struct DetailView: View {
   @Environment(ApplicationData.self) private var appData
   var book: Book

   var body: some View {
      VStack {
         Text(book.title)
            .font(.title)
         Text(book.author)
         Button(action: {
            appData.selectedBook = book
            appData.viewPath.append("Picture View")
         }, label: {
            Image(book.cover)
               .resizable()
               .scaledToFit()
               .frame(width: 100)
         })
         Spacer()
      }.padding()
      .navigationBarBackButtonHidden(true)
      .toolbar {
         ToolbarItem(placement: .topBarLeading) {
            Button("Back") {
               appData.viewPath.removeLast()
            }
         }
      }
   }
}
#Preview {
   NavigationStack {
      DetailView(book: ApplicationData.shared.userData[0])
         .environment(ApplicationData.shared)
   }
}