fix: improve TUI markdown rendering (#183)

Author: jy-tan

internal/agent/markdown_render.go

@@ -0,0 +1,41 @@
+package agent
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/Use-Tusk/tusk-drift-cli/internal/utils"
+)
+
+var (
+	gitScpLikeRemotePattern   = regexp.MustCompile(`\b[A-Za-z0-9._-]+@[A-Za-z0-9._-]+:[^\s)>\]]+`)
+	emailPatternWithDelimiter = regexp.MustCompile(`\b([A-Za-z0-9._%+\-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,})(\s|$|[),>.\]!?\]])`)
+)
+
+// renderAgentMessage renders agent output as markdown with terminal styling.
+// Falls back to wrapped plain text when markdown rendering isn't available.
+func renderAgentMessage(text string, width int) string {
+	if width <= 0 {
+		width = 80
+	}
+
+	originalText := text
+
+	// Prevent markdown autolink/email parsers from converting scp-style Git remotes
+	// (e.g., git@github.com:org/repo.git) into broken mailto links.
+	text = gitScpLikeRemotePattern.ReplaceAllStringFunc(text, func(match string) string {
+		return "`" + match + "`"
+	})
+	text = emailPatternWithDelimiter.ReplaceAllString(text, "`$1`$2")
+
+	rendered := utils.RenderMarkdownWithWidth(text, width)
+	rendered = strings.TrimRight(rendered, "\n")
+
+	// RenderMarkdownWithWidth returns raw text in non-terminal/no-color mode.
+	// Keep output readable by wrapping plain text to the viewport width.
+	if rendered == text {
+		return utils.WrapText(originalText, width)
+	}
+
+	return rendered
+}

internal/agent/markdown_render_test.go

@@ -0,0 +1,37 @@
+package agent
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestRenderAgentMessage_DoesNotCreateMailtoForGitRemote(t *testing.T) {
+	input := "Remote: origin (git@github.com:Use-Tusk/tusk-drift-cli.git)"
+
+	out := renderAgentMessage(input, 100)
+
+	if strings.Contains(out, "mailto:") {
+		t.Fatalf("expected no mailto link in rendered output, got: %q", out)
+	}
+}
+
+func TestRenderAgentMessage_DoesNotCreateMailtoForPlainEmail(t *testing.T) {
+	input := "Authenticated as jy@usetusk.ai. Continuing setup..."
+
+	out := renderAgentMessage(input, 100)
+
+	if strings.Contains(out, "mailto:") {
+		t.Fatalf("expected no mailto link in rendered output, got: %q", out)
+	}
+}
+
+func TestRenderAgentMessage_FallbackDoesNotLeakSanitizerBackticks(t *testing.T) {
+	input := "Remote: git@github.com:Use-Tusk/tusk-drift-cli.git | Email: jy@usetusk.ai"
+
+	out := renderAgentMessage(input, 100)
+
+	if strings.Contains(out, "`git@github.com:Use-Tusk/tusk-drift-cli.git`") ||
+		strings.Contains(out, "`jy@usetusk.ai`") {
+		t.Fatalf("expected fallback/rendered output to not contain sanitizer backticks, got: %q", out)
+	}
+}

internal/agent/tui.go

@@ -534,28 +534,14 @@ func (m *TUIModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			if msg.text != "" && msg.text != m.lastAgentMessage {
 				m.lastAgentMessage = msg.text
 				m.addLog("spacing", "", "")
-				// Format agent messages with proper markdown spacing
-				// Wrap text at 120 chars max for readability
 				maxWidth := min(max(m.width-8, 40), 120)
-				lines := strings.Split(msg.text, "\n")
-				for i, line := range lines {
-					trimmed := strings.TrimSpace(line)
-					switch {
-					case trimmed == "":
-						// Keep blank lines for markdown formatting
+				rendered := renderAgentMessage(msg.text, maxWidth)
+				for _, line := range strings.Split(rendered, "\n") {
+					if strings.TrimSpace(line) == "" {
 						m.addLog("spacing", "", "")
-					case strings.HasPrefix(trimmed, "#"):
-						if i > 0 {
-							m.addLog("spacing", "", "")
-						}
-						m.addLog("agent-header", trimmed, "")
-					default:
-						// Wrap long lines for readability
-						wrapped := wrapText(trimmed, maxWidth)
-						for _, wrappedLine := range strings.Split(wrapped, "\n") {
-							m.addLog("agent", wrappedLine, "")
-						}
+						continue
 					}
+					m.addLog("agent", line, "")
 				}
 			}
 		}

internal/agent/ui_headless.go

@@ -6,6 +6,9 @@ import (
 	"os"
 	"strings"
 
+	"golang.org/x/term"
+
+	"github.com/Use-Tusk/tusk-drift-cli/internal/utils"
 	"github.com/charmbracelet/lipgloss"
 )
 
@@ -97,7 +100,16 @@ func (u *HeadlessUI) AgentText(text string, streaming bool) {
 		u.isThinking = false
 	}
 	if strings.TrimSpace(text) != "" {
-		fmt.Println(text)
+		width := 90
+		if utils.IsTerminal() {
+			if w, _, err := term.GetSize(int(os.Stdout.Fd())); err == nil && w > 0 {
+				width = max(w-4, 40)
+			}
+		}
+
+		// Headless mode intentionally keeps raw markdown syntax and avoids
+		// glamour rendering for lower overhead and predictable plain output.
+		fmt.Println(utils.WrapText(text, width))
 		fmt.Println()
 	}
 }

internal/utils/markdown.go

@@ -35,6 +35,11 @@ func init() {
 		"margin": 0,
 	}
 
+	styleOverrides["link"] = map[string]any{
+		"color":     styles.PrimaryColor,
+		"underline": true,
+	}
+
 	if hasDarkBackground {
 		styleOverrides["document"].(map[string]any)["color"] = "255"
 		styleOverrides["heading"] = map[string]any{