// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Read.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Reads Dunfield's IMD 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.Collections.Generic;
using System.IO;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Console;
using Aaru.Helpers;

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

            var cmt = new MemoryStream();
            stream.Seek(0x1F, SeekOrigin.Begin);

            for(uint i = 0; i < stream.Length; i++)
            {
                byte b = (byte)stream.ReadByte();

                if(b == 0x1A)
                    break;

                cmt.WriteByte(b);
            }

            _imageInfo.Comments = StringHandlers.CToString(cmt.ToArray());
            _sectorsData        = new List<byte[]>();

            byte currentCylinder = 0;
            _imageInfo.Cylinders = 1;
            _imageInfo.Heads     = 1;
            ulong currentLba = 0;

            TransferRate mode = TransferRate.TwoHundred;

            while(stream.Position + 5 < stream.Length)
            {
                mode = (TransferRate)stream.ReadByte();
                byte     cylinder = (byte)stream.ReadByte();
                byte     head     = (byte)stream.ReadByte();
                byte     spt      = (byte)stream.ReadByte();
                byte     n        = (byte)stream.ReadByte();
                byte[]   idmap    = new byte[spt];
                byte[]   cylmap   = new byte[spt];
                byte[]   headmap  = new byte[spt];
                ushort[] bps      = new ushort[spt];

                if(cylinder != currentCylinder)
                {
                    currentCylinder = cylinder;
                    _imageInfo.Cylinders++;
                }

                if((head & 1) == 1)
                    _imageInfo.Heads = 2;

                stream.Read(idmap, 0, idmap.Length);

                if((head & SECTOR_CYLINDER_MAP_MASK) == SECTOR_CYLINDER_MAP_MASK)
                    stream.Read(cylmap, 0, cylmap.Length);

                if((head & SECTOR_HEAD_MAP_MASK) == SECTOR_HEAD_MAP_MASK)
                    stream.Read(headmap, 0, headmap.Length);

                if(n == 0xFF)
                {
                    byte[] bpsbytes = new byte[spt * 2];
                    stream.Read(bpsbytes, 0, bpsbytes.Length);

                    for(int i = 0; i < spt; i++)
                        bps[i] = BitConverter.ToUInt16(bpsbytes, i * 2);
                }
                else
                    for(int i = 0; i < spt; i++)
                        bps[i] = (ushort)(128 << n);

                if(spt > _imageInfo.SectorsPerTrack)
                    _imageInfo.SectorsPerTrack = spt;

                SortedDictionary<byte, byte[]> track = new();

                for(int i = 0; i < spt; i++)
                {
                    var    type = (SectorType)stream.ReadByte();
                    byte[] data = new byte[bps[i]];

                    // TODO; Handle disks with different bps in track 0
                    if(bps[i] > _imageInfo.SectorSize)
                        _imageInfo.SectorSize = bps[i];

                    switch(type)
                    {
                        case SectorType.Unavailable:
                            if(!track.ContainsKey(idmap[i]))
                                track.Add(idmap[i], data);

                            break;
                        case SectorType.Normal:
                        case SectorType.Deleted:
                        case SectorType.Error:
                        case SectorType.DeletedError:
                            stream.Read(data, 0, data.Length);

                            if(!track.ContainsKey(idmap[i]))
                                track.Add(idmap[i], data);

                            _imageInfo.ImageSize += (ulong)data.Length;

                            break;
                        case SectorType.Compressed:
                        case SectorType.CompressedDeleted:
                        case SectorType.CompressedError:
                        case SectorType.CompressedDeletedError:
                            byte filling = (byte)stream.ReadByte();
                            ArrayHelpers.ArrayFill(data, filling);

                            if(!track.ContainsKey(idmap[i]))
                                track.Add(idmap[i], data);

                            break;
                        default:
                            AaruConsole.ErrorWriteLine($"Invalid sector type {(byte)type}");

                            return ErrorNumber.InvalidArgument;
                    }
                }

                foreach(KeyValuePair<byte, byte[]> kvp in track)
                {
                    _sectorsData.Add(kvp.Value);
                    currentLba++;
                }
            }

            _imageInfo.Application = "IMD";

            // TODO: The header is the date of dump or the date of the application compilation?
            _imageInfo.CreationTime         = imageFilter.CreationTime;
            _imageInfo.LastModificationTime = imageFilter.LastWriteTime;
            _imageInfo.MediaTitle           = Path.GetFileNameWithoutExtension(imageFilter.Filename);
            _imageInfo.Comments             = StringHandlers.CToString(cmt.ToArray());
            _imageInfo.Sectors              = currentLba;
            _imageInfo.MediaType            = MediaType.Unknown;

            MediaEncoding mediaEncoding = MediaEncoding.MFM;

            if(mode == TransferRate.TwoHundred   ||
               mode == TransferRate.ThreeHundred ||
               mode == TransferRate.FiveHundred)
                mediaEncoding = MediaEncoding.FM;

            _imageInfo.MediaType = Geometry.GetMediaType(((ushort)_imageInfo.Cylinders, (byte)_imageInfo.Heads,
                                                          (ushort)_imageInfo.SectorsPerTrack, _imageInfo.SectorSize,
                                                          mediaEncoding, false));

            switch(_imageInfo.MediaType)
            {
                case MediaType.NEC_525_HD when mode == TransferRate.FiveHundredMfm:
                    _imageInfo.MediaType = MediaType.NEC_35_HD_8;

                    break;
                case MediaType.DOS_525_HD when mode == TransferRate.FiveHundredMfm:
                    _imageInfo.MediaType = MediaType.NEC_35_HD_15;

                    break;
                case MediaType.RX50 when mode == TransferRate.FiveHundredMfm:
                    _imageInfo.MediaType = MediaType.ATARI_35_SS_DD;

                    break;
            }

            _imageInfo.XmlMediaType = XmlMediaType.BlockMedia;

            AaruConsole.VerboseWriteLine("IMD image contains a disk of type {0}", _imageInfo.MediaType);

            if(!string.IsNullOrEmpty(_imageInfo.Comments))
                AaruConsole.VerboseWriteLine("IMD comments: {0}", _imageInfo.Comments);

            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;

            var ms = new MemoryStream();

            for(int i = 0; i < length; i++)
                ms.Write(_sectorsData[(int)sectorAddress + i], 0, _sectorsData[(int)sectorAddress + i].Length);

            buffer = ms.ToArray();

            return ErrorNumber.NoError;
        }
    }
}