// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Atari.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Partitioning scheme plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Manages Atari ST GEMDOS partitions.
//
// --[ 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 © 2011-2023 Natalia Portillo
// ****************************************************************************/

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.Helpers;
using Spectre.Console;

namespace Aaru.Partitions;

/// <inheritdoc />
/// <summary>Implements decoding of Atari GEMDOS partitions</summary>
public sealed class AtariPartitions : IPartition
{
    const uint   TYPE_GEMDOS      = 0x0047454D;
    const uint   TYPE_BIG_GEMDOS  = 0x0042474D;
    const uint   TYPE_EXTENDED    = 0x0058474D;
    const uint   TYPE_LINUX       = 0x004C4E58;
    const uint   TYPE_SWAP        = 0x00535750;
    const uint   TYPE_RAW         = 0x00524157;
    const uint   TYPE_NETBSD      = 0x004E4244;
    const uint   TYPE_NETBSD_SWAP = 0x004E4253;
    const uint   TYPE_SYSTEM_V    = 0x00554E58;
    const uint   TYPE_MAC         = 0x004D4143;
    const uint   TYPE_MINIX       = 0x004D4958;
    const uint   TYPE_MINIX2      = 0x004D4E58;
    const string MODULE_NAME      = "Atari partitions plugin";

#region IPartition Members

    /// <inheritdoc />
    public string Name => Localization.AtariPartitions_Name;

    /// <inheritdoc />
    public Guid Id => new("d1dd0f24-ec39-4c4d-9072-be31919a3b5e");

    /// <inheritdoc />
    public string Author => Authors.NATALIA_PORTILLO;

    /// <inheritdoc />
    public bool GetInformation(IMediaImage imagePlugin, out List<Partition> partitions, ulong sectorOffset)
    {
        partitions = new List<Partition>();

        ErrorNumber errno = imagePlugin.ReadSector(sectorOffset, out byte[] sector);

        if(errno != ErrorNumber.NoError || sector.Length < 512)
            return false;

        var table = new AtariTable
        {
            Boot       = new byte[342],
            IcdEntries = new AtariEntry[8],
            Unused     = new byte[12],
            Entries    = new AtariEntry[4]
        };

        Array.Copy(sector, 0, table.Boot, 0, 342);

        for(var i = 0; i < 8; i++)
        {
            table.IcdEntries[i].Type   = BigEndianBitConverter.ToUInt32(sector, 342 + i * 12 + 0);
            table.IcdEntries[i].Start  = BigEndianBitConverter.ToUInt32(sector, 342 + i * 12 + 4);
            table.IcdEntries[i].Length = BigEndianBitConverter.ToUInt32(sector, 342 + i * 12 + 8);
        }

        Array.Copy(sector, 438, table.Unused, 0, 12);

        table.Size = BigEndianBitConverter.ToUInt32(sector, 450);

        for(var i = 0; i < 4; i++)
        {
            table.Entries[i].Type   = BigEndianBitConverter.ToUInt32(sector, 454 + i * 12 + 0);
            table.Entries[i].Start  = BigEndianBitConverter.ToUInt32(sector, 454 + i * 12 + 4);
            table.Entries[i].Length = BigEndianBitConverter.ToUInt32(sector, 454 + i * 12 + 8);
        }

        table.BadStart  = BigEndianBitConverter.ToUInt32(sector, 502);
        table.BadLength = BigEndianBitConverter.ToUInt32(sector, 506);
        table.Checksum  = BigEndianBitConverter.ToUInt16(sector, 510);

        var sha1Ctx = new Sha1Context();
        sha1Ctx.Update(table.Boot);
        AaruConsole.DebugWriteLine(MODULE_NAME, Localization.Boot_code_SHA1_0, sha1Ctx.End());

        for(var i = 0; i < 8; i++)
        {
            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.icdEntries[{0}].flag = 0x{1:X2}"), i,
                                       (table.IcdEntries[i].Type & 0xFF000000) >> 24);

            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.icdEntries[{0}].type = 0x{1:X6}"), i,
                                       table.IcdEntries[i].Type & 0x00FFFFFF);

            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.icdEntries[{0}].start = {1}"), i,
                                       table.IcdEntries[i].Start);

            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.icdEntries[{0}].length = {1}"), i,
                                       table.IcdEntries[i].Length);
        }

        AaruConsole.DebugWriteLine(MODULE_NAME, "table.size = {0}", table.Size);

        for(var i = 0; i < 4; i++)
        {
            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.entries[{0}].flag = 0x{1:X2}"), i,
                                       (table.Entries[i].Type & 0xFF000000) >> 24);

            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.entries[{0}].type = 0x{1:X6}"), i,
                                       table.Entries[i].Type & 0x00FFFFFF);

            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.entries[{0}].start = {1}"), i,
                                       table.Entries[i].Start);

            AaruConsole.DebugWriteLine(MODULE_NAME, Markup.Escape("table.entries[{0}].length = {1}"), i,
                                       table.Entries[i].Length);
        }

        AaruConsole.DebugWriteLine(MODULE_NAME, "table.badStart = {0}",      table.BadStart);
        AaruConsole.DebugWriteLine(MODULE_NAME, "table.badLength = {0}",     table.BadLength);
        AaruConsole.DebugWriteLine(MODULE_NAME, "table.checksum = 0x{0:X4}", table.Checksum);

        var   validTable        = false;
        ulong partitionSequence = 0;

        for(var i = 0; i < 4; i++)
        {
            uint type = table.Entries[i].Type & 0x00FFFFFF;

            switch(type)
            {
                case TYPE_GEMDOS:
                case TYPE_BIG_GEMDOS:
                case TYPE_LINUX:
                case TYPE_SWAP:
                case TYPE_RAW:
                case TYPE_NETBSD:
                case TYPE_NETBSD_SWAP:
                case TYPE_SYSTEM_V:
                case TYPE_MAC:
                case TYPE_MINIX:
                case TYPE_MINIX2:
                    validTable = true;

                    if(table.Entries[i].Start <= imagePlugin.Info.Sectors)
                    {
                        if(table.Entries[i].Start + table.Entries[i].Length > imagePlugin.Info.Sectors)
                        {
                            AaruConsole.DebugWriteLine(MODULE_NAME,
                                                       Localization.WARNING_End_of_partition_goes_beyond_device_size);
                        }

                        ulong sectorSize = imagePlugin.Info.SectorSize;

                        if(sectorSize is 2448 or 2352)
                            sectorSize = 2048;

                        var partType = new byte[3];
                        partType[0] = (byte)((type & 0xFF0000) >> 16);
                        partType[1] = (byte)((type & 0x00FF00) >> 8);
                        partType[2] = (byte)(type & 0x0000FF);

                        var part = new Partition
                        {
                            Size     = table.Entries[i].Length * sectorSize,
                            Length   = table.Entries[i].Length,
                            Sequence = partitionSequence,
                            Name     = "",
                            Offset   = table.Entries[i].Start * sectorSize,
                            Start    = table.Entries[i].Start,
                            Type     = Encoding.ASCII.GetString(partType),
                            Scheme   = Name
                        };

                        switch(type)
                        {
                            case TYPE_GEMDOS:
                                part.Description = Localization.Atari_GEMDOS_partition;

                                break;
                            case TYPE_BIG_GEMDOS:
                                part.Description = Localization.Atari_GEMDOS_partition_bigger_than_32_MiB;

                                break;
                            case TYPE_LINUX:
                                part.Description = Localization.Linux_partition;

                                break;
                            case TYPE_SWAP:
                                part.Description = Localization.Swap_partition;

                                break;
                            case TYPE_RAW:
                                part.Description = Localization.RAW_partition;

                                break;
                            case TYPE_NETBSD:
                                part.Description = Localization.NetBSD_partition;

                                break;
                            case TYPE_NETBSD_SWAP:
                                part.Description = Localization.NetBSD_swap_partition;

                                break;
                            case TYPE_SYSTEM_V:
                                part.Description = Localization.Atari_UNIX_partition;

                                break;
                            case TYPE_MAC:
                                part.Description = Localization.Macintosh_partition;

                                break;
                            case TYPE_MINIX:
                            case TYPE_MINIX2:
                                part.Description = Localization.MINIX_partition;

                                break;
                            default:
                                part.Description = Localization.Unknown_partition_type;

                                break;
                        }

                        partitions.Add(part);
                        partitionSequence++;
                    }

                    break;
                case TYPE_EXTENDED:
                    errno = imagePlugin.ReadSector(table.Entries[i].Start, out byte[] extendedSector);

                    if(errno != ErrorNumber.NoError)
                        break;

                    var extendedTable = new AtariTable
                    {
                        Entries = new AtariEntry[4]
                    };

                    for(var j = 0; j < 4; j++)
                    {
                        extendedTable.Entries[j].Type =
                            BigEndianBitConverter.ToUInt32(extendedSector, 454 + j * 12 + 0);

                        extendedTable.Entries[j].Start =
                            BigEndianBitConverter.ToUInt32(extendedSector, 454 + j * 12 + 4);

                        extendedTable.Entries[j].Length =
                            BigEndianBitConverter.ToUInt32(extendedSector, 454 + j * 12 + 8);
                    }

                    for(var j = 0; j < 4; j++)
                    {
                        uint extendedType = extendedTable.Entries[j].Type & 0x00FFFFFF;

                        if(extendedType != TYPE_GEMDOS      &&
                           extendedType != TYPE_BIG_GEMDOS  &&
                           extendedType != TYPE_LINUX       &&
                           extendedType != TYPE_SWAP        &&
                           extendedType != TYPE_RAW         &&
                           extendedType != TYPE_NETBSD      &&
                           extendedType != TYPE_NETBSD_SWAP &&
                           extendedType != TYPE_SYSTEM_V    &&
                           extendedType != TYPE_MAC         &&
                           extendedType != TYPE_MINIX       &&
                           extendedType != TYPE_MINIX2)
                            continue;

                        validTable = true;

                        if(extendedTable.Entries[j].Start > imagePlugin.Info.Sectors)
                            continue;

                        if(extendedTable.Entries[j].Start + extendedTable.Entries[j].Length > imagePlugin.Info.Sectors)
                        {
                            AaruConsole.DebugWriteLine(MODULE_NAME,
                                                       Localization.WARNING_End_of_partition_goes_beyond_device_size);
                        }

                        ulong sectorSize = imagePlugin.Info.SectorSize;

                        if(sectorSize is 2448 or 2352)
                            sectorSize = 2048;

                        var partType = new byte[3];
                        partType[0] = (byte)((extendedType & 0xFF0000) >> 16);
                        partType[1] = (byte)((extendedType & 0x00FF00) >> 8);
                        partType[2] = (byte)(extendedType & 0x0000FF);

                        var part = new Partition
                        {
                            Size     = extendedTable.Entries[j].Length * sectorSize,
                            Length   = extendedTable.Entries[j].Length,
                            Sequence = partitionSequence,
                            Name     = "",
                            Offset   = extendedTable.Entries[j].Start * sectorSize,
                            Start    = extendedTable.Entries[j].Start,
                            Type     = Encoding.ASCII.GetString(partType),
                            Scheme   = Name
                        };

                        switch(extendedType)
                        {
                            case TYPE_GEMDOS:
                                part.Description = Localization.Atari_GEMDOS_partition;

                                break;
                            case TYPE_BIG_GEMDOS:
                                part.Description = Localization.Atari_GEMDOS_partition_bigger_than_32_MiB;

                                break;
                            case TYPE_LINUX:
                                part.Description = Localization.Linux_partition;

                                break;
                            case TYPE_SWAP:
                                part.Description = Localization.Swap_partition;

                                break;
                            case TYPE_RAW:
                                part.Description = Localization.RAW_partition;

                                break;
                            case TYPE_NETBSD:
                                part.Description = Localization.NetBSD_partition;

                                break;
                            case TYPE_NETBSD_SWAP:
                                part.Description = Localization.NetBSD_swap_partition;

                                break;
                            case TYPE_SYSTEM_V:
                                part.Description = Localization.Atari_UNIX_partition;

                                break;
                            case TYPE_MAC:
                                part.Description = Localization.Macintosh_partition;

                                break;
                            case TYPE_MINIX:
                            case TYPE_MINIX2:
                                part.Description = Localization.MINIX_partition;

                                break;
                            default:
                                part.Description = Localization.Unknown_partition_type;

                                break;
                        }

                        partitions.Add(part);
                        partitionSequence++;
                    }

                    break;
            }
        }

        if(!validTable)
            return partitions.Count > 0;

        for(var i = 0; i < 8; i++)
        {
            uint type = table.IcdEntries[i].Type & 0x00FFFFFF;

            if(type != TYPE_GEMDOS      &&
               type != TYPE_BIG_GEMDOS  &&
               type != TYPE_LINUX       &&
               type != TYPE_SWAP        &&
               type != TYPE_RAW         &&
               type != TYPE_NETBSD      &&
               type != TYPE_NETBSD_SWAP &&
               type != TYPE_SYSTEM_V    &&
               type != TYPE_MAC         &&
               type != TYPE_MINIX       &&
               type != TYPE_MINIX2)
                continue;

            if(table.IcdEntries[i].Start > imagePlugin.Info.Sectors)
                continue;

            if(table.IcdEntries[i].Start + table.IcdEntries[i].Length > imagePlugin.Info.Sectors)
                AaruConsole.DebugWriteLine(MODULE_NAME, Localization.WARNING_End_of_partition_goes_beyond_device_size);

            ulong sectorSize = imagePlugin.Info.SectorSize;

            if(sectorSize is 2448 or 2352)
                sectorSize = 2048;

            var partType = new byte[3];
            partType[0] = (byte)((type & 0xFF0000) >> 16);
            partType[1] = (byte)((type & 0x00FF00) >> 8);
            partType[2] = (byte)(type & 0x0000FF);

            var part = new Partition
            {
                Size     = table.IcdEntries[i].Length * sectorSize,
                Length   = table.IcdEntries[i].Length,
                Sequence = partitionSequence,
                Name     = "",
                Offset   = table.IcdEntries[i].Start * sectorSize,
                Start    = table.IcdEntries[i].Start,
                Type     = Encoding.ASCII.GetString(partType),
                Scheme   = Name
            };

            switch(type)
            {
                case TYPE_GEMDOS:
                    part.Description = Localization.Atari_GEMDOS_partition;

                    break;
                case TYPE_BIG_GEMDOS:
                    part.Description = Localization.Atari_GEMDOS_partition_bigger_than_32_MiB;

                    break;
                case TYPE_LINUX:
                    part.Description = Localization.Linux_partition;

                    break;
                case TYPE_SWAP:
                    part.Description = Localization.Swap_partition;

                    break;
                case TYPE_RAW:
                    part.Description = Localization.RAW_partition;

                    break;
                case TYPE_NETBSD:
                    part.Description = Localization.NetBSD_partition;

                    break;
                case TYPE_NETBSD_SWAP:
                    part.Description = Localization.NetBSD_swap_partition;

                    break;
                case TYPE_SYSTEM_V:
                    part.Description = Localization.Atari_UNIX_partition;

                    break;
                case TYPE_MAC:
                    part.Description = Localization.Macintosh_partition;

                    break;
                case TYPE_MINIX:
                case TYPE_MINIX2:
                    part.Description = Localization.MINIX_partition;

                    break;
                default:
                    part.Description = Localization.Unknown_partition_type;

                    break;
            }

            partitions.Add(part);
            partitionSequence++;
        }

        return partitions.Count > 0;
    }

#endregion

#region Nested type: AtariEntry

    /// <summary>Atari partition entry</summary>
    struct AtariEntry
    {
        /// <summary>First byte flag, three bytes type in ASCII. Flag bit 0 = active Flag bit 7 = bootable</summary>
        public uint Type;
        /// <summary>Starting sector</summary>
        public uint Start;
        /// <summary>Length in sectors</summary>
        public uint Length;
    }

#endregion

#region Nested type: AtariTable

    struct AtariTable
    {
        /// <summary>Boot code for 342 bytes</summary>
        public byte[] Boot;
        /// <summary>8 extra entries for ICDPro driver</summary>
        public AtariEntry[] IcdEntries;
        /// <summary>Unused, 12 bytes</summary>
        public byte[] Unused;
        /// <summary>Disk size in sectors</summary>
        public uint Size;
        /// <summary>4 partition entries</summary>
        public AtariEntry[] Entries;
        /// <summary>Starting sector of bad block list</summary>
        public uint BadStart;
        /// <summary>Length in sectors of bad block list</summary>
        public uint BadLength;
        /// <summary>Checksum for bootable disks</summary>
        public ushort Checksum;
    }

#endregion
}