// ZipPartStream.cs created with MonoDevelop
// User: alan at 13:13 23/10/2008
//
// To change standard headers go to Edit->Preferences->Coding->Standard Headers
//

using System;
using System.IO;
using zipsharp;

namespace System.IO.Packaging
{
	internal class ZipPartStream : Stream
	{
		public MemoryStream BaseStream { get; private set; }
		public ZipPackage Package { get; private set; }
		
		public override bool CanRead {
			get {
				return BaseStream.CanRead;
			}
		}
		
		public override bool CanSeek {
			get {
				return BaseStream.CanSeek;
			}
		}

		public override bool CanTimeout {
			get { return BaseStream.CanTimeout; }
		}

		public override bool CanWrite {
			get { return Writeable; }
		}

		public override long Length {
			get { return BaseStream.Length; }
		}
		
		public override long Position {
			get; set;
		}

		public bool Writeable {
			get; set;
		}

		public override int WriteTimeout {
			get {
				return BaseStream.WriteTimeout;
			}
			set {
				BaseStream.WriteTimeout = value;
			}
		}
		
		public override int ReadTimeout {
			get {
				return BaseStream.ReadTimeout;
			}
			set {
				BaseStream.ReadTimeout = value;
			}
		}

		public ZipPartStream (ZipPackage package, MemoryStream stream, FileAccess access)
		{
			BaseStream = stream;
			Package = package;
			Writeable = access != FileAccess.Read;
		}

		public override void Flush ()
		{
			// If the user flushes any of the part streams,
			// we need to flush the entire package
			
			// FIXME: Ensure that this actually happens with a testcase
			// ...if possible
			Package.Flush ();
		}
		
		public override int Read (byte[] buffer, int offset, int count)
		{
			Seek (Position, SeekOrigin.Begin);
			int read = BaseStream.Read (buffer, offset, count);
			Position += read;
			return read;
		}

		public override long Seek (long offset, SeekOrigin origin)
		{
			Position = BaseStream.Seek (offset, origin);
			return Position;
		}

		public override void SetLength (long value)
		{
			if (!CanWrite)
				throw new InvalidOperationException ("Stream is not writeable");
			
			BaseStream.SetLength (value);
		}

		public override void Write(byte[] buffer, int offset, int count)
		{
			if (!CanWrite)
				throw new InvalidOperationException ("Stream is not writeable");
			
			Seek (Position, SeekOrigin.Begin);
			BaseStream.Write (buffer, offset, count);
			Position += count;
		}
	}
}