// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Write.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Writes VirtualBox disk images.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library is distributed in the hope that it will be useful, but
//     WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2021 Natalia Portillo
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Structs;
using Aaru.Helpers;
using Schemas;
using Marshal = Aaru.Helpers.Marshal;

namespace Aaru.DiscImages
{
    public sealed partial class Vdi
    {
        /// <inheritdoc />
        public bool Create(string path, MediaType mediaType, Dictionary<string, string> options, ulong sectors,
                           uint sectorSize)
        {
            if(sectorSize != 512)
            {
                ErrorMessage = "Unsupported sector size";

                return false;
            }

            if(!SupportedMediaTypes.Contains(mediaType))
            {
                ErrorMessage = $"Unsupported media format {mediaType}";

                return false;
            }

            if(sectors * sectorSize / DEFAULT_BLOCK_SIZE > uint.MaxValue)
            {
                ErrorMessage = "Too many sectors for selected cluster size";

                return false;
            }

            _imageInfo = new ImageInfo
            {
                MediaType  = mediaType,
                SectorSize = sectorSize,
                Sectors    = sectors
            };

            try
            {
                _writingStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None);
            }
            catch(IOException e)
            {
                ErrorMessage = $"Could not create new image file, exception {e.Message}";

                return false;
            }

            uint ibmEntries = (uint)(sectors * sectorSize / DEFAULT_BLOCK_SIZE);

            if(sectors * sectorSize % DEFAULT_BLOCK_SIZE > 0)
                ibmEntries++;

            uint headerSectors = 1 + (ibmEntries * 4 / sectorSize);

            if(ibmEntries * 4 % sectorSize != 0)
                headerSectors++;

            _ibm                    = new uint[ibmEntries];
            _currentWritingPosition = headerSectors * sectorSize;

            _vHdr = new Header
            {
                creator      = DIC_AARU,
                magic        = VDI_MAGIC,
                majorVersion = 1,
                minorVersion = 1,
                headerSize   = Marshal.SizeOf<Header>() - 72,
                imageType    = VdiImageType.Normal,
                offsetBlocks = sectorSize,
                offsetData   = (uint)_currentWritingPosition,
                sectorSize   = sectorSize,
                size         = sectors * sectorSize,
                blockSize    = DEFAULT_BLOCK_SIZE,
                blocks       = ibmEntries,
                uuid         = Guid.NewGuid(),
                snapshotUuid = Guid.NewGuid()
            };

            for(uint i = 0; i < ibmEntries; i++)
                _ibm[i] = VDI_EMPTY;

            IsWriting    = true;
            ErrorMessage = null;

            return true;
        }

        /// <inheritdoc />
        public bool WriteMediaTag(byte[] data, MediaTagType tag)
        {
            ErrorMessage = "Writing media tags is not supported.";

            return false;
        }

        /// <inheritdoc />
        public bool WriteSector(byte[] data, ulong sectorAddress)
        {
            if(!IsWriting)
            {
                ErrorMessage = "Tried to write on a non-writable image";

                return false;
            }

            if(data.Length != _imageInfo.SectorSize)
            {
                ErrorMessage = "Incorrect data size";

                return false;
            }

            if(sectorAddress >= _imageInfo.Sectors)
            {
                ErrorMessage = "Tried to write past image size";

                return false;
            }

            // Ignore empty sectors
            if(ArrayHelpers.ArrayIsNullOrEmpty(data))
                return true;

            ulong index  = sectorAddress * _vHdr.sectorSize / _vHdr.blockSize;
            ulong secOff = sectorAddress * _vHdr.sectorSize % _vHdr.blockSize;

            uint ibmOff = _ibm[index];

            if(ibmOff == VDI_EMPTY)
            {
                ibmOff                  =  (uint)((_currentWritingPosition - _vHdr.offsetData) / _vHdr.blockSize);
                _ibm[index]             =  ibmOff;
                _currentWritingPosition += _vHdr.blockSize;
                _vHdr.allocatedBlocks++;
            }

            ulong imageOff = _vHdr.offsetData + ((ulong)ibmOff * _vHdr.blockSize);

            _writingStream.Seek((long)imageOff, SeekOrigin.Begin);
            _writingStream.Seek((long)secOff, SeekOrigin.Current);
            _writingStream.Write(data, 0, data.Length);

            ErrorMessage = "";

            return true;
        }

        // TODO: This can be optimized
        /// <inheritdoc />
        public bool WriteSectors(byte[] data, ulong sectorAddress, uint length)
        {
            if(!IsWriting)
            {
                ErrorMessage = "Tried to write on a non-writable image";

                return false;
            }

            if(data.Length % _imageInfo.SectorSize != 0)
            {
                ErrorMessage = "Incorrect data size";

                return false;
            }

            if(sectorAddress + length > _imageInfo.Sectors)
            {
                ErrorMessage = "Tried to write past image size";

                return false;
            }

            // Ignore empty sectors
            if(ArrayHelpers.ArrayIsNullOrEmpty(data))
                return true;

            for(uint i = 0; i < length; i++)
            {
                byte[] tmp = new byte[_imageInfo.SectorSize];
                Array.Copy(data, i * _imageInfo.SectorSize, tmp, 0, _imageInfo.SectorSize);

                if(!WriteSector(tmp, sectorAddress + i))
                    return false;
            }

            ErrorMessage = "";

            return true;
        }

        /// <inheritdoc />
        public bool WriteSectorLong(byte[] data, ulong sectorAddress)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";

            return false;
        }

        /// <inheritdoc />
        public bool WriteSectorsLong(byte[] data, ulong sectorAddress, uint length)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";

            return false;
        }

        /// <inheritdoc />
        public bool Close()
        {
            if(!IsWriting)
            {
                ErrorMessage = "Image is not opened for writing";

                return false;
            }

            if(!string.IsNullOrEmpty(_imageInfo.Comments))
                _vHdr.comments = _imageInfo.Comments.Length > 255 ? _imageInfo.Comments.Substring(0, 255)
                                     : _imageInfo.Comments;

            if(_vHdr.logicalCylinders == 0)
            {
                _vHdr.logicalCylinders = (uint)(_imageInfo.Sectors / 16 / 63);
                _vHdr.logicalHeads     = 16;
                _vHdr.logicalSpt       = 63;

                while(_vHdr.logicalCylinders == 0)
                {
                    _vHdr.logicalHeads--;

                    if(_vHdr.logicalHeads == 0)
                    {
                        _vHdr.logicalSpt--;
                        _vHdr.logicalHeads = 16;
                    }

                    _vHdr.logicalCylinders = (uint)(_imageInfo.Sectors / _vHdr.logicalHeads / _vHdr.logicalSpt);

                    if(_vHdr.logicalCylinders == 0 &&
                       _vHdr.logicalHeads     == 0 &&
                       _vHdr.logicalSpt       == 0)
                        break;
                }
            }

            byte[] hdr    = new byte[Marshal.SizeOf<Header>()];
            IntPtr hdrPtr = System.Runtime.InteropServices.Marshal.AllocHGlobal(Marshal.SizeOf<Header>());
            System.Runtime.InteropServices.Marshal.StructureToPtr(_vHdr, hdrPtr, true);
            System.Runtime.InteropServices.Marshal.Copy(hdrPtr, hdr, 0, hdr.Length);
            System.Runtime.InteropServices.Marshal.FreeHGlobal(hdrPtr);

            _writingStream.Seek(0, SeekOrigin.Begin);
            _writingStream.Write(hdr, 0, hdr.Length);

            _writingStream.Seek(_vHdr.offsetBlocks, SeekOrigin.Begin);
            _writingStream.Write(MemoryMarshal.Cast<uint, byte>(_ibm).ToArray(), 0, 4 * _ibm.Length);

            _writingStream.Flush();
            _writingStream.Close();

            IsWriting    = false;
            ErrorMessage = "";

            return true;
        }

        /// <inheritdoc />
        public bool SetMetadata(ImageInfo metadata)
        {
            _imageInfo.Comments = metadata.Comments;

            return true;
        }

        /// <inheritdoc />
        public bool SetGeometry(uint cylinders, uint heads, uint sectorsPerTrack)
        {
            _vHdr.cylinders = cylinders;
            _vHdr.heads     = heads;
            _vHdr.spt       = sectorsPerTrack;

            return true;
        }

        /// <inheritdoc />
        public bool WriteSectorTag(byte[] data, ulong sectorAddress, SectorTagType tag)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";

            return false;
        }

        /// <inheritdoc />
        public bool WriteSectorsTag(byte[] data, ulong sectorAddress, uint length, SectorTagType tag)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";

            return false;
        }

        /// <inheritdoc />
        public bool SetDumpHardware(List<DumpHardwareType> dumpHardware) => false;

        /// <inheritdoc />
        public bool SetCicmMetadata(CICMMetadataType metadata) => false;
    }
}