feat(cards): Generate placeholders for cards without a pair

handlers/card.go

@@ -47,8 +47,7 @@ func GenerateCard(c *fiber.Ctx) error {
 	}
 
 	genConfig := &models.CardTemplateOptions{
-		Cards:         cardRequest.Cards,
-		CardsSwapped:  invertCardArrayItems(cardRequest.Cards),
+		CardSegments:  splitCardSegments(cardRequest.Cards),
 		EventName:     "Event name",
 		CardSubtitle:  "Card subtitle",
 		BarcodeFormat: "ean13",
@@ -74,10 +73,38 @@ func GenerateCard(c *fiber.Ctx) error {
 	return c.Send(pdf)
 }
 
-func invertCardArrayItems(cards []models.Card) []models.Card {
+func invertCardArrayItemPairs(cards []models.Card) []models.Card {
 	inverted := make([]models.Card, 0)
-	for i := len(cards) - 1; i >= 0; i-- {
+	for i := 0; i < len(cards); i += 2 {
+		if i+1 < len(cards) {
+			inverted = append(inverted, cards[i+1])
+		}
 		inverted = append(inverted, cards[i])
 	}
 	return inverted
 }
+
+func splitCardSegments(cards []models.Card) []models.CardTemplateSegment {
+	cardSegments := make([]models.CardTemplateSegment, 0)
+	const currentCards = 0
+	for i := 0; i < len(cards); i += 10 {
+		segmentLength := 10
+		if len(cards)-i < 10 {
+			segmentLength = len(cards) - i
+		}
+		segment := cards[i : i+segmentLength]
+		if segmentLength%2 != 0 {
+			segment = append(segment, models.Card{
+				ID:      0,
+				Enabled: false,
+				Runner:  models.Runner{},
+				Code:    "",
+			})
+		}
+		cardSegments = append(cardSegments, models.CardTemplateSegment{
+			Cards:        segment,
+			CardsSwapped: invertCardArrayItemPairs(segment),
+		})
+	}
+	return cardSegments
+}