sanjay.kumar
Jan 3, 2023
  1781
(7 votes)

Custom promotion - Buy at least X items from catalog entries and get a discount on related catalog entries.

Problem: Buy at least X items from catalog entries and get related catalog entries at a discount that satisfy the below formula.

 or

Create a custom promotion to ‘Buy Products for Discount from Other Selections’ and apply the below formula to get a discount on other selections.

Formula = m x n,  then get the discounts on n items.

m = Spend at least X items

n = Multiplier

e.g.

m = 2

n = 1, 2,3……

CART
Main Product SKU Qty. Other Selection SKU Qty. Eligible Discount Qty.
2 x 1 1 1
2 x 2 2 2
2 x 3 4 3
2 x 4 5 4
.... .... ....
m x n .... n

If you notice the above table ‘Other Selection SKU Qty.’ column, customer added more than the eligible discounted qty in the cart. So, we need to make sure the discount is only eligible for 'Eligible Discount Qty.' not for all ‘Other Selection SKU Qty.’.

Solution:

  1. Create a custom entry promotion
   [ContentType(
        GUID = "CB99C622-A170-4EF6-B28D-077B18BAFD81",
        GroupName = "Custom - Promotions",
        DisplayName = "Custom - Buy products for discount from other selection",
        Description = "Buy at least X items from catalog entries and get related catalog entries at a discount e.g. (2 + 1),  (4 + 2),  (6 + 3) ... ",
        Order = 30000)]
    [PromotionSettings(FixedRedemptionsPerOrder = 1)]
    [ImageUrl("~/Static/Img/CustomBuyQuantityGetItemDiscount.png")]
    public class CustomBuyQuantityGetItemDiscount : EntryPromotion, IMonetaryDiscount
    {
        [Display(Order = 10)]
        [PromotionRegion("Condition")]
        public virtual PurchaseQuantity Condition { get; set; }

        [Display(Order = 20)]
        [PromotionRegion("Reward")]
        public virtual DiscountItems DiscountTarget { get; set; }

        [Display(Order = 30)]
        [PromotionRegion("Discount")]
        public virtual MonetaryReward Discount { get; set; }
    }

2. Create custom discount processor and override following methods:

  • GetPromotionItems
    • Return promotion conditions and reward items.
  • RewardDescription
    • Read all discounted SKUs with the max eligible qty for discounts.
    • Create Redemption Description into GetRedemptions.
public class CustomBuyQuantityGetItemDiscountProcessor : EntryPromotionProcessorBase<CustomBuyQuantityGetItemDiscount>
{
        private readonly IContentLoader _contentLoader;

        public CustomBuyQuantityGetItemDiscountProcessor(
            RedemptionDescriptionFactory redemptionDescriptionFactory,
            IContentLoader contentLoader)
            : base(redemptionDescriptionFactory)
        {
            _contentLoader = contentLoader ?? throw new ArgumentNullException(nameof(contentLoader));
        }

        protected override PromotionItems GetPromotionItems(CustomBuyQuantityGetItemDiscount promotionData)
        {
            return new PromotionItems(
                promotionData,
                new CatalogItemSelection(promotionData.Condition.Items, CatalogItemSelectionType.Specific, true),
                new CatalogItemSelection(promotionData.DiscountTarget.Items, CatalogItemSelectionType.Specific, true));
        }

        protected override RewardDescription Evaluate(
            CustomBuyQuantityGetItemDiscount promotionData,
            PromotionProcessorContext context)
        {
            var allLineItems = this.GetLineItems(context.OrderForm)?
                .Where(x => !x.IsGift)?
                .ToList();

            if (promotionData?.DiscountTarget?.Items == null ||
                promotionData?.Condition?.Items == null ||
                promotionData?.Condition?.RequiredQuantity == 0 ||
                allLineItems.Count() == 0)
            {
                return
                    RewardDescription.CreateNotFulfilledDescription(
                    promotionData,
                    FulfillmentStatus.NotFulfilled);
            }

            //Read all excluded variants 
            var excludedVariants = new List<string>() { };
            if (promotionData.ExcludedItems != null && promotionData.ExcludedItems.Count > 0)
            {
                foreach (ContentReference item in promotionData.ExcludedItems)
                {
                    if (_contentLoader.TryGet(item, out NodeContent content))
                    {
                        excludedVariants.AddRange(
                            _contentLoader.GetDescendantsOfType<VariationContent>(content.ContentLink)
                            .Select(x => x.Code)
                            .ToList());
                    }
                    else if (_contentLoader.TryGet(item, out ProductContent productContent))
                    {
                        excludedVariants.AddRange(
                            _contentLoader.GetDescendantsOfType<VariationContent>(productContent.ContentLink)
                            .Select(x => x.Code)
                            .ToList());
                    }
                    else
                    {
                        excludedVariants.Add(_contentLoader.TryGet<VariationContent>(item)?.Code);
                    }
                }
            }
          
           //Read all condition variants
            var conditionSkus = new List<string>() { };
            foreach (ContentReference item in promotionData.Condition.Items)
            {
                if (_contentLoader.TryGet(item, out NodeContent content))
                {
                    conditionSkus.AddRange(
                        _contentLoader.GetDescendantsOfType<VariationContent>(content.ContentLink)
                        .Select(x => x.Code)
                        .ToList());
                }
                else if (_contentLoader.TryGet(item, out ProductContent productContent))
                {
                    conditionSkus.AddRange(
                        _contentLoader.GetDescendantsOfType<VariationContent>(productContent.ContentLink)
                        .Select(x => x.Code)
                        .ToList());
                }
                else
                {
                    conditionSkus.Add(_contentLoader.TryGet<VariationContent>(item)?.Code);
                }
            }
            //Read all discounted variants
            var discountSkus = new List<string>() { };
            foreach (ContentReference item in promotionData.DiscountTarget.Items)
            {
                if (_contentLoader.TryGet(item, out NodeContent content))
                {
                    discountSkus.AddRange(
                        _contentLoader.GetDescendantsOfType<VariationContent>(content.ContentLink)
                        .Select(x => x.Code)
                        .ToList());
                }
                else if (_contentLoader.TryGet(item, out ProductContent productContent))
                {
                    discountSkus.AddRange(
                        _contentLoader.GetDescendantsOfType<VariationContent>(productContent.ContentLink)
                        .Select(x => x.Code)
                        .ToList());
                }
                else
                {
                    discountSkus.Add(_contentLoader.TryGet<VariationContent>(item)?.Code);
                }
            }

            //remove the discounted SKUs if exist in the excluded list.
            if (excludedVariants.Count() > 0)
            {
                discountSkus = discountSkus.Where(x => !excludedVariants.Contains(x)).ToList();
                conditionSkus = conditionSkus.Where(x => !excludedVariants.Contains(x)).ToList();
            }

            var totalPurchasedQty = allLineItems.Where(x => conditionSkus.Contains(x.Code)).Sum(x => x.Quantity);
            var maxDiscountedQty = Math.Floor(totalPurchasedQty / promotionData.Condition.RequiredQuantity);
            if (promotionData.DiscountTarget.MaxQuantity != null &&
                maxDiscountedQty > promotionData.DiscountTarget.MaxQuantity)
            {
                maxDiscountedQty = (decimal)promotionData.DiscountTarget.MaxQuantity;
            }

            if (maxDiscountedQty == decimal.Zero)
            {
                return RewardDescription.CreateNotFulfilledDescription(
                       promotionData,
                       FulfillmentStatus.InvalidCoupon);
            }

            var discountedLineItems = allLineItems
                .Where(x => discountSkus.Contains(x.Code))
                .OrderByDescending(x => x.PlacedPrice)
                .ThenBy(x => x.Quantity)
                .ToList();

            return
                RewardDescription.CreateMoneyOrPercentageRewardDescription(
                         FulfillmentStatus.Fulfilled,
                         GetRedemptions(promotionData, context, discountedLineItems, maxDiscountedQty),
                         promotionData,
                         promotionData.Discount,
                         context.OrderGroup.Currency,
                         promotionData.Name);
        }

        private IEnumerable<RedemptionDescription> GetRedemptions(
          CustomBuyQuantityGetItemDiscount promotionData,
          PromotionProcessorContext context,
          List<ILineItem> discountedLineItems,
          decimal maxQty)
        {
            List<RedemptionDescription> redemptionDescriptionList = new List<RedemptionDescription>();
            var applicableCodes = discountedLineItems.Select(x => x.Code);
            decimal val2 = GetLineItems(context.OrderForm).Where(li => applicableCodes.Contains(li.Code)).Sum(li => li.Quantity);
            decimal num = Math.Min(GetMaxRedemptions(promotionData.RedemptionLimits), val2);

            for (int index = 0; index < num; ++index)
            {
                AffectedEntries entries = context.EntryPrices.ExtractEntries(applicableCodes, Math.Min(maxQty, val2), promotionData);
                if (entries != null)
                {
                    redemptionDescriptionList.Add(this.CreateRedemptionDescription(affectedEntries: entries));
                }
            }

            return redemptionDescriptionList;
        }
    }

Wishing you a year full of blessing and filled with a new adventure.

Happy new year 2023!

Cheers🥂

Jan 03, 2023

Comments

Ashish Rasal
Ashish Rasal Jan 6, 2023 03:57 AM

Nicely explained.

Please login to comment.
Latest blogs
Create a multi-site aware custom search provider using Search & Navigation

In a multisite setup using Optimizely CMS, searching for pages can be confusing. The default CMS search regardless of search provider does not...

dada | Jun 12, 2025

Tunning Application Insights telemetry filtering in Optimizely

Application Insights is a cloud-based service designed to monitor web applications, providing insights into performance, errors, and user behavior,...

Stanisław Szołkowski | Jun 12, 2025 |

JavaScript SDK v6: Lightest, Most Efficient SDK Yet

Need a faster site and less frontend bloat? JavaScript SDK v6 is here —and it’s the lightest, smartest SDK we’ve ever released for Optimizely Featu...

Sarah Ager | Jun 11, 2025

Boosting Indexing Efficiency: Reindex Pages Directly from Optimizely’s Navigation Pane

There can be various reasons why you might want to trigger indexing or reindexing of a page/node directly from the navigation pane. In my case, we...

Praful Jangid | Jun 11, 2025

How to Get Started with Google Gemini and Imagen in Optimizely CMS

Bringing AI into your editorial workflow has never been easier. With Epicweb’s AI Assistant now supporting Google Gemini and Imagen, editors workin...

Luc Gosso (MVP) | Jun 9, 2025 |

Avoid Field Type Conflicts in Search & Navigation

When using  Optimizely Search & Navigation , reusing the same property name across different content types is fine — as long as the type is...

dada | Jun 5, 2025