// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : WriteProtect.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
//     Decodes SCSI's MMC write protection 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.Text;

namespace DiscImageChef.Decoders.SCSI.MMC
{
    /// <summary>
    /// Information from the following standards:
    /// ANSI X3.304-1997
    /// T10/1048-D revision 9.0
    /// T10/1048-D revision 10a
    /// T10/1228-D revision 7.0c
    /// T10/1228-D revision 11a
    /// T10/1363-D revision 10g
    /// T10/1545-D revision 1d
    /// T10/1545-D revision 5
    /// T10/1545-D revision 5a
    /// T10/1675-D revision 2c
    /// T10/1675-D revision 4
    /// T10/1836-D revision 2g
    /// </summary>
    public static class WriteProtect
    {
        public struct WriteProtectionStatus
        {
            /// <summary>
            /// Bytes 0 to 1
            /// Data Length
            /// </summary>
            public ushort DataLength;
            /// <summary>
            /// Byte 2
            /// Reserved
            /// </summary>
            public byte Reserved1;
            /// <summary>
            /// Byte 3
            /// Reserved
            /// </summary>
            public byte Reserved2;
            /// <summary>
            /// Byte 4, bits 7 to 4
            /// Reserved
            /// </summary>
            public byte Reserved3;
            /// <summary>
            /// Byte 4, bit 3
            /// Writing inhibited by media specific reason
            /// </summary>
            public bool MSWI;
            /// <summary>
            /// Byte 4, bit 2
            /// Cartridge sets write protection
            /// </summary>
            public bool CWP;
            /// <summary>
            /// Byte 4, bit 1
            /// Media surface sets write protection
            /// </summary>
            public bool PWP;
            /// <summary>
            /// Byte 4, bit 0
            /// Software write protection until power down
            /// </summary>
            public bool SWPP;
            /// <summary>
            /// Byte 5
            /// Reserved
            /// </summary>
            public byte Reserved4;
            /// <summary>
            /// Byte 6
            /// Reserved
            /// </summary>
            public byte Reserved5;
            /// <summary>
            /// Byte 7
            /// Reserved
            /// </summary>
            public byte Reserved6;
        }

        public static WriteProtectionStatus? DecodeWriteProtectionStatus(byte[] WPSResponse)
        {
            if(WPSResponse == null)
                return null;

            WriteProtectionStatus decoded = new WriteProtectionStatus();

            BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;

            decoded.DataLength = BigEndianBitConverter.ToUInt16(WPSResponse, 0);
            decoded.Reserved1 = WPSResponse[2];
            decoded.Reserved2 = WPSResponse[3];
            decoded.Reserved3 = (byte)((WPSResponse[4] & 0xF0) >> 4);
            decoded.MSWI = Convert.ToBoolean(WPSResponse[4] & 0x08);
            decoded.CWP = Convert.ToBoolean(WPSResponse[4] & 0x04);
            decoded.PWP = Convert.ToBoolean(WPSResponse[4] & 0x02);
            decoded.SWPP = Convert.ToBoolean(WPSResponse[4] & 0x01);
            decoded.Reserved4 = WPSResponse[5];
            decoded.Reserved5 = WPSResponse[6];
            decoded.Reserved6 = WPSResponse[7];

            return decoded;
        }

        public static string PrettifyWriteProtectionStatus(WriteProtectionStatus? WPSResponse)
        {
            if(WPSResponse == null)
                return null;

            WriteProtectionStatus response = WPSResponse.Value;

            StringBuilder sb = new StringBuilder();

            if(response.MSWI)
                sb.AppendLine("Writing inhibited by media specific reason");
            if(response.CWP)
                sb.AppendLine("Cartridge sets write protection");
            if(response.PWP)
                sb.AppendLine("Media surface sets write protection");
            if(response.SWPP)
                sb.AppendLine("Software write protection is set until power down");

#if DEBUG
            if(response.Reserved1 != 0)
                sb.AppendFormat("Reserved1 = 0x{0:X2}", response.Reserved1).AppendLine();
            if(response.Reserved2 != 0)
                sb.AppendFormat("Reserved2 = 0x{0:X2}", response.Reserved2).AppendLine();
            if(response.Reserved3 != 0)
                sb.AppendFormat("Reserved3 = 0x{0:X2}", response.Reserved3).AppendLine();
            if(response.Reserved4 != 0)
                sb.AppendFormat("Reserved4 = 0x{0:X2}", response.Reserved4).AppendLine();
            if(response.Reserved5 != 0)
                sb.AppendFormat("Reserved5 = 0x{0:X2}", response.Reserved5).AppendLine();
            if(response.Reserved6 != 0)
                sb.AppendFormat("Reserved6 = 0x{0:X2}", response.Reserved6).AppendLine();
#endif

            return sb.ToString();
        }

        public static string PrettifyWriteProtectionStatus(byte[] WPSResponse)
        {
            WriteProtectionStatus? decoded = DecodeWriteProtectionStatus(WPSResponse);
            return PrettifyWriteProtectionStatus(decoded);
        }
    }
}

