// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : Virtual98.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Manages Virtual98 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 © 2011-2018 Natalia Portillo
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.Filters;
using Schemas;

namespace DiscImageChef.DiscImages
{
    // Info from Neko Project II emulator
    public class Virtual98 : IWritableImage
    {
        readonly byte[] signature = {0x56, 0x48, 0x44, 0x31, 0x2E, 0x30, 0x30, 0x00};
        ImageInfo       imageInfo;
        IFilter         nhdImageFilter;

        Virtual98Header v98Hdr;
        FileStream      writingStream;

        public Virtual98()
        {
            imageInfo = new ImageInfo
            {
                ReadableSectorTags    = new List<SectorTagType>(),
                ReadableMediaTags     = new List<MediaTagType>(),
                HasPartitions         = false,
                HasSessions           = false,
                Version               = null,
                Application           = null,
                ApplicationVersion    = null,
                Creator               = null,
                Comments              = null,
                MediaManufacturer     = null,
                MediaModel            = null,
                MediaSerialNumber     = null,
                MediaBarcode          = null,
                MediaPartNumber       = null,
                MediaSequence         = 0,
                LastMediaSequence     = 0,
                DriveManufacturer     = null,
                DriveModel            = null,
                DriveSerialNumber     = null,
                DriveFirmwareRevision = null
            };
        }

        public ImageInfo Info => imageInfo;

        public string Name => "Virtual98 Disk Image";
        public Guid   Id   => new Guid("C0CDE13D-04D0-4913-8740-AFAA44D0A107");

        public string Format => "Virtual98 disk image";

        public List<Partition> Partitions =>
            throw new FeatureUnsupportedImageException("Feature not supported by image format");

        public List<Track> Tracks =>
            throw new FeatureUnsupportedImageException("Feature not supported by image format");

        public List<Session> Sessions =>
            throw new FeatureUnsupportedImageException("Feature not supported by image format");

        public bool Identify(IFilter imageFilter)
        {
            Stream stream = imageFilter.GetDataForkStream();
            stream.Seek(0, SeekOrigin.Begin);
            // Even if comment is supposedly ASCII, I'm pretty sure most emulators allow Shift-JIS to be used :p
            Encoding shiftjis = Encoding.GetEncoding("shift_jis");

            v98Hdr = new Virtual98Header();

            if(stream.Length < Marshal.SizeOf(v98Hdr)) return false;

            byte[] hdrB = new byte[Marshal.SizeOf(v98Hdr)];
            stream.Read(hdrB, 0, hdrB.Length);

            GCHandle handle = GCHandle.Alloc(hdrB, GCHandleType.Pinned);
            v98Hdr          =
                (Virtual98Header)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(Virtual98Header));
            handle.Free();

            if(!v98Hdr.signature.SequenceEqual(signature)) return false;

            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.signature = \"{0}\"",
                                      StringHandlers.CToString(v98Hdr.signature, shiftjis));
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.comment = \"{0}\"",
                                      StringHandlers.CToString(v98Hdr.comment, shiftjis));
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.padding = {0}",    v98Hdr.padding);
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.mbsize = {0}",     v98Hdr.mbsize);
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.sectorsize = {0}", v98Hdr.sectorsize);
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.sectors = {0}",    v98Hdr.sectors);
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.surfaces = {0}",   v98Hdr.surfaces);
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.cylinders = {0}",  v98Hdr.cylinders);
            DicConsole.DebugWriteLine("Virtual98 plugin", "v98hdr.totals = {0}",     v98Hdr.totals);

            return true;
        }

        public bool Open(IFilter imageFilter)
        {
            Stream stream = imageFilter.GetDataForkStream();
            stream.Seek(0, SeekOrigin.Begin);
            // Even if comment is supposedly ASCII, I'm pretty sure most emulators allow Shift-JIS to be used :p
            Encoding shiftjis = Encoding.GetEncoding("shift_jis");

            v98Hdr = new Virtual98Header();

            if(stream.Length < Marshal.SizeOf(v98Hdr)) return false;

            byte[] hdrB = new byte[Marshal.SizeOf(v98Hdr)];
            stream.Read(hdrB, 0, hdrB.Length);

            GCHandle handle = GCHandle.Alloc(hdrB, GCHandleType.Pinned);
            v98Hdr          =
                (Virtual98Header)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(Virtual98Header));
            handle.Free();

            imageInfo.MediaType = MediaType.GENERIC_HDD;

            imageInfo.ImageSize            = (ulong)(stream.Length - 0xDC);
            imageInfo.CreationTime         = imageFilter.GetCreationTime();
            imageInfo.LastModificationTime = imageFilter.GetLastWriteTime();
            imageInfo.MediaTitle           = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
            imageInfo.Sectors              = v98Hdr.totals;
            imageInfo.XmlMediaType         = XmlMediaType.BlockMedia;
            imageInfo.SectorSize           = v98Hdr.sectorsize;
            imageInfo.Cylinders            = v98Hdr.cylinders;
            imageInfo.Heads                = v98Hdr.surfaces;
            imageInfo.SectorsPerTrack      = v98Hdr.sectors;
            imageInfo.Comments             = StringHandlers.CToString(v98Hdr.comment, shiftjis);

            nhdImageFilter = imageFilter;

            return true;
        }

        public byte[] ReadSector(ulong sectorAddress)
        {
            return ReadSectors(sectorAddress, 1);
        }

        public byte[] ReadSectors(ulong sectorAddress, uint length)
        {
            if(sectorAddress > imageInfo.Sectors - 1)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            if(sectorAddress + length > imageInfo.Sectors)
                throw new ArgumentOutOfRangeException(nameof(length), "Requested more sectors than available");

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

            Stream stream = nhdImageFilter.GetDataForkStream();

            // V98 are lazy allocated
            if((long)(0xDC + sectorAddress * imageInfo.SectorSize) >= stream.Length) return buffer;

            stream.Seek((long)(0xDC + sectorAddress * imageInfo.SectorSize), SeekOrigin.Begin);

            int toRead = (int)(length * imageInfo.SectorSize);

            if(toRead + stream.Position > stream.Length) toRead = (int)(stream.Length - stream.Position);

            stream.Read(buffer, 0, toRead);

            return buffer;
        }

        public byte[] ReadDiskTag(MediaTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorTag(ulong sectorAddress, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSector(ulong sectorAddress, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorTag(ulong sectorAddress, uint track, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorsTag(ulong sectorAddress, uint length, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectors(ulong sectorAddress, uint length, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorsTag(ulong sectorAddress, uint length, uint track, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorLong(ulong sectorAddress)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorLong(ulong sectorAddress, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorsLong(ulong sectorAddress, uint length)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public byte[] ReadSectorsLong(ulong sectorAddress, uint length, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public List<Track> GetSessionTracks(Session session)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public List<Track> GetSessionTracks(ushort session)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public bool? VerifySector(ulong sectorAddress)
        {
            return null;
        }

        public bool? VerifySector(ulong sectorAddress, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public bool? VerifySectors(ulong sectorAddress, uint length, out List<ulong> failingLbas,
                                   out                                   List<ulong> unknownLbas)
        {
            failingLbas = new List<ulong>();
            unknownLbas = new List<ulong>();
            for(ulong i = 0; i < imageInfo.Sectors; i++) unknownLbas.Add(i);

            return null;
        }

        public bool? VerifySectors(ulong sectorAddress, uint length, uint track, out List<ulong> failingLbas,
                                   out                                               List<ulong> unknownLbas)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public bool? VerifyMediaImage()
        {
            return null;
        }

        public List<DumpHardwareType> DumpHardware => null;
        public CICMMetadataType       CicmMetadata => null;

        public IEnumerable<MediaTagType>  SupportedMediaTags  => new MediaTagType[] { };
        public IEnumerable<SectorTagType> SupportedSectorTags => new SectorTagType[] { };
        public IEnumerable<MediaType>     SupportedMediaTypes =>
            new[]
            {
                MediaType.GENERIC_HDD, MediaType.Unknown, MediaType.FlashDrive, MediaType.CompactFlash,
                MediaType.CompactFlashType2, MediaType.PCCardTypeI, MediaType.PCCardTypeII, MediaType.PCCardTypeIII,
                MediaType.PCCardTypeIV
            };
        public IEnumerable<(string name, Type type, string description)> SupportedOptions =>
            new (string name, Type type, string description)[] { };
        public IEnumerable<string> KnownExtensions => new[] {".v98"};
        public bool                IsWriting       { get; private set; }
        public string              ErrorMessage    { get; private set; }

        public bool Create(string path, MediaType mediaType, Dictionary<string, string> options, ulong sectors,
                           uint   sectorSize)
        {
            if(sectorSize != 512)
            {
                ErrorMessage = "Unsupported sector size";
                return false;
            }

            if(sectors > uint.MaxValue)
            {
                ErrorMessage = "Too many sectors";
                return false;
            }

            if(!SupportedMediaTypes.Contains(mediaType))
            {
                ErrorMessage = $"Unsupport media format {mediaType}";
                return false;
            }

            imageInfo = new ImageInfo {MediaType = mediaType, SectorSize = sectorSize, Sectors = sectors};

            try { writingStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None); }
            catch(IOException e)
            {
                ErrorMessage = $"Could not create new image file, exception {e.Message}";
                return false;
            }

            IsWriting    = true;
            ErrorMessage = null;
            return true;
        }

        public bool WriteMediaTag(byte[] data, MediaTagType tag)
        {
            ErrorMessage = "Writing media tags is not supported.";
            return false;
        }

        public bool WriteSector(byte[] data, ulong sectorAddress)
        {
            if(!IsWriting)
            {
                ErrorMessage = "Tried to write on a non-writable image";
                return false;
            }

            if(data.Length != 512)
            {
                ErrorMessage = "Incorrect data size";
                return false;
            }

            if(sectorAddress >= imageInfo.Sectors)
            {
                ErrorMessage = "Tried to write past image size";
                return false;
            }

            writingStream.Seek((long)(0xDC + sectorAddress * 512), SeekOrigin.Begin);
            writingStream.Write(data, 0, data.Length);

            ErrorMessage = "";
            return true;
        }

        public bool WriteSectors(byte[] data, ulong sectorAddress, uint length)
        {
            if(!IsWriting)
            {
                ErrorMessage = "Tried to write on a non-writable image";
                return false;
            }

            if(data.Length % 512 != 0)
            {
                ErrorMessage = "Incorrect data size";
                return false;
            }

            if(sectorAddress + length > imageInfo.Sectors)
            {
                ErrorMessage = "Tried to write past image size";
                return false;
            }

            writingStream.Seek((long)(0xDC + sectorAddress * 512), SeekOrigin.Begin);
            writingStream.Write(data, 0, data.Length);

            ErrorMessage = "";
            return true;
        }

        public bool WriteSectorLong(byte[] data, ulong sectorAddress)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";
            return false;
        }

        public bool WriteSectorsLong(byte[] data, ulong sectorAddress, uint length)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";
            return false;
        }

        public bool SetTracks(List<Track> tracks)
        {
            ErrorMessage = "Unsupported feature";
            return false;
        }

        public bool Close()
        {
            if(!IsWriting)
            {
                ErrorMessage = "Image is not opened for writing";
                return false;
            }

            if(imageInfo.Cylinders == 0)
            {
                imageInfo.Cylinders       = (uint)(imageInfo.Sectors / 16 / 63);
                imageInfo.Heads           = 16;
                imageInfo.SectorsPerTrack = 63;

                while(imageInfo.Cylinders == 0)
                {
                    imageInfo.Heads--;

                    if(imageInfo.Heads == 0)
                    {
                        imageInfo.SectorsPerTrack--;
                        imageInfo.Heads = 16;
                    }

                    imageInfo.Cylinders = (uint)(imageInfo.Sectors / imageInfo.Heads / imageInfo.SectorsPerTrack);

                    if(imageInfo.Cylinders == 0 && imageInfo.Heads == 0 && imageInfo.SectorsPerTrack == 0) break;
                }
            }

            byte[] commentsBytes = null;
            if(!string.IsNullOrEmpty(imageInfo.Comments))
                commentsBytes = Encoding.GetEncoding("shift_jis").GetBytes(imageInfo.Comments);

            v98Hdr = new Virtual98Header
            {
                comment    = new byte[128],
                cylinders  = (ushort)imageInfo.Cylinders,
                padding2   = new byte[0x44],
                sectors    = (byte)imageInfo.SectorsPerTrack,
                sectorsize = (ushort)imageInfo.SectorSize,
                signature  = signature,
                surfaces   = (byte)imageInfo.Heads,
                totals     = (uint)imageInfo.Sectors
            };

            if(commentsBytes != null)
                Array.Copy(commentsBytes, 0, v98Hdr.comment, 0,
                           commentsBytes.Length >= 128 ? 128 : commentsBytes.Length);

            byte[] hdr    = new byte[Marshal.SizeOf(v98Hdr)];
            IntPtr hdrPtr = Marshal.AllocHGlobal(Marshal.SizeOf(v98Hdr));
            Marshal.StructureToPtr(v98Hdr, hdrPtr, true);
            Marshal.Copy(hdrPtr, hdr, 0, hdr.Length);
            Marshal.FreeHGlobal(hdrPtr);

            writingStream.Seek(0, SeekOrigin.Begin);
            writingStream.Write(hdr, 0, hdr.Length);

            writingStream.Flush();
            writingStream.Close();

            IsWriting    = false;
            ErrorMessage = "";
            return true;
        }

        public bool SetMetadata(ImageInfo metadata)
        {
            imageInfo.Comments = metadata.Comments;
            return true;
        }

        public bool SetGeometry(uint cylinders, uint heads, uint sectorsPerTrack)
        {
            if(cylinders > ushort.MaxValue)
            {
                ErrorMessage = "Too many cylinders.";
                return false;
            }

            if(heads > byte.MaxValue)
            {
                ErrorMessage = "Too many heads.";
                return false;
            }

            if(sectorsPerTrack > byte.MaxValue)
            {
                ErrorMessage = "Too many sectors per track.";
                return false;
            }

            imageInfo.SectorsPerTrack = sectorsPerTrack;
            imageInfo.Heads           = heads;
            imageInfo.Cylinders       = cylinders;

            return true;
        }

        public bool WriteSectorTag(byte[] data, ulong sectorAddress, SectorTagType tag)
        {
            ErrorMessage = "Unsupported feature";
            return false;
        }

        public bool WriteSectorsTag(byte[] data, ulong sectorAddress, uint length, SectorTagType tag)
        {
            ErrorMessage = "Unsupported feature";
            return false;
        }

        public bool SetDumpHardware(List<DumpHardwareType> dumpHardware)
        {
            // Not supported
            return false;
        }

        public bool SetCicmMetadata(CICMMetadataType metadata)
        {
            // Not supported
            return false;
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct Virtual98Header
        {
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
            public byte[] signature;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 128)]
            public byte[] comment;
            public uint   padding;
            public ushort mbsize;
            public ushort sectorsize;
            public byte   sectors;
            public byte   surfaces;
            public ushort cylinders;
            public uint   totals;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 0x44)]
            public byte[] padding2;
        }
    }
}