/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

* 

* Description:

*

*/

using System;

using System.IO;

using System.Text;

using System.Threading;

using System.Collections;

using SymbianUtils.Tracer;

namespace SymbianUtils

{

	public abstract class AsyncTextDataReader : AsyncTextReader

	{

		#region Enumerations

		public enum TReadDirection

		{

			EReadDirectionForwards = 0,

			EReadDirectionBackwards

		}

		#endregion

		#region Construct & destruct

		protected AsyncTextDataReader( string[] aLines )

			: this( aLines, new AsyncTextReaderPrefix() )

		{

		}

        protected AsyncTextDataReader( string[] aLines, ITracer aTracer )

            : this( aLines, new AsyncTextReaderPrefix(), aTracer )

        {

        }

        protected AsyncTextDataReader( string[] aLines, AsyncTextReaderPrefix aPrefixes )

			: this( aLines, TReadDirection.EReadDirectionForwards, aPrefixes )

		{

		}

        protected AsyncTextDataReader( string[] aLines, AsyncTextReaderPrefix aPrefixes, ITracer aTracer )

            : this( aLines, TReadDirection.EReadDirectionForwards, aPrefixes, aTracer )

        {

        }

        protected AsyncTextDataReader( string[] aLines, TReadDirection aReadDirection )

			: this( aLines, TReadDirection.EReadDirectionForwards, new AsyncTextReaderPrefix(), null )

		{

		}

        protected AsyncTextDataReader( string[] aLines, TReadDirection aReadDirection, ITracer aTracer )

            : this( aLines, TReadDirection.EReadDirectionForwards, new AsyncTextReaderPrefix(), aTracer )

		{

		}

        protected AsyncTextDataReader( string[] aLines, TReadDirection aReadDirection, AsyncTextReaderPrefix aPrefixes )

            : this( aLines, aReadDirection, aPrefixes, null )

        {

		}

        protected AsyncTextDataReader( string[] aLines, TReadDirection aReadDirection, AsyncTextReaderPrefix aPrefixes, ITracer aTracer )

			: base( aPrefixes, aTracer )

		{

			iLines = aLines;

			iReadDirection = aReadDirection;

			//

			switch( iReadDirection )

			{

			default:

			case TReadDirection.EReadDirectionForwards:

				iLineIndex = 0;

				break;

			case TReadDirection.EReadDirectionBackwards:

				iLineIndex = iLines.Length - 1;

				break;

			}

		}

		#endregion

        #region Properties

        public int LineNumber

		{

			get { return iLineIndex; }

		}

		#endregion

		#region Abstract reading framework

		protected override int CalculateProgress()

		{

			int prog = 0;

			//

			switch( iReadDirection )

			{

			default:

			case TReadDirection.EReadDirectionForwards:

				{

				prog = base.CalculateProgress();

				break;

				}

			case TReadDirection.EReadDirectionBackwards:

				{

				float positionAsFloat = (float)Position;

				float sizeAsFloat = (float)Size;

				prog = (int)((positionAsFloat / sizeAsFloat) * 100.0);

				prog = System.Math.Max(1, System.Math.Min(100, prog));

				break;

				}

			}

			//

			return prog;

		}

		protected override string ProvideReadLine()

		{

			string ret = null;

			//

			switch( iReadDirection )

			{

			default:

			case TReadDirection.EReadDirectionForwards:

				if	( iLineIndex < iLines.Length )

				{

					ret = iLines[ iLineIndex++ ];

				}

				break;

			case TReadDirection.EReadDirectionBackwards:

				if	( iLineIndex >= 0 )

				{

					ret = iLines[ iLineIndex-- ];

				}

				break;

			}

			//

			return ret;

		}

		protected override long Size

		{

			get

			{

				long size = iLines.LongLength;

				return size;

			}

		}

		protected override long Position

		{

			get

			{

				long position = (long) iLineIndex;

				return position;

			}

		}

		#endregion

		#region Data members

		private readonly string[] iLines;

		private readonly TReadDirection iReadDirection;

		private int iLineIndex = 0;

		#endregion

	}

}