/V2/trunk/RI/Desktop/StockTraderRI.Modules.WatchList/WatchList/WatchListPresentationModel.cs

//===================================================================================

// Microsoft patterns & practices

// Composite Application Guidance for Windows Presentation Foundation and Silverlight

//===================================================================================

// Copyright (c) Microsoft Corporation.  All rights reserved.

// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY

// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT

// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

// FITNESS FOR A PARTICULAR PURPOSE.

//===================================================================================

// The example companies, organizations, products, domain names,

// e-mail addresses, logos, people, places, and events depicted

// herein are fictitious.  No association with any real company,

// organization, product, domain name, email address, logo, person,

// places, or events is intended or should be inferred.

//===================================================================================

using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

using System.ComponentModel;

using System.Linq;

using System.Windows.Input;

using Microsoft.Practices.Composite.Events;

using Microsoft.Practices.Composite.Presentation.Commands;

using Microsoft.Practices.Composite.Presentation.Events;

using StockTraderRI.Infrastructure;

using StockTraderRI.Infrastructure.Interfaces;

using StockTraderRI.Modules.Watch.Properties;

using StockTraderRI.Modules.Watch.Services;



namespace StockTraderRI.Modules.Watch.WatchList

{

    public class WatchListPresentationModel : IWatchListPresentationModel, INotifyPropertyChanged, IHeaderInfoProvider<string>

    {

        private readonly IMarketFeedService marketFeedService;

        private readonly IEventAggregator eventAggregator;

        private readonly ObservableCollection<string> watchList;

        private ICommand removeWatchCommand;

        private ObservableCollection<WatchItem> watchListItems;

        private WatchItem currentWatchItem;



        public WatchListPresentationModel(IWatchListView view, IWatchListService watchListService, IMarketFeedService marketFeedService, IEventAggregator eventAggregator)

        {

            this.View = view;

            this.HeaderInfo = Resources.WatchListTitle;

            this.WatchListItems = new ObservableCollection<WatchItem>();

            this.View.SetModel(this);



            this.marketFeedService = marketFeedService;



            this.watchList = watchListService.RetrieveWatchList();

            this.watchList.CollectionChanged += delegate { this.PopulateWatchItemsList(this.watchList); };

            this.PopulateWatchItemsList(this.watchList);



            this.eventAggregator = eventAggregator;

            this.eventAggregator.GetEvent<MarketPricesUpdatedEvent>().Subscribe(this.MarketPricesUpdated, ThreadOption.UIThread);

            this.RemoveWatchCommand = new DelegateCommand<string>(this.RemoveWatch);

        }



        public event PropertyChangedEventHandler PropertyChanged = delegate { };



        public ObservableCollection<WatchItem> WatchListItems

        {

            get

            {

                return this.watchListItems;

            }



            set

            {

                if (this.watchListItems != value)

                {

                    this.watchListItems = value;

                    this.OnPropertyChanged("WatchListItems");

                }

            }

        }



        public WatchItem CurrentWatchItem

        {

            get

            {

                return this.currentWatchItem;

            }



            set

            {

                if (value != null && this.currentWatchItem != value)

                {

                    this.currentWatchItem = value;

                    this.OnPropertyChanged("CurrentWatchItem");

                    this.eventAggregator.GetEvent<TickerSymbolSelectedEvent>().Publish(this.currentWatchItem.TickerSymbol);

                }

            }

        }



        public string HeaderInfo { get; set; }



        public IWatchListView View { get; private set; }



        public ICommand RemoveWatchCommand

        {

            get

            {

                return this.removeWatchCommand;

            }



            private set

            {

                this.removeWatchCommand = value;

                this.OnPropertyChanged("RemoveWatchCommand");

            }

        }



        public void MarketPricesUpdated(IDictionary<string, decimal> updatedPrices)

        {

            foreach (WatchItem watchItem in this.WatchListItems)

            {

                if (updatedPrices.ContainsKey(watchItem.TickerSymbol))

                {

                    watchItem.CurrentPrice = updatedPrices[watchItem.TickerSymbol];

                }

            }

        }



        private void RemoveWatch(string tickerSymbol)

        {

            this.watchList.Remove(tickerSymbol);

        }



        private void PopulateWatchItemsList(IEnumerable<string> watchItemsList)

        {

            this.WatchListItems.Clear();

            foreach (string tickerSymbol in watchItemsList)

            {

                decimal? currentPrice;

                try

                {

                    currentPrice = this.marketFeedService.GetPrice(tickerSymbol);

                }

                catch (ArgumentException)

                {

                    currentPrice = null;

                }



                this.WatchListItems.Add(new WatchItem(tickerSymbol, currentPrice));

            }

        }



        private void OnPropertyChanged(string propertyName)

        {

            PropertyChangedEventHandler handler = this.PropertyChanged;

            if (handler != null)

            {

                handler(this, new PropertyChangedEventArgs(propertyName));

            }

        }

    }

}