// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Info.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : ISO9660 filesystem plugin.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies the ISO9660 filesystem and shows information.
//
// --[ 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 © 2011-2022 Natalia Portillo
// In the loving memory of Facunda "Tata" Suárez Domínguez, R.I.P. 2019/07/24
// ****************************************************************************/

namespace Aaru.Filesystems;

using System;
using System.Collections.Generic;
using System.Text;
using Aaru.Checksums;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Console;
using Aaru.Decoders.Sega;
using Aaru.Helpers;
using Schemas;

public sealed partial class ISO9660
{
    /// <inheritdoc />
    public bool Identify(IMediaImage imagePlugin, Partition partition)
    {
        // ISO9660 is designed for 2048 bytes/sector devices
        if(imagePlugin.Info.SectorSize < 2048)
            return false;

        // ISO9660 Primary Volume Descriptor starts at sector 16, so that's minimal size.
        if(partition.End <= 16 + partition.Start)
            return false;

        // Read to Volume Descriptor
        ErrorNumber errno = imagePlugin.ReadSector(16 + partition.Start, out byte[] vdSector);

        if(errno != ErrorNumber.NoError)
            return false;

        var xaOff = 0;

        if(vdSector.Length == 2336)
            xaOff = 8;

        byte vdType  = vdSector[0 + xaOff];
        var  vdMagic = new byte[5];
        var  hsMagic = new byte[5];

        // This indicates the end of a volume descriptor. HighSierra here would have 16 so no problem
        if(vdType == 255)
            return false;

        Array.Copy(vdSector, 0x001 + xaOff, vdMagic, 0, 5);
        Array.Copy(vdSector, 0x009 + xaOff, hsMagic, 0, 5);

        AaruConsole.DebugWriteLine("ISO9660 plugin", "VDMagic = {0}", Encoding.ASCII.GetString(vdMagic));
        AaruConsole.DebugWriteLine("ISO9660 plugin", "HSMagic = {0}", Encoding.ASCII.GetString(hsMagic));

        return Encoding.ASCII.GetString(vdMagic) == ISO_MAGIC         ||
               Encoding.ASCII.GetString(hsMagic) == HIGH_SIERRA_MAGIC || Encoding.ASCII.GetString(vdMagic) == CDI_MAGIC;
    }

    /// <inheritdoc />
    public void GetInformation(IMediaImage imagePlugin, Partition partition, out string information, Encoding encoding)
    {
        Encoding    = encoding ?? Encoding.ASCII;
        information = "";
        var isoMetadata = new StringBuilder();
        var vdMagic     = new byte[5]; // Volume Descriptor magic "CD001"
        var hsMagic     = new byte[5]; // Volume Descriptor magic "CDROM"

        var bootSpec = "";

        PrimaryVolumeDescriptor?           pvd      = null;
        PrimaryVolumeDescriptor?           jolietvd = null;
        BootRecord?                        bvd      = null;
        HighSierraPrimaryVolumeDescriptor? hsvd     = null;
        FileStructureVolumeDescriptor?     fsvd     = null;
        ElToritoBootRecord?                torito   = null;

        // ISO9660 is designed for 2048 bytes/sector devices
        if(imagePlugin.Info.SectorSize < 2048)
            return;

        // ISO9660 Primary Volume Descriptor starts at sector 16, so that's minimal size.
        if(partition.End < 16)
            return;

        ulong counter = 0;

        ErrorNumber errno = imagePlugin.ReadSector(16 + counter + partition.Start, out byte[] vdSector);

        if(errno != ErrorNumber.NoError)
            return;

        int xaOff = vdSector.Length == 2336 ? 8 : 0;
        Array.Copy(vdSector, 0x009 + xaOff, hsMagic, 0, 5);
        bool highSierraInfo = Encoding.GetString(hsMagic) == HIGH_SIERRA_MAGIC;
        var  hsOff          = 0;

        if(highSierraInfo)
            hsOff = 8;

        var cdiInfo = false;
        var evd     = false;
        var vpd     = false;

        while(true)
        {
            AaruConsole.DebugWriteLine("ISO9660 plugin", "Processing VD loop no. {0}", counter);

            // Seek to Volume Descriptor
            AaruConsole.DebugWriteLine("ISO9660 plugin", "Reading sector {0}", 16 + counter + partition.Start);
            errno = imagePlugin.ReadSector(16 + counter + partition.Start, out byte[] vdSectorTmp);

            if(errno != ErrorNumber.NoError)
                return;

            vdSector = new byte[vdSectorTmp.Length - xaOff];
            Array.Copy(vdSectorTmp, xaOff, vdSector, 0, vdSector.Length);

            byte vdType = vdSector[0 + hsOff]; // Volume Descriptor Type, should be 1 or 2.
            AaruConsole.DebugWriteLine("ISO9660 plugin", "VDType = {0}", vdType);

            if(vdType == 255) // Supposedly we are in the PVD.
            {
                if(counter == 0)
                    return;

                break;
            }

            Array.Copy(vdSector, 0x001, vdMagic, 0, 5);
            Array.Copy(vdSector, 0x009, hsMagic, 0, 5);

            if(Encoding.GetString(vdMagic) != ISO_MAGIC         &&
               Encoding.GetString(hsMagic) != HIGH_SIERRA_MAGIC &&
               Encoding.GetString(vdMagic) != CDI_MAGIC) // Recognized, it is an ISO9660, now check for rest of data.
            {
                if(counter == 0)
                    return;

                break;
            }

            cdiInfo |= Encoding.GetString(vdMagic) == CDI_MAGIC;

            switch(vdType)
            {
                case 0:
                {
                    bvd = Marshal.ByteArrayToStructureLittleEndian<BootRecord>(vdSector, hsOff, 2048 - hsOff);

                    bootSpec = "Unknown";

                    if(Encoding.GetString(bvd.Value.system_id).Substring(0, 23) == "EL TORITO SPECIFICATION")
                    {
                        bootSpec = "El Torito";

                        torito =
                            Marshal.ByteArrayToStructureLittleEndian<ElToritoBootRecord>(vdSector, hsOff, 2048 - hsOff);
                    }

                    break;
                }

                case 1:
                {
                    if(highSierraInfo)
                        hsvd = Marshal.ByteArrayToStructureLittleEndian<HighSierraPrimaryVolumeDescriptor>(vdSector);
                    else if(cdiInfo)
                        fsvd = Marshal.ByteArrayToStructureBigEndian<FileStructureVolumeDescriptor>(vdSector);
                    else
                        pvd = Marshal.ByteArrayToStructureLittleEndian<PrimaryVolumeDescriptor>(vdSector);

                    break;
                }

                case 2:
                {
                    PrimaryVolumeDescriptor svd =
                        Marshal.ByteArrayToStructureLittleEndian<PrimaryVolumeDescriptor>(vdSector);

                    // Check if this is Joliet
                    if(svd.version == 1)
                    {
                        if(svd.escape_sequences[0] == '%' &&
                           svd.escape_sequences[1] == '/')
                            if(svd.escape_sequences[2] == '@' ||
                               svd.escape_sequences[2] == 'C' ||
                               svd.escape_sequences[2] == 'E')
                                jolietvd = svd;
                            else
                                AaruConsole.WriteLine("ISO9660 plugin",
                                                      "Found unknown supplementary volume descriptor");
                    }
                    else
                        evd = true;

                    break;
                }

                case 3:
                {
                    vpd = true;

                    break;
                }
            }

            counter++;
        }

        DecodedVolumeDescriptor decodedVd;
        var                     decodedJolietVd = new DecodedVolumeDescriptor();

        XmlFsType = new FileSystemType();

        if(pvd  == null &&
           hsvd == null &&
           fsvd == null)
        {
            information = "ERROR: Could not find primary volume descriptor";

            return;
        }

        if(highSierraInfo)
            decodedVd = DecodeVolumeDescriptor(hsvd.Value);
        else if(cdiInfo)
            decodedVd = DecodeVolumeDescriptor(fsvd.Value);
        else
            decodedVd = DecodeVolumeDescriptor(pvd.Value);

        if(jolietvd != null)
            decodedJolietVd = DecodeJolietDescriptor(jolietvd.Value);

        uint rootLocation = 0;
        uint rootSize     = 0;

        // No need to read root on CD-i, as extensions are not supported...
        if(!cdiInfo)
        {
            rootLocation = highSierraInfo ? hsvd.Value.root_directory_record.extent
                               : pvd.Value.root_directory_record.extent;

            if(highSierraInfo)
            {
                rootSize = hsvd.Value.root_directory_record.size / hsvd.Value.logical_block_size;

                if(hsvd.Value.root_directory_record.size % hsvd.Value.logical_block_size > 0)
                    rootSize++;
            }
            else
            {
                rootSize = pvd.Value.root_directory_record.size / pvd.Value.logical_block_size;

                if(pvd.Value.root_directory_record.size % pvd.Value.logical_block_size > 0)
                    rootSize++;
            }
        }

        byte[]                 rootDir         = Array.Empty<byte>();
        var                    rootOff         = 0;
        var                    xaExtensions    = false;
        var                    apple           = false;
        var                    susp            = false;
        var                    rrip            = false;
        var                    ziso            = false;
        var                    amiga           = false;
        var                    aaip            = false;
        List<ContinuationArea> contareas       = new();
        List<byte[]>           refareas        = new();
        var                    suspInformation = new StringBuilder();

        if(rootLocation + rootSize < imagePlugin.Info.Sectors)
        {
            errno = imagePlugin.ReadSectors(rootLocation, rootSize, out rootDir);

            if(errno != ErrorNumber.NoError)
                return;
        }

        // Walk thru root directory to see system area extensions in use
        while(rootOff + Marshal.SizeOf<DirectoryRecord>() < rootDir.Length &&
              !cdiInfo)
        {
            DirectoryRecord record =
                Marshal.ByteArrayToStructureLittleEndian<DirectoryRecord>(rootDir, rootOff,
                                                                          Marshal.SizeOf<DirectoryRecord>());

            int saOff = Marshal.SizeOf<DirectoryRecord>() + record.name_len;
            saOff += saOff % 2;
            int saLen = record.length - saOff;

            if(saLen                   > 0 &&
               rootOff + saOff + saLen <= rootDir.Length)
            {
                var sa = new byte[saLen];
                Array.Copy(rootDir, rootOff + saOff, sa, 0, saLen);
                saOff = 0;

                while(saOff < saLen)
                {
                    var noneFound = true;

                    if(Marshal.SizeOf<CdromXa>() + saOff <= saLen)
                    {
                        CdromXa xa = Marshal.ByteArrayToStructureBigEndian<CdromXa>(sa);

                        if(xa.signature == XA_MAGIC)
                        {
                            xaExtensions =  true;
                            saOff        += Marshal.SizeOf<CdromXa>();
                            noneFound    =  false;
                        }
                    }

                    if(saOff + 2 >= saLen)
                        break;

                    var nextSignature = BigEndianBitConverter.ToUInt16(sa, saOff);

                    switch(nextSignature)
                    {
                        // Easy, contains size field
                        case APPLE_MAGIC:
                            apple     =  true;
                            saOff     += sa[saOff + 2];
                            noneFound =  false;

                            break;

                        // Not easy, contains size field
                        case APPLE_MAGIC_OLD:
                            apple = true;
                            var appleId = (AppleOldId)sa[saOff + 2];
                            noneFound = false;

                            switch(appleId)
                            {
                                case AppleOldId.ProDOS:
                                    saOff += Marshal.SizeOf<AppleProDOSOldSystemUse>();

                                    break;
                                case AppleOldId.TypeCreator:
                                case AppleOldId.TypeCreatorBundle:
                                    saOff += Marshal.SizeOf<AppleHFSTypeCreatorSystemUse>();

                                    break;
                                case AppleOldId.TypeCreatorIcon:
                                case AppleOldId.TypeCreatorIconBundle:
                                    saOff += Marshal.SizeOf<AppleHFSIconSystemUse>();

                                    break;
                                case AppleOldId.HFS:
                                    saOff += Marshal.SizeOf<AppleHFSOldSystemUse>();

                                    break;
                            }

                            break;

                        // IEEE-P1281 aka SUSP 1.12
                        case SUSP_INDICATOR:
                            susp      =  true;
                            saOff     += sa[saOff + 2];
                            noneFound =  false;

                            while(saOff + 2 < saLen)
                            {
                                nextSignature = BigEndianBitConverter.ToUInt16(sa, saOff);

                                switch(nextSignature)
                                {
                                    case APPLE_MAGIC:
                                        if(sa[saOff + 3] == 1 &&
                                           sa[saOff + 2] == 7)
                                            apple = true;
                                        else
                                            apple |= sa[saOff + 3] != 1;

                                        break;
                                    case SUSP_CONTINUATION when saOff + sa[saOff + 2] <= saLen:
                                        var ce = new byte[sa[saOff + 2]];
                                        Array.Copy(sa, saOff, ce, 0, ce.Length);

                                        ContinuationArea ca =
                                            Marshal.ByteArrayToStructureBigEndian<ContinuationArea>(ce);

                                        contareas.Add(ca);

                                        break;
                                    case SUSP_REFERENCE when saOff + sa[saOff + 2] <= saLen:
                                        var er = new byte[sa[saOff + 2]];
                                        Array.Copy(sa, saOff, er, 0, er.Length);
                                        refareas.Add(er);

                                        break;
                                }

                                rrip |= nextSignature == RRIP_MAGIC        || nextSignature == RRIP_POSIX_ATTRIBUTES ||
                                        nextSignature == RRIP_POSIX_DEV_NO || nextSignature == RRIP_SYMLINK          ||
                                        nextSignature == RRIP_NAME         || nextSignature == RRIP_CHILDLINK        ||
                                        nextSignature == RRIP_PARENTLINK   || nextSignature == RRIP_RELOCATED_DIR    ||
                                        nextSignature == RRIP_TIMESTAMPS   || nextSignature == RRIP_SPARSE;

                                ziso  |= nextSignature == ZISO_MAGIC;
                                amiga |= nextSignature == AMIGA_MAGIC;

                                aaip |= nextSignature == AAIP_MAGIC || nextSignature == AAIP_MAGIC_OLD &&
                                        sa[saOff + 3]                                == 1 && sa[saOff + 2] >= 9;

                                saOff += sa[saOff + 2];

                                if(nextSignature == SUSP_TERMINATOR)
                                    break;
                            }

                            break;
                    }

                    if(noneFound)
                        break;
                }
            }

            rootOff += record.length;

            if(record.length == 0)
                break;
        }

        foreach(ContinuationArea ca in contareas)
        {
            uint caLen = (ca.ca_length_be + ca.offset_be) /
                         (highSierraInfo ? hsvd.Value.logical_block_size : pvd.Value.logical_block_size);

            if((ca.ca_length_be + ca.offset_be) %
               (highSierraInfo ? hsvd.Value.logical_block_size : pvd.Value.logical_block_size) > 0)
                caLen++;

            errno = imagePlugin.ReadSectors(ca.block_be, caLen, out byte[] caSectors);

            if(errno != ErrorNumber.NoError)
                return;

            var caData = new byte[ca.ca_length_be];
            Array.Copy(caSectors, ca.offset_be, caData, 0, ca.ca_length_be);
            var caOff = 0;

            while(caOff < ca.ca_length_be)
            {
                var nextSignature = BigEndianBitConverter.ToUInt16(caData, caOff);

                switch(nextSignature)
                {
                    // Apple never said to include its extensions inside a continuation area, but just in case
                    case APPLE_MAGIC:
                        if(caData[caOff + 3] == 1 &&
                           caData[caOff + 2] == 7)
                            apple = true;
                        else
                            apple |= caData[caOff + 3] != 1;

                        break;
                    case SUSP_REFERENCE when caOff + caData[caOff + 2] <= ca.ca_length_be:
                        var er = new byte[caData[caOff + 2]];
                        Array.Copy(caData, caOff, er, 0, er.Length);
                        refareas.Add(er);

                        break;
                }

                rrip |= nextSignature == RRIP_MAGIC        || nextSignature == RRIP_POSIX_ATTRIBUTES ||
                        nextSignature == RRIP_POSIX_DEV_NO || nextSignature == RRIP_SYMLINK          ||
                        nextSignature == RRIP_NAME         || nextSignature == RRIP_CHILDLINK        ||
                        nextSignature == RRIP_PARENTLINK   || nextSignature == RRIP_RELOCATED_DIR    ||
                        nextSignature == RRIP_TIMESTAMPS   || nextSignature == RRIP_SPARSE;

                ziso  |= nextSignature == ZISO_MAGIC;
                amiga |= nextSignature == AMIGA_MAGIC;

                aaip |= nextSignature == AAIP_MAGIC || nextSignature == AAIP_MAGIC_OLD && caData[caOff + 3] == 1 &&
                        caData[caOff                                                                   + 2] >= 9;

                caOff += caData[caOff + 2];
            }
        }

        if(refareas.Count > 0)
        {
            suspInformation.AppendLine("----------------------------------------");
            suspInformation.AppendLine("SYSTEM USE SHARING PROTOCOL INFORMATION:");
            suspInformation.AppendLine("----------------------------------------");

            counter = 1;

            foreach(byte[] erb in refareas)
            {
                ReferenceArea er    = Marshal.ByteArrayToStructureBigEndian<ReferenceArea>(erb);
                string        extId = Encoding.GetString(erb, Marshal.SizeOf<ReferenceArea>(), er.id_len);

                string extDes = Encoding.GetString(erb, Marshal.SizeOf<ReferenceArea>() + er.id_len, er.des_len);

                string extSrc = Encoding.GetString(erb, Marshal.SizeOf<ReferenceArea>() + er.id_len + er.des_len,
                                                   er.src_len);

                suspInformation.AppendFormat("Extension: {0}", counter).AppendLine();
                suspInformation.AppendFormat("\tID: {0}, version {1}", extId, er.ext_ver).AppendLine();
                suspInformation.AppendFormat("\tDescription: {0}", extDes).AppendLine();
                suspInformation.AppendFormat("\tSource: {0}", extSrc).AppendLine();
                counter++;
            }
        }

        errno = imagePlugin.ReadSector(0 + partition.Start, out byte[] ipbinSector);

        if(errno != ErrorNumber.NoError)
            return;

        CD.IPBin?        segaCd    = CD.DecodeIPBin(ipbinSector);
        Saturn.IPBin?    saturn    = Saturn.DecodeIPBin(ipbinSector);
        Dreamcast.IPBin? dreamcast = Dreamcast.DecodeIPBin(ipbinSector);

        string fsFormat;

        if(highSierraInfo)
            fsFormat = "High Sierra Format";
        else if(cdiInfo)
            fsFormat = "CD-i";
        else
            fsFormat = "ISO9660";

        isoMetadata.AppendFormat("{0} file system", fsFormat).AppendLine();

        if(xaExtensions)
            isoMetadata.AppendLine("CD-ROM XA extensions present.");

        if(amiga)
            isoMetadata.AppendLine("Amiga extensions present.");

        if(apple)
            isoMetadata.AppendLine("Apple extensions present.");

        if(jolietvd != null)
            isoMetadata.AppendLine("Joliet extensions present.");

        if(susp)
            isoMetadata.AppendLine("System Use Sharing Protocol present.");

        if(rrip)
            isoMetadata.AppendLine("Rock Ridge Interchange Protocol present.");

        if(aaip)
            isoMetadata.AppendLine("Arbitrary Attribute Interchange Protocol present.");

        if(ziso)
            isoMetadata.AppendLine("zisofs compression present.");

        if(evd)
            isoMetadata.AppendLine("Contains Enhanved Volume Descriptor.");

        if(vpd)
            isoMetadata.AppendLine("Contains Volume Partition Descriptor.");

        if(bvd != null)
            isoMetadata.AppendFormat("Disc bootable following {0} specifications.", bootSpec).AppendLine();

        if(segaCd != null)
        {
            isoMetadata.AppendLine("This is a SegaCD / MegaCD disc.");
            isoMetadata.AppendLine(CD.Prettify(segaCd));
        }

        if(saturn != null)
        {
            isoMetadata.AppendLine("This is a Sega Saturn disc.");
            isoMetadata.AppendLine(Saturn.Prettify(saturn));
        }

        if(dreamcast != null)
        {
            isoMetadata.AppendLine("This is a Sega Dreamcast disc.");
            isoMetadata.AppendLine(Dreamcast.Prettify(dreamcast));
        }

        isoMetadata.AppendFormat("{0}------------------------------", cdiInfo ? "---------------" : "").AppendLine();

        isoMetadata.AppendFormat("{0}VOLUME DESCRIPTOR INFORMATION:", cdiInfo ? "FILE STRUCTURE " : "").AppendLine();

        isoMetadata.AppendFormat("{0}------------------------------", cdiInfo ? "---------------" : "").AppendLine();

        isoMetadata.AppendFormat("System identifier: {0}", decodedVd.SystemIdentifier).AppendLine();
        isoMetadata.AppendFormat("Volume identifier: {0}", decodedVd.VolumeIdentifier).AppendLine();
        isoMetadata.AppendFormat("Volume set identifier: {0}", decodedVd.VolumeSetIdentifier).AppendLine();
        isoMetadata.AppendFormat("Publisher identifier: {0}", decodedVd.PublisherIdentifier).AppendLine();
        isoMetadata.AppendFormat("Data preparer identifier: {0}", decodedVd.DataPreparerIdentifier).AppendLine();
        isoMetadata.AppendFormat("Application identifier: {0}", decodedVd.ApplicationIdentifier).AppendLine();
        isoMetadata.AppendFormat("Volume creation date: {0}", decodedVd.CreationTime).AppendLine();

        if(decodedVd.HasModificationTime)
            isoMetadata.AppendFormat("Volume modification date: {0}", decodedVd.ModificationTime).AppendLine();
        else
            isoMetadata.AppendFormat("Volume has not been modified.").AppendLine();

        if(decodedVd.HasExpirationTime)
            isoMetadata.AppendFormat("Volume expiration date: {0}", decodedVd.ExpirationTime).AppendLine();
        else
            isoMetadata.AppendFormat("Volume does not expire.").AppendLine();

        if(decodedVd.HasEffectiveTime)
            isoMetadata.AppendFormat("Volume effective date: {0}", decodedVd.EffectiveTime).AppendLine();
        else
            isoMetadata.AppendFormat("Volume has always been effective.").AppendLine();

        isoMetadata.AppendFormat("Volume has {0} blocks of {1} bytes each", decodedVd.Blocks, decodedVd.BlockSize).
                    AppendLine();

        if(jolietvd != null)
        {
            isoMetadata.AppendLine("-------------------------------------");
            isoMetadata.AppendLine("JOLIET VOLUME DESCRIPTOR INFORMATION:");
            isoMetadata.AppendLine("-------------------------------------");
            isoMetadata.AppendFormat("System identifier: {0}", decodedJolietVd.SystemIdentifier).AppendLine();
            isoMetadata.AppendFormat("Volume identifier: {0}", decodedJolietVd.VolumeIdentifier).AppendLine();

            isoMetadata.AppendFormat("Volume set identifier: {0}", decodedJolietVd.VolumeSetIdentifier).AppendLine();

            isoMetadata.AppendFormat("Publisher identifier: {0}", decodedJolietVd.PublisherIdentifier).AppendLine();

            isoMetadata.AppendFormat("Data preparer identifier: {0}", decodedJolietVd.DataPreparerIdentifier).
                        AppendLine();

            isoMetadata.AppendFormat("Application identifier: {0}", decodedJolietVd.ApplicationIdentifier).AppendLine();

            isoMetadata.AppendFormat("Volume creation date: {0}", decodedJolietVd.CreationTime).AppendLine();

            if(decodedJolietVd.HasModificationTime)
                isoMetadata.AppendFormat("Volume modification date: {0}", decodedJolietVd.ModificationTime).
                            AppendLine();
            else
                isoMetadata.AppendFormat("Volume has not been modified.").AppendLine();

            if(decodedJolietVd.HasExpirationTime)
                isoMetadata.AppendFormat("Volume expiration date: {0}", decodedJolietVd.ExpirationTime).AppendLine();
            else
                isoMetadata.AppendFormat("Volume does not expire.").AppendLine();

            if(decodedJolietVd.HasEffectiveTime)
                isoMetadata.AppendFormat("Volume effective date: {0}", decodedJolietVd.EffectiveTime).AppendLine();
            else
                isoMetadata.AppendFormat("Volume has always been effective.").AppendLine();
        }

        if(torito != null)
        {
            errno = imagePlugin.ReadSector(torito.Value.catalog_sector + partition.Start, out vdSector);

            if(errno != ErrorNumber.NoError)
                return;

            var toritoOff = 0;

            if(vdSector[toritoOff] != 1)
                goto exit_torito;

            ElToritoValidationEntry valentry =
                Marshal.ByteArrayToStructureLittleEndian<ElToritoValidationEntry>(vdSector, toritoOff,
                    EL_TORITO_ENTRY_SIZE);

            if(valentry.signature != EL_TORITO_MAGIC)
                goto exit_torito;

            toritoOff = EL_TORITO_ENTRY_SIZE;

            ElToritoInitialEntry initialEntry =
                Marshal.ByteArrayToStructureLittleEndian<ElToritoInitialEntry>(vdSector, toritoOff,
                                                                               EL_TORITO_ENTRY_SIZE);

            initialEntry.boot_type = (ElToritoEmulation)((byte)initialEntry.boot_type & 0xF);

            AaruConsole.DebugWriteLine("DEBUG (ISO9660 plugin)", "initialEntry.load_rba = {0}", initialEntry.load_rba);

            AaruConsole.DebugWriteLine("DEBUG (ISO9660 plugin)", "initialEntry.sector_count = {0}",
                                       initialEntry.sector_count);

            byte[] bootImage = null;

            if(initialEntry.load_rba + partition.Start + initialEntry.sector_count - 1 <= partition.End)
                imagePlugin.ReadSectors(initialEntry.load_rba + partition.Start, initialEntry.sector_count,
                                        out bootImage);

            isoMetadata.AppendLine("----------------------");
            isoMetadata.AppendLine("EL TORITO INFORMATION:");
            isoMetadata.AppendLine("----------------------");

            isoMetadata.AppendLine("Initial entry:");
            isoMetadata.AppendFormat("\tDeveloper ID: {0}", Encoding.GetString(valentry.developer_id)).AppendLine();

            if(initialEntry.bootable == ElToritoIndicator.Bootable)
            {
                isoMetadata.AppendFormat("\tBootable on {0}", valentry.platform_id).AppendLine();

                isoMetadata.AppendFormat("\tBootable image starts at sector {0} and runs for {1} sectors",
                                         initialEntry.load_rba, initialEntry.sector_count).AppendLine();

                if(valentry.platform_id == ElToritoPlatform.x86)
                    isoMetadata.AppendFormat("\tBootable image will be loaded at segment {0:X4}h",
                                             initialEntry.load_seg == 0 ? 0x7C0 : initialEntry.load_seg).AppendLine();
                else
                    isoMetadata.AppendFormat("\tBootable image will be loaded at 0x{0:X8}",
                                             (uint)initialEntry.load_seg * 10).AppendLine();

                switch(initialEntry.boot_type)
                {
                    case ElToritoEmulation.None:
                        isoMetadata.AppendLine("\tImage uses no emulation");

                        break;
                    case ElToritoEmulation.Md2Hd:
                        isoMetadata.AppendLine("\tImage emulates a 5.25\" high-density (MD2HD, 1.2Mb) floppy");

                        break;
                    case ElToritoEmulation.Mf2Hd:
                        isoMetadata.AppendLine("\tImage emulates a 3.5\" high-density (MF2HD, 1.44Mb) floppy");

                        break;
                    case ElToritoEmulation.Mf2Ed:
                        isoMetadata.AppendLine("\tImage emulates a 3.5\" extra-density (MF2ED, 2.88Mb) floppy");

                        break;
                    default:
                        isoMetadata.AppendFormat("\tImage uses unknown emulation type {0}",
                                                 (byte)initialEntry.boot_type).AppendLine();

                        break;
                }

                isoMetadata.AppendFormat("\tSystem type: 0x{0:X2}", initialEntry.system_type).AppendLine();

                if(bootImage != null)
                    isoMetadata.AppendFormat("\tBootable image's SHA1: {0}", Sha1Context.Data(bootImage, out _)).
                                AppendLine();
            }
            else
                isoMetadata.AppendLine("\tNot bootable");

            toritoOff += EL_TORITO_ENTRY_SIZE;

            const int sectionCounter = 2;

            while(toritoOff < vdSector.Length &&
                  (vdSector[toritoOff] == (byte)ElToritoIndicator.Header ||
                   vdSector[toritoOff] == (byte)ElToritoIndicator.LastHeader))
            {
                ElToritoSectionHeaderEntry sectionHeader =
                    Marshal.ByteArrayToStructureLittleEndian<ElToritoSectionHeaderEntry>(vdSector, toritoOff,
                        EL_TORITO_ENTRY_SIZE);

                toritoOff += EL_TORITO_ENTRY_SIZE;

                isoMetadata.AppendFormat("Boot section {0}:", sectionCounter);

                isoMetadata.AppendFormat("\tSection ID: {0}", Encoding.GetString(sectionHeader.identifier)).
                            AppendLine();

                for(var entryCounter = 1; entryCounter <= sectionHeader.entries && toritoOff < vdSector.Length;
                    entryCounter++)
                {
                    ElToritoSectionEntry sectionEntry =
                        Marshal.ByteArrayToStructureLittleEndian<ElToritoSectionEntry>(vdSector, toritoOff,
                            EL_TORITO_ENTRY_SIZE);

                    toritoOff += EL_TORITO_ENTRY_SIZE;

                    isoMetadata.AppendFormat("\tEntry {0}:", entryCounter);

                    if(sectionEntry.bootable == ElToritoIndicator.Bootable)
                    {
                        bootImage = null;

                        if(sectionEntry.load_rba + partition.Start + sectionEntry.sector_count - 1 <= partition.End)
                            imagePlugin.ReadSectors(sectionEntry.load_rba + partition.Start, sectionEntry.sector_count,
                                                    out bootImage);

                        isoMetadata.AppendFormat("\t\tBootable on {0}", sectionHeader.platform_id).AppendLine();

                        isoMetadata.AppendFormat("\t\tBootable image starts at sector {0} and runs for {1} sectors",
                                                 sectionEntry.load_rba, sectionEntry.sector_count).AppendLine();

                        if(valentry.platform_id == ElToritoPlatform.x86)
                            isoMetadata.AppendFormat("\t\tBootable image will be loaded at segment {0:X4}h",
                                                     sectionEntry.load_seg == 0 ? 0x7C0 : sectionEntry.load_seg).
                                        AppendLine();
                        else
                            isoMetadata.AppendFormat("\t\tBootable image will be loaded at 0x{0:X8}",
                                                     (uint)sectionEntry.load_seg * 10).AppendLine();

                        switch((ElToritoEmulation)((byte)sectionEntry.boot_type & 0xF))
                        {
                            case ElToritoEmulation.None:
                                isoMetadata.AppendLine("\t\tImage uses no emulation");

                                break;
                            case ElToritoEmulation.Md2Hd:
                                isoMetadata.
                                    AppendLine("\t\tImage emulates a 5.25\" high-density (MD2HD, 1.2Mb) floppy");

                                break;
                            case ElToritoEmulation.Mf2Hd:
                                isoMetadata.
                                    AppendLine("\t\tImage emulates a 3.5\" high-density (MF2HD, 1.44Mb) floppy");

                                break;
                            case ElToritoEmulation.Mf2Ed:
                                isoMetadata.
                                    AppendLine("\t\tImage emulates a 3.5\" extra-density (MF2ED, 2.88Mb) floppy");

                                break;
                            default:
                                isoMetadata.AppendFormat("\t\tImage uses unknown emulation type {0}",
                                                         (byte)initialEntry.boot_type).AppendLine();

                                break;
                        }

                        isoMetadata.AppendFormat("\t\tSelection criteria type: {0}",
                                                 sectionEntry.selection_criteria_type).AppendLine();

                        isoMetadata.AppendFormat("\t\tSystem type: 0x{0:X2}", sectionEntry.system_type).AppendLine();

                        if(bootImage != null)
                            isoMetadata.AppendFormat("\t\tBootable image's SHA1: {0}",
                                                     Sha1Context.Data(bootImage, out _)).AppendLine();
                    }
                    else
                        isoMetadata.AppendLine("\t\tNot bootable");

                    var flags = (ElToritoFlags)((byte)sectionEntry.boot_type & 0xF0);

                    if(flags.HasFlag(ElToritoFlags.ATAPI))
                        isoMetadata.AppendLine("\t\tImage contains ATAPI drivers");

                    if(flags.HasFlag(ElToritoFlags.SCSI))
                        isoMetadata.AppendLine("\t\tImage contains SCSI drivers");

                    if(!flags.HasFlag(ElToritoFlags.Continued))
                        continue;

                    while(toritoOff < vdSector.Length)
                    {
                        ElToritoSectionEntryExtension sectionExtension =
                            Marshal.ByteArrayToStructureLittleEndian<ElToritoSectionEntryExtension>(vdSector, toritoOff,
                                EL_TORITO_ENTRY_SIZE);

                        toritoOff += EL_TORITO_ENTRY_SIZE;

                        if(!sectionExtension.extension_flags.HasFlag(ElToritoFlags.Continued))
                            break;
                    }
                }

                if(sectionHeader.header_id == ElToritoIndicator.LastHeader)
                    break;
            }
        }

    exit_torito:

        if(refareas.Count > 0)
            isoMetadata.Append(suspInformation);

        XmlFsType.Type = fsFormat;

        if(jolietvd != null)
        {
            XmlFsType.VolumeName = decodedJolietVd.VolumeIdentifier;

            if(string.IsNullOrEmpty(decodedJolietVd.SystemIdentifier) ||
               decodedVd.SystemIdentifier.Length > decodedJolietVd.SystemIdentifier.Length)
                XmlFsType.SystemIdentifier = decodedVd.SystemIdentifier;
            else
                XmlFsType.SystemIdentifier = string.IsNullOrEmpty(decodedJolietVd.SystemIdentifier) ? null
                                                 : decodedJolietVd.SystemIdentifier;

            if(string.IsNullOrEmpty(decodedJolietVd.VolumeSetIdentifier) ||
               decodedVd.VolumeSetIdentifier.Length > decodedJolietVd.VolumeSetIdentifier.Length)
                XmlFsType.VolumeSetIdentifier = decodedVd.VolumeSetIdentifier;
            else
                XmlFsType.VolumeSetIdentifier = string.IsNullOrEmpty(decodedJolietVd.VolumeSetIdentifier) ? null
                                                    : decodedJolietVd.VolumeSetIdentifier;

            if(string.IsNullOrEmpty(decodedJolietVd.PublisherIdentifier) ||
               decodedVd.PublisherIdentifier.Length > decodedJolietVd.PublisherIdentifier.Length)
                XmlFsType.PublisherIdentifier = decodedVd.PublisherIdentifier;
            else
                XmlFsType.PublisherIdentifier = string.IsNullOrEmpty(decodedJolietVd.PublisherIdentifier) ? null
                                                    : decodedJolietVd.PublisherIdentifier;

            if(string.IsNullOrEmpty(decodedJolietVd.DataPreparerIdentifier) ||
               decodedVd.DataPreparerIdentifier.Length > decodedJolietVd.DataPreparerIdentifier.Length)
                XmlFsType.DataPreparerIdentifier = decodedVd.DataPreparerIdentifier;
            else
                XmlFsType.DataPreparerIdentifier = string.IsNullOrEmpty(decodedJolietVd.DataPreparerIdentifier) ? null
                                                       : decodedJolietVd.DataPreparerIdentifier;

            if(string.IsNullOrEmpty(decodedJolietVd.ApplicationIdentifier) ||
               decodedVd.ApplicationIdentifier.Length > decodedJolietVd.ApplicationIdentifier.Length)
                XmlFsType.ApplicationIdentifier = decodedVd.ApplicationIdentifier;
            else
                XmlFsType.ApplicationIdentifier = string.IsNullOrEmpty(decodedJolietVd.ApplicationIdentifier) ? null
                                                      : decodedJolietVd.ApplicationIdentifier;

            XmlFsType.CreationDate          = decodedJolietVd.CreationTime;
            XmlFsType.CreationDateSpecified = true;

            if(decodedJolietVd.HasModificationTime)
            {
                XmlFsType.ModificationDate          = decodedJolietVd.ModificationTime;
                XmlFsType.ModificationDateSpecified = true;
            }

            if(decodedJolietVd.HasExpirationTime)
            {
                XmlFsType.ExpirationDate          = decodedJolietVd.ExpirationTime;
                XmlFsType.ExpirationDateSpecified = true;
            }

            if(decodedJolietVd.HasEffectiveTime)
            {
                XmlFsType.EffectiveDate          = decodedJolietVd.EffectiveTime;
                XmlFsType.EffectiveDateSpecified = true;
            }
        }
        else
        {
            XmlFsType.SystemIdentifier       = decodedVd.SystemIdentifier;
            XmlFsType.VolumeName             = decodedVd.VolumeIdentifier;
            XmlFsType.VolumeSetIdentifier    = decodedVd.VolumeSetIdentifier;
            XmlFsType.PublisherIdentifier    = decodedVd.PublisherIdentifier;
            XmlFsType.DataPreparerIdentifier = decodedVd.DataPreparerIdentifier;
            XmlFsType.ApplicationIdentifier  = decodedVd.ApplicationIdentifier;
            XmlFsType.CreationDate           = decodedVd.CreationTime;
            XmlFsType.CreationDateSpecified  = true;

            if(decodedVd.HasModificationTime)
            {
                XmlFsType.ModificationDate          = decodedVd.ModificationTime;
                XmlFsType.ModificationDateSpecified = true;
            }

            if(decodedVd.HasExpirationTime)
            {
                XmlFsType.ExpirationDate          = decodedVd.ExpirationTime;
                XmlFsType.ExpirationDateSpecified = true;
            }

            if(decodedVd.HasEffectiveTime)
            {
                XmlFsType.EffectiveDate          = decodedVd.EffectiveTime;
                XmlFsType.EffectiveDateSpecified = true;
            }
        }

        XmlFsType.Bootable    |= bvd != null || segaCd != null || saturn != null || dreamcast != null;
        XmlFsType.Clusters    =  decodedVd.Blocks;
        XmlFsType.ClusterSize =  decodedVd.BlockSize;

        information = isoMetadata.ToString();
    }
}