using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using Filtr.Core.FacebookUsers;
using Filtr.Core.FacebookUsers.Data;
using Sony.Filtr.DistributedCaching;

namespace Sony.Filtr.Core.Facebook
{
    public class FacebookUserManager
    {
        private readonly FacebookUserFactory factory;
        private readonly DistributedCacheHandler cacheHandler;

        private HashSet<CultureInfo> cachedCultures = new HashSet<CultureInfo>();

        public FacebookUserManager(FacebookUserFactory factory, DistributedCacheHandler cacheHandler)
        {
            this.factory = factory;
            this.cacheHandler = cacheHandler;
        }

        public void SaveFacebookUser(FacebookUser facebookUser)
        {
            factory.SaveFacebookUser(facebookUser);
            ClearCache();
        }

        public List<NativeFacebookUserInfo> GetFacebookUsers(CultureInfo culture)
        {
            var cacheKey = GetCacheKey(culture);
            var facebookUsers = cacheHandler.GetList<NativeFacebookUserInfo>(cacheKey) as List<NativeFacebookUserInfo>;
            if (facebookUsers == null)
            {
                if (culture != null)
                {
                    facebookUsers = GetFacebookUsers(null);
                }
                else
                {
                    var internalFacebookUsers = factory.GetFacebookUsers();
                    facebookUsers = internalFacebookUsers.Select(u => u.NativeFacebookUserInfo).ToList();
                }

                if (culture != null)
                    facebookUsers = facebookUsers.Where(u => u.Culture != null && IsSameCountry(u.Culture, culture)).ToList();

                facebookUsers = facebookUsers.OrderBy(u => u.FirstName).ThenBy(u => u.LastName).ToList();

                cacheHandler.PutList(cacheKey, facebookUsers);
            }
            return facebookUsers;
        }

        private static bool IsSameCountry(CultureInfo cultureInfo, CultureInfo culture)
        {
            //TODO: check neutral culture.
            var region1 = new RegionInfo(cultureInfo.LCID);
            var region2 = new RegionInfo(culture.LCID);
            return region1.TwoLetterISORegionName == region2.TwoLetterISORegionName;
        }

        public string GetCacheKey(CultureInfo culture)
        {
            if (culture != null)
                cachedCultures.Add(culture);
            return "FacebookUsers" + (culture != null ? culture.Name : "null");
        }

        private void ClearCache()
        {
            cacheHandler.Remove(GetCacheKey(null));
            foreach (var cachedCulture in cachedCultures)
            {
                cacheHandler.Remove(GetCacheKey(cachedCulture));
            }
        }
    }
}