FacetsBlock.cs

namespace Sitecore.Services.Examples.Indexing
{
    using System.Threading.Tasks;

    using Sitecore.Commerce.Core;
    using Sitecore.Framework.Pipelines;
    using Sitecore.Commerce.Plugin.Catalog;
    using System.Collections.Generic;
    using System;

    [PipelineDisplayName("FacetsBlock")]
    public class FacetsBlock : PipelineBlock<GenerateFacetsArgument, GenerateFacetsArgument, CommercePipelineExecutionContext>
    {
        CommerceCommander _commander;

        public FacetsBlock(CommerceCommander commander)
        {
            _commander = commander;
        }
        public override async Task<GenerateFacetsArgument> Run(GenerateFacetsArgument arg, CommercePipelineExecutionContext context)
        {

            var getItemsCommand = _commander.Command<GetCatalogItemsCommand>();

            //Here we just loop through all the products and set the values, price are retrieved for a specific catalog
            //Ideally we should be doing this in a more effiecient way e.g. using the paging functionality etc.
            //You may want to do this in a minion or part of your catalog import
            //You should also look at spliting up the variant property fields from pricing as pricing changes more often.
            var items = await getItemsCommand.Process(context.CommerceContext,context.CommerceContext.Environment.Name, 0, int.MaxValue);

            foreach (var catalogItem in items.Items)
            {
                SellableItem item;
                if (catalogItem is SellableItem == false)
                {
                    continue;
                }
                else
                {
                    item = catalogItem as SellableItem;
                }

                var variationComponent = item.GetComponent<ItemVariationsComponent>();
                var facetsComponent = item.GetComponent<FacetsComponent>();

                facetsComponent.Colors = string.Empty;
                facetsComponent.Sizes = string.Empty;
                facetsComponent.Styles = string.Empty;
                facetsComponent.SellPrices = string.Empty;
                facetsComponent.ListPrices = string.Empty;
                facetsComponent.PercentagesOff = string.Empty;
                facetsComponent.PriceRange = string.Empty;

                List<string> ids = new List<string>();

                foreach (var variant in variationComponent.Variations)
                {
                    var displayProperties = variant.GetComponent<DisplayPropertiesComponent>();
                    facetsComponent.Colors += " " + displayProperties.Color;
                    facetsComponent.Sizes += " " + displayProperties.Size;
                    facetsComponent.Styles += " " + displayProperties.Style;
                }

                //We only get prices for the specific catalog
                ids.Add(arg.CatalogId + "|" + item.ProductId + "|");

                var getBulkPricesCommand = _commander.Command<GetBulkPricesCommand>();

                var priceResults = getBulkPricesCommand.Process(context.CommerceContext, ids).Result;

                decimal highestPrice = 0.0M;
                decimal lowestPrice = 0.0M;

                foreach (var price in priceResults)
                {
                    foreach (var variations in price.Variations)
                    {
                        if (Convert.ToDecimal(variations?.SellPrice?.Amount) > highestPrice)
                        {
                            highestPrice = Convert.ToDecimal(variations?.SellPrice?.Amount);
                        }

                        if (Convert.ToDecimal(variations?.SellPrice?.Amount) < lowestPrice || lowestPrice == 0)
                        {
                            lowestPrice = Convert.ToDecimal(variations?.SellPrice?.Amount);
                        }

                        facetsComponent.SellPrices += " " + variations?.SellPrice?.Amount;
                        facetsComponent.ListPrices += " " + variations?.ListPrice?.Amount;

                        //Percentages off
                        var difference = variations?.SellPrice?.Amount - variations?.ListPrice?.Amount;
                        var percentage = Decimal.Round(Convert.ToDecimal((difference / variations?.SellPrice?.Amount) * 100), 0);

                        facetsComponent.PercentagesOff += " " + (percentage >= 0 ? string.Empty : (percentage * -1).ToString() + "%");
                    }
                }

                //Price range
                if ((highestPrice >= 0 && highestPrice <= 1000) && (lowestPrice >= 0 && lowestPrice <= 1000))
                {
                    facetsComponent.PriceRange = "0 to 1000";
                }
                else if ((highestPrice >= 1001 && highestPrice <= 2000) && (lowestPrice >= 1001 && lowestPrice <= 2000))
                {
                    facetsComponent.PriceRange = "1001 to 2000";
                }
                else if ((highestPrice >= 2001 && highestPrice <= 3000) && (lowestPrice >= 2001 && lowestPrice <= 3000))
                {
                    facetsComponent.PriceRange = "2001 to 3000";
                }
                else if (highestPrice >= 3001 && lowestPrice >= 3001)
                {
                    facetsComponent.PriceRange = "more than 3000";
                }

                facetsComponent.Colors = facetsComponent.Colors.TrimStart();
                facetsComponent.Sizes = facetsComponent.Sizes.TrimStart();
                facetsComponent.Styles = facetsComponent.Styles.TrimStart();
                facetsComponent.SellPrices = facetsComponent.SellPrices.TrimStart();
                facetsComponent.ListPrices = facetsComponent.ListPrices.TrimStart();
                facetsComponent.PercentagesOff = facetsComponent.PercentagesOff.TrimStart();

                await _commander.Pipeline<PersistEntityPipeline>().Run(new PersistEntityArgument(item), context);
            }

            return await Task.FromResult(arg);
        }
    }
}