tui: improve footer truncation

pkg/tui/tui.go

@@ -22,6 +22,7 @@ import (
 	"github.com/charmbracelet/bubbles/viewport"
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
+	"github.com/muesli/reflow/ansi"
 	"github.com/muesli/reflow/wordwrap"
 )
 
@@ -411,9 +412,15 @@ func (m *model) footerView() string {
 	footer := left + padding + right
 	if remaining < 0 {
 		ellipses := "... "
-		// this doesn't work very well, due to trying to trim a string with
-		// ansii chars already in it
-		footer = footer[:(len(footer)+remaining)-len(ellipses)-3] + ellipses
+		for {
+			truncWidth := ansi.PrintableRuneWidth(footer) + len(ellipses)
+			if truncWidth <= m.width {
+				break
+			}
+			// truncate the minimum amount, not accounting for printed width
+			footer = footer[:len(footer)-(truncWidth-m.width)]
+		}
+		footer += ellipses
 	}
 	return footerStyle.Width(m.width).Render(footer)
 }