From 6a942e74a3a9e9037a8f6ae69cd111ee8a425e8e Mon Sep 17 00:00:00 2001
From: Derek Ellis <derekellis170@gmail.com>
Date: Thu, 14 Mar 2024 23:21:35 -0400
Subject: [PATCH] Remove nullable view models from view interface

---
 .../ca/derekellis/reroute/home/HomeView.kt    |  2 +-
 .../ca/derekellis/reroute/map/MapView.kt      |  4 +--
 .../derekellis/reroute/search/SearchView.kt   |  4 +--
 .../ca/derekellis/reroute/stops/StopView.kt   |  6 ++---
 .../ca/derekellis/reroute/ui/ScreenWrapper.kt | 27 ++++++-------------
 .../kotlin/ca/derekellis/reroute/ui/View.kt   |  2 +-
 6 files changed, 14 insertions(+), 31 deletions(-)

diff --git a/web/src/jsMain/kotlin/ca/derekellis/reroute/home/HomeView.kt b/web/src/jsMain/kotlin/ca/derekellis/reroute/home/HomeView.kt
index c268be1..8319760 100644
--- a/web/src/jsMain/kotlin/ca/derekellis/reroute/home/HomeView.kt
+++ b/web/src/jsMain/kotlin/ca/derekellis/reroute/home/HomeView.kt
@@ -5,7 +5,7 @@ import ca.derekellis.reroute.ui.View
 
 class HomeView : View<Unit, Unit> {
   @Composable
-  override fun Content(model: Unit?, emit: (Unit) -> Unit) {
+  override fun Content(model: Unit, emit: (Unit) -> Unit) {
     /* No-op */
   }
 }
diff --git a/web/src/jsMain/kotlin/ca/derekellis/reroute/map/MapView.kt b/web/src/jsMain/kotlin/ca/derekellis/reroute/map/MapView.kt
index 706785d..60c0633 100644
--- a/web/src/jsMain/kotlin/ca/derekellis/reroute/map/MapView.kt
+++ b/web/src/jsMain/kotlin/ca/derekellis/reroute/map/MapView.kt
@@ -27,9 +27,7 @@ import org.jetbrains.compose.web.dom.Div
 @Inject
 class MapView : View<MapViewModel, MapViewEvent> {
   @Composable
-  override fun Content(model: MapViewModel?, emit: (MapViewEvent) -> Unit) {
-    model ?: return
-
+  override fun Content(model: MapViewModel, emit: (MapViewEvent) -> Unit) {
     val mapState = rememberMapboxState(center = LngLat(-75.7181, 45.3922), zoom = 11.0)
 
     LaunchedEffect(model.targetStop) {
diff --git a/web/src/jsMain/kotlin/ca/derekellis/reroute/search/SearchView.kt b/web/src/jsMain/kotlin/ca/derekellis/reroute/search/SearchView.kt
index 2135adb..50419c7 100644
--- a/web/src/jsMain/kotlin/ca/derekellis/reroute/search/SearchView.kt
+++ b/web/src/jsMain/kotlin/ca/derekellis/reroute/search/SearchView.kt
@@ -39,9 +39,7 @@ import org.jetbrains.compose.web.dom.Input
 
 class SearchView : View<SearchViewModel, SearchViewEvent> {
   @Composable
-  override fun Content(model: SearchViewModel?, emit: (SearchViewEvent) -> Unit) {
-    model ?: return
-
+  override fun Content(model: SearchViewModel, emit: (SearchViewEvent) -> Unit) {
     var isFocused by remember { mutableStateOf(false) }
 
     Style(SearchStyleSheet)
diff --git a/web/src/jsMain/kotlin/ca/derekellis/reroute/stops/StopView.kt b/web/src/jsMain/kotlin/ca/derekellis/reroute/stops/StopView.kt
index b3b2a80..6290337 100644
--- a/web/src/jsMain/kotlin/ca/derekellis/reroute/stops/StopView.kt
+++ b/web/src/jsMain/kotlin/ca/derekellis/reroute/stops/StopView.kt
@@ -14,9 +14,7 @@ import org.jetbrains.compose.web.dom.Text
 
 class StopView : View<StopViewModel, StopViewEvent> {
   @Composable
-  override fun Content(model: StopViewModel?, emit: (StopViewEvent) -> Unit) {
-    model ?: return
-
+  override fun Content(model: StopViewModel, emit: (StopViewEvent) -> Unit) {
     Style(StopsStyleSheet)
     InfoPanel(onClose = { emit(Close) }) {
       StopContent(model)
@@ -31,7 +29,7 @@ private fun StopContent(model: StopViewModel) {
   when (model) {
     is StopViewModel.Loaded -> {
       H1 { Text(model.stop.name) }
-      H2 { Text(model.stop.code ?: "") }
+      H2 { Text(model.stop.code) }
       Div { Text(model.stop.id) }
       Hr()
       model.groupedRoutes.forEach { routes -> RouteInfo(routes) }
diff --git a/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/ScreenWrapper.kt b/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/ScreenWrapper.kt
index bd64cba..4c52e67 100644
--- a/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/ScreenWrapper.kt
+++ b/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/ScreenWrapper.kt
@@ -1,15 +1,9 @@
 package ca.derekellis.reroute.ui
 
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.setValue
-import app.cash.molecule.RecompositionClock
-import app.cash.molecule.moleculeFlow
-import kotlinx.coroutines.channels.Channel
-import kotlinx.coroutines.flow.consumeAsFlow
-import kotlinx.coroutines.flow.filterNotNull
+import androidx.compose.runtime.remember
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
 import me.tatarka.inject.annotations.Inject
 
 @Inject
@@ -17,19 +11,14 @@ class ScreenWrapper(
   private val presenter: Presenter<Any, Any>,
   private val view: View<Any, Any>,
 ) {
-  private val eventsChannel = Channel<Any?>()
-  private val events = eventsChannel.consumeAsFlow().filterNotNull()
-
-  private val models = moleculeFlow(RecompositionClock.ContextClock) { presenter.produceModel(events) }
-  private var model by mutableStateOf<Any?>(null)
-
   @Composable
   fun screen() {
-    LaunchedEffect(presenter) {
-      models.collect { model = it }
-    }
+    val triggerFlow = remember { MutableSharedFlow<Any>(replay = 1) }
+    val listenerFlow = remember { triggerFlow.asSharedFlow() }
+
+    val model = presenter.produceModel(listenerFlow)
 
-    view.Content(model) { eventsChannel.trySend(it) }
+    view.Content(model) { triggerFlow.tryEmit(it) }
   }
 
   override fun equals(other: Any?): Boolean {
diff --git a/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/View.kt b/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/View.kt
index bf13301..6eaab05 100644
--- a/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/View.kt
+++ b/web/src/jsMain/kotlin/ca/derekellis/reroute/ui/View.kt
@@ -4,5 +4,5 @@ import androidx.compose.runtime.Composable
 
 interface View<ViewModel, ViewEvent> {
   @Composable
-  fun Content(model: ViewModel?, emit: (ViewEvent) -> Unit)
+  fun Content(model: ViewModel, emit: (ViewEvent) -> Unit)
 }