props/Props/Services/Modules/LiveSearchManager.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Castle.Core.Logging;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Props.Models.Search;
using Props.Options;
using Props.Shop.Framework;

namespace Props.Services.Modules
{
    public class LiveSearchManager : ISearchManager
    {
        private ILogger<LiveSearchManager> logger;
        private SearchOptions searchOptions;
        public IShopManager ShopManager { get; private set; }
        private IMetricsManager metricsManager;

        public LiveSearchManager(IMetricsManager metricsManager, IShopManager shopManager, IConfiguration configuration, ILogger<LiveSearchManager> logger)
        {
            this.logger = logger;
            this.metricsManager = metricsManager;
            this.ShopManager = shopManager;
            this.searchOptions = configuration.GetSection(SearchOptions.Search).Get<SearchOptions>();
        }
        public async Task<IEnumerable<ProductListing>> Search(string query, SearchOutline searchOutline)
        {
            if (string.IsNullOrWhiteSpace(query)) throw new ArgumentException($"Query \"{query}\" is null or whitepsace.");
            if (searchOutline == null) throw new ArgumentNullException("searchOutline");
            List<ProductListing> results = new List<ProductListing>();
            metricsManager.RegisterSearchQuery(query);
            logger.LogDebug("Searching for \"{0}\".", query);

            foreach (string shopName in await ShopManager.GetAllShopNames())
            {
                if (searchOutline.Enabled[shopName])
                {
                    logger.LogDebug("Checking \"{0}\".", shopName);
                    int amount = 0;
                    await foreach (ProductListing product in (await ShopManager.GetShop(shopName)).Search(query, searchOutline.Filters))
                    {
                        if (searchOutline.Filters.Validate(product))
                        {
                            amount += 1;
                            metricsManager.RegisterListing(product, shopName);
                            results.Add(product);
                        }
                        if (amount >= searchOptions.MaxResults) break;
                    }
                    logger.LogDebug("Found {0} listings that satisfy the search filters from {1}.", amount, shopName);
                }
            }

            return results;
        }
    }
}