// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : DensitySupport.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
//     Decodes SCSI's SSC density support structures.
//
// --[ 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 © 2011-2017 Natalia Portillo
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.Text;

namespace DiscImageChef.Decoders.SCSI.SSC
{
    public static class DensitySupport
    {
        public struct DensitySupportHeader
        {
            public ushort length;
            public ushort reserved;
            public DensitySupportDescriptor[] descriptors;
        }

        public struct MediaTypeSupportHeader
        {
            public ushort length;
            public ushort reserved;
            public MediaTypeSupportDescriptor[] descriptors;
        }

        public struct DensitySupportDescriptor
        {
            public byte primaryCode;
            public byte secondaryCode;
            public bool writable;
            public bool duplicate;
            public bool defaultDensity;
            public byte reserved;
            public bool lenvalid;
            public ushort len;
            public uint bpmm;
            public ushort width;
            public ushort tracks;
            public uint capacity;
            public string organization;
            public string name;
            public string description;
        }

        public struct MediaTypeSupportDescriptor
        {
            public byte mediumType;
            public byte reserved1;
            public ushort len;
            public byte numberOfCodes;
            public byte[] densityCodes;
            public ushort width;
            public ushort length;
            public byte reserved2;
            public byte reserved3;
            public string organization;
            public string name;
            public string description;
        }

        public static DensitySupportHeader? DecodeDensity(byte[] response)
        {
            if(response == null)
                return null;

            if(response.Length <= 56)
                return null;

            ushort responseLen = (ushort)((response[0] << 8) + response[1] + 2);

            if(response.Length != responseLen)
                return null;

            List<DensitySupportDescriptor> descriptors = new List<DensitySupportDescriptor>();
            int offset = 4;
            byte[] tmp;

            while(offset < response.Length)
            {
                DensitySupportDescriptor descriptor = new DensitySupportDescriptor();
                descriptor.primaryCode = response[offset + 0];
                descriptor.secondaryCode = response[offset + 1];
                descriptor.writable |= (response[offset + 2] & 0x80) == 0x80;
                descriptor.duplicate |= (response[offset + 2] & 0x40) == 0x40;
                descriptor.defaultDensity |= (response[offset + 2] & 0x20) == 0x20;
                descriptor.reserved = (byte)((response[offset + 2] & 0x1E) >> 1);
                descriptor.lenvalid |= (response[offset + 2] & 0x01) == 0x01;
                descriptor.len = (ushort)((response[offset + 3] << 8) + response[offset + 4]);
                descriptor.bpmm = (uint)((response[offset + 5] << 16) + (response[offset + 6] << 8) + response[offset + 7]);
                descriptor.width = (ushort)((response[offset + 8] << 8) + response[offset + 9]);
                descriptor.tracks = (ushort)((response[offset + 10] << 8) + response[offset + 11]);
                descriptor.capacity = (uint)((response[offset + 12] << 24) + (response[offset + 13] << 16) + (response[offset + 14] << 8) + response[offset + 15]);
                tmp = new byte[8];
                Array.Copy(response, offset + 16, tmp, 0, 8);
                descriptor.organization = StringHandlers.CToString(tmp).Trim();
                tmp = new byte[8];
                Array.Copy(response, offset + 24, tmp, 0, 8);
                descriptor.name = StringHandlers.CToString(tmp).Trim();
                tmp = new byte[20];
                Array.Copy(response, offset + 32, tmp, 0, 20);
                descriptor.description = StringHandlers.CToString(tmp).Trim();

                if(descriptor.lenvalid)
                    offset += descriptor.len + 5;
                else
                    offset += 52;

                descriptors.Add(descriptor);
            }

            DensitySupportHeader decoded = new DensitySupportHeader();
            decoded.length = responseLen;
            decoded.reserved = (ushort)((response[2] << 8) + response[3] + 2);
            decoded.descriptors = descriptors.ToArray();

            return decoded;
        }

        public static string PrettifyDensity(DensitySupportHeader? density)
        {
            if(density == null)
                return null;

            DensitySupportHeader decoded = density.Value;
            StringBuilder sb = new StringBuilder();

            foreach(DensitySupportDescriptor descriptor in decoded.descriptors)
            {
                sb.AppendFormat("Density \"{0}\" defined by \"{1}\".", descriptor.name, descriptor.organization).AppendLine();
                sb.AppendFormat("\tPrimary code: {0:X2}h", descriptor.primaryCode).AppendLine();
                if(descriptor.primaryCode != descriptor.secondaryCode)
                    sb.AppendFormat("\tSecondary code: {0:X2}h", descriptor.secondaryCode).AppendLine();
                if(descriptor.writable)
                    sb.AppendLine("\tDrive can write this density");
                if(descriptor.duplicate)
                    sb.AppendLine("\tThis descriptor is duplicated");
                if(descriptor.defaultDensity)
                    sb.AppendLine("\tThis is the default density on the drive");
                sb.AppendFormat("\tDensity has {0} bits per mm, with {1} tracks in a {2} mm width tape",
#pragma warning disable IDE0004 // Remove Unnecessary Cast
                    descriptor.bpmm, descriptor.tracks, (double)((double)descriptor.width / (double)10)).AppendLine();
#pragma warning restore IDE0004 // Remove Unnecessary Cast
                sb.AppendFormat("\tDensity maximum capacity is {0} megabytes", descriptor.capacity).AppendLine();
                sb.AppendFormat("\tDensity description: {0}", descriptor.description).AppendLine();
                sb.AppendLine();
            }

            return sb.ToString();
        }

        public static string PrettifyDensity(byte[] response)
        {
            return PrettifyDensity(DecodeDensity(response));
        }

        public static MediaTypeSupportHeader? DecodeMediumType(byte[] response)
        {
            if(response == null)
                return null;

            if(response.Length <= 60)
                return null;

            ushort responseLen = (ushort)((response[0] << 8) + response[1] + 2);

            if(response.Length != responseLen)
                return null;

            List<MediaTypeSupportDescriptor> descriptors = new List<MediaTypeSupportDescriptor>();
            int offset = 4;
            byte[] tmp;

            while(offset < response.Length)
            {
                MediaTypeSupportDescriptor descriptor = new MediaTypeSupportDescriptor();
                descriptor.mediumType = response[offset + 0];
                descriptor.reserved1 = response[offset + 1];
                descriptor.len = (ushort)((response[offset + 2] << 8) + response[offset + 3]);
                if(descriptor.len != 52)
                    return null;
                descriptor.numberOfCodes = response[offset + 4];
                descriptor.densityCodes = new byte[9];
                Array.Copy(response, offset + 5, descriptor.densityCodes, 0, 9);
                descriptor.width = (ushort)((response[offset + 14] << 8) + response[offset + 15]);
                descriptor.length = (ushort)((response[offset + 16] << 8) + response[offset + 17]);
                descriptor.reserved1 = response[offset + 18];
                descriptor.reserved1 = response[offset + 19];
                tmp = new byte[8];
                Array.Copy(response, offset + 20, tmp, 0, 8);
                descriptor.organization = StringHandlers.CToString(tmp).Trim();
                tmp = new byte[8];
                Array.Copy(response, offset + 28, tmp, 0, 8);
                descriptor.name = StringHandlers.CToString(tmp).Trim();
                tmp = new byte[20];
                Array.Copy(response, offset + 36, tmp, 0, 20);
                descriptor.description = StringHandlers.CToString(tmp).Trim();

                offset += 56;

                descriptors.Add(descriptor);
            }

            MediaTypeSupportHeader decoded = new MediaTypeSupportHeader();
            decoded.length = responseLen;
            decoded.reserved = (ushort)((response[2] << 8) + response[3] + 2);
            decoded.descriptors = descriptors.ToArray();

            return decoded;
        }

        public static string PrettifyMediumType(MediaTypeSupportHeader? mediumType)
        {
            if(mediumType == null)
                return null;

            MediaTypeSupportHeader decoded = mediumType.Value;
            StringBuilder sb = new StringBuilder();

            foreach(MediaTypeSupportDescriptor descriptor in decoded.descriptors)
            {
                sb.AppendFormat("Medium type \"{0}\" defined by \"{1}\".", descriptor.name, descriptor.organization).AppendLine();
                sb.AppendFormat("\tMedium type code: {0:X2}h", descriptor.mediumType).AppendLine();
                if(descriptor.numberOfCodes > 0)
                {
                    sb.AppendFormat("\tMedium supports following density codes:");
                    for(int i = 0; i < descriptor.numberOfCodes; i++)
                        sb.AppendFormat(" {0:X2}h", descriptor.densityCodes[i]);
                    sb.AppendLine();
                }

                sb.AppendFormat("\tMedium has a nominal length of {0} m in a {1} mm width tape",
#pragma warning disable IDE0004 // Remove Unnecessary Cast
                    descriptor.length, (double)((double)descriptor.width / (double)10)).AppendLine();
#pragma warning restore IDE0004 // Remove Unnecessary Cast
                sb.AppendFormat("\tMedium description: {0}", descriptor.description).AppendLine();
                sb.AppendLine();
            }

            return sb.ToString();
        }

        public static string PrettifyMediumType(byte[] response)
        {
            return PrettifyMediumType(DecodeMediumType(response));
        }
    }
}

