fix bug in logging middleware

cmd/themis-server/main.go

@@ -897,7 +897,23 @@ func logCommandInvocation(name string, s *discordgo.Session, i *discordgo.Intera
 		Str("params", func() string {
 			p := make([]string, 0, len(i.ApplicationCommandData().Options))
 			for _, o := range i.ApplicationCommandData().Options {
-				p = append(p, o.Name+"="+o.StringValue())
+				sb := strings.Builder{}
+				sb.WriteString(o.Name)
+				sb.WriteRune('=')
+
+				switch o.Type {
+				case discordgo.ApplicationCommandOptionSubCommand, discordgo.ApplicationCommandOptionSubCommandGroup:
+					panic("unreachable")
+				case discordgo.ApplicationCommandOptionString:
+					sb.WriteString(o.StringValue())
+				case discordgo.ApplicationCommandOptionInteger:
+					sb.WriteString(fmt.Sprint(o.IntValue()))
+				case discordgo.ApplicationCommandOptionBoolean:
+					sb.WriteString(fmt.Sprint(o.BoolValue()))
+				default:
+					sb.WriteString("[unsupported type]")
+				}
+				p = append(p, sb.String())
 			}
 			return strings.Join(p, ", ")
 		}()).