feat(commands): improve discovery and normalize parameters

internal/modules/validate.go

@@ -3,10 +3,14 @@ package modules
 import (
 	"fmt"
 	"regexp"
+	"strings"
+	"unicode/utf8"
 )
 
 var commandNameRe = regexp.MustCompile(`^[a-z0-9_]{1,32}$`)
 
+const telegramCommandDescriptionMaxRunes = 256
+
 func validateCommand(c Command) error {
 	if !commandNameRe.MatchString(c.Name) {
 		return fmt.Errorf("command name %q must match %s", c.Name, commandNameRe)
@@ -16,9 +20,27 @@ func validateCommand(c Command) error {
 	default:
 		return fmt.Errorf("command %q: unknown visibility %d", c.Name, c.Visibility)
 	}
-	if c.Description == "" {
+	if strings.TrimSpace(c.Description) == "" {
 		return fmt.Errorf("command %q: description is required", c.Name)
 	}
+	if strings.ContainsAny(c.Description, "\r\n") {
+		return fmt.Errorf("command %q: description must be single-line", c.Name)
+	}
+	if strings.ContainsAny(c.Parameters, "\r\n") {
+		return fmt.Errorf("command %q: parameters must be single-line", c.Name)
+	}
+	if strings.ContainsAny(c.Example, "\r\n") {
+		return fmt.Errorf("command %q: example must be single-line", c.Name)
+	}
+	if example := strings.TrimSpace(c.Example); example != "" {
+		prefix := "/" + c.Name
+		if example != prefix && !strings.HasPrefix(example, prefix+" ") {
+			return fmt.Errorf("command %q: example must invoke %s", c.Name, prefix)
+		}
+	}
+	if c.Visibility == VisibilityPublic && utf8.RuneCountInString(c.TelegramMenuDescription()) > telegramCommandDescriptionMaxRunes {
+		return fmt.Errorf("command %q: Telegram menu description exceeds %d characters", c.Name, telegramCommandDescriptionMaxRunes)
+	}
 	if c.Handler == nil {
 		return fmt.Errorf("command %q: handler is nil", c.Name)
 	}