checkout: dynamic height for picker

internal/tui/checkoutview/model.go

@@ -253,23 +253,22 @@ func (m *Model) moveCursor(delta int) {
 	m.ensureVisible()
 }
 
-// maxVisibleRows caps how many stack rows the inline picker shows at once. The
-// rest are reached by scrolling, so the picker never takes over the screen.
-const maxVisibleRows = 10
+// initialVisibleRows caps the picker before the terminal size is known, so the
+// first frame cannot overflow a large stack.
+const initialVisibleRows = 10
 
 // bodyHeight returns the number of table rows shown at once: the row count
-// capped at maxVisibleRows, and further shrunk to fit a short terminal. It never
-// returns less than 1 (a line is reserved for the empty-state message).
+// capped by the available terminal height. Before the terminal size is known,
+// it falls back to initialVisibleRows. It never returns less than 1 (a line is
+// reserved for the empty-state message).
 func (m Model) bodyHeight() int {
 	rows := len(m.filtered)
 	if rows < 1 {
 		rows = 1
 	}
-	limit := maxVisibleRows
+	limit := initialVisibleRows
 	if m.height > 0 {
-		if avail := m.height - m.chromeHeight(); avail < limit {
-			limit = avail
-		}
+		limit = m.height - m.chromeHeight()
 	}
 	if limit < 1 {
 		limit = 1
@@ -281,9 +280,9 @@ func (m Model) bodyHeight() int {
 }
 
 // chromeHeight is the number of lines reserved around the table body when
-// fitting the picker to a short terminal: title, tabs, blank, header, footer
-// (5), plus one line of breathing room so the inline picker never exactly fills
-// the terminal (which would make it scroll). The search line adds one more.
+// fitting the picker to the terminal: title, tabs, blank, header, footer (5),
+// plus one line of breathing room so the inline picker never exactly fills the
+// terminal (which would make it scroll). The search line adds one more.
 func (m Model) chromeHeight() int {
 	chrome := 6
 	if m.searching {

internal/tui/checkoutview/model_test.go

@@ -317,21 +317,49 @@ func manyRows(n int) []StackRow {
 	return rows
 }
 
-func TestView_InlineHeightIsBounded(t *testing.T) {
-	// A long list on a tall terminal must not take over the screen: it shows at
-	// most maxVisibleRows rows plus a little chrome, and offers a scroll hint.
-	m := drive(New(manyRows(30)), tea.WindowSizeMsg{Width: 90, Height: 50})
+func TestBodyHeight_UsesAvailableTerminalSpace(t *testing.T) {
+	tests := []struct {
+		name      string
+		rows      int
+		height    int
+		searching bool
+		want      int
+	}{
+		{name: "unknown terminal size uses fallback", rows: 30, want: initialVisibleRows},
+		{name: "small list stays compact", rows: 3, height: 50, want: 3},
+		{name: "tall terminal expands past fallback", rows: 100, height: 50, want: 44},
+		{name: "short terminal shrinks", rows: 30, height: 12, want: 6},
+		{name: "search reserves another line", rows: 100, height: 50, searching: true, want: 43},
+		{name: "empty list reserves one row", height: 50, want: 1},
+		{name: "tiny terminal reserves one row", rows: 30, height: 3, want: 1},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			m := New(manyRows(tt.rows))
+			m.height = tt.height
+			m.searching = tt.searching
+			assert.Equal(t, tt.want, m.bodyHeight())
+		})
+	}
+}
+
+func TestView_ExpandsToAvailableTerminalHeight(t *testing.T) {
+	const terminalHeight = 50
+	m := drive(New(manyRows(100)), tea.WindowSizeMsg{Width: 90, Height: terminalHeight})
+
+	assert.Greater(t, m.bodyHeight(), initialVisibleRows)
+	assert.Equal(t, terminalHeight-m.chromeHeight(), m.bodyHeight())
 	lines := len(strings.Split(m.View(), "\n"))
-	assert.LessOrEqual(t, lines, maxVisibleRows+6, "picker must not fill a tall terminal")
-	assert.GreaterOrEqual(t, lines, maxVisibleRows, "shows up to maxVisibleRows rows")
-	assert.Contains(t, stripANSI(m.View()), "of 30", "shows a scroll position indicator")
+	assert.Equal(t, terminalHeight-1, lines, "picker keeps one safety row free")
+	assert.Contains(t, stripANSI(m.View()), "of 100", "shows a scroll position indicator")
 }
 
 func TestView_ShrinksToShortTerminal(t *testing.T) {
 	m := drive(New(manyRows(30)), tea.WindowSizeMsg{Width: 90, Height: 12})
 	lines := len(strings.Split(m.View(), "\n"))
+	assert.Equal(t, 12-m.chromeHeight(), m.bodyHeight())
 	assert.LessOrEqual(t, lines, 12, "must fit within a short terminal")
-	assert.Less(t, lines, maxVisibleRows+6)
 }
 
 func TestView_ClearsOnExit(t *testing.T) {