// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Read.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Reads T98 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 © 2011-2021 Natalia Portillo
// ****************************************************************************/

using System;
using System.IO;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;

namespace Aaru.DiscImages
{
    public sealed partial class T98
    {
        /// <inheritdoc />
        public ErrorNumber Open(IFilter imageFilter)
        {
            Stream stream = imageFilter.GetDataForkStream();
            stream.Seek(0, SeekOrigin.Begin);

            if(stream.Length % 256 != 0)
                return ErrorNumber.InvalidArgument;

            byte[] hdrB = new byte[256];
            stream.Read(hdrB, 0, hdrB.Length);

            for(int i = 4; i < 256; i++)
                if(hdrB[i] != 0)
                    return ErrorNumber.InvalidArgument;

            int cylinders = BitConverter.ToInt32(hdrB, 0);

            _imageInfo.MediaType = MediaType.GENERIC_HDD;

            _imageInfo.ImageSize            = (ulong)(stream.Length - 256);
            _imageInfo.CreationTime         = imageFilter.CreationTime;
            _imageInfo.LastModificationTime = imageFilter.LastWriteTime;
            _imageInfo.MediaTitle           = Path.GetFileNameWithoutExtension(imageFilter.Filename);
            _imageInfo.Sectors              = (ulong)((stream.Length / 256) - 1);
            _imageInfo.XmlMediaType         = XmlMediaType.BlockMedia;
            _imageInfo.SectorSize           = 256;
            _imageInfo.Cylinders            = (uint)cylinders;
            _imageInfo.Heads                = 8;
            _imageInfo.SectorsPerTrack      = 33;

            _t98ImageFilter = imageFilter;

            return ErrorNumber.NoError;
        }

        /// <inheritdoc />
        public ErrorNumber ReadSector(ulong sectorAddress, out byte[] buffer) =>
            ReadSectors(sectorAddress, 1, out buffer);

        /// <inheritdoc />
        public ErrorNumber ReadSectors(ulong sectorAddress, uint length, out byte[] buffer)
        {
            buffer = null;

            if(sectorAddress > _imageInfo.Sectors - 1)
                return ErrorNumber.OutOfRange;

            if(sectorAddress + length > _imageInfo.Sectors)
                return ErrorNumber.OutOfRange;

            buffer = new byte[length * _imageInfo.SectorSize];

            Stream stream = _t98ImageFilter.GetDataForkStream();

            stream.Seek((long)(256 + (sectorAddress * _imageInfo.SectorSize)), SeekOrigin.Begin);

            stream.Read(buffer, 0, (int)(length * _imageInfo.SectorSize));

            return ErrorNumber.NoError;
        }
    }
}