import SwiftUI
import SwiftData

struct HomeView: View {
    @EnvironmentObject private var router: AppRouter
    @Environment(\.dependencies) private var dependencies
    @Query(sort: \LibraryBook.dateAdded, order: .reverse) private var libraryBooks: [LibraryBook]
    @StateObject private var viewModel: HomeViewModel

    init(viewModel: HomeViewModel) {
        _viewModel = StateObject(wrappedValue: viewModel)
    }

    var body: some View {
        ScrollView {
            VStack(spacing: 28) {
                header

                ForEach(viewModel.categories) { category in
                    ShelfSectionView(
                        title: category.name,
                        books: category.books,
                        gradient: viewModel.gradient(for: category.name),
                        imageCache: dependencies.imageCache,
                        onTapCategory: { router.path.append(.category(name: category.name)) },
                        onTapBook: { router.path.append(.detail($0)) }
                    )
                }
            }
            .padding(.top, 16)
            .padding(.bottom, 120)
        }
        .background(Theme.background.ignoresSafeArea())
        .safeAreaInset(edge: .bottom, spacing: 0) {
            ZStack {
                BlurFogOverlay()
                    .frame(height: 96)
                PrimaryPillButton(title: String(localized: "home.addBooks")) {
                    router.path.append(.addBooks)
                }
                .padding(.horizontal, 24)
                .padding(.bottom, 12)
            }
            .frame(height: 100)
        }
        .onAppear {
            viewModel.refresh(from: libraryBooks)
        }
        .onChange(of: libraryBooks.map(\.localId)) { _, _ in
            viewModel.refresh(from: libraryBooks)
        }
        .task(id: libraryBooks.count) {
            viewModel.refresh(from: libraryBooks)
        }
    }

    private var header: some View {
        VStack(spacing: 4) {
            Text(String(localized: "home.myFavourite"))
                .font(.footnote.weight(.light))
                .kerning(1.2)
                .foregroundStyle(Color.black.opacity(0.7))

            Text(String(localized: "home.books"))
                .font(Theme.headerSerif(size: 56).weight(.bold))
                .foregroundStyle(.black)
                .kerning(1)
        }
        .frame(maxWidth: .infinity)
        .padding(.top, 12)
        .accessibilityElement(children: .combine)
    }
}