offer set user password on creation

app.go

@@ -355,7 +355,9 @@ func (a *App) ensureUsers(users []string) error {
 		}
 
 		a.printf("Created local user %s\n", name)
-		a.println("If Samba authentication is required, add a Samba password with: smbpasswd -a " + name)
+		if err := a.offerSetSambaPassword(name); err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -397,6 +399,70 @@ func (a *App) createUser(name string) error {
 	}
 }
 
+func (a *App) offerSetSambaPassword(name string) error {
+	a.println("")
+	a.println("This share can use a Samba password for sign-in.")
+	a.println("I can set that up now and ask you to type the password you want to use.")
+	a.flush()
+
+	setPassword, err := a.confirm(fmt.Sprintf("Set a Samba password for %q now", name), true)
+	if err != nil {
+		return err
+	}
+	if !setPassword {
+		a.println("You can do this later with: smbpasswd -a " + name)
+		return nil
+	}
+
+	return a.setSambaPassword(name)
+}
+
+func (a *App) setSambaPassword(name string) error {
+	if a.lookPath != nil {
+		if _, err := a.lookPath("smbpasswd"); err != nil {
+			a.println("I couldn't find the smbpasswd tool yet.")
+			a.println("If Samba was just installed, try opening the app again after the installation finishes.")
+			return fmt.Errorf("set Samba password for %s: smbpasswd command not found", name)
+		}
+	}
+
+	if err := a.runner.Run("smbpasswd", "-a", name); err == nil {
+		a.printf("Samba password set for %s\n", name)
+		return nil
+	} else if shouldOfferPrivilegeRetry(err) {
+		a.println("")
+		a.println("Setting a Samba password usually needs administrator permission.")
+		a.println("I can try again using sudo so you can enter your admin password.")
+		a.flush()
+
+		canUseSudo := false
+		if a.lookPath != nil {
+			_, sudoErr := a.lookPath("sudo")
+			canUseSudo = sudoErr == nil
+		}
+		if !canUseSudo {
+			return fmt.Errorf("set Samba password for %s: %w", name, err)
+		}
+
+		retry, promptErr := a.confirm("Retry Samba password setup with sudo", true)
+		if promptErr != nil {
+			return promptErr
+		}
+		if !retry {
+			return fmt.Errorf("set Samba password for %s: %w", name, err)
+		}
+
+		if sudoErr := a.runner.Run("sudo", "smbpasswd", "-a", name); sudoErr != nil {
+			return fmt.Errorf("set Samba password for %s with sudo: %w", name, sudoErr)
+		}
+
+		a.printf("Samba password set for %s\n", name)
+		return nil
+	} else {
+		return fmt.Errorf("set Samba password for %s: %w", name, err)
+	}
+}
+
 func (a *App) prompt(label string) (string, error) {
 	a.printf("%s: ", label)
 	a.flush()