Mini Kabibi Habibi

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.SessionState;
using System.Xml.Linq;
public class Data {
    const int PopularCountriesCount = 20;
    const string SearchQuerySID = "SQ";
    const string AllHotelsSID = "AH";

    public static Data Instance {
        get {
            if(HttpContext.Current.Items["DG"] == null)
                HttpContext.Current.Items["DG"] = new Data();
            return (Data)HttpContext.Current.Items["DG"];
        }
    }

    public Data() {
        FakeDataHelper = new FakeDataHelper();
        LoadXmlData();
    }

    public SearchQuery CurrentQuery {
        get { return Session[SearchQuerySID] as SearchQuery; }
        set { Session[SearchQuerySID] = value; }
    }
    // Data
    public List<Country> Countries { get; protected set; }
    public List<string> HotelServices { get; protected set; }
    public List<string> RoomServices { get; protected set; }
    public List<string> RoomTypes { get; protected set; }
    public List<string> CommonDescriptions { get; protected set; }
    public List<string> HotelDescriptions { get; protected set; }
    public List<string> RoomDescriptions { get; protected set; }
    public List<int> RoomTypesMaxChildrenCount { get; protected set; }
    public List<int> HotelStars { get; protected set; }
    public List<Hotel> Hotels {
        get {
            if(Session[AllHotelsSID] == null)
                Session[AllHotelsSID] = new List<Hotel>();
            return (List<Hotel>)Session[AllHotelsSID];
        }
    }
    public IEnumerable<Country> GetPopularCountries() {
        return FakeDataHelper.GetPopularCountries(Countries, PopularCountriesCount);
    }
    public List<Hotel> GetExclusiveHotels() {
        if(!Hotels.Any(hotel => hotel.IsExclusive))
            Hotels.AddRange(FakeDataHelper.GetHotels(SearchQuery.MostExclusive, TitleGroups, 10));
        return Hotels.Where(hotel => hotel.IsExclusive).ToList();
    }
    public IEnumerable<Hotel> GetSearchResults() {
        FakeDataHelper.UpdateHotelsList(TitleGroups);
        return Hotels.Where(h => CurrentQuery.IsMatch(h));
    }
    public void ClearMemory() {
        Session.Clear();
        Session.Timeout = 3 * 24 * 60;
    }

    protected List<XElement> TitleGroups { get; set; }
    protected FakeDataHelper FakeDataHelper { get; set; }
    protected HttpSessionState Session {
        get { return HttpContext.Current.Session; }
    }

    // Xml load
    void LoadXmlData() {
        Countries = LoadXmlDataInternal<Country>("Countries", "HotelDestinations", 
            el => new Country(
                el.Attribute("Title").Value,
                el.Attribute("Image").Value,
                el.Elements().Select(c => c.Value).OrderBy(oc => oc), 
                FakeDataHelper.GetPopularity(el.Attribute("MostPopular") != null)
                ));
        HotelServices = LoadXmlDataInternal("HotelParameters", "HotelServices");
        RoomServices = LoadXmlDataInternal("HotelParameters", "RoomServices");
        RoomTypes = LoadXmlDataInternal("HotelParameters", "RoomTypes");
        RoomTypesMaxChildrenCount = LoadXmlDataInternal("HotelParameters", "RoomTypes", "Children").ConvertAll<int>(v => Convert.ToInt32(v));
        HotelStars = new List<int>(new int[] { 1, 2, 3, 4, 5 });
        TitleGroups = LoadXmlDataInternal("TitleWordsDictionary", "Dictionary", el => el);

        CommonDescriptions = LoadXmlDataInternal("HotelParameters", "CommonDesc", "Text");
        HotelDescriptions = LoadXmlDataInternal("HotelParameters", "HotelDesc", "Text");
        RoomDescriptions = LoadXmlDataInternal("HotelParameters", "RoomDesc", "Text");
    }
    List<string> LoadXmlDataInternal(string fileName, string rootNodeName) {
        return LoadXmlDataInternal(fileName, rootNodeName, "Title");
    }
    List<string> LoadXmlDataInternal(string fileName, string rootNodeName, string attrName) {
        return LoadXmlDataInternal(fileName, rootNodeName, el => el.Attribute(attrName).Value);
    }
    List<T> LoadXmlDataInternal<T>(string fileName, string rootNodeName, Func<XElement, T> getElement) {
        XDocument doc = XDocument.Load(HttpContext.Current.Server.MapPath(string.Format("~\\App_Data\\{0}.xml", fileName)));
        return (from node in doc.Root.Element(rootNodeName).Elements()
                select getElement(node)).ToList();
    }
}