using System;
using System.IO;

namespace Storage
{
    public class StreamWrapper: Stream
    {
        public Stream Stream { get; private set; }

        private readonly Action<StreamWrapper,object> onDispose;

        public object Context { get; private set; }

        public StreamWrapper(Stream stream, object context, Action<StreamWrapper,object> onDispose)
        {
            Context = context; Stream = stream; this.onDispose = onDispose;
        }

        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing); Exception error = null;
            if (disposing && onDispose != null) try { onDispose(this, Context); } catch (Exception e) { error = e; }
            Stream.Dispose(); if (error != null) throw error;
        }

        public override bool CanRead { get { return Stream.CanRead; } }

        public override bool CanSeek { get { return Stream.CanSeek; } }

        public override bool CanWrite { get { return Stream.CanWrite; } }

        public override void Flush() { Stream.Flush(); }

        public override long Length { get { return Stream.Length; } }

        public override long Position { get { return Stream.Position; } set { Stream.Position = value; } }

        public override int Read(byte[] buffer, int offset, int count) { return Stream.Read(buffer, offset, count); }

        public override long Seek(long offset, SeekOrigin origin) { return Stream.Seek(offset, origin); }

        public override void SetLength(long value) { Stream.SetLength(value); }

        public override void Write(byte[] buffer, int offset, int count) { Stream.Write(buffer, offset, count); }

        public byte[] Buffer { get { return Stream is MemoryStream ? (Stream as MemoryStream).ToArray() : null; } }
    }
}