using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using umbraco.interfaces;

namespace Umbraco.Core
{
	/// <summary>
	/// A resolver to return all ICacheRefresher objects
	/// </summary>
	internal sealed class CacheRefreshersResolver : LegacyTransientObjectsResolver<ICacheRefresher>
	{

		#region Singleton

		private static readonly CacheRefreshersResolver Instance = new CacheRefreshersResolver(PluginTypeResolver.Current.ResolveCacheRefreshers());

		public static CacheRefreshersResolver Current
		{
			get { return Instance; }
		}
		#endregion

		#region Constructors
		static CacheRefreshersResolver() { }

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="refreshers"></param>		
		internal CacheRefreshersResolver(IEnumerable<Type> refreshers)
			: base(refreshers)
		{
			
		}
		#endregion

		/// <summary>
		/// Gets the <see cref="ICacheRefresher"/> implementations.
		/// </summary>
		public IEnumerable<ICacheRefresher> CacheResolvers
		{
			get
			{
				EnsureRefreshersList();
				return Values;
			}
		}

		protected override Guid GetUniqueIdentifier(ICacheRefresher obj)
		{
			return obj.UniqueIdentifier;
		}
	}
}