fix(ui): follow scroll when at bottom (#2336)

Ayman Bagabas created 1 week ago

* fix(ui): follow scroll when at bottom

This change attempt to completely fix the agent scroll issue when at
bottom. It should follow the agent when the follow flag is set.

* fix(ui): make sure we select the last item when at bottom

Change summary

internal/ui/model/ui.go | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)

Detailed changes

internal/ui/model/ui.go

@@ -556,6 +556,11 @@ func (m *UI) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case tea.WindowSizeMsg:
 		m.width, m.height = msg.Width, msg.Height
 		m.updateLayoutAndSize()
+		if m.state == uiChat && m.chat.Follow() {
+			if cmd := m.chat.ScrollToBottomAndAnimate(); cmd != nil {
+				cmds = append(cmds, cmd)
+			}
+		}
 	case tea.KeyboardEnhancementsMsg:
 		m.keyenh = msg
 		if msg.SupportsKeyDisambiguation() {
@@ -680,7 +685,11 @@ func (m *UI) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 					cmds = append(cmds, cmd)
 				}
 				if !m.chat.SelectedItemInView() {
-					m.chat.SelectNext()
+					if m.chat.AtBottom() {
+						m.chat.SelectLast()
+					} else {
+						m.chat.SelectNext()
+					}
 					if cmd := m.chat.ScrollToSelectedAndAnimate(); cmd != nil {
 						cmds = append(cmds, cmd)
 					}
@@ -692,6 +701,11 @@ func (m *UI) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			if cmd := m.chat.Animate(msg); cmd != nil {
 				cmds = append(cmds, cmd)
 			}
+			if m.chat.Follow() {
+				if cmd := m.chat.ScrollToBottomAndAnimate(); cmd != nil {
+					cmds = append(cmds, cmd)
+				}
+			}
 		}
 	case spinner.TickMsg:
 		if m.dialog.HasDialogs() {
@@ -822,7 +836,7 @@ func (m *UI) setSessionMessages(msgs []message.Message) tea.Cmd {
 		cmds = append(cmds, cmd)
 	}
 	m.chat.SelectLast()
-	return tea.Batch(cmds...)
+	return tea.Sequence(cmds...)
 }
 
 // loadNestedToolCalls recursively loads nested tool calls for agent/agentic_fetch tools.
@@ -950,7 +964,7 @@ func (m *UI) appendSessionMessage(msg message.Message) tea.Cmd {
 			}
 		}
 	}
-	return tea.Batch(cmds...)
+	return tea.Sequence(cmds...)
 }
 
 func (m *UI) handleClickFocus(msg tea.MouseClickMsg) (cmd tea.Cmd) {
@@ -1029,16 +1043,16 @@ func (m *UI) updateSessionMessage(msg message.Message) tea.Cmd {
 		if cmd := m.chat.ScrollToBottomAndAnimate(); cmd != nil {
 			cmds = append(cmds, cmd)
 		}
+		m.chat.SelectLast()
 	}
 
-	return tea.Batch(cmds...)
+	return tea.Sequence(cmds...)
 }
 
 // handleChildSessionMessage handles messages from child sessions (agent tools).
 func (m *UI) handleChildSessionMessage(event pubsub.Event[message.Message]) tea.Cmd {
 	var cmds []tea.Cmd
 
-	atBottom := m.chat.AtBottom()
 	// Only process messages with tool calls or results.
 	if len(event.Payload.ToolCalls()) == 0 && len(event.Payload.ToolResults()) == 0 {
 		return nil
@@ -1118,13 +1132,14 @@ func (m *UI) handleChildSessionMessage(event pubsub.Event[message.Message]) tea.
 	// Update the chat so it updates the index map for animations to work as expected
 	m.chat.UpdateNestedToolIDs(toolCallID)
 
-	if atBottom {
+	if m.chat.Follow() {
 		if cmd := m.chat.ScrollToBottomAndAnimate(); cmd != nil {
 			cmds = append(cmds, cmd)
 		}
+		m.chat.SelectLast()
 	}
 
-	return tea.Batch(cmds...)
+	return tea.Sequence(cmds...)
 }
 
 func (m *UI) handleDialogMsg(msg tea.Msg) tea.Cmd {
@@ -1804,7 +1819,7 @@ func (m *UI) handleKeyPressMsg(msg tea.KeyPressMsg) tea.Cmd {
 		handleGlobalKeys(msg)
 	}
 
-	return tea.Batch(cmds...)
+	return tea.Sequence(cmds...)
 }
 
 // drawHeader draws the header section of the UI.