tickets/tickets_bot.go: return meaningful error upon reaching categor…

…y channel limit (#1805)

tickets/tickets_bot.go

@@ -50,9 +50,10 @@ func (t TicketUserError) Error() string {
 }
 
 const (
-	ErrNoTicketCateogry TicketUserError = "No category for ticket channels set"
-	ErrTitleTooLong     TicketUserError = "Title is too long (max 90 characters.) Please shorten it down, you can add more details in the ticket after it has been created"
-	ErrMaxOpenTickets   TicketUserError = "You're currently in over 10 open tickets on this server, please close some of the ones you're in."
+	ErrNoTicketCategory    TicketUserError = "No category for ticket channels set"
+	ErrTitleTooLong        TicketUserError = "Title is too long (max 90 characters.) Please shorten it down, you can add more details in the ticket after it has been created"
+	ErrMaxOpenTickets      TicketUserError = "You're currently in over 10 open tickets on this server, please close some of the ones you're in."
+	ErrMaxCategoryChannels TicketUserError = "Max channels in category reached (50)"
 )
 
 const (
@@ -62,7 +63,18 @@ const (
 
 func CreateTicket(ctx context.Context, gs *dstate.GuildSet, ms *dstate.MemberState, conf *models.TicketConfig, topic string, checkMaxTickets, executedByCommandTemplate bool) (*dstate.GuildSet, *models.Ticket, error) {
 	if gs.GetChannel(conf.TicketsChannelCategory) == nil {
-		return gs, nil, ErrNoTicketCateogry
+		return gs, nil, ErrNoTicketCategory
+	}
+
+	categoryChannels := 0
+	for _, v := range gs.Channels {
+		if v.ParentID == conf.TicketsChannelCategory {
+			categoryChannels++
+		}
+
+		if categoryChannels == 50 {
+			return gs, nil, ErrMaxCategoryChannels
+		}
 	}
 
 	if hasPerms, _ := bot.BotHasPermissionGS(gs, conf.TicketsChannelCategory, InTicketPerms); !hasPerms {