Recreate the iOS app UI on a new deep link incoming

With this change whenever a deep link is received, we create a
completely new AppComponent so that we start from a clean slate.
In order to be able to observe this change from SwiftUI we also store a
local @State object which we increment at the same time in order to
trigger a re-render of the View.
This is absolutely a hack and we should find a better approach as soon
as possible

iosApp/iosApp/AppDelegate.swift

@@ -11,7 +11,7 @@ import ConfettiKit
 
 class AppDelegate : NSObject, UIApplicationDelegate {
 
-    let root: AppComponent
+    var root: AppComponent
 
     override init() {
         KoinKt.doInitKoin()
@@ -24,4 +24,14 @@ class AppDelegate : NSObject, UIApplicationDelegate {
             initialConferenceId: nil
         )
     }
+
+    func onConferenceDeepLink(conferenceId: String) {
+        root = DefaultAppComponent(
+            componentContext: DefaultComponentContext(lifecycle: ApplicationLifecycle()),
+            onSignOut: {},
+            onSignIn: {},
+            isMultiPane: UIDevice.current.userInterfaceIdiom != UIUserInterfaceIdiom.phone,
+            initialConferenceId: conferenceId
+        )
+    }
 }

iosApp/iosApp/iOSApp.swift

@@ -10,8 +10,12 @@ struct iOSApp: App {
     @UIApplicationDelegateAdaptor(AppDelegate.self)
     var appDelegate: AppDelegate
 
+    @State
+    private var reRenderIndex: Int = 0
+
     var body: some Scene {
         WindowGroup {
+            EmptyView(reRenderIndex: reRenderIndex)
             ConfettiApp(appDelegate.root)
                 .onOpenURL(perform: { url in
                     let pathComponents = url.pathComponents
@@ -21,7 +25,8 @@ struct iOSApp: App {
                     for char in conferenceId {
                         if !char.isLetter && !char.isNumber { return }
                     }
-                    appDelegate.root.onConferenceDeepLink(conferenceId: conferenceId)
+                    appDelegate.onConferenceDeepLink(conferenceId: conferenceId)
+                    reRenderIndex += 1
                 })
         }
         .onChange(of: phase) { newPhase in
@@ -41,3 +46,14 @@ func scheduleDataRefresh() {
     request.earliestBeginDate = .now.addingTimeInterval(24 * 3600)
     try? BGTaskScheduler.shared.submit(request)
 }
+
+/**
+ This view exists so that there is a way for us to read the change in `@State reloadIndex`, so that the view will try to re-render itself and pick up the latest value from appDelegate.root. This is done since `AppComponent` is not an object that can be observed by SwiftUI in some way, so this workaround was added.
+ */
+private struct EmptyView: View {
+    var reRenderIndex: Int
+
+    var body: some View {
+        Group {}
+    }
+}

shared/src/commonMain/kotlin/dev/johnoreilly/confetti/decompose/AppComponent.kt

@@ -22,8 +22,6 @@ import org.koin.core.component.inject
 interface AppComponent {
     val stack: Value<ChildStack<*, Child>>
 
-    fun onConferenceDeepLink(conferenceId: String)
-
     sealed class Child {
         object Loading : Child()
         class Conferences(val component: ConferencesComponent) : Child()
@@ -80,12 +78,6 @@ class DefaultAppComponent(
         }
     }
 
-    override fun onConferenceDeepLink(conferenceId: String) {
-        coroutineScope.launch {
-            selectAndNavigateToDeepLinkedConference(conferenceId)
-        }
-    }
-
     private suspend fun selectAndNavigateToDeepLinkedConference(conferenceId: String) {
         // todo, consider changing how conference theme colors are decided so that only knowing the conference
         //  ID is enough to also get the right color