cli: improve usage and help output

Implement custom usage functions to provide more comprehensive and
discoverable help messages for the top-level tool and profile
management subcommands.

- Add printUsage and printProfileUsage methods to App.
- Override FlagSet.Usage to display professional help messages.
- Ensure profile subcommands are listed in the main help output.
- Trigger profile usage on missing or invalid subcommands.

1 files changed, 34 insertions, 5 deletions

diff --git a/internal/cli/cli.go b/internal/cli/cli.go
index 9041670..a4b9a9a 100644
--- a/internal/cli/cli.go
+++ b/internal/cli/cli.go
@@ -102,6 +102,7 @@ func (a *App) Run() error {
 	cfg := &config.Config{}
 
 	fs := flag.NewFlagSet("wg-wrap", flag.ExitOnError)
+	fs.Usage = a.printUsage
 	fs.StringVar(&cfg.Profile, "profile", "", "WireGuard profile to use")
 	fs.StringVar(&cfg.DNSServer, "dns-server", "", "Override DNS server to use")
 
@@ -158,9 +159,32 @@ func (a *App) isVerbose() bool {
 	return os.Getenv("WG_WRAP_VERBOSE") == "1"
 }
 
+func (a *App) printUsage() {
+	fmt.Fprintf(os.Stderr, "Usage: wg-wrap [options] [-- command [args]]\n\n")
+	fmt.Fprintf(os.Stderr, "Options:\n")
+	fmt.Fprintf(os.Stderr, "  -profile string\n\tWireGuard profile to use (default \"default\")\n")
+	fmt.Fprintf(os.Stderr, "  -dns-server string\n\tOverride DNS server to use\n\n")
+	fmt.Fprintf(os.Stderr, "Commands:\n")
+	fmt.Fprintf(os.Stderr, "  show-config\n\tDisplay the current configuration and environment details\n")
+	fmt.Fprintf(os.Stderr, "  profile <command>\n\tManage WireGuard profiles\n\t\t(list, import, configure, delete, stop)\n\n")
+	fmt.Fprintf(os.Stderr, "Run the wrapped command:\n")
+	fmt.Fprintf(os.Stderr, "  wg-wrap [options] -- <command> [args]\n")
+}
+
+func (a *App) printProfileUsage() {
+	fmt.Fprintf(os.Stderr, "Usage: wg-wrap profile <command> [args]\n\n")
+	fmt.Fprintf(os.Stderr, "Commands:\n")
+	fmt.Fprintf(os.Stderr, "  list\n\tList all available profiles\n")
+	fmt.Fprintf(os.Stderr, "  import <path> [name]\n\tImport a WireGuard .conf file\n")
+	fmt.Fprintf(os.Stderr, "  configure <name>\n\tEdit a profile in the default editor\n")
+	fmt.Fprintf(os.Stderr, "  delete <name>\n\tRemove a profile\n")
+	fmt.Fprintf(os.Stderr, "  stop <name>\n\tStop a running profile and unpin its namespace\n")
+}
+
 func (a *App) handleProfileCmd() error {
 	if len(a.Args) < 3 {
-		return fmt.Errorf("usage: wg-wrap profile <list|import|configure|delete|stop> [args]")
+		a.printProfileUsage()
+		return fmt.Errorf("missing profile subcommand")
 	}
 
 	subCmd := a.Args[2]
@@ -169,7 +193,8 @@ func (a *App) handleProfileCmd() error {
 		return a.handleProfileList()
 	case "import":
 		if len(a.Args) < 4 {
-			return fmt.Errorf("usage: wg-wrap profile import <path> [name]")
+			a.printProfileUsage()
+			return fmt.Errorf("missing import path")
 		}
 		var name string
 		if len(a.Args) > 4 {
@@ -178,17 +203,20 @@ func (a *App) handleProfileCmd() error {
 		return a.handleProfileImport(a.Args[3], name)
 	case "configure":
 		if len(a.Args) < 4 {
-			return fmt.Errorf("usage: wg-wrap profile configure <name>")
+			a.printProfileUsage()
+			return fmt.Errorf("missing profile name")
 		}
 		return a.handleProfileConfigure(a.Args[3])
 	case "delete":
 		if len(a.Args) < 4 {
-			return fmt.Errorf("usage: wg-wrap profile delete <name>")
+			a.printProfileUsage()
+			return fmt.Errorf("missing profile name")
 		}
 		return a.handleProfileDelete(a.Args[3])
 	case "stop":
 		if len(a.Args) < 4 {
-			return fmt.Errorf("usage: wg-wrap profile stop <name>")
+			a.printProfileUsage()
+			return fmt.Errorf("missing profile name")
 		}
 		if !IsValidProfileName(a.Args[3]) {
 			return fmt.Errorf("invalid profile name: %q", a.Args[3])
@@ -200,6 +228,7 @@ func (a *App) handleProfileCmd() error {
 		fmt.Printf("Profile %s stopped and unpinned.\n", a.Args[3])
 		return nil
 	default:
+		a.printProfileUsage()
 		return fmt.Errorf("unknown profile subcommand: %s", subCmd)
 	}
 }