CodeSample.cs

using EPiServer;
using EPiServer.Commerce.Marketing;
using EPiServer.Core;
using EPiServer.ServiceLocation;
using Mediachase.Commerce;
using Mediachase.Commerce.Catalog;
using Mediachase.Commerce.Marketing;
using Mediachase.Commerce.Orders;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;

namespace CodeSamples.EPiServer.Commerce.Marketing
{
    #region PercentagePromotionProcessorSample

    /// <summary>
    /// Sample of a promotion processor for <see cref="PercentagePromotionSample"/>.
    /// </summary>
    [ServiceConfiguration(Lifecycle = ServiceInstanceScope.Singleton)]
    public class PercentagePromotionProcessorSample : PromotionProcessorBase<PercentagePromotionSample>
    {
        private readonly CollectionTargetEvaluator _targetEvaluator;
        private readonly IContentLoader _contentLoader;
        private readonly ReferenceConverter _referenceConverter;

        /// <summary>
        /// Creates a new instance of a <see cref="PercentagePromotionProcessorSample"/>.
        /// </summary>
        /// <param name="targetEvaluator">The service that is used to evaluate an order against a promotion's target properties.</param>
        /// <param name="contentLoader">The content loader used for finding the content of any <see cref="AffectedItem"/>s.</param>
        /// <param name="contentLoader">The reference converter used for converting line items into <see cref="ContentReference"/>s.</param>
        public PercentagePromotionProcessorSample(CollectionTargetEvaluator targetEvaluator, IContentLoader contentLoader, ReferenceConverter referenceConverter)
        {
            _contentLoader = contentLoader;
            _targetEvaluator = targetEvaluator;
            _referenceConverter = referenceConverter;
        }

        /// <summary>
        /// Evaluates a promotion against an order form.
        /// </summary>
        /// <param name="orderForm">The order form to use for the evaluation.</param>
        /// <param name="currency">The currency.</param>
        /// <param name="promotionData">The promotion to evaluate.</param>
        /// <returns>
        /// A <see cref="RewardDescription" /> telling whether the promotion was fulfilled,
        /// which items the promotion was applied to and to which discount percentage.
        /// </returns>
        public override RewardDescription Evaluate(IOrderForm orderForm, PercentagePromotionSample promotionData, PromotionProcessorContext context)
        {
            if (promotionData.PercentageDiscount <= 0)
            {
                return RewardDescription.CreatePercentageReward(
                    FulfillmentStatus.NotFulfilled, 
                    Enumerable.Empty<AffectedItem>(),
                    promotionData,
                    0,
                    GetRewardDescriptionText(Enumerable.Empty<AffectedItem>(), FulfillmentStatus.NotFulfilled, promotionData));
            }

            var lineItems = GetLineItems(orderForm);
            var affectedItems = _targetEvaluator.GetApplicableItems(lineItems, promotionData.Condition.Items, promotionData.Condition.MatchRecursive);
            var status = FulfillmentEvaluator.GetStatusForBuyQuantityPromotion(affectedItems.Select(x => x.LineItem), promotionData.Condition.RequiredQuantity, promotionData.Condition.PartiallyFulfilledThreshold);

            return RewardDescription.CreatePercentageReward(
                status, 
                affectedItems,
                promotionData,
                promotionData.PercentageDiscount,
                GetRewardDescriptionText(affectedItems, status, promotionData));
        }

        /// <summary>
        /// Gets the reward description text based on a promotion's <see cref="FulfillmentStatus"/>.
        /// </summary>
        /// <param name="affectedItems">A collection of <see cref="AffectedItem"/>s a that a promotion has been applied to.</param>
        /// <param name="fulfillmentStatus">The promotion's fulfillment status.</param>
        /// <param name="promotion">The related promotion.</param>
        /// <returns>The reward description text.</returns>
        protected virtual string GetRewardDescriptionText(IEnumerable<AffectedItem> affectedItems, FulfillmentStatus fulfillmentStatus, PercentagePromotionSample promotion)
        {
            if (fulfillmentStatus.HasFlag(FulfillmentStatus.Fulfilled))
            {
                var contentNames = GetContentNames(affectedItems);

                return String.Format(CultureInfo.InvariantCulture, "{0}% discount has been given for the items '{1}'!", promotion.PercentageDiscount, contentNames);
            }

            if (fulfillmentStatus.HasFlag(FulfillmentStatus.PartiallyFulfilled))
            {
                var remainingQuantity = promotion.Condition.RequiredQuantity - affectedItems.Sum(x => x.LineItem.Quantity);

                return String.Format(CultureInfo.InvariantCulture, "Buy {0} more items and get a {1}% discount!", remainingQuantity, promotion.PercentageDiscount);
            }

            return "The promotion is not applicable for the current order.";
        }

        /// <summary>
        /// Gets the names of the affected items.
        /// </summary>
        /// <param name="affectedItems">A collection of <see cref="AffectedItem"/>s used for getting the names.</param>
        /// <returns>The names of all affected items combined into a string.</returns>
        private string GetContentNames(IEnumerable<AffectedItem> affectedItems)
        {
            var affectedContentLinks = affectedItems.Select(x => _referenceConverter.GetContentLink(x.LineItem.Code));
            var contentNames = _contentLoader.GetItems(affectedContentLinks, CultureInfo.InvariantCulture).Select(x => x.Name);

            return String.Join(", ", contentNames);
        }
    }

    #endregion
}