// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : Read.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Reads Spectrum FDI 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 © 2011-2019 Natalia Portillo
// ****************************************************************************/

using System;
using System.IO;
using DiscImageChef.CommonTypes;
using DiscImageChef.CommonTypes.Enums;
using DiscImageChef.CommonTypes.Interfaces;
using DiscImageChef.Console;
using DiscImageChef.Helpers;

namespace DiscImageChef.DiscImages
{
    public partial class UkvFdi
    {
        public bool Open(IFilter imageFilter)
        {
            Stream stream = imageFilter.GetDataForkStream();
            stream.Seek(0, SeekOrigin.Begin);

            FdiHeader hdr = new FdiHeader();

            if(stream.Length < Marshal.SizeOf<FdiHeader>()) return false;

            byte[] hdrB = new byte[Marshal.SizeOf<FdiHeader>()];
            stream.Read(hdrB, 0, hdrB.Length);

            hdr = Marshal.ByteArrayToStructureLittleEndian<FdiHeader>(hdrB);

            DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.addInfoLen = {0}", hdr.addInfoLen);
            DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.cylinders = {0}",  hdr.cylinders);
            DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.dataOff = {0}",    hdr.dataOff);
            DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.descOff = {0}",    hdr.descOff);
            DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.flags = {0}",      hdr.flags);
            DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.heads = {0}",      hdr.heads);

            stream.Seek(hdr.descOff, SeekOrigin.Begin);
            byte[] description = new byte[hdr.dataOff - hdr.descOff];
            stream.Read(description, 0, description.Length);
            imageInfo.Comments = StringHandlers.CToString(description);

            DicConsole.DebugWriteLine("UkvFdi plugin", "hdr.description = \"{0}\"", imageInfo.Comments);

            stream.Seek(0xE + hdr.addInfoLen, SeekOrigin.Begin);

            long       spt        = long.MaxValue;
            uint[][][] sectorsOff = new uint[hdr.cylinders][][];
            sectorsData = new byte[hdr.cylinders][][][];

            imageInfo.Cylinders = hdr.cylinders;
            imageInfo.Heads     = hdr.heads;

            // Read track descriptors
            for(ushort cyl = 0; cyl < hdr.cylinders; cyl++)
            {
                sectorsOff[cyl]  = new uint[hdr.heads][];
                sectorsData[cyl] = new byte[hdr.heads][][];

                for(ushort head = 0; head < hdr.heads; head++)
                {
                    byte[] sctB = new byte[4];
                    stream.Read(sctB, 0, 4);
                    stream.Seek(2, SeekOrigin.Current);
                    byte sectors = (byte)stream.ReadByte();
                    uint trkOff  = BitConverter.ToUInt32(sctB, 0);

                    DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.c = {0}",       cyl);
                    DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.h = {0}",       head);
                    DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.sectors = {0}", sectors);
                    DicConsole.DebugWriteLine("UkvFdi plugin", "trkhdr.off = {0}",     trkOff);

                    sectorsOff[cyl][head]  = new uint[sectors];
                    sectorsData[cyl][head] = new byte[sectors][];

                    if(sectors < spt && sectors > 0) spt = sectors;

                    for(ushort sec = 0; sec < sectors; sec++)
                    {
                        byte        c    = (byte)stream.ReadByte();
                        byte        h    = (byte)stream.ReadByte();
                        byte        r    = (byte)stream.ReadByte();
                        byte        n    = (byte)stream.ReadByte();
                        SectorFlags f    = (SectorFlags)stream.ReadByte();
                        byte[]      offB = new byte[2];
                        stream.Read(offB, 0, 2);
                        ushort secOff = BitConverter.ToUInt16(offB, 0);

                        DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.c = {0}",       c);
                        DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.h = {0}",       h);
                        DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.r = {0}",       r);
                        DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.n = {0} ({1})", n, 128 << n);
                        DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.f = {0}",       f);
                        DicConsole.DebugWriteLine("UkvFdi plugin", "sechdr.off = {0} ({1})", secOff,
                                                  secOff + trkOff + hdr.dataOff);

                        // TODO: This assumes sequential sectors.
                        sectorsOff[cyl][head][sec]  = secOff + trkOff + hdr.dataOff;
                        sectorsData[cyl][head][sec] = new byte[128 << n];

                        if(128 << n > imageInfo.SectorSize) imageInfo.SectorSize = (uint)(128 << n);
                    }
                }
            }

            // Read sectors
            for(ushort cyl = 0; cyl < hdr.cylinders; cyl++)
            {
                bool emptyCyl = false;

                for(ushort head = 0; head < hdr.heads; head++)
                {
                    for(ushort sec = 0; sec < sectorsOff[cyl][head].Length; sec++)
                    {
                        stream.Seek(sectorsOff[cyl][head][sec], SeekOrigin.Begin);
                        stream.Read(sectorsData[cyl][head][sec], 0, sectorsData[cyl][head][sec].Length);
                    }

                    // For empty cylinders
                    if(sectorsOff[cyl][head].Length != 0) continue;

                    if(cyl + 1 == hdr.cylinders ||
                       // Next cylinder is also empty
                       sectorsOff[cyl + 1][head].Length == 0) emptyCyl = true;
                    // Create empty sectors
                    else
                    {
                        sectorsData[cyl][head] = new byte[spt][];
                        for(int i = 0; i < spt; i++) sectorsData[cyl][head][i] = new byte[imageInfo.SectorSize];
                    }
                }

                if(emptyCyl) imageInfo.Cylinders--;
            }

            // TODO: What about double sided, half track pitch compact floppies?
            imageInfo.MediaType            = MediaType.CompactFloppy;
            imageInfo.ImageSize            = (ulong)stream.Length - hdr.dataOff;
            imageInfo.CreationTime         = imageFilter.GetCreationTime();
            imageInfo.LastModificationTime = imageFilter.GetLastWriteTime();
            imageInfo.MediaTitle           = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
            imageInfo.SectorsPerTrack      = (uint)spt;
            imageInfo.Sectors              = imageInfo.Cylinders * imageInfo.Heads * imageInfo.SectorsPerTrack;
            imageInfo.XmlMediaType         = XmlMediaType.BlockMedia;

            return true;
        }

        public byte[] ReadSector(ulong sectorAddress)
        {
            (ushort cylinder, byte head, byte sector) = LbaToChs(sectorAddress);

            if(cylinder >= sectorsData.Length)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            if(head >= sectorsData[cylinder].Length)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            if(sector > sectorsData[cylinder][head].Length)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            return sectorsData[cylinder][head][sector - 1];
        }

        public byte[] ReadSectors(ulong sectorAddress, uint length)
        {
            if(sectorAddress > imageInfo.Sectors - 1)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            if(sectorAddress + length > imageInfo.Sectors)
                throw new ArgumentOutOfRangeException(nameof(length), "Requested more sectors than available");

            MemoryStream buffer = new MemoryStream();
            for(uint i = 0; i < length; i++)
            {
                byte[] sector = ReadSector(sectorAddress + i);
                buffer.Write(sector, 0, sector.Length);
            }

            return buffer.ToArray();
        }
    }
}