chore: improve terminal for long subprocess outputs

cmd/model.go

@@ -257,47 +257,39 @@ func getLatestRamalamaVersion() (string, error) {
 func provisionRamalama() error {
 	guest := lima.New(host.New())
 
-	log.Println("Installing AI model runner...")
-
-	// step 1: Install ramalama binary (uses normal scrolling output)
-	installScript := `set -e
+	script := `set -e
 export PATH="$HOME/.local/bin:$PATH"
+
+# install ramalama
 curl -fsSL https://ramalama.ai/install.sh | bash
-`
-	if err := guest.Run("sh", "-c", installScript); err != nil {
-		return fmt.Errorf("error installing AI model runner: %w", err)
-	}
 
-	// step 2: Pull container images (uses alternate screen for progress bars)
-	pullScript := `set -e
+# pull ramalama container images
 docker pull quay.io/ramalama/ramalama
 docker pull quay.io/ramalama/ramalama-rag
-`
-	if err := terminal.WithAltScreen(func() error {
-		log.Println()
-		log.Println("  Colima - AI Model Runner Setup")
-		log.Println("  ===============================")
-		log.Println()
-		log.Println("  Pulling container images...")
-		log.Println("  This may take a few minutes depending on your internet connection.")
-		log.Println()
-		return guest.RunInteractive("sh", "-c", pullScript)
-	}); err != nil {
-		return fmt.Errorf("error pulling container images: %w", err)
-	}
-
-	log.Println("Configuring AI model runner...")
 
-	// step 3: Post-install setup (uses normal scrolling output)
-	setupScript := `set -e
+# fix ownership of persistent data dir and symlink to expected location
 sudo chown -R $(id -u):$(id -g) /var/lib/ramalama
 mkdir -p "$HOME/.local/share"
 ln -sfn /var/lib/ramalama "$HOME/.local/share/ramalama"
 `
-	if err := guest.Run("sh", "-c", setupScript); err != nil {
-		return fmt.Errorf("error configuring AI model runner: %w", err)
+
+	log.Println("installing AI model runner...")
+
+	if err := terminal.WithAltScreen(func() error {
+		return guest.RunInteractive("sh", "-c", script)
+	},
+		"",
+		"  Colima - AI Model Runner Setup",
+		"  ===============================",
+		"",
+		"  Installing AI model runner.",
+		"  This may take several minutes depending on your internet connection speed.",
+	); err != nil {
+		return fmt.Errorf("error setting up AI model runner: %w", err)
 	}
 
+	log.Println("AI model runner installed")
+
 	// mark as provisioned
 	if err := store.Set(func(s *store.Store) {
 		s.RamalamaProvisioned = true

util/terminal/terminal.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"os/signal"
+	"strings"
 
 	"golang.org/x/term"
 )
@@ -42,8 +43,21 @@ func ExitAltScreen() {
 // WithAltScreen runs the provided function in the alternate screen buffer.
 // The main terminal content is preserved and restored after the function completes.
 // Handles Ctrl-C to ensure the terminal is restored even on interrupt.
-func WithAltScreen(fn func() error) error {
+//
+// If header lines are provided, they are joined with newlines and displayed as a
+// fixed header at the top of the screen. The command output scrolls below the header.
+// The number of header lines is computed automatically based on newlines and terminal width.
+func WithAltScreen(fn func() error, header ...string) error {
+	hasHeader := len(header) > 0
+	var headerText string
+	if hasHeader {
+		headerText = strings.Join(header, "\n")
+	}
+
 	if !isTerminal {
+		if hasHeader {
+			fmt.Println(headerText)
+		}
 		return fn()
 	}
 
@@ -58,17 +72,73 @@ func WithAltScreen(fn func() error) error {
 	go func() {
 		select {
 		case <-sigCh:
+			if hasHeader {
+				fmt.Print("\033[r") // Reset scroll region
+			}
 			ExitAltScreen()
 			os.Exit(1)
 		case <-done:
 			return
 		}
 	}()
 
+	if hasHeader {
+		// Get terminal dimensions
+		width, height, err := term.GetSize(int(os.Stdout.Fd()))
+		if err != nil {
+			width = 80
+			height = 24
+		}
+
+		// Print the header
+		fmt.Println(headerText)
+
+		// Calculate number of lines used by the header
+		headerLines := countLines(headerText, width) + 1 // +1 for padding
+
+		// Set scroll region from headerLines+1 to bottom
+		// This keeps the header fixed while everything below scrolls
+		fmt.Printf("\033[%d;%dr", headerLines+1, height)
+
+		// Move cursor to the first line of the scroll region
+		fmt.Printf("\033[%d;1H", headerLines+1)
+	}
+
 	err := fn()
 
+	if hasHeader {
+		// Reset scroll region
+		fmt.Print("\033[r")
+	}
+
 	close(done)
 	ExitAltScreen()
 
 	return err
 }
+
+// countLines calculates the number of terminal lines a string will occupy,
+// accounting for newlines and line wrapping based on terminal width.
+func countLines(s string, termWidth int) int {
+	if termWidth <= 0 {
+		termWidth = 80
+	}
+
+	lines := 1
+	currentLineLen := 0
+
+	for _, ch := range s {
+		if ch == '\n' {
+			lines++
+			currentLineLen = 0
+		} else {
+			currentLineLen++
+			if currentLineLen >= termWidth {
+				lines++
+				currentLineLen = 0
+			}
+		}
+	}
+
+	return lines
+}