Unfinished work on neoirc-cli hanging on keys and typed lines

Saved from a stopped session, not checked or reviewed.

Model: opus-5-5

internal/cli/ui.go

@@ -16,7 +16,9 @@ type Buffer struct {
 	Unread int
 }
 
-// UI manages the terminal interface.
+// UI manages the terminal interface. Its methods wait for the
+// tview event loop to run their update, so code running on that
+// loop, such as a key handler, must not call them.
 type UI struct {
 	app       *tview.Application
 	messages  *tview.TextView
@@ -28,6 +30,9 @@ type UI struct {
 	currentBuffer int
 
 	onInput func(string)
+	// inputDone is closed once the line last passed to onInput
+	// has been handled.
+	inputDone chan struct{}
 }
 
 // NewUI creates the tview-based IRC-like UI.
@@ -176,9 +181,24 @@ func (ui *UI) SetStatus(
 	})
 }
 
-// BufferCount returns the number of buffers.
-func (ui *UI) BufferCount() int {
-	return len(ui.buffers)
+// BufferName returns the name of the buffer at index n, and
+// whether there is such a buffer.
+func (ui *UI) BufferName(bufIndex int) (string, bool) {
+	var (
+		name  string
+		found bool
+	)
+
+	ui.app.QueueUpdate(func() {
+		if bufIndex < 0 || bufIndex >= len(ui.buffers) {
+			return
+		}
+
+		name = ui.buffers[bufIndex].Name
+		found = true
+	})
+
+	return name, found
 }
 
 // BufferIndex returns the index of a named buffer.
@@ -226,10 +246,7 @@ func (ui *UI) initInput() {
 		}
 
 		ui.input.SetText("")
-
-		if ui.onInput != nil {
-			ui.onInput(text)
-		}
+		ui.callOnInput(text)
 	})
 }
 
@@ -244,9 +261,7 @@ func (ui *UI) initKeyCapture() {
 			// SwitchBuffer alone would leave the target as it was.
 			r := event.Rune()
 			if r >= '0' && r <= '9' {
-				if ui.onInput != nil {
-					ui.onInput("/window " + string(r))
-				}
+				ui.callOnInput("/window " + string(r))
 
 				return nil
 			}
@@ -256,6 +271,30 @@ func (ui *UI) initKeyCapture() {
 	)
 }
 
+// callOnInput passes text to the input callback on a new
+// goroutine, which first waits until the lines passed before it
+// have been handled. The key handlers call it on the event loop,
+// and the callback waits on that loop to update the screen, so
+// they must not wait for the callback.
+func (ui *UI) callOnInput(text string) {
+	if ui.onInput == nil {
+		return
+	}
+
+	previous := ui.inputDone
+	done := make(chan struct{})
+	ui.inputDone = done
+
+	go func() {
+		if previous != nil {
+			<-previous
+		}
+
+		ui.onInput(text)
+		close(done)
+	}()
+}
+
 func (ui *UI) refreshStatusBar() {
 	// Placeholder; full refresh needs nick/target context.
 }