// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : 05.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
//     Decodes SCSI MODE PAGE 05h: Flexible disk page.
//
// --[ 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.Diagnostics.CodeAnalysis;
using System.Text;

namespace DiscImageChef.Decoders.SCSI
{
    [SuppressMessage("ReSharper", "InconsistentNaming")]
    [SuppressMessage("ReSharper", "MemberCanBeInternal")]
    [SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
    public static partial class Modes
    {
        #region Mode Page 0x05: Flexible disk page
        /// <summary>
        ///     Disconnect-reconnect page
        ///     Page code 0x05
        ///     32 bytes in SCSI-2, SBC-1
        /// </summary>
        public struct ModePage_05
        {
            /// <summary>
            ///     Parameters can be saved
            /// </summary>
            public bool PS;
            /// <summary>
            ///     Data rate of peripheral device on kbit/s
            /// </summary>
            public ushort TransferRate;
            /// <summary>
            ///     Heads for reading and/or writing
            /// </summary>
            public byte Heads;
            /// <summary>
            ///     Sectors per revolution per head
            /// </summary>
            public byte SectorsPerTrack;
            /// <summary>
            ///     Bytes of data per sector
            /// </summary>
            public ushort BytesPerSector;
            /// <summary>
            ///     Cylinders used for data storage
            /// </summary>
            public ushort Cylinders;
            /// <summary>
            ///     Cylinder where write precompensation starts
            /// </summary>
            public ushort WritePrecompCylinder;
            /// <summary>
            ///     Cylinder where write current reduction starts
            /// </summary>
            public ushort WriteReduceCylinder;
            /// <summary>
            ///     Step rate in 100 μs units
            /// </summary>
            public ushort DriveStepRate;
            /// <summary>
            ///     Width of step pulse in μs
            /// </summary>
            public byte DriveStepPulse;
            /// <summary>
            ///     Head settle time in 100 μs units
            /// </summary>
            public ushort HeadSettleDelay;
            /// <summary>
            ///     If <see cref="TRDY" /> is <c>true</c>, specified in 1/10s of a
            ///     second the time waiting for read status before aborting medium
            ///     access. Otherwise, indicates time to way before medimum access
            ///     after motor on signal is asserted.
            /// </summary>
            public byte MotorOnDelay;
            /// <summary>
            ///     Time in 1/10s of a second to wait before releasing the motor on
            ///     signal after an idle condition. 0xFF means to never release the
            ///     signal
            /// </summary>
            public byte MotorOffDelay;
            /// <summary>
            ///     Specifies if a signal indicates that the medium is ready to be accessed
            /// </summary>
            public bool TRDY;
            /// <summary>
            ///     If <c>true</c> sectors start with one. Otherwise, they start with zero.
            /// </summary>
            public bool SSN;
            /// <summary>
            ///     If <c>true</c> specifies that motor on shall remain released.
            /// </summary>
            public bool MO;
            /// <summary>
            ///     Number of additional step pulses per cylinder.
            /// </summary>
            public byte SPC;
            /// <summary>
            ///     Write compensation value
            /// </summary>
            public byte WriteCompensation;
            /// <summary>
            ///     Head loading time in ms.
            /// </summary>
            public byte HeadLoadDelay;
            /// <summary>
            ///     Head unloading time in ms.
            /// </summary>
            public byte HeadUnloadDelay;
            /// <summary>
            ///     Description of shugart's bus pin 34 usage
            /// </summary>
            public byte Pin34;
            /// <summary>
            ///     Description of shugart's bus pin 2 usage
            /// </summary>
            public byte Pin2;
            /// <summary>
            ///     Description of shugart's bus pin 4 usage
            /// </summary>
            public byte Pin4;
            /// <summary>
            ///     Description of shugart's bus pin 1 usage
            /// </summary>
            public byte Pin1;
            /// <summary>
            ///     Medium speed in rpm
            /// </summary>
            public ushort MediumRotationRate;
        }

        public static ModePage_05? DecodeModePage_05(byte[] pageResponse)
        {
            if((pageResponse?[0] & 0x40) == 0x40) return null;

            if((pageResponse?[0] & 0x3F) != 0x05) return null;

            if(pageResponse[1] + 2 != pageResponse.Length) return null;

            if(pageResponse.Length < 32) return null;

            ModePage_05 decoded = new ModePage_05();

            decoded.PS                   |= (pageResponse[0] & 0x80) == 0x80;
            decoded.TransferRate         =  (ushort)((pageResponse[2] << 8) + pageResponse[3]);
            decoded.Heads                =  pageResponse[4];
            decoded.SectorsPerTrack      =  pageResponse[5];
            decoded.BytesPerSector       =  (ushort)((pageResponse[6]  << 8) + pageResponse[7]);
            decoded.Cylinders            =  (ushort)((pageResponse[8]  << 8) + pageResponse[9]);
            decoded.WritePrecompCylinder =  (ushort)((pageResponse[10] << 8) + pageResponse[11]);
            decoded.WriteReduceCylinder  =  (ushort)((pageResponse[12] << 8) + pageResponse[13]);
            decoded.DriveStepRate        =  (ushort)((pageResponse[14] << 8) + pageResponse[15]);
            decoded.DriveStepPulse       =  pageResponse[16];
            decoded.HeadSettleDelay      =  (ushort)((pageResponse[17] << 8) + pageResponse[18]);
            decoded.MotorOnDelay         =  pageResponse[19];
            decoded.MotorOffDelay        =  pageResponse[20];
            decoded.TRDY                 |= (pageResponse[21]       & 0x80) == 0x80;
            decoded.SSN                  |= (pageResponse[21]       & 0x40) == 0x40;
            decoded.MO                   |= (pageResponse[21]       & 0x20) == 0x20;
            decoded.SPC                  =  (byte)(pageResponse[22] & 0x0F);
            decoded.WriteCompensation    =  pageResponse[23];
            decoded.HeadLoadDelay        =  pageResponse[24];
            decoded.HeadUnloadDelay      =  pageResponse[25];
            decoded.Pin34                =  (byte)((pageResponse[26] & 0xF0) >> 4);
            decoded.Pin2                 =  (byte)(pageResponse[26] & 0x0F);
            decoded.Pin4                 =  (byte)((pageResponse[27] & 0xF0) >> 4);
            decoded.Pin1                 =  (byte)(pageResponse[27] & 0x0F);
            decoded.MediumRotationRate   =  (ushort)((pageResponse[28] << 8) + pageResponse[29]);

            return decoded;
        }

        public static string PrettifyModePage_05(byte[] pageResponse) =>
            PrettifyModePage_05(DecodeModePage_05(pageResponse));

        public static string PrettifyModePage_05(ModePage_05? modePage)
        {
            if(!modePage.HasValue) return null;

            ModePage_05   page = modePage.Value;
            StringBuilder sb   = new StringBuilder();

            sb.AppendLine("SCSI Flexible disk page:");

            if(page.PS) sb.AppendLine("\tParameters can be saved");

            sb.AppendFormat("\tTransfer rate: {0} kbit/s", page.TransferRate).AppendLine();
            sb.AppendFormat("\t{0} heads", page.Heads).AppendLine();
            sb.AppendFormat("\t{0} cylinders", page.Cylinders).AppendLine();
            sb.AppendFormat("\t{0} sectors per track", page.SectorsPerTrack).AppendLine();
            sb.AppendFormat("\t{0} bytes per sector", page.BytesPerSector).AppendLine();
            if(page.WritePrecompCylinder < page.Cylinders)
                sb.AppendFormat("\tWrite pre-compensation starts at cylinder {0}", page.WritePrecompCylinder)
                  .AppendLine();
            if(page.WriteReduceCylinder < page.Cylinders)
                sb.AppendFormat("\tWrite current reduction starts at cylinder {0}", page.WriteReduceCylinder)
                  .AppendLine();
            if(page.DriveStepRate > 0)
                sb.AppendFormat("\tDrive steps in {0} μs", (uint)page.DriveStepRate * 100).AppendLine();
            if(page.DriveStepPulse > 0)
                sb.AppendFormat("\tEach step pulse is {0} ms", page.DriveStepPulse).AppendLine();
            if(page.HeadSettleDelay > 0)
                sb.AppendFormat("\tHeads settles in {0} μs", (uint)page.HeadSettleDelay * 100).AppendLine();

            if(!page.TRDY)
                sb
                   .AppendFormat("\tTarget shall wait {0} seconds before attempting to access the medium after motor on is asserted",
                                 (double)page.MotorOnDelay * 10).AppendLine();
            else
                sb
                   .AppendFormat("\tTarget shall wait {0} seconds after drive is ready before aborting medium access attemps",
                                 (double)page.MotorOnDelay * 10).AppendLine();

            if(page.MotorOffDelay != 0xFF)
                sb
                   .AppendFormat("\tTarget shall wait {0} seconds before releasing the motor on signal after becoming idle",
                                 (double)page.MotorOffDelay * 10).AppendLine();
            else sb.AppendLine("\tTarget shall never release the motor on signal");

            if(page.TRDY) sb.AppendLine("\tThere is a drive ready signal");
            if(page.SSN) sb.AppendLine("\tSectors start at 1");
            if(page.MO) sb.AppendLine("\tThe motor on signal shall remain released");

            sb.AppendFormat("\tDrive needs to do {0} step pulses per cylinder", page.SPC + 1).AppendLine();

            if(page.WriteCompensation > 0)
                sb.AppendFormat("\tWrite pre-compensation is {0}", page.WriteCompensation).AppendLine();
            if(page.HeadLoadDelay > 0) sb.AppendFormat("\tHead takes {0} ms to load", page.HeadLoadDelay).AppendLine();
            if(page.HeadUnloadDelay > 0)
                sb.AppendFormat("\tHead takes {0} ms to unload", page.HeadUnloadDelay).AppendLine();

            if(page.MediumRotationRate > 0)
                sb.AppendFormat("\tMedium rotates at {0} rpm", page.MediumRotationRate).AppendLine();

            switch(page.Pin34 & 0x07)
            {
                case 0:
                    sb.AppendLine("\tPin 34 is unconnected");
                    break;
                case 1:
                    sb.Append("\tPin 34 indicates drive is ready when active ");
                    sb.Append((page.Pin34 & 0x08) == 0x08 ? "high" : "low");
                    break;
                case 2:
                    sb.Append("\tPin 34 indicates disk has changed when active ");
                    sb.Append((page.Pin34 & 0x08) == 0x08 ? "high" : "low");
                    break;
                default:
                    sb.AppendFormat("\tPin 34 indicates unknown function {0} when active ", page.Pin34 & 0x07);
                    sb.Append((page.Pin34 & 0x08) == 0x08 ? "high" : "low");
                    break;
            }

            switch(page.Pin4 & 0x07)
            {
                case 0:
                    sb.AppendLine("\tPin 4 is unconnected");
                    break;
                case 1:
                    sb.Append("\tPin 4 indicates drive is in use when active ");
                    sb.Append((page.Pin4 & 0x08) == 0x08 ? "high" : "low");
                    break;
                case 2:
                    sb.Append("\tPin 4 indicates eject when active ");
                    sb.Append((page.Pin4 & 0x08) == 0x08 ? "high" : "low");
                    break;
                case 3:
                    sb.Append("\tPin 4 indicates head load when active ");
                    sb.Append((page.Pin4 & 0x08) == 0x08 ? "high" : "low");
                    break;
                default:
                    sb.AppendFormat("\tPin 4 indicates unknown function {0} when active ", page.Pin4 & 0x07);
                    sb.Append((page.Pin4 & 0x08) == 0x08 ? "high" : "low");
                    break;
            }

            switch(page.Pin2 & 0x07)
            {
                case 0:
                    sb.AppendLine("\tPin 2 is unconnected");
                    break;
                default:
                    sb.AppendFormat("\tPin 2 indicates unknown function {0} when active ", page.Pin2 & 0x07);
                    sb.Append((page.Pin2 & 0x08) == 0x08 ? "high" : "low");
                    break;
            }

            switch(page.Pin1 & 0x07)
            {
                case 0:
                    sb.AppendLine("\tPin 1 is unconnected");
                    break;
                case 1:
                    sb.Append("\tPin 1 indicates disk change reset when active ");
                    sb.Append((page.Pin1 & 0x08) == 0x08 ? "high" : "low");
                    break;
                default:
                    sb.AppendFormat("\tPin 1 indicates unknown function {0} when active ", page.Pin1 & 0x07);
                    sb.Append((page.Pin1 & 0x08) == 0x08 ? "high" : "low");
                    break;
            }

            return sb.ToString();
        }
        #endregion Mode Page 0x05: Flexible disk page
    }
}