/*

* 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.Collections.Generic;

using System.Text;

using System.IO;

using SymbianUtils.Tracer;

using SymbianUtils.Streams;

using SymbianStructuresLib.Uids;

using SymbianStructuresLib.Version;

namespace SymbianImageLib.ROFS.Structures

{

    internal class TRofsDir : IEnumerable<TRofsEntry>

    {

        #region Constructors

        public TRofsDir( string aName, uint aFileAddress, SymbianStreamReaderLE aReader, ITracer aTracer )

        {

            //aTracer.Trace( "[Dir ] @ 0x{0:x8} {1}", aFileAddress, aName );

            //

            iName = aName;

            //

            aReader.Seek( aFileAddress, SeekOrigin.Begin );

            //

            iStructSize = aReader.ReadUInt16();

            iPadding = aReader.ReadUInt8();

            iFirstEntryOffset = aReader.ReadUInt8();

            iFileBlockAddress = aReader.ReadUInt32();

            iFileBlockSize = aReader.ReadUInt32();

            //

            if ( iFileBlockAddress != 0 )

            {

                // Directory has files in it

                AddFiles( aReader, aTracer, iFileBlockAddress, iFileBlockSize );

            }

            if ( iStructSize > KMinimumDirectoryEntrySize )

            {

                // Directory has subdirectories

                AddSubDirs( aReader, aTracer, aFileAddress + iStructSize );

            }

        }

        #endregion

        #region API

        #endregion

        #region Constants

        // The minimum standard entry size, irrespective of whether the directory 

        // contains subdirs or files.

        public const uint KMinimumDirectoryEntrySize = 2 + 1 + 1 + 4 + 4;

        #endregion

        #region Properties

        public uint Size

        {

            get { return iStructSize; }

        }

        public string Name

        {

            get { return iName; }

        }

        public uint FirstEntryOffset

        {

            get { return iFirstEntryOffset; }

        }

        public uint FileBlockAddress

        {

            get { return iFileBlockAddress; }

        }

        public uint FileBlockSize

        {

            get { return iFileBlockSize; }

        }

        public TRofsDir[] SubDirectories

        {

            get

            {

                return iSubdirectories.ToArray();

            }

        }

        #endregion

        #region Internal methods

        private void AddFiles( SymbianStreamReaderLE aReader, ITracer aTracer, long aStartPosition, uint aSize )

        {

            long originalPosition = aReader.Position;

            long endPos = aStartPosition + aSize;

            //

            long filePosition = aStartPosition;

            while ( filePosition < endPos )

            {

                // Seek to start of file and read it

                aReader.Seek( filePosition, SeekOrigin.Begin );

                TRofsEntry entry = new TRofsEntry( aReader, aTracer );

                iFiles.Add( entry );

                //aTracer.Trace( "[File] @ 0x{0:x8} {1:d8} {2}", filePosition, entry.FileSize, entry.Name );

                // Move to next file

                filePosition += entry.Size;

            }

            // Restore original position

            aReader.Seek( originalPosition, SeekOrigin.Begin );

        }

        private void AddSubDirs( SymbianStreamReaderLE aReader, ITracer aTracer, long aEndDirPos )

        {

            long originalPosition = aReader.Position;

            //

            long filePosition = aReader.BaseStream.Position;

            while ( filePosition < aEndDirPos )

            {

                // Seek to start of subdir and read basic properties

                aReader.Seek( filePosition, SeekOrigin.Begin );

                TRofsEntry entry = new TRofsEntry( aReader, aTracer );

                // Create a new subdirectory that we'll process recursively.

                TRofsDir subdir = new TRofsDir( entry.Name, entry.FileAddress, aReader, aTracer );

                iSubdirectories.Add( subdir );

                // Move to next subdir, rounding to 4 bytes

                long nextSubDirOffset = entry.Size;

                nextSubDirOffset += ( ( 4 - nextSubDirOffset ) & 0x3 );

                filePosition += nextSubDirOffset;

            }

            // Restore original position

            aReader.Seek( originalPosition, SeekOrigin.Begin );

        }

        #endregion

        #region From IEnumerable<TRofsEntry>

        public IEnumerator<TRofsEntry> GetEnumerator()

        {

            foreach ( TRofsEntry entry in iFiles )

            {

                yield return entry;

            }

        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()

        {

            foreach ( TRofsEntry entry in iFiles )

            {

                yield return entry;

            }

        }

        #endregion

        #region Data members

        private readonly string iName;

        private ushort iStructSize;		    // Total size of this directory block including padding

        private byte iPadding;

        private byte iFirstEntryOffset;	    // offset to first entry

        private uint iFileBlockAddress;	    // address of associated file block

        private uint iFileBlockSize;		// size of associated file block

        private List<TRofsEntry> iFiles = new List<TRofsEntry>();

        private List<TRofsDir> iSubdirectories = new List<TRofsDir>();

        #endregion

    }

}