--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MetroWpf/Stocks.Service/StocksService.cs	Tue Mar 20 13:37:46 2012 +0000
@@ -0,0 +1,149 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using NLog;
+using Stocks.Common;
+using Stocks.Common.Core;
+using Stocks.Common.Events;
+using Stocks.Common.Models;
+
+namespace Stocks.Service
+{
+    public class StocksService : IStocksService
+    {
+        private static readonly Logger Log = LogManager.GetCurrentClassLogger();
+
+        private IList<Company> _companies;
+        private readonly IConfigurationService _configurationService;
+        private List<Price> _currentPrices;
+        private string _serviceUrl;
+        private readonly IWebClientShim _webClient;
+
+        public bool IsRunning { get; private set; }
+        public SummaryStats Stats { get; private set; }
+
+        public StocksService(
+          IConfigurationService configurationService,
+          IWebClientShim webClientShim)
+        {
+            new AssemblyInit();
+
+            _webClient = webClientShim;
+            _configurationService = configurationService;
+            Stats = new SummaryStats();
+
+            GetCompanyList();
+        }
+
+        private void GetCompanyList()
+        {
+            _companies = _configurationService.GetCompanies();
+
+            var symbolsCsv = _companies.Select(
+              c => c.Symbol).Aggregate((c, d) => c + "," + d);
+
+            _serviceUrl = _configurationService.GetServiceUrl(symbolsCsv);
+        }
+
+        public IList<Price> GetFullCurrentPrices()
+        {
+            return _companies.Select(company => new Price(company.Symbol, 0, 0)).ToList();
+        }
+
+        public event PriceChangedEventHandler PriceChanged;
+        public delegate void PriceChangedEventHandler(object sender, PriceChangedEventArgs e);
+        protected virtual void OnPriceChanged(Price price)
+        {
+            Stats.PriceChangeEvents++;
+
+            if (PriceChanged != null)
+                PriceChanged(this, new PriceChangedEventArgs() { Price = price });
+        }
+
+        public void Start()
+        {
+            PrepareForServiceStarting();
+            Task.Factory.StartNew(DownloadPrices);
+        }
+
+        public void Stop()
+        {
+            IsRunning = false;
+            Log.Debug("StockService stopped");
+        }
+
+        private void PrepareForServiceStarting()
+        {
+            Log.Debug("StockService starting");
+            IsRunning = true;
+            Stats.Reset();
+            _currentPrices = new List<Price>(_companies.Count);
+        }
+
+        private void DownloadPrices()
+        {
+            try
+            {
+                while (IsRunning)
+                {
+                    Stopwatch timeToDownload;
+                    var webResponse = TimedDelegates.Execute(
+                      _webClient.DownloadString,
+                      _serviceUrl,
+                      out timeToDownload);
+
+                    PopulatePricesFromWebResponse(webResponse);
+                    UpdateStats(timeToDownload, webResponse);
+                }
+            }
+            catch (Exception e)
+            {
+                Log.Error("Exception during DownloadPrices()");
+                Log.Error("Stack Trace {0}: /r/nException Message: {1}", e.StackTrace, e.Message);
+                this.Stop();
+            }
+        }
+
+        private void PopulatePricesFromWebResponse(string webResponse)
+        {
+            var webPrices = webResponse.Split(
+              new[] { "\n", "\r\n" },
+              StringSplitOptions.RemoveEmptyEntries);
+
+            foreach (var webPriceData in webPrices)
+            {
+                var webPrice = Factory.CreatePrice(webPriceData);
+                var localPrice = _currentPrices.Find(x => x.Symbol == webPrice.Symbol);
+
+                if (localPrice == null)
+                {
+                    _currentPrices.Add(new Price(webPrice.Symbol, webPrice.CurrentPrice, webPrice.PreviousPrice));
+                    continue;
+                }
+
+                if (!localPrice.Equals(webPrice))
+                    UpdateLocalPrice(webPrice, localPrice);
+            }
+        }
+
+        private void UpdateLocalPrice(Price webPrice, Price localPrice)
+        {
+            localPrice.PreviousPrice = localPrice.CurrentPrice;
+            localPrice.CurrentPrice = webPrice.CurrentPrice;
+            OnPriceChanged(localPrice);
+        }
+
+        private void UpdateStats(Stopwatch timeToDownload, string webResponse)
+        {
+            Stats.LastWebRequest.Duration = (int)timeToDownload.ElapsedMilliseconds;
+            Stats.LastWebRequest.PricesDownloaded = _currentPrices.Count;
+            Stats.LastWebRequest.Response = webResponse;
+            Stats.LastWebRequest.Request = _serviceUrl;
+            Stats.LastWebRequest.SymbolCount = _companies.Count;
+            Stats.NumberOfRequests++;
+            Log.Trace(Stats);
+        }
+    }
+}
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