// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : CSS&CPRM.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
//     Decodes DVD CSS & CPRM 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 © 2011-2018 Natalia Portillo
// ****************************************************************************/

using System.Text;

namespace DiscImageChef.Decoders.DVD
{
    /// <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
    /// ECMA 365
    /// </summary>
    public static class CSS_CPRM
    {
        public struct LeadInCopyright
        {
            /// <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
            /// Copy protection system type
            /// </summary>
            public CopyrightType CopyrightType;
            /// <summary>
            /// Byte 5
            /// Bitmask of regions where this disc is playable
            /// </summary>
            public byte RegionInformation;
            /// <summary>
            /// Byte 6
            /// Reserved
            /// </summary>
            public byte Reserved3;
            /// <summary>
            /// Byte 7
            /// Reserved
            /// </summary>
            public byte Reserved4;
        }

        public struct DiscKey
        {
            /// <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>
            /// Bytes 4 to 2052
            /// Disc key for CSS, Album Identifier for CPPM
            /// </summary>
            public byte[] Key;
        }

        public static LeadInCopyright? DecodeLeadInCopyright(byte[] response)
        {
            if(response == null) return null;

            if(response.Length != 8) return null;

            LeadInCopyright cmi = new LeadInCopyright();

            cmi.DataLength = (ushort)((response[0] << 8) + response[1]);
            cmi.Reserved1 = response[2];
            cmi.Reserved2 = response[3];
            cmi.CopyrightType = (CopyrightType)response[4];
            cmi.RegionInformation = response[5];
            cmi.Reserved3 = response[6];
            cmi.Reserved4 = response[7];

            return cmi;
        }

        public static string PrettifyLeadInCopyright(LeadInCopyright? cmi)
        {
            if(cmi == null) return null;

            LeadInCopyright decoded = cmi.Value;
            StringBuilder sb = new StringBuilder();

            switch(decoded.CopyrightType)
            {
                case CopyrightType.NoProtection:
                    sb.AppendLine("Disc has no encryption.");
                    break;
                case CopyrightType.CSS:
                    sb.AppendLine("Disc is encrypted using CSS or CPPM.");
                    break;
                case CopyrightType.CPRM:
                    sb.AppendLine("Disc is encrypted using CPRM.");
                    break;
                case CopyrightType.AACS:
                    sb.AppendLine("Disc is encrypted using AACS.");
                    break;
                default:
                    sb.AppendFormat("Disc is encrypted using unknown algorithm with ID {0}.", decoded.CopyrightType);
                    break;
            }

            if(decoded.CopyrightType == 0) return sb.ToString();

            if(decoded.RegionInformation == 0xFF) sb.AppendLine("Disc cannot be played in any region at all.");
            else if(decoded.RegionInformation == 0x00) sb.AppendLine("Disc can be played in any region.");
            else
            {
                sb.Append("Disc can be played in the following regions:");
                if((decoded.RegionInformation & 0x01) != 0x01) sb.Append(" 0");
                if((decoded.RegionInformation & 0x02) != 0x02) sb.Append(" 1");
                if((decoded.RegionInformation & 0x04) != 0x04) sb.Append(" 2");
                if((decoded.RegionInformation & 0x08) != 0x08) sb.Append(" 3");
                if((decoded.RegionInformation & 0x10) != 0x10) sb.Append(" 4");
                if((decoded.RegionInformation & 0x20) != 0x20) sb.Append(" 5");
                if((decoded.RegionInformation & 0x40) != 0x40) sb.Append(" 6");
                if((decoded.RegionInformation & 0x80) != 0x80) sb.Append(" 7");
            }

            return sb.ToString();
        }

        public static string PrettifyLeadInCopyright(byte[] response)
        {
            return PrettifyLeadInCopyright(DecodeLeadInCopyright(response));
        }
    }
}