From 2f1cadcf40c08080bf15fb59f010223cee06edbb Mon Sep 17 00:00:00 2001
From: Rob Watson <rob@netflux.io>
Date: Fri, 25 Apr 2025 18:06:31 +0200
Subject: [PATCH] refactor(app): add DestinationWentOffAirEvent

---
 internal/app/app.go           | 10 ++--------
 internal/event/events.go      | 11 +++++++++++
 internal/terminal/terminal.go | 28 ++++++++++++++--------------
 3 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/internal/app/app.go b/internal/app/app.go
index 91db45a..c3c3a00 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -197,7 +197,8 @@ func (a *App) Run(ctx context.Context) error {
 			destErrors := applyReplicatorState(replState, state)
 
 			for _, destError := range destErrors {
-				handleDestError(destError, repl, ui)
+				a.eventBus.Send(event.DestinationStreamExitedEvent{Name: destError.name, Err: destError.err})
+				repl.StopDestination(destError.url)
 			}
 
 			updateUI()
@@ -316,13 +317,6 @@ func applyReplicatorState(replState replicator.State, appState *domain.AppState)
 	return errorsToDisplay
 }
 
-// handleDestError displays a modal to the user, and stops the destination.
-func handleDestError(destError destinationError, repl *replicator.Actor, ui *terminal.UI) {
-	ui.ShowDestinationErrorModal(destError.name, destError.err)
-
-	repl.StopDestination(destError.url)
-}
-
 // applyConfig applies the config to the app state. For now we only set the
 // destinations.
 func applyConfig(cfg config.Config, appState *domain.AppState) {
diff --git a/internal/event/events.go b/internal/event/events.go
index c7c8ff8..b9d15a7 100644
--- a/internal/event/events.go
+++ b/internal/event/events.go
@@ -8,6 +8,7 @@ const (
 	EventNameAppStateChanged         Name = "app_state_changed"
 	EventNameDestinationAdded        Name = "destination_added"
 	EventNameAddDestinationFailed    Name = "add_destination_failed"
+	EventNameDestinationStreamExited Name = "destination_stream_exited"
 	EventNameStartDestinationFailed  Name = "start_destination_failed"
 	EventNameDestinationRemoved      Name = "destination_removed"
 	EventNameRemoveDestinationFailed Name = "remove_destination_failed"
@@ -48,6 +49,16 @@ func (e AddDestinationFailedEvent) name() Name {
 	return EventNameAddDestinationFailed
 }
 
+// DestinationStreamExitedEvent is emitted when a destination goes off-air unexpectedly.
+type DestinationStreamExitedEvent struct {
+	Name string
+	Err  error
+}
+
+func (e DestinationStreamExitedEvent) name() Name {
+	return EventNameDestinationStreamExited
+}
+
 // StartDestinationFailedEvent is emitted when a destination fails to start.
 type StartDestinationFailedEvent struct{}
 
diff --git a/internal/terminal/terminal.go b/internal/terminal/terminal.go
index f7e25ab..97ec572 100644
--- a/internal/terminal/terminal.go
+++ b/internal/terminal/terminal.go
@@ -305,6 +305,8 @@ func (ui *UI) run(ctx context.Context) {
 					ui.handleStartDestinationFailed(evt)
 				case event.AddDestinationFailedEvent:
 					ui.handleDestinationEventError(evt.Err)
+				case event.DestinationStreamExitedEvent:
+					ui.handleDestinationStreamExited(evt)
 				case event.DestinationRemovedEvent:
 					ui.handleDestinationRemoved(evt)
 				case event.RemoveDestinationFailedEvent:
@@ -431,20 +433,18 @@ func (ui *UI) handleOtherInstanceDetected(event.OtherInstanceDetectedEvent) {
 	)
 }
 
-func (ui *UI) ShowDestinationErrorModal(name string, err error) {
-	ui.app.QueueUpdateDraw(func() {
-		ui.showModal(
-			pageNameModalDestinationError,
-			fmt.Sprintf(
-				"Streaming to %s failed:\n\n%s",
-				cmp.Or(name, "this destination"),
-				err,
-			),
-			[]string{"Ok"},
-			true,
-			nil,
-		)
-	})
+func (ui *UI) handleDestinationStreamExited(evt event.DestinationStreamExitedEvent) {
+	ui.showModal(
+		pageNameModalDestinationError,
+		fmt.Sprintf(
+			"Streaming to %s failed:\n\n%s",
+			cmp.Or(evt.Name, "this destination"),
+			evt.Err,
+		),
+		[]string{"Ok"},
+		true,
+		nil,
+	)
 }
 
 func (ui *UI) handleFatalErrorOccurred(evt event.FatalErrorOccurredEvent) {