// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : UkvFdi.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Component
//
// --[ Description ] ----------------------------------------------------------
//
//     Description
//
// --[ 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 © 2011-2017 Natalia Portillo
// ****************************************************************************/
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.Filters;

namespace DiscImageChef.ImagePlugins
{
	public class UkvFdi : ImagePlugin
	{
		#region Internal enumerations
		[Flags]
		enum DiskFlags : byte
		{
			WriteProtected = 1
		}

		[Flags]
		enum SectorFlags : byte
		{
			CrcOk128 = 0x01,
			CrcOk256 = 0x02,
			CrcOk512 = 0x04,
			CrcOk1024 = 0x08,
			CrcOk2048 = 0x10,
			CrcOk4096 = 0x20,
			Deleted = 0x80,
		}
		#endregion

		#region Internal constants
		readonly byte[] signature = { 0x46, 0x44, 0x49 };
		#endregion

		#region Internal structures
		[StructLayout(LayoutKind.Sequential, Pack = 1)]
		struct FdiHeader
		{
			[MarshalAs(UnmanagedType.ByValArray, SizeConst = 3)]
			public byte[] magic;
			public DiskFlags flags;
			public ushort cylinders;
			public ushort heads;
			public ushort descOff;
			public ushort dataOff;
			public ushort addInfoLen;
		}
		#endregion

		// Cylinder by head, sector data matrix
		byte[][][][] sectorsData;

		public UkvFdi()
		{
			Name = "Spectrum Floppy Disk Image";
			PluginUUID = new Guid("DADFC9B2-67C1-42A3-B124-825528163FC0");
			ImageInfo = new ImageInfo()
			{
				readableSectorTags = new List<SectorTagType>(),
				readableMediaTags = new List<MediaTagType>(),
				imageHasPartitions = false,
				imageHasSessions = false,
				imageVersion = null,
				imageApplication = null,
				imageApplicationVersion = null,
				imageCreator = null,
				imageComments = null,
				mediaManufacturer = null,
				mediaModel = null,
				mediaSerialNumber = null,
				mediaBarcode = null,
				mediaPartNumber = null,
				mediaSequence = 0,
				lastMediaSequence = 0,
				driveManufacturer = null,
				driveModel = null,
				driveSerialNumber = null,
				driveFirmwareRevision = null
			};
		}

		public override bool IdentifyImage(Filter imageFilter)
		{
			Stream stream = imageFilter.GetDataForkStream();
			stream.Seek(0, SeekOrigin.Begin);

			FdiHeader hdr = new FdiHeader();

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

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

			GCHandle handle = GCHandle.Alloc(hdr_b, GCHandleType.Pinned);
			hdr = (FdiHeader)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(FdiHeader));
			handle.Free();

			return hdr.magic.SequenceEqual(signature);
		}

		public override bool OpenImage(Filter imageFilter)
		{
			Stream stream = imageFilter.GetDataForkStream();
			stream.Seek(0, SeekOrigin.Begin);

			FdiHeader hdr = new FdiHeader();

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

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

			GCHandle handle = GCHandle.Alloc(hdr_b, GCHandleType.Pinned);
			hdr = (FdiHeader)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(FdiHeader));
			handle.Free();

			DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.addInfoLen = {0}", hdr.addInfoLen);
			DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.cylinders = {0}", hdr.cylinders);
			DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.dataOff = {0}", hdr.dataOff);
			DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.descOff = {0}", hdr.descOff);
			DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.flags = {0}", hdr.flags);
			DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.heads = {0}", hdr.heads);

			stream.Seek(hdr.descOff, SeekOrigin.Begin);
			byte[] description = new byte[hdr.dataOff - hdr.descOff];
			stream.Read(description, 0, description.Length);
			ImageInfo.imageComments = StringHandlers.CToString(description);

			DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.description = \"{0}\"", ImageInfo.imageComments);

			stream.Seek(0xE + hdr.addInfoLen, SeekOrigin.Begin);

			long spt = long.MaxValue;
			uint[][][] sectorsOff = new uint[hdr.cylinders][][];
			sectorsData = new byte[hdr.cylinders][][][];

			ImageInfo.cylinders = hdr.cylinders;
			ImageInfo.heads = hdr.heads;

			// Read track descriptors
			for(ushort cyl = 0; cyl < hdr.cylinders; cyl++)
			{
				sectorsOff[cyl] = new uint[hdr.heads][];
				sectorsData[cyl] = new byte[hdr.heads][][];

				for(ushort head = 0; head < hdr.heads; head++)
				{
					byte[] sct_b = new byte[4];
					stream.Read(sct_b, 0, 4);
					stream.Seek(2, SeekOrigin.Current);
					byte sectors = (byte)stream.ReadByte();
					uint trkOff = BitConverter.ToUInt32(sct_b, 0);

					DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.c = {0}", cyl);
					DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.h = {0}", head);
					DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.sectors = {0}", sectors);
					DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.off = {0}", trkOff);

					sectorsOff[cyl][head] = new uint[sectors];
					sectorsData[cyl][head] = new byte[sectors][];

					if(sectors < spt && sectors > 0)
						spt = sectors;

					for(ushort sec = 0; sec < sectors; sec++)
					{
						byte c = (byte)stream.ReadByte();
						byte h = (byte)stream.ReadByte();
						byte r = (byte)stream.ReadByte();
						byte n = (byte)stream.ReadByte();
						SectorFlags f = (SectorFlags)stream.ReadByte();
						byte[] off_b = new byte[2];
						stream.Read(off_b, 0, 2);
						ushort secOff = BitConverter.ToUInt16(off_b, 0);

						DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.c = {0}", c);
						DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.h = {0}", h);
						DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.r = {0}", r);
						DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.n = {0} ({1})", n, 128 << n);
						DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.f = {0}", f);
						DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.off = {0} ({1})", secOff, secOff + trkOff + hdr.dataOff);

						// TODO: This assumes sequential sectors.
						sectorsOff[cyl][head][sec] = secOff + trkOff + hdr.dataOff;
						sectorsData[cyl][head][sec] = new byte[128 << n];

						if(128 << n > ImageInfo.sectorSize)
							ImageInfo.sectorSize = (uint)(128 << n);
					}
				}
			}

			// Read sectors
			for(ushort cyl = 0; cyl < hdr.cylinders; cyl++)
			{
				bool emptyCyl = false;

				for(ushort head = 0; head < hdr.heads; head++)
				{
					for(ushort sec = 0; sec < sectorsOff[cyl][head].Length; sec++)
					{
						stream.Seek(sectorsOff[cyl][head][sec], SeekOrigin.Begin);
						stream.Read(sectorsData[cyl][head][sec], 0, sectorsData[cyl][head][sec].Length);
					}

					// For empty cylinders
					if(sectorsOff[cyl][head].Length == 0)
					{
						// Last cylinder
						if(cyl + 1 == hdr.cylinders ||
						   // Next cylinder is also empty
						   sectorsOff[cyl + 1][head].Length == 0
						  )
							emptyCyl = true;
						// Create empty sectors
						else
						{
							sectorsData[cyl][head] = new byte[spt][];
							for(int i = 0; i < spt; i++)
								sectorsData[cyl][head][i] = new byte[ImageInfo.sectorSize];
						}
					}
				}

				if(emptyCyl)
					ImageInfo.cylinders--;
			}

			// TODO: What about double sided, half track pitch compact floppies?
			ImageInfo.mediaType = MediaType.CompactFloppy;
			ImageInfo.imageSize = (ulong)stream.Length - hdr.dataOff;
			ImageInfo.imageCreationTime = imageFilter.GetCreationTime();
			ImageInfo.imageLastModificationTime = imageFilter.GetLastWriteTime();
			ImageInfo.imageName = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
			ImageInfo.sectorsPerTrack = (uint)spt;
			ImageInfo.sectors = ImageInfo.cylinders*ImageInfo.heads*ImageInfo.sectorsPerTrack;
			ImageInfo.xmlMediaType = XmlMediaType.BlockMedia;

			return true;
		}

		public override bool ImageHasPartitions()
		{
			return false;
		}

		public override ulong GetImageSize()
		{
			return ImageInfo.imageSize;
		}

		public override ulong GetSectors()
		{
			return ImageInfo.sectors;
		}

		public override uint GetSectorSize()
		{
			return ImageInfo.sectorSize;
		}

		public override string GetImageFormat()
		{
			return "Spectrum floppy disk image";
		}

		public override string GetImageVersion()
		{
			return ImageInfo.imageVersion;
		}

		public override string GetImageApplication()
		{
			return ImageInfo.imageApplication;
		}

		public override string GetImageApplicationVersion()
		{
			return ImageInfo.imageApplicationVersion;
		}

		public override string GetImageCreator()
		{
			return ImageInfo.imageCreator;
		}

		public override DateTime GetImageCreationTime()
		{
			return ImageInfo.imageCreationTime;
		}

		public override DateTime GetImageLastModificationTime()
		{
			return ImageInfo.imageLastModificationTime;
		}

		public override string GetImageName()
		{
			return ImageInfo.imageName;
		}

		public override string GetImageComments()
		{
			return ImageInfo.imageComments;
		}

		public override MediaType GetMediaType()
		{
			return ImageInfo.mediaType;
		}

		public override byte[] ReadSector(ulong sectorAddress)
		{
			(ushort cylinder, byte head, byte sector) = LbaToChs(sectorAddress);

			if(cylinder >= sectorsData.Length)
				throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

			if(head >= sectorsData[cylinder].Length)
				throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

			if(sector > sectorsData[cylinder][head].Length)
				throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

			return sectorsData[cylinder][head][sector - 1];
		}

		public override 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");

			MemoryStream buffer = new MemoryStream();
			for(uint i = 0; i < length; i++)
			{
				byte[] sector = ReadSector(sectorAddress + i);
				buffer.Write(sector, 0, sector.Length);
			}

			return buffer.ToArray();
		}

		(ushort cylinder, byte head, byte sector) LbaToChs(ulong lba)
		{
			ushort cylinder = (ushort)(lba / (ImageInfo.heads * ImageInfo.sectorsPerTrack));
			byte head = (byte)((lba / ImageInfo.sectorsPerTrack) % ImageInfo.heads);
			byte sector = (byte)((lba % ImageInfo.sectorsPerTrack) + 1);

			return (cylinder, head, sector);
		}

		#region Unsupported features

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

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

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

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

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

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

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

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

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

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

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

		public override string GetMediaManufacturer()
		{
			return null;
		}

		public override string GetMediaModel()
		{
			return null;
		}

		public override string GetMediaSerialNumber()
		{
			return null;
		}

		public override string GetMediaBarcode()
		{
			return null;
		}

		public override string GetMediaPartNumber()
		{
			return null;
		}

		public override int GetMediaSequence()
		{
			return 0;
		}

		public override int GetLastDiskSequence()
		{
			return 0;
		}

		public override string GetDriveManufacturer()
		{
			return null;
		}

		public override string GetDriveModel()
		{
			return null;
		}

		public override string GetDriveSerialNumber()
		{
			return null;
		}

		public override List<Partition> GetPartitions()
		{
			throw new FeatureUnsupportedImageException("Feature not supported by image format");
		}

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

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

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

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

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

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

		public override 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 override 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 override bool? VerifyMediaImage()
		{
			return null;
		}

		#endregion
	}
}