feat: Improve mouse handling (#66)

Two improvements:
1) notify the user in the status bar when it looks like they're trying to do that to let
   them know shift+select works.
2) add ctrl-o (mOuse) to toggle mouse scrolling/selection.  ctrl-m doesn't work since that's
   a newline.

---------

Co-authored-by: Steve Calvert <steve.calvert@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

internal/tui/model.go

@@ -99,6 +99,10 @@ type Model struct {
 	currentStage  string               // Glean thinking stage shown while streaming: "Searching", "Reading", etc.
 	currentDetail string               // optional detail for the current stage
 	streamCh      chan tea.Msg         // channel from the API goroutine; nil when not streaming
+
+	// Mouse state
+	mouseEnabled  bool // when true, mouse scrolling works but text selection requires Shift+drag
+	showMouseHint bool // show hint about Shift+drag and ctrl+o toggle when user tries to select
 }
 
 // New creates a fully-initialized TUI model.
@@ -131,19 +135,20 @@ func New(cfg *config.Config, session *Session, identity, version string, ctx con
 	}
 
 	m := &Model{
-		viewport:   vp,
-		textarea:   ta,
-		spinner:    sp,
-		stopwatch:  stopwatch.New(),
-		renderer:   renderer,
-		cfg:        cfg,
-		session:    session,
-		identity:   identity,
-		version:    version,
-		ctx:        ctx,
-		startTime:  time.Now(),
-		historyIdx: -1,
-		agentMode:  components.AgentEnumAuto,
+		viewport:     vp,
+		textarea:     ta,
+		spinner:      sp,
+		stopwatch:    stopwatch.New(),
+		renderer:     renderer,
+		cfg:          cfg,
+		session:      session,
+		identity:     identity,
+		version:      version,
+		ctx:          ctx,
+		startTime:    time.Now(),
+		historyIdx:   -1,
+		agentMode:    components.AgentEnumAuto,
+		mouseEnabled: true,
 	}
 
 	for _, turn := range session.Turns {
@@ -162,7 +167,7 @@ func (m *Model) Session() *Session {
 
 // Init implements tea.Model.
 func (m *Model) Init() tea.Cmd {
-	return textarea.Blink
+	return tea.Batch(textarea.Blink, tea.EnableMouseCellMotion)
 }
 
 // Update implements tea.Model.
@@ -255,6 +260,17 @@ func (m *Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			m.showHelp = !m.showHelp
 			return m, nil
 
+		case "ctrl+o":
+			m.mouseEnabled = !m.mouseEnabled
+			m.showMouseHint = false
+			var cmd tea.Cmd
+			if m.mouseEnabled {
+				cmd = tea.EnableMouseCellMotion
+			} else {
+				cmd = tea.DisableMouse
+			}
+			return m, cmd
+
 		case "ctrl+l":
 			m.lastErr = nil
 			m.viewport.SetContent(m.renderConversation())
@@ -456,6 +472,16 @@ func (m *Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 	// Mouse scroll events go to the viewport when there is content.
 	case tea.MouseMsg:
+		// Detect potential text selection attempts (click/drag, not scroll).
+		// Show hint about Shift+drag and ctrl+o toggle when user drags with left button.
+		if m.mouseEnabled && msg.Button == tea.MouseButtonLeft && msg.Action == tea.MouseActionMotion {
+			m.showMouseHint = true
+		}
+		// Hide hint when button is released
+		if msg.Action == tea.MouseActionRelease {
+			m.showMouseHint = false
+		}
+
 		if m.session != nil && len(m.session.Turns) > 0 {
 			m.viewport, vpCmd = m.viewport.Update(msg)
 			return m, vpCmd

internal/tui/tui_test.go

@@ -507,3 +507,107 @@ func TestClosePickerResetsState(t *testing.T) {
 	assert.Nil(t, m.filePickerItems)
 	assert.Equal(t, 0, m.filePickerIdx)
 }
+
+// TestMouseEnabledByDefault verifies that mouse is enabled on init.
+func TestMouseEnabledByDefault(t *testing.T) {
+	m := newTestModel(t)
+	assert.True(t, m.mouseEnabled, "mouse should be enabled by default")
+}
+
+// TestCtrlOTogglesMouse verifies that ctrl+o toggles mouseEnabled state.
+func TestCtrlOTogglesMouse(t *testing.T) {
+	m := newTestModel(t)
+	assert.True(t, m.mouseEnabled, "starts enabled")
+
+	// First toggle: disable
+	updated, cmd := m.Update(tea.KeyMsg{Type: tea.KeyCtrlO})
+	r := updated.(*Model)
+	assert.False(t, r.mouseEnabled, "ctrl+o should disable mouse")
+	assert.NotNil(t, cmd, "should return DisableMouse command")
+
+	// Second toggle: re-enable
+	updated2, cmd2 := r.Update(tea.KeyMsg{Type: tea.KeyCtrlO})
+	r2 := updated2.(*Model)
+	assert.True(t, r2.mouseEnabled, "ctrl+o should re-enable mouse")
+	assert.NotNil(t, cmd2, "should return EnableMouseCellMotion command")
+}
+
+// TestMouseHintShowsWhileSelecting verifies the selection hint behavior.
+func TestMouseHintShowsWhileSelecting(t *testing.T) {
+	m := newTestModel(t)
+	m.session.Turns = []Turn{{Role: roleUser, Content: "test"}}
+	assert.False(t, m.showMouseHint, "hint should start hidden")
+
+	// Simulate left-button drag motion - should show hint
+	dragMsg := tea.MouseMsg{
+		Button: tea.MouseButtonLeft,
+		Action: tea.MouseActionMotion,
+	}
+	updated, _ := m.Update(dragMsg)
+	r := updated.(*Model)
+	assert.True(t, r.showMouseHint, "dragging with left button should show hint")
+
+	// Simulate mouse button release - should hide hint
+	releaseMsg := tea.MouseMsg{
+		Action: tea.MouseActionRelease,
+	}
+	updated2, _ := r.Update(releaseMsg)
+	r2 := updated2.(*Model)
+	assert.False(t, r2.showMouseHint, "releasing mouse should hide hint")
+}
+
+// TestMouseHintNotShownWhenDisabled verifies hint doesn't show when mouse is disabled.
+func TestMouseHintNotShownWhenDisabled(t *testing.T) {
+	m := newTestModel(t)
+	m.mouseEnabled = false
+	m.session.Turns = []Turn{{Role: roleUser, Content: "test"}}
+
+	// Simulate left-button drag motion
+	msg := tea.MouseMsg{
+		Button: tea.MouseButtonLeft,
+		Action: tea.MouseActionMotion,
+	}
+	updated, _ := m.Update(msg)
+	r := updated.(*Model)
+
+	assert.False(t, r.showMouseHint, "hint should not show when mouse is disabled")
+}
+
+// TestCtrlOClearsMouseHint verifies that toggling mouse mode clears the hint.
+func TestCtrlOClearsMouseHint(t *testing.T) {
+	m := newTestModel(t)
+	m.showMouseHint = true
+
+	updated, _ := m.Update(tea.KeyMsg{Type: tea.KeyCtrlO})
+	r := updated.(*Model)
+
+	assert.False(t, r.showMouseHint, "ctrl+o should clear mouse hint")
+}
+
+// TestViewShowsMouseHint verifies the hint is displayed in the view.
+func TestViewShowsMouseHint(t *testing.T) {
+	m := newTestModel(t)
+	m.showMouseHint = true
+
+	view := m.View()
+	assert.Contains(t, view, "To select text: hold Shift+drag")
+	assert.Contains(t, view, "ctrl+o to toggle mouse mode")
+}
+
+// TestStatusBarShowsMouseIndicator verifies mouse-off indicator in status bar.
+func TestStatusBarShowsMouseIndicator(t *testing.T) {
+	m := newTestModel(t)
+	m.mouseEnabled = false
+
+	status := m.statusLine()
+	assert.Contains(t, status, "🖱️ off", "status bar should show mouse indicator when disabled")
+}
+
+// TestStatusBarNoMouseIndicatorWhenEnabled verifies no indicator when mouse is enabled.
+func TestStatusBarNoMouseIndicatorWhenEnabled(t *testing.T) {
+	m := newTestModel(t)
+	m.mouseEnabled = true
+
+	status := m.statusLine()
+	assert.NotContains(t, status, "🖱️ off", "status bar should not show indicator when mouse is enabled")
+}

internal/tui/view.go

@@ -36,6 +36,9 @@ func (m *Model) View() string {
 	if m.showExitHint {
 		bottom = styleExitHint.Render("  Press ctrl+c again to exit  ·  esc to cancel")
 	}
+	if m.showMouseHint && !m.showExitHint {
+		bottom = styleExitHint.Render("  To select text: hold Shift+drag  ·  ctrl+o to toggle mouse mode")
+	}
 
 	// Chip shows attached files above the input box (always).
 	chip := m.attachedFilesView()
@@ -157,7 +160,11 @@ func (m *Model) statusLine() string {
 		left = modeLabel
 	}
 
-	right := styleStatusBar.Render("ctrl+r new  ctrl+l clear  ctrl+y copy  ctrl+h help  ctrl+c quit")
+	mouseIndicator := ""
+	if !m.mouseEnabled {
+		mouseIndicator = "  🖱️ off"
+	}
+	right := styleStatusBar.Render("ctrl+r new  ctrl+l clear  ctrl+y copy  ctrl+h help  ctrl+c quit" + mouseIndicator)
 
 	leftW := lipgloss.Width(left)
 	rightW := lipgloss.Width(right)
@@ -176,6 +183,7 @@ func (m *Model) helpView() string {
 		{"↑ / ↓  or  pgup / pgdn", "Scroll history"},
 		{"ctrl+r", "New session (clear history)"},
 		{"ctrl+l", "Clear screen"},
+		{"ctrl+o", "Toggle mouse scrolling/selection"},
 		{"ctrl+c  /  esc", "Quit"},
 		{"ctrl+h", "Toggle this help"},
 		{"", ""},