using System;
using System.IO;
namespace sharp.json
{
	public class FileBackedJSONValue<T>
	{
		public string FileName { get; set; }
		public DateTime LoadedWriteTime { get; set; }

		T current;
		JSON jsource;

		public FileBackedJSONValue(string filename)
		{
			FileName = filename;
		}

		public T CurrentValue { 
			get 
			{
				if (!File.Exists(FileName)){
					current = default(T);
				} else if ((current == null) || (File.GetLastWriteTime(FileName) != LoadedWriteTime))
				{
					jsource = JSON.ReadFrom(FileName);
					LoadedWriteTime = File.GetLastWriteTime(FileName);

					current = jsource.To<T>();
				}
				return current;
			}
			set
			{
				current = value;
				Save();
			}
		}

		public void Save(){
			JSONConverter.From(current).WriteTo(FileName,true);
			LoadedWriteTime = File.GetLastWriteTime(FileName);
		}

	}
}