command and help ux pass

internal/menu/menu.go

@@ -14,9 +14,11 @@ import (
 
 // Item is one selectable command.
 type Item struct {
-	Label string   // e.g. "module build"
-	Desc  string   // e.g. "build/extract/validate/compare the .mod"
-	Args  []string // dispatcher args, e.g. {"module", "build"}
+	Label   string   // e.g. "module build"
+	Desc    string   // e.g. "build the configured module"
+	Args    []string // dispatcher args, e.g. {"module", "build"}
+	Usage   string
+	Options []string
 }
 
 // ANSI styling; terminals that don't support it simply ignore the codes.
@@ -35,9 +37,15 @@ func Select(out io.Writer, in io.Reader, items []Item) ([]string, error) {
 		return nil, fmt.Errorf("no commands available")
 	}
 	fmt.Fprintf(out, "%s%sCrucible%s — pick a command:\n\n", cBold, cCyan, cReset)
+	labelWidth := 0
+	for _, item := range items {
+		if len(item.Label) > labelWidth {
+			labelWidth = len(item.Label)
+		}
+	}
 	for i, it := range items {
-		fmt.Fprintf(out, "  %s%2d%s  %s%-24s%s %s%s%s\n",
-			cCyan, i+1, cReset, cBold, it.Label, cReset, cDim, it.Desc, cReset)
+		fmt.Fprintf(out, "  %s%2d%s  %s%-*s%s  %s%s%s\n",
+			cCyan, i+1, cReset, cBold, labelWidth, it.Label, cReset, cDim, it.Desc, cReset)
 	}
 	fmt.Fprintf(out, "   %sq%s  quit\n\nselection: ", cCyan, cReset)
 
@@ -52,7 +60,16 @@ func Select(out io.Writer, in io.Reader, items []Item) ([]string, error) {
 			return nil, fmt.Errorf("invalid selection %q", choice)
 		}
 		it := items[n-1]
-		fmt.Fprintf(out, "extra args for %q (optional): ", it.Label)
+		if it.Usage != "" {
+			fmt.Fprintf(out, "\nusage: %s\n", it.Usage)
+		}
+		if len(it.Options) > 0 {
+			fmt.Fprintln(out, "options:")
+			for _, option := range it.Options {
+				fmt.Fprintf(out, "  %s\n", option)
+			}
+		}
+		fmt.Fprint(out, "\narguments (press Enter to use defaults): ")
 		argLine, _ := r.ReadString('\n')
 		extra := strings.Fields(strings.TrimSpace(argLine))
 		return append(append([]string{}, it.Args...), extra...), nil