using System;
using System.Collections.Generic;
using System.Linq;
using ln.types.btree;
using System.Threading;
using System.Runtime.ConstrainedExecution;
using ln.types.threads;
using ln.objects.catalog;

namespace ln.types.odb.ng.storage.bases
{
    public abstract class StorageBase : IStorage
	{
		BTree<Guid> lockedDocuments = new BTree<Guid>();

		public StorageBase()
		{
		}
		public abstract bool Open();
		public abstract void Close();
		public abstract bool IsOpen { get; }


		public abstract Document Load(Guid documentID);
		public abstract void Save(Document document);
		public abstract void Delete(Guid documentID);

		public virtual DateTime GetStorageTimestamp(Guid documentID)
		{
			Document doc = Load(documentID);
			return doc.StorageTimeStamp;
		}

		/* Enumeration */
		public abstract IEnumerable<Guid> GetDocumentIDs();
		public abstract IEnumerable<Guid> GetDocumentIDs(string path, Predicate<ODBEntity> predicate);

		/* Indeces */
		public abstract void EnsureIndex(params string[] path);

		public virtual void Dispose()
		{
			if (IsOpen)
				Close();
		}

		public virtual bool Contains(Guid documentID)
		{
			return GetDocumentIDs().Contains(documentID);
		}

        public virtual IDisposable Lock()
        {
            return new DisposableLock(this);
        }

        public abstract bool Refresh(Document document);
        public abstract bool IsCaching { get; }
    }
}