1 files changed, 46 insertions, 4 deletions
diff --git a/menu/model.go b/menu/model.go
index 4eb2577..d1b9435 100644
--- a/menu/model.go
+++ b/menu/model.go
@@ -2,8 +2,12 @@ package menu
 
 import (
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/x/term"
+	"github.com/spf13/pflag"
 	"pik/model"
+	"pik/motd"
 	"pik/spool"
+	"pik/viewport"
 )
 
 type Model struct {
@@ -11,24 +15,55 @@ type Model struct {
 	Index         int
 	Indices       map[int]model.HydratedTarget
 	SourceIndices map[int]*model.HydratedSource
-	Quit          bool
+	Cancel        bool
+	Done          bool
+	Height        int
+	Alt           bool
+	AutoAlt       bool
+	Motd          string
 }
 
 func (m *Model) Init() tea.Cmd {
+	_, h, err := term.GetSize(0)
+	if err != nil {
+		_, _ = spool.Warn("%v\n", err)
+	}
+	m.Height = h
+	wantsAlt := viewport.NeedsViewport(m.State(), m.Height)
+	if m.AutoAlt && wantsAlt {
+		return tea.EnterAltScreen
+	}
 	return nil
 }
 
+func (m *Model) HandleResize(msg tea.WindowSizeMsg) tea.Cmd {
+	if !m.AutoAlt {
+		return nil
+	}
+	m.Height = msg.Height
+	if viewport.NeedsViewport(m.State(), msg.Height) {
+		m.Alt = true
+		return tea.EnterAltScreen
+	} else {
+		m.Alt = false
+		return tea.ExitAltScreen
+	}
+
+}
+
 func (m *Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	var err error
 	var result tea.Cmd
 	switch mt := msg.(type) {
+	case tea.WindowSizeMsg:
+		result = m.HandleResize(mt)
 	case tea.KeyMsg:
 		result, err = m.HandleInput(mt)
 	case tea.Cmd:
 		result, err = m.HandleSignal(mt)
 	}
 	if err != nil {
-		spool.Warn("%v\n", err)
+		_, _ = spool.Warn("%v\n", err)
 	}
 	return m, result
 }
@@ -38,11 +73,16 @@ func (m *Model) HandleSignal(cmd tea.Cmd) (tea.Cmd, error) {
 }
 
 func (m *Model) View() string {
-	return m.State(m.HydratedState)
+	if m.Cancel || m.Done {
+		return ""
+	}
+	result := m.State()
+	result = viewport.Process(result, m.Height)
+	return result
 }
 
 func (m *Model) Result() (*model.HydratedSource, model.HydratedTarget) {
-	if m.Quit {
+	if m.Cancel {
 		return nil, nil
 	}
 	return m.SourceIndices[m.Index], m.Indices[m.Index]
@@ -63,6 +103,8 @@ func NewModel(st *model.State, hydrators []model.Modder) *Model {
 		Index:         0,
 		Indices:       make(map[int]model.HydratedTarget),
 		SourceIndices: make(map[int]*model.HydratedSource),
+		AutoAlt:       !pflag.Lookup("inline").Changed,
+		Motd:          motd.One(),
 	}
 	idx := 0
 	for _, src := range st.Sources {