Kmp Starter Navigation

@Serializable
@Stable
sealed class AppScreens : NavKey {
    @Serializable
    data object Home : AppScreens()
}

val navigationPolymorphicBuilder: PolymorphicModuleBuilder<NavKey>.() -> Unit = {
    subclass(AppScreens.Home::class)
    // ... every screen
}

val appNavigationModule = module {
    includes(navigationCoreModule)

    navigation<AppScreens.Home> { route ->
        val navigator = StarterNavigator.getCurrent()
        HomeScreen(onTaskComplete = { navigator.navigateUp() })
    }
}

val navigator = StarterNavigator.getCurrent()

navigator.navigateTo(route)            // push
navigator.popAndNavigate(route)        // pop current, then push
navigator.popAllAndNavigate(route)     // clear stack, then push
navigator.navigateOrBringToTop(route)  // single instance, bring to top
navigator.navigateUp()                 // pop
navigator.remove(route)                // remove a destination

@Serializable
sealed class FeatureScreens : NavKey {
    @Serializable data object Home : FeatureScreens()
    @Serializable data object History : FeatureScreens()
    @Serializable data object Settings : FeatureScreens()
}

internal object FeatureNavScope {
    private val QUALIFIER = qualifier<FeatureNavScope>()
    private val ID = QUALIFIER.toString()

    @Composable
    fun getOrCreateScope() = getKoin().getOrCreateScope(scopeId = ID, qualifier = QUALIFIER)
}

internal class FeatureNestedNavigator : BaseNavigator() {
    companion object {
        @Composable
        fun getCurrent(): FeatureNestedNavigator =
            koinInject(scope = FeatureNavScope.getOrCreateScope())
    }
}

    private val scope = CoroutineScope(Dispatchers.Main + SupervisorJob())
    private val _events = MutableSharedFlow<FeatureNestedNavigationEvents>(replay = 0)
    val events: SharedFlow<FeatureNestedNavigationEvents> = _events.asSharedFlow()

    fun emitEvent(event: FeatureNestedNavigationEvents) {
        scope.launch { _events.emit(event) }
    }

internal sealed class FeatureNestedNavigationEvents {
    data class OnNavigateToDetail(val id: String) : FeatureNestedNavigationEvents()
    data object OnNavigateToPurchases : FeatureNestedNavigationEvents()
}

val featureNestedNavigationModule = module {
    scope<FeatureNavScope> {
        scoped { FeatureNestedNavigator() }
        navigation<FeatureScreens.Home> {
            val navigator = FeatureNestedNavigator.getCurrent()
            HomeScreen(
                onNavigateToDetail = { id ->
                    navigator.emitEvent(FeatureNestedNavigationEvents.OnNavigateToDetail(id))
                },
                onNavigateToPurchases = {
                    navigator.emitEvent(FeatureNestedNavigationEvents.OnNavigateToPurchases)
                },
            )
        }
        navigation<FeatureScreens.History> { HistoryScreen() }
        navigation<FeatureScreens.Settings> {
            val navigator = FeatureNestedNavigator.getCurrent()
            SettingsScreen(
                onNavigateToPurchases = {
                    navigator.emitEvent(FeatureNestedNavigationEvents.OnNavigateToPurchases)
                },
            )
        }
    }
}