// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : BSD.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Partitioning scheme plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Manages BSD disklabels.
//
// --[ 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.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Runtime.InteropServices;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Console;
using Aaru.Helpers;
using Marshal = Aaru.Helpers.Marshal;

namespace Aaru.Partitions
{
    /// <inheritdoc />
    /// <summary>Implements decoding of BSD disklabels</summary>
    [SuppressMessage("ReSharper", "UnusedMember.Local")]
    public sealed class BSD : IPartition
    {
        const uint DISK_MAGIC = 0x82564557;
        const uint DISK_CIGAM = 0x57455682;
        /// <summary>Maximum size of a disklabel with 22 partitions</summary>
        const uint MAX_LABEL_SIZE = 500;
        /// <summary>Known sector locations for BSD disklabel</summary>
        readonly ulong[] _labelLocations =
        {
            0, 1, 2, 9
        };
        /// <summary>Known byte offsets for BSD disklabel</summary>
        readonly uint[] _labelOffsets =
        {
            0, 9, 64, 128, 516
        };

        /// <inheritdoc />
        public string Name => "BSD disklabel";
        /// <inheritdoc />
        public Guid Id => new("246A6D93-4F1A-1F8A-344D-50187A5513A9");
        /// <inheritdoc />
        public string Author => "Natalia Portillo";

        /// <inheritdoc />
        public bool GetInformation(IMediaImage imagePlugin, out List<Partition> partitions, ulong sectorOffset)
        {
            partitions = new List<Partition>();
            uint run = (MAX_LABEL_SIZE + _labelOffsets.Last()) / imagePlugin.Info.SectorSize;

            if((MAX_LABEL_SIZE + _labelOffsets.Last()) % imagePlugin.Info.SectorSize > 0)
                run++;

            var  dl    = new DiskLabel();
            bool found = false;

            foreach(ulong location in _labelLocations)
            {
                if(location + run + sectorOffset >= imagePlugin.Info.Sectors)
                    return false;

                ErrorNumber errno = imagePlugin.ReadSectors(location + sectorOffset, run, out byte[] tmp);

                if(errno != ErrorNumber.NoError)
                    continue;

                foreach(uint offset in _labelOffsets)
                {
                    byte[] sector = new byte[MAX_LABEL_SIZE];

                    if(offset + MAX_LABEL_SIZE > tmp.Length)
                        break;

                    Array.Copy(tmp, offset, sector, 0, MAX_LABEL_SIZE);
                    dl = Marshal.ByteArrayToStructureLittleEndian<DiskLabel>(sector);

                    AaruConsole.DebugWriteLine("BSD plugin",
                                               "dl.magic on sector {0} at offset {1} = 0x{2:X8} (expected 0x{3:X8})",
                                               location + sectorOffset, offset, dl.d_magic, DISK_MAGIC);

                    if((dl.d_magic != DISK_MAGIC || dl.d_magic2 != DISK_MAGIC) &&
                       (dl.d_magic != DISK_CIGAM || dl.d_magic2 != DISK_CIGAM))
                        continue;

                    found = true;

                    break;
                }

                if(found)
                    break;
            }

            if(!found)
                return false;

            if(dl.d_magic  == DISK_CIGAM &&
               dl.d_magic2 == DISK_CIGAM)
                dl = SwapDiskLabel(dl);

            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_type = {0}", dl.d_type);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_subtype = {0}", dl.d_subtype);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_typename = {0}", StringHandlers.CToString(dl.d_typename));
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_packname = {0}", StringHandlers.CToString(dl.d_packname));
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_secsize = {0}", dl.d_secsize);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_nsectors = {0}", dl.d_nsectors);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_ntracks = {0}", dl.d_ntracks);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_ncylinders = {0}", dl.d_ncylinders);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_secpercyl = {0}", dl.d_secpercyl);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_secperunit = {0}", dl.d_secperunit);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_sparespertrack = {0}", dl.d_sparespertrack);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_sparespercyl = {0}", dl.d_sparespercyl);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_acylinders = {0}", dl.d_acylinders);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_rpm = {0}", dl.d_rpm);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_interleave = {0}", dl.d_interleave);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_trackskew = {0}", dl.d_trackskew);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_cylskeew = {0}", dl.d_cylskeew);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_headswitch = {0}", dl.d_headswitch);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_trkseek = {0}", dl.d_trkseek);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_flags = {0}", dl.d_flags);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[0] = {0}", dl.d_drivedata[0]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[1] = {0}", dl.d_drivedata[1]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[2] = {0}", dl.d_drivedata[2]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[3] = {0}", dl.d_drivedata[3]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[4] = {0}", dl.d_drivedata[4]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_spare[0] = {0}", dl.d_spare[0]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_spare[1] = {0}", dl.d_spare[1]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_spare[2] = {0}", dl.d_spare[2]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_spare[3] = {0}", dl.d_spare[3]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_spare[4] = {0}", dl.d_spare[4]);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_magic2 = 0x{0:X8}", dl.d_magic2);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_checksum = 0x{0:X8}", dl.d_checksum);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_npartitions = {0}", dl.d_npartitions);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_bbsize = {0}", dl.d_bbsize);
            AaruConsole.DebugWriteLine("BSD plugin", "dl.d_sbsize = {0}", dl.d_sbsize);

            ulong counter         = 0;
            bool  addSectorOffset = false;

            for(int i = 0; i < dl.d_npartitions && i < 22; i++)
            {
                AaruConsole.DebugWriteLine("BSD plugin", "dl.d_partitions[i].p_offset = {0}",
                                           dl.d_partitions[i].p_offset);

                AaruConsole.DebugWriteLine("BSD plugin", "dl.d_partitions[i].p_size = {0}", dl.d_partitions[i].p_size);

                AaruConsole.DebugWriteLine("BSD plugin", "dl.d_partitions[i].p_fstype = {0} ({1})",
                                           dl.d_partitions[i].p_fstype, FSTypeToString(dl.d_partitions[i].p_fstype));

                var part = new Partition
                {
                    Start    = dl.d_partitions[i].p_offset * dl.d_secsize / imagePlugin.Info.SectorSize,
                    Offset   = dl.d_partitions[i].p_offset                * dl.d_secsize,
                    Length   = dl.d_partitions[i].p_size * dl.d_secsize   / imagePlugin.Info.SectorSize,
                    Size     = dl.d_partitions[i].p_size                  * dl.d_secsize,
                    Type     = FSTypeToString(dl.d_partitions[i].p_fstype),
                    Sequence = counter,
                    Scheme   = Name
                };

                if(dl.d_partitions[i].p_fstype == fsType.Unused)
                    continue;

                // Crude and dirty way to know if the disklabel is relative to its parent partition...
                if(dl.d_partitions[i].p_offset < sectorOffset &&
                   !addSectorOffset)
                    addSectorOffset = true;

                if(addSectorOffset)
                {
                    part.Start  += sectorOffset;
                    part.Offset += sectorOffset * imagePlugin.Info.SectorSize;
                }

                AaruConsole.DebugWriteLine("BSD plugin", "part.start = {0}", part.Start);
                AaruConsole.DebugWriteLine("BSD plugin", "Adding it...");
                partitions.Add(part);
                counter++;
            }

            return partitions.Count > 0;
        }

        internal static string FSTypeToString(fsType typ)
        {
            switch(typ)
            {
                case fsType.Unused:  return "Unused entry";
                case fsType.Swap:    return "Swap partition";
                case fsType.V6:      return "UNIX 6th Edition";
                case fsType.V7:      return "UNIX 7th Edition";
                case fsType.SystemV: return "UNIX System V";
                case fsType.V7_1K:   return "UNIX 7th Edition with 1K blocks";
                case fsType.V8:      return "UNIX 8th Edition with 4K blocks";
                case fsType.BSDFFS:  return "4.2BSD Fast File System";
                case fsType.BSDLFS:  return "4.4LFS";
                case fsType.HPFS:    return "HPFS";
                case fsType.ISO9660: return "ISO9660";
                case fsType.Boot:
                case fsType.SysVBoot: return "Boot";
                case fsType.AFFS:       return "Amiga FFS";
                case fsType.HFS:        return "Apple HFS";
                case fsType.ADVfs:      return "Digital Advanced File System";
                case fsType.LSMpublic:  return "Digital LSM Public Region";
                case fsType.LSMprivate: return "Digital LSM Private Region";
                case fsType.LSMsimple:  return "Digital LSM Simple Disk";
                case fsType.CCD:        return "Concatenated disk";
                case fsType.JFS2:       return "IBM JFS2";
                case fsType.HAMMER:     return "Hammer";
                case fsType.HAMMER2:    return "Hammer2";
                case fsType.UDF:        return "UDF";
                case fsType.EFS:        return "EFS";
                case fsType.ZFS:        return "ZFS";
                case fsType.NANDFS:     return "FreeBSD nandfs";
                case fsType.MSDOS:      return "FAT";
                case fsType.Other:      return "Other or unknown";
                default:                return "Unknown";
            }
        }

        static DiskLabel SwapDiskLabel(DiskLabel dl)
        {
            dl = (DiskLabel)Marshal.SwapStructureMembersEndian(dl);

            for(int i = 0; i < dl.d_drivedata.Length; i++)
                dl.d_drivedata[i] = Swapping.Swap(dl.d_drivedata[i]);

            for(int i = 0; i < dl.d_spare.Length; i++)
                dl.d_spare[i] = Swapping.Swap(dl.d_spare[i]);

            for(int i = 0; i < dl.d_partitions.Length; i++)
                dl.d_partitions[i] = (BSDPartition)Marshal.SwapStructureMembersEndian(dl.d_partitions[i]);

            return dl;
        }

        /// <summary>Drive type</summary>
        [SuppressMessage("ReSharper", "InconsistentNaming")]
        enum dType : ushort
        {
            /// <summary>SMD, XSMD</summary>
            SMD = 1,
            /// <summary>MSCP</summary>
            MSCP = 2,
            /// <summary>Other DEC (rk, rl)</summary>
            DEC = 3,
            /// <summary>SCSI</summary>
            SCSI = 4,
            /// <summary>ESDI</summary>
            ESDI = 5,
            /// <summary>ST506 et al</summary>
            ST506 = 6,
            /// <summary>CS/80 on HP-IB</summary>
            HPIB = 7,
            /// <summary>HP Fiber-link</summary>
            HPFL = 8,
            /// <summary>Floppy</summary>
            FLOPPY = 10,
            /// <summary>Concatenated disk</summary>
            CCD = 11,
            /// <summary>uvnode pseudo-disk</summary>
            VND = 12,
            /// <summary>DiskOnChip</summary>
            DOC2K = 13,
            /// <summary>ATAPI</summary>
            ATAPI = 13,
            /// <summary>CMU RAIDframe</summary>
            RAID = 14,
            /// <summary>Logical disk</summary>
            LD = 15,
            /// <summary>IBM JFS 2</summary>
            JFS2 = 16,
            /// <summary>Cryptographic pseudo-disk</summary>
            CGD = 17,
            /// <summary>Vinum volume</summary>
            VINUM = 18,
            /// <summary>Flash memory devices</summary>
            FLASH = 19,
            /// <summary>Device-mapper pseudo-disk devices</summary>
            DM = 20,
            /// <summary>Rump virtual disk</summary>
            RUMPD = 21,
            /// <summary>Memory disk</summary>
            MD = 22
        }

        /// <summary>Filesystem type</summary>
        [SuppressMessage("ReSharper", "InconsistentNaming")]
        internal enum fsType : byte
        {
            /// <summary>Unused entry</summary>
            Unused = 0,
            /// <summary>Swap partition</summary>
            Swap = 1,
            /// <summary>UNIX 6th Edition</summary>
            V6 = 2,
            /// <summary>UNIX 7th Edition</summary>
            V7 = 3,
            /// <summary>UNIX System V</summary>
            SystemV = 4,
            /// <summary>UNIX 7th Edition with 1K blocks</summary>
            V7_1K = 5,
            /// <summary>UNIX 8th Edition with 4K blocks</summary>
            V8 = 6,
            /// <summary>4.2BSD Fast File System</summary>
            BSDFFS = 7,
            /// <summary>MS-DOS filesystem</summary>
            MSDOS = 8,
            /// <summary>4.4LFS</summary>
            BSDLFS = 9,
            /// <summary>In use, unknown or unsupported</summary>
            Other = 10,
            /// <summary>HPFS</summary>
            HPFS = 11,
            /// <summary>ISO9660</summary>
            ISO9660 = 12,
            /// <summary>Boot partition</summary>
            Boot = 13,
            /// <summary>Amiga FFS</summary>
            AFFS = 14,
            /// <summary>Apple HFS</summary>
            HFS = 15,
            /// <summary>Acorn ADFS</summary>
            FileCore = 16,
            /// <summary>Digital Advanced File System</summary>
            ADVfs = 16,
            /// <summary>Digital LSM Public Region</summary>
            LSMpublic = 17,
            /// <summary>Linux ext2</summary>
            ext2 = 17,
            /// <summary>Digital LSM Private Region</summary>
            LSMprivate = 18,
            /// <summary>NTFS</summary>
            NTFS = 18,
            /// <summary>Digital LSM Simple Disk</summary>
            LSMsimple = 19,
            /// <summary>RAIDframe component</summary>
            RAID = 19,
            /// <summary>Concatenated disk component</summary>
            CCD = 20,
            /// <summary>IBM JFS2</summary>
            JFS2 = 21,
            /// <summary>Apple UFS</summary>
            AppleUFS = 22,
            /// <summary>Hammer filesystem</summary>
            HAMMER = 22,
            /// <summary>Hammer2 filesystem</summary>
            HAMMER2 = 23,
            /// <summary>UDF</summary>
            UDF = 24,
            /// <summary>System V Boot filesystem</summary>
            SysVBoot = 25,
            /// <summary>EFS</summary>
            EFS = 26,
            /// <summary>ZFS</summary>
            ZFS = 27,
            /// <summary>NiLFS</summary>
            NILFS = 27,
            /// <summary>Cryptographic disk</summary>
            CGD = 28,
            /// <summary>MINIX v3</summary>
            MINIX = 29,
            /// <summary>FreeBSD nandfs</summary>
            NANDFS = 30
        }

        /// <summary>Drive flags</summary>
        [SuppressMessage("ReSharper", "InconsistentNaming"), Flags]
        enum dFlags : uint
        {
            /// <summary>Removable media</summary>
            Removable = 0x01,
            /// <summary>Drive supports ECC</summary>
            ECC = 0x02,
            /// <summary>Drive supports bad sector forwarding</summary>
            BadSectorForward = 0x04,
            /// <summary>Disk emulator</summary>
            RAMDisk = 0x08,
            /// <summary>Can do back to back transfer</summary>
            Chain = 0x10,
            /// <summary>Dynamic geometry device</summary>
            DynamicGeometry = 0x20
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct DiskLabel
        {
            /// <summary>
            ///     <see cref="BSD.DISK_MAGIC" />
            /// </summary>
            public readonly uint d_magic;
            /// <summary>
            ///     <see cref="dType" />
            /// </summary>
            public readonly dType d_type;
            /// <summary>Disk subtype</summary>
            public readonly ushort d_subtype;
            /// <summary>Type name</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
            public readonly byte[] d_typename;
            /// <summary>Pack identifier</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
            public readonly byte[] d_packname;
            /// <summary>Bytes per sector</summary>
            public readonly uint d_secsize;
            /// <summary>Sectors per track</summary>
            public readonly uint d_nsectors;
            /// <summary>Tracks per cylinder</summary>
            public readonly uint d_ntracks;
            /// <summary>Cylinders per unit</summary>
            public readonly uint d_ncylinders;
            /// <summary>Sectors per cylinder</summary>
            public readonly uint d_secpercyl;
            /// <summary>Sectors per unit</summary>
            public readonly uint d_secperunit;
            /// <summary>Spare sectors per track</summary>
            public readonly ushort d_sparespertrack;
            /// <summary>Spare sectors per cylinder</summary>
            public readonly ushort d_sparespercyl;
            /// <summary>Alternate cylinders</summary>
            public readonly uint d_acylinders;
            /// <summary>Rotational speed</summary>
            public readonly ushort d_rpm;
            /// <summary>Hardware sector interleave</summary>
            public readonly ushort d_interleave;
            /// <summary>Sector 0 skew per track</summary>
            public readonly ushort d_trackskew;
            /// <summary>Sector 0 sker per cylinder</summary>
            public readonly ushort d_cylskeew;
            /// <summary>Head switch time in microseconds</summary>
            public readonly uint d_headswitch;
            /// <summary>Track to track seek in microseconds</summary>
            public readonly uint d_trkseek;
            /// <summary>
            ///     <see cref="dFlags" />
            /// </summary>
            public readonly dFlags d_flags;
            /// <summary>Drive-specific information</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 5)]
            public readonly uint[] d_drivedata;
            /// <summary>Reserved</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 5)]
            public readonly uint[] d_spare;
            /// <summary><see cref="BSD.DISK_MAGIC" /> again</summary>
            public readonly uint d_magic2;
            /// <summary>XOR of data</summary>
            public readonly ushort d_checksum;
            /// <summary>How many partitions</summary>
            public readonly ushort d_npartitions;
            /// <summary>Size of boot area in bytes</summary>
            public readonly uint d_bbsize;
            /// <summary>Maximum size of superblock in bytes</summary>
            public readonly uint d_sbsize;
            /// <summary>Partitions</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 22)]
            public readonly BSDPartition[] d_partitions;
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct BSDPartition
        {
            /// <summary>Sectors in partition</summary>
            public readonly uint p_size;
            /// <summary>Starting sector</summary>
            public readonly uint p_offset;
            /// <summary>Fragment size</summary>
            public readonly uint p_fsize;
            /// <summary>Filesystem type, <see cref="fsType" /></summary>
            public readonly fsType p_fstype;
            /// <summary>Fragment size</summary>
            public readonly byte p_frag;
            /// <summary>Cylinder per group</summary>
            public readonly ushort p_cpg;
        }
    }
}