignoresSafeArea()
                content
            }
            .navigationTitle("Entdecken")
            .navigationDestination(for: MarketplaceRoute.self) { route in
                switch route {
                case .browse:
                    BrowseView()
                case let .publicDeck(slug):
                    PublicDeckView(slug: slug)
                }
            }
            .navigationDestination(for: String.self) { deckId in
                DeckDetailView(deckId: deckId)
            }
            .refreshable {
                await store?.loadExplore()
            }
            .task {
                if store == nil {
                    store = MarketplaceStore(auth: auth)
                }
                await store?.loadExplore()
            }
            .onChange(of: deepLinkSlug) { _, newSlug in
                guard let slug = newSlug else { return }
                path = [.publicDeck(slug: slug)]
                deepLinkSlug = nil
            }
        }
    }

    @ViewBuilder
    private var content: some View {
        if let store {
            if store.isLoadingExplore, store.featured.isEmpty, store.trending.isEmpty {
                ProgressView()
                    .tint(CardsTheme.primary)
            } else if let message = store.errorMessage, store.featured.isEmpty {
                ContentUnavailableView(
                    "Marketplace nicht erreichbar",
                    systemImage: "wifi.exclamationmark",
                    description: Text(message)
                )
                .foregroundStyle(CardsTheme.foreground)
            } else {
                ScrollView {
                    VStack(alignment: .leading, spacing: 24) {
                        if !store.featured.isEmpty {
                            section(title: "Vorgestellt", items: store.featured)
                        }
                        if !store.trending.isEmpty {
                            section(title: "Im Trend", items: store.trending)
                        }

                        NavigationLink(value: MarketplaceRoute.browse) {
                            HStack {
                                Label("Alle Decks durchsuchen", systemImage: "magnifyingglass")
                                Spacer()
                                Image(systemName: "chevron.right")
                                    .font(.footnote)
                            }
                            .padding()
                            .background(CardsTheme.surface, in: RoundedRectangle(cornerRadius: 10))
                            .overlay(
                                RoundedRectangle(cornerRadius: 10)
                                    .stroke(CardsTheme.border, lineWidth: 1)
                            )
                            .foregroundStyle(CardsTheme.foreground)
                        }
                        .buttonStyle(.plain)
                        .padding(.horizontal, 16)
                    }
                    .padding(.vertical, 16)
                }
            }
        }
    }

    private func section(title: String, items: [PublicDeckEntry]) -> some View {
        VStack(alignment: .leading, spacing: 12) {
            Text(title)
                .font(.title3.weight(.semibold))
                .foregroundStyle(CardsTheme.foreground)
                .padding(.horizontal, 16)

            ScrollView(.horizontal, showsIndicators: false) {
                HStack(spacing: 12) {
                    ForEach(items) { item in
                        NavigationLink(value: MarketplaceRoute.publicDeck(slug: item.slug)) {
                            PublicDeckCard(entry: item)
                        }
                        .buttonStyle(.plain)
                    }
                }
                .padding(.horizontal, 16)
            }
        }
    }
}

/// Routen-Enum für die Marketplace-NavigationStack.
enum MarketplaceRoute: Hashable {
    case browse
    case publicDeck(slug: String)
}

/// Public-Deck-Karten-Tile in Featured/Trending-Carousels und Browse-Grid.
struct PublicDeckCard: View {
    let entry: PublicDeckEntry

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            HStack {
                Text(entry.title)
                    .font(.headline)
                    .foregroundStyle(CardsTheme.foreground)
                    .lineLimit(2)
                Spacer()
                if entry.isFeatured {
                    Image(systemName: "star.fill")
                        .font(.caption)
                        .foregroundStyle(CardsTheme.warning)
                }
            }
            if let description = entry.description, !description.isEmpty {
                Text(description)
                    .font(.caption)
                    .foregroundStyle(CardsTheme.mutedForeground)
                    .lineLimit(2)
            }
            HStack(spacing: 12) {
                Label("\(entry.cardCount)", systemImage: "rectangle.stack")
                Label("\(entry.starCount)", systemImage: "star")
                if entry.isPaid {
                    Label("\(entry.priceCredits) Credits", systemImage: "creditcard")
                        .foregroundStyle(CardsTheme.primary)
                }
            }
            .font(.caption2)
            .foregroundStyle(CardsTheme.mutedForeground)

            HStack(spacing: 4) {
                Text(entry.owner.displayName)
                    .font(.caption2)
                    .foregroundStyle(CardsTheme.mutedForeground)
                if entry.owner.verifiedMana {
                    Image(systemName: "checkmark.seal.fill")
                        .font(.caption2)
                        .foregroundStyle(CardsTheme.primary)
                }
            }
        }
        .padding(12)
        .frame(width: 260, alignment: .leading)
        .background(CardsTheme.surface, in: RoundedRectangle(cornerRadius: 10))
        .overlay(
            RoundedRectangle(cornerRadius: 10)
                .stroke(CardsTheme.border, lineWidth: 1)
        )
    }
}