fixup! wip: refactor: API

cmd/client/main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"log/slog"
 	"os"
@@ -90,7 +89,7 @@ func run() error {
 		}
 	})
 
-	ui, err := terminal.StartUI(ctx, terminal.StartParams{
+	ui, err := terminal.NewUI(ctx, terminal.Params{
 		EventBus: bus,
 		Dispatcher: func(cmd event.Command) {
 			logger.Info("Command dispatched", "cmd", cmd.Name())
@@ -112,18 +111,11 @@ func run() error {
 	}
 	defer ui.Close()
 
-	errUIClosed := errors.New("UI closed")
-	g.Go(func() error {
-		ui.Wait()
-		logger.Info("UI closed!")
-		return errUIClosed
-	})
+	g.Go(func() error { return ui.Run(ctx) })
 
-	if err := g.Wait(); err == errUIClosed {
-		logger.Info("UI closed, exiting")
+	if err := g.Wait(); err == terminal.ErrUserClosed {
 		return nil
 	} else {
-		logger.Error("UI closed with error", "err", err)
 		return fmt.Errorf("errgroup.Wait: %w", err)
 	}
 }

internal/terminal/terminal.go

@@ -3,6 +3,7 @@ package terminal
 import (
 	"cmp"
 	"context"
+	"errors"
 	"fmt"
 	"log/slog"
 	"maps"
@@ -46,7 +47,7 @@ type UI struct {
 	clipboardAvailable bool
 	rtmpURL, rtmpsURL  string
 	buildInfo          domain.BuildInfo
-	doneC              chan struct{}
+	appExitC           chan error
 	logger             *slog.Logger
 
 	// tview state
@@ -92,9 +93,9 @@ type ScreenCapture struct {
 	Width, Height int
 }
 
-// StartParams contains the parameters for starting a new terminal user
+// Params contains the parameters for starting a new terminal user
 // interface.
-type StartParams struct {
+type Params struct {
 	EventBus           *event.Bus
 	Dispatcher         func(event.Command)
 	Logger             *slog.Logger
@@ -103,8 +104,9 @@ type StartParams struct {
 	Screen             *Screen // Screen may be nil.
 }
 
-// StartUI starts the terminal user interface.
-func StartUI(ctx context.Context, params StartParams) (*UI, error) {
+// NewUI creates the user interface. Call [Run] on the *UI instance to block
+// until it is completed.
+func NewUI(ctx context.Context, params Params) (*UI, error) {
 	app := tview.NewApplication()
 
 	var screen tcell.Screen
@@ -210,7 +212,7 @@ func StartUI(ctx context.Context, params StartParams) (*UI, error) {
 		eventBus:           params.EventBus,
 		dispatch:           params.Dispatcher,
 		clipboardAvailable: params.ClipboardAvailable,
-		doneC:              make(chan struct{}, 1),
+		appExitC:           make(chan error, 1),
 		buildInfo:          params.BuildInfo,
 		logger:             params.Logger,
 		app:                app,
@@ -236,8 +238,6 @@ func StartUI(ctx context.Context, params StartParams) (*UI, error) {
 	app.SetInputCapture(ui.inputCaptureHandler)
 	app.SetAfterDrawFunc(ui.afterDrawHandler)
 
-	go ui.run(ctx)
-
 	return ui, nil
 }
 
@@ -264,23 +264,28 @@ func (ui *UI) renderAboutView() {
 	ui.aboutView.AddItem(tview.NewTextView().SetDynamicColors(true).SetText("[grey]?[-]        About"), 1, 0, false)
 }
 
-func (ui *UI) run(ctx context.Context) {
+var ErrUserClosed = errors.New("user closed UI")
+
+// Run runs the user interface. It always returns a non-nil error, which will
+// be [ErrUserClosed] if the user voluntarily closed the UI.
+func (ui *UI) Run(ctx context.Context) error {
 	eventC := ui.eventBus.Register()
 	defer ui.eventBus.Deregister(eventC)
 
 	go func() {
-		defer close(ui.doneC)
-
-		if err := ui.app.Run(); err != nil {
+		err := ui.app.Run()
+		if err != nil {
 			ui.logger.Error("Error in UI run loop, exiting", "err", err)
 		}
+		ui.appExitC <- err
 	}()
 
 	for {
 		select {
 		case evt, ok := <-eventC:
 			if !ok {
-				return
+				// should never happen
+				return errors.New("event channel closed")
 			}
 			ui.app.QueueUpdateDraw(func() {
 				switch evt := evt.(type) {
@@ -307,12 +312,11 @@ func (ui *UI) run(ctx context.Context) {
 				default:
 					ui.logger.Warn("unhandled event", "event", evt)
 				}
-
 			})
 		case <-ctx.Done():
-			return
-		case <-ui.doneC:
-			return
+			return ctx.Err()
+		case err := <-ui.appExitC:
+			return cmp.Or(err, ErrUserClosed)
 		}
 	}
 }
@@ -819,7 +823,7 @@ func (ui *UI) Close() {
 
 // Wait waits for the terminal user interface to finish.
 func (ui *UI) Wait() {
-	<-ui.doneC
+	<-ui.appExitC
 }
 
 func (ui *UI) addDestination() {