// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Identify.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies VMware disk images.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library is distributed in the hope that it will be useful, but
//     WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2025 Natalia Portillo
// ****************************************************************************/

using System.IO;
using System.Linq;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;

namespace Aaru.Images;

public sealed partial class VMware
{
#region IWritableImage Members

    /// <inheritdoc />
    public bool Identify(IFilter imageFilter)
    {
        Stream stream = imageFilter.GetDataForkStream();

        var ddfMagic = new byte[0x15];

        if(stream.Length > Marshal.SizeOf<ExtentHeader>())
        {
            stream.Seek(0, SeekOrigin.Begin);
            var vmEHdrB = new byte[Marshal.SizeOf<ExtentHeader>()];
            stream.EnsureRead(vmEHdrB, 0, Marshal.SizeOf<ExtentHeader>());
            _vmEHdr = Marshal.ByteArrayToStructureLittleEndian<ExtentHeader>(vmEHdrB);

            stream.Seek(0, SeekOrigin.Begin);
            stream.EnsureRead(ddfMagic, 0, 0x15);

            _vmCHdr = new CowHeader();

            if(stream.Length <= Marshal.SizeOf<CowHeader>())
            {
                return _ddfMagicBytes.SequenceEqual(ddfMagic) ||
                       _vmEHdr.magic == VMWARE_EXTENT_MAGIC   ||
                       _vmCHdr.magic == VMWARE_COW_MAGIC;
            }

            stream.Seek(0, SeekOrigin.Begin);
            var vmCHdrB = new byte[Marshal.SizeOf<CowHeader>()];
            stream.EnsureRead(vmCHdrB, 0, Marshal.SizeOf<CowHeader>());
            _vmCHdr = Marshal.ByteArrayToStructureLittleEndian<CowHeader>(vmCHdrB);

            return _ddfMagicBytes.SequenceEqual(ddfMagic) ||
                   _vmEHdr.magic == VMWARE_EXTENT_MAGIC   ||
                   _vmCHdr.magic == VMWARE_COW_MAGIC;
        }

        stream.Seek(0, SeekOrigin.Begin);
        stream.EnsureRead(ddfMagic, 0, 0x15);

        return _ddfMagicBytes.SequenceEqual(ddfMagic);
    }

#endregion
}