Add a terminal size guard

Author: kevinmcconnell

internal/ui/app.go

@@ -63,6 +63,7 @@ type App struct {
 	systemScraper   *system.Scraper
 	userStats       *userstats.Reader
 	currentScreen   Component
+	sizeGuard       TerminalSizeGuard
 	lastSize        tea.WindowSizeMsg
 	eventChan       <-chan struct{}
 	watchCtx        context.Context
@@ -117,6 +118,7 @@ func NewApp(ns *docker.Namespace, installImageRef string) *App {
 		systemScraper:   systemScraper,
 		userStats:       userStats,
 		currentScreen:   screen,
+		sizeGuard:       NewTerminalSizeGuard(80, 24),
 		eventChan:       eventChan,
 		watchCtx:        ctx,
 		watchCancel:     cancel,
@@ -139,6 +141,7 @@ func (m *App) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	switch msg := msg.(type) {
 	case tea.WindowSizeMsg:
 		m.lastSize = msg
+		m.sizeGuard = m.sizeGuard.Update(msg)
 
 	case tea.MouseClickMsg:
 		ms := msg.Mouse()
@@ -247,10 +250,14 @@ func (m *App) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 }
 
 func (m *App) View() tea.View {
-	content := m.currentScreen.View()
-	cleaned := mouse.Sweep(content)
+	var content string
+	if m.sizeGuard.LargeEnough() {
+		content = mouse.Sweep(m.currentScreen.View())
+	} else {
+		content = m.sizeGuard.View()
+	}
 
-	v := tea.NewView(cleaned)
+	v := tea.NewView(content)
 	v.AltScreen = true
 	v.MouseMode = tea.MouseModeAllMotion
 	return v

internal/ui/terminal_size_guard.go

@@ -0,0 +1,36 @@
+package ui
+
+import (
+	"fmt"
+
+	tea "charm.land/bubbletea/v2"
+	"charm.land/lipgloss/v2"
+)
+
+type TerminalSizeGuard struct {
+	minWidth, minHeight int
+	width, height       int
+}
+
+func NewTerminalSizeGuard(minWidth, minHeight int) TerminalSizeGuard {
+	return TerminalSizeGuard{minWidth: minWidth, minHeight: minHeight}
+}
+
+func (g TerminalSizeGuard) Update(msg tea.WindowSizeMsg) TerminalSizeGuard {
+	g.width = msg.Width
+	g.height = msg.Height
+	return g
+}
+
+func (g TerminalSizeGuard) LargeEnough() bool {
+	return g.width >= g.minWidth && g.height >= g.minHeight
+}
+
+func (g TerminalSizeGuard) View() string {
+	line1 := fmt.Sprintf("Terminal too small: %d×%d", g.width, g.height)
+	line2 := fmt.Sprintf("Minimum size is %d×%d", g.minWidth, g.minHeight)
+
+	style := lipgloss.NewStyle().Foreground(Colors.Muted)
+	msg := lipgloss.JoinVertical(lipgloss.Center, style.Render(line1), "", style.Render(line2))
+	return lipgloss.Place(g.width, g.height, lipgloss.Center, lipgloss.Center, msg)
+}

internal/ui/terminal_size_guard_test.go

@@ -0,0 +1,43 @@
+package ui
+
+import (
+	"testing"
+
+	tea "charm.land/bubbletea/v2"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTerminalSizeGuard_InitiallyTooSmall(t *testing.T) {
+	g := NewTerminalSizeGuard(80, 24)
+	assert.False(t, g.LargeEnough())
+}
+
+func TestTerminalSizeGuard_LargeEnough(t *testing.T) {
+	g := NewTerminalSizeGuard(80, 24)
+	g = g.Update(tea.WindowSizeMsg{Width: 80, Height: 24})
+	assert.True(t, g.LargeEnough())
+
+	g = g.Update(tea.WindowSizeMsg{Width: 120, Height: 40})
+	assert.True(t, g.LargeEnough())
+}
+
+func TestTerminalSizeGuard_TooNarrow(t *testing.T) {
+	g := NewTerminalSizeGuard(80, 24)
+	g = g.Update(tea.WindowSizeMsg{Width: 79, Height: 24})
+	assert.False(t, g.LargeEnough())
+}
+
+func TestTerminalSizeGuard_TooShort(t *testing.T) {
+	g := NewTerminalSizeGuard(80, 24)
+	g = g.Update(tea.WindowSizeMsg{Width: 80, Height: 23})
+	assert.False(t, g.LargeEnough())
+}
+
+func TestTerminalSizeGuard_ViewShowsDimensions(t *testing.T) {
+	g := NewTerminalSizeGuard(80, 24)
+	g = g.Update(tea.WindowSizeMsg{Width: 60, Height: 20})
+
+	view := g.View()
+	assert.Contains(t, view, "Terminal too small: 60×20")
+	assert.Contains(t, view, "Minimum size is 80×24")
+}