// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : ProDOS.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Apple ProDOS filesystem plugin.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies the Apple ProDOS 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
// ****************************************************************************/

// ReSharper disable NotAccessedField.Local

namespace Aaru.Filesystems;

using System;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Text;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Console;
using Claunia.Encoding;
using Schemas;
using Encoding = System.Text.Encoding;

// Information from Apple ProDOS 8 Technical Reference
/// <inheritdoc />
/// <summary>Implements detection of Apple ProDOS filesystem</summary>
[SuppressMessage("ReSharper", "UnusedMember.Local"), SuppressMessage("ReSharper", "UnusedType.Local")]
public sealed class ProDOSPlugin : IFilesystem
{
    const byte EMPTY_STORAGE_TYPE = 0x00;
    /// <summary>A file that occupies one block or less</summary>
    const byte SEEDLING_FILE_TYPE = 0x01;
    /// <summary>A file that occupies between 2 and 256 blocks</summary>
    const byte SAPLING_FILE_TYPE = 0x02;
    /// <summary>A file that occupies between 257 and 32768 blocks</summary>
    const byte TREE_FILE_TYPE = 0x03;
    const byte PASCAL_AREA_TYPE         = 0x04;
    const byte SUBDIRECTORY_TYPE        = 0x0D;
    const byte SUBDIRECTORY_HEADER_TYPE = 0x0E;
    const byte ROOT_DIRECTORY_TYPE      = 0x0F;

    const byte VERSION1 = 0x00;

    const uint YEAR_MASK   = 0xFE000000;
    const uint MONTH_MASK  = 0x1E00000;
    const uint DAY_MASK    = 0x1F0000;
    const uint HOUR_MASK   = 0x1F00;
    const uint MINUTE_MASK = 0x3F;

    const byte DESTROY_ATTRIBUTE       = 0x80;
    const byte RENAME_ATTRIBUTE        = 0x40;
    const byte BACKUP_ATTRIBUTE        = 0x20;
    const byte WRITE_ATTRIBUTE         = 0x02;
    const byte READ_ATTRIBUTE          = 0x01;
    const byte RESERVED_ATTRIBUTE_MASK = 0x1C;

    const byte STORAGE_TYPE_MASK = 0xF0;
    const byte NAME_LENGTH_MASK  = 0x0F;
    const byte ENTRY_LENGTH      = 0x27;
    const byte ENTRIES_PER_BLOCK = 0x0D;

    /// <inheritdoc />
    public FileSystemType XmlFsType { get; private set; }
    /// <inheritdoc />
    public Encoding Encoding { get; private set; }
    /// <inheritdoc />
    public string Name => "Apple ProDOS filesystem";
    /// <inheritdoc />
    public Guid Id => new("43874265-7B8A-4739-BCF7-07F80D5932BF");
    /// <inheritdoc />
    public string Author => "Natalia Portillo";

    /// <inheritdoc />
    public bool Identify(IMediaImage imagePlugin, Partition partition)
    {
        if(partition.Length < 3)
            return false;

        var multiplier = (uint)(imagePlugin.Info.SectorSize == 256 ? 2 : 1);

        // Blocks 0 and 1 are boot code
        ErrorNumber errno = imagePlugin.ReadSectors(2 * multiplier + partition.Start, multiplier,
                                                    out byte[] rootDirectoryKeyBlock);

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

        var apmFromHddOnCd = false;

        if(imagePlugin.Info.SectorSize is 2352 or 2448 or 2048)
        {
            errno = imagePlugin.ReadSectors(partition.Start, 2, out byte[] tmp);

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

            foreach(int offset in new[]
                    {
                        0, 0x200, 0x400, 0x600, 0x800, 0xA00
                    }.Where(offset => tmp.Length > offset + 0x200 && BitConverter.ToUInt16(tmp, offset) == 0 &&
                                      (byte)((tmp[offset + 0x04] & STORAGE_TYPE_MASK) >> 4) == ROOT_DIRECTORY_TYPE &&
                                      tmp[offset + 0x23] == ENTRY_LENGTH && tmp[offset + 0x24] == ENTRIES_PER_BLOCK))
            {
                Array.Copy(tmp, offset, rootDirectoryKeyBlock, 0, 0x200);
                apmFromHddOnCd = true;

                break;
            }
        }

        var prePointer = BitConverter.ToUInt16(rootDirectoryKeyBlock, 0);
        AaruConsole.DebugWriteLine("ProDOS plugin", "prePointer = {0}", prePointer);

        if(prePointer != 0)
            return false;

        var storageType = (byte)((rootDirectoryKeyBlock[0x04] & STORAGE_TYPE_MASK) >> 4);
        AaruConsole.DebugWriteLine("ProDOS plugin", "storage_type = {0}", storageType);

        if(storageType != ROOT_DIRECTORY_TYPE)
            return false;

        byte entryLength = rootDirectoryKeyBlock[0x23];
        AaruConsole.DebugWriteLine("ProDOS plugin", "entry_length = {0}", entryLength);

        if(entryLength != ENTRY_LENGTH)
            return false;

        byte entriesPerBlock = rootDirectoryKeyBlock[0x24];
        AaruConsole.DebugWriteLine("ProDOS plugin", "entries_per_block = {0}", entriesPerBlock);

        if(entriesPerBlock != ENTRIES_PER_BLOCK)
            return false;

        var bitMapPointer = BitConverter.ToUInt16(rootDirectoryKeyBlock, 0x27);
        AaruConsole.DebugWriteLine("ProDOS plugin", "bit_map_pointer = {0}", bitMapPointer);

        if(bitMapPointer > partition.End)
            return false;

        var totalBlocks = BitConverter.ToUInt16(rootDirectoryKeyBlock, 0x29);

        if(apmFromHddOnCd)
            totalBlocks /= 4;

        AaruConsole.DebugWriteLine("ProDOS plugin", "{0} <= ({1} - {2} + 1)? {3}", totalBlocks, partition.End,
                                   partition.Start, totalBlocks <= partition.End - partition.Start + 1);

        return totalBlocks <= partition.End - partition.Start + 1;
    }

    /// <inheritdoc />
    public void GetInformation(IMediaImage imagePlugin, Partition partition, out string information, Encoding encoding)
    {
        Encoding    = encoding ?? new Apple2c();
        information = "";
        var sbInformation = new StringBuilder();
        var multiplier    = (uint)(imagePlugin.Info.SectorSize == 256 ? 2 : 1);

        // Blocks 0 and 1 are boot code
        ErrorNumber errno = imagePlugin.ReadSectors(2 * multiplier + partition.Start, multiplier,
                                                    out byte[] rootDirectoryKeyBlockBytes);

        if(errno != ErrorNumber.NoError)
            return;

        var apmFromHddOnCd = false;

        if(imagePlugin.Info.SectorSize is 2352 or 2448 or 2048)
        {
            errno = imagePlugin.ReadSectors(partition.Start, 2, out byte[] tmp);

            if(errno != ErrorNumber.NoError)
                return;

            foreach(int offset in new[]
                    {
                        0, 0x200, 0x400, 0x600, 0x800, 0xA00
                    }.Where(offset => BitConverter.ToUInt16(tmp, offset) == 0 &&
                                      (byte)((tmp[offset + 0x04] & STORAGE_TYPE_MASK) >> 4) == ROOT_DIRECTORY_TYPE &&
                                      tmp[offset + 0x23] == ENTRY_LENGTH && tmp[offset + 0x24] == ENTRIES_PER_BLOCK))
            {
                Array.Copy(tmp, offset, rootDirectoryKeyBlockBytes, 0, 0x200);
                apmFromHddOnCd = true;

                break;
            }
        }

        var rootDirectoryKeyBlock = new RootDirectoryKeyBlock
        {
            header       = new RootDirectoryHeader(),
            zero         = BitConverter.ToUInt16(rootDirectoryKeyBlockBytes, 0x00),
            next_pointer = BitConverter.ToUInt16(rootDirectoryKeyBlockBytes, 0x02)
        };

        rootDirectoryKeyBlock.header.storage_type = (byte)((rootDirectoryKeyBlockBytes[0x04] & STORAGE_TYPE_MASK) >> 4);

        rootDirectoryKeyBlock.header.name_length = (byte)(rootDirectoryKeyBlockBytes[0x04] & NAME_LENGTH_MASK);
        var temporal = new byte[rootDirectoryKeyBlock.header.name_length];
        Array.Copy(rootDirectoryKeyBlockBytes, 0x05, temporal, 0, rootDirectoryKeyBlock.header.name_length);
        rootDirectoryKeyBlock.header.volume_name = Encoding.GetString(temporal);
        rootDirectoryKeyBlock.header.reserved    = BitConverter.ToUInt64(rootDirectoryKeyBlockBytes, 0x14);

        var tempTimestampLeft  = BitConverter.ToUInt16(rootDirectoryKeyBlockBytes, 0x1C);
        var tempTimestampRight = BitConverter.ToUInt16(rootDirectoryKeyBlockBytes, 0x1E);

        bool dateCorrect;

        try
        {
            var tempTimestamp = (uint)((tempTimestampLeft << 16) + tempTimestampRight);
            var year          = (int)((tempTimestamp & YEAR_MASK)  >> 25);
            var month         = (int)((tempTimestamp & MONTH_MASK) >> 21);
            var day           = (int)((tempTimestamp & DAY_MASK)   >> 16);
            var hour          = (int)((tempTimestamp & HOUR_MASK)  >> 8);
            var minute        = (int)(tempTimestamp & MINUTE_MASK);
            year += 1900;

            if(year < 1940)
                year += 100;

            AaruConsole.DebugWriteLine("ProDOS plugin", "temp_timestamp_left = 0x{0:X4}", tempTimestampLeft);
            AaruConsole.DebugWriteLine("ProDOS plugin", "temp_timestamp_right = 0x{0:X4}", tempTimestampRight);
            AaruConsole.DebugWriteLine("ProDOS plugin", "temp_timestamp = 0x{0:X8}", tempTimestamp);

            AaruConsole.DebugWriteLine("ProDOS plugin",
                                       "Datetime field year {0}, month {1}, day {2}, hour {3}, minute {4}.", year,
                                       month, day, hour, minute);

            rootDirectoryKeyBlock.header.creation_time = new DateTime(year, month, day, hour, minute, 0);
            dateCorrect                                = true;
        }
        catch(ArgumentOutOfRangeException)
        {
            dateCorrect = false;
        }

        rootDirectoryKeyBlock.header.version           = rootDirectoryKeyBlockBytes[0x20];
        rootDirectoryKeyBlock.header.min_version       = rootDirectoryKeyBlockBytes[0x21];
        rootDirectoryKeyBlock.header.access            = rootDirectoryKeyBlockBytes[0x22];
        rootDirectoryKeyBlock.header.entry_length      = rootDirectoryKeyBlockBytes[0x23];
        rootDirectoryKeyBlock.header.entries_per_block = rootDirectoryKeyBlockBytes[0x24];

        rootDirectoryKeyBlock.header.file_count      = BitConverter.ToUInt16(rootDirectoryKeyBlockBytes, 0x25);
        rootDirectoryKeyBlock.header.bit_map_pointer = BitConverter.ToUInt16(rootDirectoryKeyBlockBytes, 0x27);
        rootDirectoryKeyBlock.header.total_blocks    = BitConverter.ToUInt16(rootDirectoryKeyBlockBytes, 0x29);

        if(apmFromHddOnCd)
            sbInformation.AppendLine("ProDOS uses 512 bytes/sector while devices uses 2048 bytes/sector.").AppendLine();

        if(rootDirectoryKeyBlock.header.version     != VERSION1 ||
           rootDirectoryKeyBlock.header.min_version != VERSION1)
        {
            sbInformation.AppendLine("Warning! Detected unknown ProDOS version ProDOS filesystem.");
            sbInformation.AppendLine("All of the following information may be incorrect");
        }

        if(rootDirectoryKeyBlock.header.version == VERSION1)
            sbInformation.AppendLine("ProDOS version 1 used to create this volume.");
        else
            sbInformation.AppendFormat("Unknown ProDOS version with field {0} used to create this volume.",
                                       rootDirectoryKeyBlock.header.version).AppendLine();

        if(rootDirectoryKeyBlock.header.min_version == VERSION1)
            sbInformation.AppendLine("ProDOS version 1 at least required for reading this volume.");
        else
            sbInformation.
                AppendFormat("Unknown ProDOS version with field {0} is at least required for reading this volume.",
                             rootDirectoryKeyBlock.header.min_version).AppendLine();

        sbInformation.AppendFormat("Volume name is {0}", rootDirectoryKeyBlock.header.volume_name).AppendLine();

        if(dateCorrect)
            sbInformation.AppendFormat("Volume created on {0}", rootDirectoryKeyBlock.header.creation_time).
                          AppendLine();

        sbInformation.AppendFormat("{0} bytes per directory entry", rootDirectoryKeyBlock.header.entry_length).
                      AppendLine();

        sbInformation.AppendFormat("{0} entries per directory block", rootDirectoryKeyBlock.header.entries_per_block).
                      AppendLine();

        sbInformation.AppendFormat("{0} files in root directory", rootDirectoryKeyBlock.header.file_count).AppendLine();

        sbInformation.AppendFormat("{0} blocks in volume", rootDirectoryKeyBlock.header.total_blocks).AppendLine();

        sbInformation.AppendFormat("Bitmap starts at block {0}", rootDirectoryKeyBlock.header.bit_map_pointer).
                      AppendLine();

        if((rootDirectoryKeyBlock.header.access & READ_ATTRIBUTE) == READ_ATTRIBUTE)
            sbInformation.AppendLine("Volume can be read");

        if((rootDirectoryKeyBlock.header.access & WRITE_ATTRIBUTE) == WRITE_ATTRIBUTE)
            sbInformation.AppendLine("Volume can be written");

        if((rootDirectoryKeyBlock.header.access & RENAME_ATTRIBUTE) == RENAME_ATTRIBUTE)
            sbInformation.AppendLine("Volume can be renamed");

        if((rootDirectoryKeyBlock.header.access & DESTROY_ATTRIBUTE) == DESTROY_ATTRIBUTE)
            sbInformation.AppendLine("Volume can be destroyed");

        if((rootDirectoryKeyBlock.header.access & BACKUP_ATTRIBUTE) == BACKUP_ATTRIBUTE)
            sbInformation.AppendLine("Volume must be backed up");

        if((rootDirectoryKeyBlock.header.access & RESERVED_ATTRIBUTE_MASK) != 0)
            AaruConsole.DebugWriteLine("ProDOS plugin", "Reserved attributes are set: {0:X2}",
                                       rootDirectoryKeyBlock.header.access);

        information = sbInformation.ToString();

        XmlFsType = new FileSystemType
        {
            VolumeName     = rootDirectoryKeyBlock.header.volume_name,
            Files          = rootDirectoryKeyBlock.header.file_count,
            FilesSpecified = true,
            Clusters       = rootDirectoryKeyBlock.header.total_blocks,
            Type           = "ProDOS"
        };

        XmlFsType.ClusterSize = (uint)((partition.End - partition.Start + 1) * imagePlugin.Info.SectorSize /
                                       XmlFsType.Clusters);

        if(!dateCorrect)
            return;

        XmlFsType.CreationDate          = rootDirectoryKeyBlock.header.creation_time;
        XmlFsType.CreationDateSpecified = true;
    }

    /// <summary>ProDOS directory entry, decoded structure</summary>
    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct Entry
    {
        /// <summary>Type of file pointed by this entry Offset 0x00, mask 0xF0</summary>
        public byte storage_type;
        /// <summary>Length of name_length pascal string Offset 0x00, mask 0x0F</summary>
        public byte name_length;
        /// <summary>Pascal string of file name Offset 0x01, 15 bytes</summary>
        public string file_name;
        /// <summary>Descriptor of internal structure of the file Offset 0x10, 1 byte</summary>
        public byte file_type;
        /// <summary>
        ///     Block address of master index block for tree files. Block address of index block for sapling files. Block
        ///     address of block for seedling files. Offset 0x11, 2 bytes
        /// </summary>
        public ushort key_pointer;
        /// <summary>Blocks used by file or directory, including index blocks. Offset 0x13, 2 bytes</summary>
        public ushort blocks_used;
        /// <summary>Size of file in bytes Offset 0x15, 3 bytes</summary>
        public uint EOF;
        /// <summary>File creation datetime Offset 0x18, 4 bytes</summary>
        public DateTime creation_time;
        /// <summary>Version of ProDOS that created this file Offset 0x1C, 1 byte</summary>
        public byte version;
        /// <summary>Minimum version of ProDOS needed to access this file Offset 0x1D, 1 byte</summary>
        public byte min_version;
        /// <summary>File permissions Offset 0x1E, 1 byte</summary>
        public byte access;
        /// <summary>General purpose field to store additional information about file format Offset 0x1F, 2 bytes</summary>
        public ushort aux_type;
        /// <summary>File last modification date time Offset 0x21, 4 bytes</summary>
        public DateTime last_mod;
        /// <summary>Block address pointer to key block of the directory containing this entry Offset 0x25, 2 bytes</summary>
        public ushort header_pointer;
    }

    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct RootDirectoryHeader
    {
        /// <summary>Constant 0x0F Offset 0x04, mask 0xF0</summary>
        public byte storage_type;
        /// <summary>Length of volume_name pascal string Offset 0x04, mask 0x0F</summary>
        public byte name_length;
        /// <summary>The name of the volume. Offset 0x05, 15 bytes</summary>
        public string volume_name;
        /// <summary>Reserved for future expansion Offset 0x14, 8 bytes</summary>
        public ulong reserved;
        /// <summary>Creation time of the volume Offset 0x1C, 4 bytes</summary>
        public DateTime creation_time;
        /// <summary>Version number of the volume format Offset 0x20, 1 byte</summary>
        public byte version;
        /// <summary>Reserved for future use Offset 0x21, 1 byte</summary>
        public byte min_version;
        /// <summary>Permissions for the volume Offset 0x22, 1 byte</summary>
        public byte access;
        /// <summary>Length of an entry in this directory Const 0x27 Offset 0x23, 1 byte</summary>
        public byte entry_length;
        /// <summary>Number of entries per block Const 0x0D Offset 0x24, 1 byte</summary>
        public byte entries_per_block;
        /// <summary>Number of active files in this directory Offset 0x25, 2 bytes</summary>
        public ushort file_count;
        /// <summary>
        ///     Block address of the first block of the volume's bitmap, one for every 4096 blocks or fraction Offset 0x27, 2
        ///     bytes
        /// </summary>
        public ushort bit_map_pointer;
        /// <summary>Total number of blocks in the volume Offset 0x29, 2 bytes</summary>
        public ushort total_blocks;
    }

    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct DirectoryHeader
    {
        /// <summary>Constant 0x0E Offset 0x04, mask 0xF0</summary>
        public byte storage_type;
        /// <summary>Length of volume_name pascal string Offset 0x04, mask 0x0F</summary>
        public byte name_length;
        /// <summary>The name of the directory. Offset 0x05, 15 bytes</summary>
        public string directory_name;
        /// <summary>Reserved for future expansion Offset 0x14, 8 bytes</summary>
        public ulong reserved;
        /// <summary>Creation time of the volume Offset 0x1C, 4 bytes</summary>
        public DateTime creation_time;
        /// <summary>Version number of the volume format Offset 0x20, 1 byte</summary>
        public byte version;
        /// <summary>Reserved for future use Offset 0x21, 1 byte</summary>
        public byte min_version;
        /// <summary>Permissions for the volume Offset 0x22, 1 byte</summary>
        public byte access;
        /// <summary>Length of an entry in this directory Const 0x27 Offset 0x23, 1 byte</summary>
        public byte entry_length;
        /// <summary>Number of entries per block Const 0x0D Offset 0x24, 1 byte</summary>
        public byte entries_per_block;
        /// <summary>Number of active files in this directory Offset 0x25, 2 bytes</summary>
        public ushort file_count;
        /// <summary>Block address of parent directory block that contains this entry Offset 0x27, 2 bytes</summary>
        public ushort parent_pointer;
        /// <summary>Entry number within the block indicated in parent_pointer Offset 0x29, 1 byte</summary>
        public byte parent_entry_number;
        /// <summary>Length of the entry that holds this directory, in the parent entry Const 0x27 Offset 0x2A, 1 byte</summary>
        public byte parent_entry_length;
    }

    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct DirectoryKeyBlock
    {
        /// <summary>Always 0 Offset 0x00, 2 bytes</summary>
        public ushort zero;
        /// <summary>Pointer to next directory block, 0 if last Offset 0x02, 2 bytes</summary>
        public ushort next_pointer;
        /// <summary>Directory header Offset 0x04, 39 bytes</summary>
        public DirectoryHeader header;
        /// <summary>Directory entries Offset 0x2F, 39 bytes each, 12 entries</summary>
        public Entry[] entries;
    }

    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct RootDirectoryKeyBlock
    {
        /// <summary>Always 0 Offset 0x00, 2 bytes</summary>
        public ushort zero;
        /// <summary>Pointer to next directory block, 0 if last Offset 0x02, 2 bytes</summary>
        public ushort next_pointer;
        /// <summary>Directory header Offset 0x04, 39 bytes</summary>
        public RootDirectoryHeader header;
        /// <summary>Directory entries Offset 0x2F, 39 bytes each, 12 entries</summary>
        public Entry[] entries;
    }

    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct DirectoryBlock
    {
        /// <summary>Pointer to previous directory block Offset 0x00, 2 bytes</summary>
        public ushort zero;
        /// <summary>Pointer to next directory block, 0 if last Offset 0x02, 2 bytes</summary>
        public ushort next_pointer;
        /// <summary>Directory entries Offset 0x2F, 39 bytes each, 13 entries</summary>
        public Entry[] entries;
    }

    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct IndexBlock
    {
        /// <summary>Up to 256 pointers to blocks, 0 to indicate the block is sparsed (non-allocated)</summary>
        public ushort[] block_pointer;
    }

    [SuppressMessage("ReSharper", "InconsistentNaming")]
    struct MasterIndexBlock
    {
        /// <summary>Up to 128 pointers to index blocks</summary>
        public ushort[] index_block_pointer;
    }
}