// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : File.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Apple Macintosh File System plugin.
//
// --[ Description ] ----------------------------------------------------------
//
//     Methods to handle files.
//
// --[ 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.IO;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Structs;
using Aaru.Console;
using Aaru.Helpers;
using FileAttributes = Aaru.CommonTypes.Structs.FileAttributes;

namespace Aaru.Filesystems
{
    // Information from Inside Macintosh Volume II
    public sealed partial class AppleMFS
    {
        /// <inheritdoc />
        public Errno MapBlock(string path, long fileBlock, out long deviceBlock)
        {
            deviceBlock = new long();

            if(!_mounted)
                return Errno.AccessDenied;

            string[] pathElements = path.Split(new[]
            {
                '/'
            }, StringSplitOptions.RemoveEmptyEntries);

            if(pathElements.Length != 1)
                return Errno.NotSupported;

            path = pathElements[0];

            if(!_filenameToId.TryGetValue(path.ToLowerInvariant(), out uint fileId))
                return Errno.NoSuchFile;

            if(!_idToEntry.TryGetValue(fileId, out FileEntry entry))
                return Errno.NoSuchFile;

            if(fileBlock > entry.flPyLen / _volMdb.drAlBlkSiz)
                return Errno.InvalidArgument;

            uint nextBlock = entry.flStBlk;
            long relBlock  = 0;

            while(true)
            {
                if(relBlock == fileBlock)
                {
                    deviceBlock = ((nextBlock - 2) * _sectorsPerBlock) + _volMdb.drAlBlSt + (long)_partitionStart;

                    return Errno.NoError;
                }

                if(_blockMap[nextBlock] == BMAP_FREE ||
                   _blockMap[nextBlock] == BMAP_LAST)
                    break;

                nextBlock = _blockMap[nextBlock];
                relBlock++;
            }

            return Errno.InOutError;
        }

        /// <inheritdoc />
        public Errno GetAttributes(string path, out FileAttributes attributes)
        {
            attributes = new FileAttributes();

            if(!_mounted)
                return Errno.AccessDenied;

            string[] pathElements = path.Split(new[]
            {
                '/'
            }, StringSplitOptions.RemoveEmptyEntries);

            if(pathElements.Length != 1)
                return Errno.NotSupported;

            path = pathElements[0];

            if(!_filenameToId.TryGetValue(path.ToLowerInvariant(), out uint fileId))
                return Errno.NoSuchFile;

            if(!_idToEntry.TryGetValue(fileId, out FileEntry entry))
                return Errno.NoSuchFile;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kIsAlias))
                attributes |= FileAttributes.Alias;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kHasBundle))
                attributes |= FileAttributes.Bundle;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kHasBeenInited))
                attributes |= FileAttributes.HasBeenInited;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kHasCustomIcon))
                attributes |= FileAttributes.HasCustomIcon;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kHasNoINITs))
                attributes |= FileAttributes.HasNoINITs;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kIsInvisible))
                attributes |= FileAttributes.Hidden;

            if(entry.flFlags.HasFlag(FileFlags.Locked))
                attributes |= FileAttributes.Immutable;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kIsOnDesk))
                attributes |= FileAttributes.IsOnDesk;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kIsShared))
                attributes |= FileAttributes.Shared;

            if(entry.flUsrWds.fdFlags.HasFlag(AppleCommon.FinderFlags.kIsStationery))
                attributes |= FileAttributes.Stationery;

            if(!attributes.HasFlag(FileAttributes.Alias)  &&
               !attributes.HasFlag(FileAttributes.Bundle) &&
               !attributes.HasFlag(FileAttributes.Stationery))
                attributes |= FileAttributes.File;

            attributes |= FileAttributes.BlockUnits;

            return Errno.NoError;
        }

        /// <inheritdoc />
        public Errno Read(string path, long offset, long size, ref byte[] buf)
        {
            if(!_mounted)
                return Errno.AccessDenied;

            byte[] file;
            Errno  error = Errno.NoError;

            if(_debug && string.Compare(path, "$", StringComparison.InvariantCulture) == 0)
                file = _directoryBlocks;
            else if(_debug                                                                &&
                    string.Compare(path, "$Boot", StringComparison.InvariantCulture) == 0 &&
                    _bootBlocks                                                      != null)
                file = _bootBlocks;
            else if(_debug && string.Compare(path, "$Bitmap", StringComparison.InvariantCulture) == 0)
                file = _blockMapBytes;
            else if(_debug && string.Compare(path, "$MDB", StringComparison.InvariantCulture) == 0)
                file = _mdbBlocks;
            else
                error = ReadFile(path, out file, false, false);

            if(error != Errno.NoError)
                return error;

            if(size == 0)
            {
                buf = Array.Empty<byte>();

                return Errno.NoError;
            }

            if(offset >= file.Length)
                return Errno.InvalidArgument;

            if(size + offset >= file.Length)
                size = file.Length - offset;

            buf = new byte[size];

            Array.Copy(file, offset, buf, 0, size);

            return Errno.NoError;
        }

        /// <inheritdoc />
        public Errno Stat(string path, out FileEntryInfo stat)
        {
            stat = null;

            if(!_mounted)
                return Errno.AccessDenied;

            string[] pathElements = path.Split(new[]
            {
                '/'
            }, StringSplitOptions.RemoveEmptyEntries);

            if(pathElements.Length != 1)
                return Errno.NotSupported;

            path = pathElements[0];

            if(_debug)
                if(string.Compare(path, "$", StringComparison.InvariantCulture)       == 0 ||
                   string.Compare(path, "$Boot", StringComparison.InvariantCulture)   == 0 ||
                   string.Compare(path, "$Bitmap", StringComparison.InvariantCulture) == 0 ||
                   string.Compare(path, "$MDB", StringComparison.InvariantCulture)    == 0)
                {
                    stat = new FileEntryInfo
                    {
                        BlockSize  = _device.Info.SectorSize,
                        Inode      = 0,
                        Links      = 1,
                        Attributes = FileAttributes.System
                    };

                    if(string.Compare(path, "$", StringComparison.InvariantCulture) == 0)
                    {
                        stat.Blocks = (_directoryBlocks.Length / stat.BlockSize) +
                                      (_directoryBlocks.Length % stat.BlockSize);

                        stat.Length = _directoryBlocks.Length;
                    }
                    else if(string.Compare(path, "$Bitmap", StringComparison.InvariantCulture) == 0)
                    {
                        stat.Blocks = (_blockMapBytes.Length / stat.BlockSize) +
                                      (_blockMapBytes.Length % stat.BlockSize);

                        stat.Length = _blockMapBytes.Length;
                    }
                    else if(string.Compare(path, "$Boot", StringComparison.InvariantCulture) == 0 &&
                            _bootBlocks                                                      != null)
                    {
                        stat.Blocks = (_bootBlocks.Length / stat.BlockSize) + (_bootBlocks.Length % stat.BlockSize);
                        stat.Length = _bootBlocks.Length;
                    }
                    else if(string.Compare(path, "$MDB", StringComparison.InvariantCulture) == 0)
                    {
                        stat.Blocks = (_mdbBlocks.Length / stat.BlockSize) + (_mdbBlocks.Length % stat.BlockSize);
                        stat.Length = _mdbBlocks.Length;
                    }
                    else
                        return Errno.InvalidArgument;

                    return Errno.NoError;
                }

            if(!_filenameToId.TryGetValue(path.ToLowerInvariant(), out uint fileId))
                return Errno.NoSuchFile;

            if(!_idToEntry.TryGetValue(fileId, out FileEntry entry))
                return Errno.NoSuchFile;

            Errno error = GetAttributes(path, out FileAttributes attr);

            if(error != Errno.NoError)
                return error;

            stat = new FileEntryInfo
            {
                Attributes    = attr,
                Blocks        = entry.flPyLen / _volMdb.drAlBlkSiz,
                BlockSize     = _volMdb.drAlBlkSiz,
                CreationTime  = DateHandlers.MacToDateTime(entry.flCrDat),
                Inode         = entry.flFlNum,
                LastWriteTime = DateHandlers.MacToDateTime(entry.flMdDat),
                Length        = entry.flLgLen,
                Links         = 1
            };

            return Errno.NoError;
        }

        /// <inheritdoc />
        public Errno ReadLink(string path, out string dest)
        {
            dest = null;

            return Errno.NotImplemented;
        }

        Errno ReadFile(string path, out byte[] buf, bool resourceFork, bool tags)
        {
            buf = null;

            if(!_mounted)
                return Errno.AccessDenied;

            string[] pathElements = path.Split(new[]
            {
                '/'
            }, StringSplitOptions.RemoveEmptyEntries);

            if(pathElements.Length != 1)
                return Errno.NotSupported;

            path = pathElements[0];

            if(!_filenameToId.TryGetValue(path.ToLowerInvariant(), out uint fileId))
                return Errno.NoSuchFile;

            if(!_idToEntry.TryGetValue(fileId, out FileEntry entry))
                return Errno.NoSuchFile;

            uint nextBlock;

            if(resourceFork)
            {
                if(entry.flRPyLen == 0)
                {
                    buf = Array.Empty<byte>();

                    return Errno.NoError;
                }

                nextBlock = entry.flRStBlk;
            }
            else
            {
                if(entry.flPyLen == 0)
                {
                    buf = Array.Empty<byte>();

                    return Errno.NoError;
                }

                nextBlock = entry.flStBlk;
            }

            var ms = new MemoryStream();

            do
            {
                byte[] sectors;

                if(tags)
                    sectors =
                        _device.
                            ReadSectorsTag((ulong)((nextBlock - 2) * _sectorsPerBlock) + _volMdb.drAlBlSt + _partitionStart,
                                           (uint)_sectorsPerBlock, SectorTagType.AppleSectorTag);
                else
                    sectors =
                        _device.
                            ReadSectors((ulong)((nextBlock - 2) * _sectorsPerBlock) + _volMdb.drAlBlSt + _partitionStart,
                                        (uint)_sectorsPerBlock);

                ms.Write(sectors, 0, sectors.Length);

                if(_blockMap[nextBlock] == BMAP_FREE)
                {
                    AaruConsole.ErrorWriteLine("File truncated at block {0}", nextBlock);

                    break;
                }

                nextBlock = _blockMap[nextBlock];
            } while(nextBlock > BMAP_LAST);

            if(tags)
                buf = ms.ToArray();
            else
            {
                if(resourceFork)
                    if(ms.Length < entry.flRLgLen)
                        buf = ms.ToArray();
                    else
                    {
                        buf = new byte[entry.flRLgLen];
                        Array.Copy(ms.ToArray(), 0, buf, 0, buf.Length);
                    }
                else
                {
                    if(ms.Length < entry.flLgLen)
                        buf = ms.ToArray();
                    else
                    {
                        buf = new byte[entry.flLgLen];
                        Array.Copy(ms.ToArray(), 0, buf, 0, buf.Length);
                    }
                }
            }

            return Errno.NoError;
        }
    }
}