Creating navigation graph and app screens

MainActivity.kt

@OptIn(ExperimentalLifecycleComposeApi::class)
    @Composable
    private fun App() {
        val db = remember { UserDatabase.getUserDatabase(this) }
        val viewModel =
            viewModel<MainViewModel>(factory = MainViewModel.Companion.MainViewModelFactory(db))
        val navController = rememberNavController()
        val users by viewModel.users.collectAsStateWithLifecycle()

        NavHost(navController = navController, startDestination = Destinations.Home.route) {
            // main screen
            composable(
                route = Destinations.Home.route
            ) {
                HomeScreen(
                    users = users,
                    onUserClicked = { id ->
                        navController.navigate(
                            Destinations.Details.setAndGetArgumentRoute(
                                id
                            )
                        )
                    }
                )
            }

            // details screen
            composable(
                route = Destinations.Details.route,
                deepLinks = listOf(
                    navDeepLink {
                       val c = this@MainActivity
                        val scheme = c.getString(R.string.scheme)
                        val host = c.getString(R.string.host)
                        val path = c.getString(R.string.path_to_existed_user)
                        val uri = "$scheme://$host$path?userId={userId}"
                        uriPattern = uri
                    }
                ),
                arguments = listOf(
                    navArgument("userId") {
                        this.type = NavType.IntType
                    }
                )
            ) { navBackStackEntry ->
                val userId = navBackStackEntry.arguments?.getInt("userId")
                val  user = users.find { it.id == userId }
                DetailsScreen(
                    user = user,
                    onDismiss = {  },
                    onAddNewUserClicked = {
                        
                    },
                    onSharing = {
                           
                    }
                )
            }
        }
    }