/* Copyright (C) 2014-2017 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
 * 
 * You can redistribute this program and/or modify it under the terms of
 * the GNU Lesser Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 */
using System;
using System.Collections.Generic;
using Utilities;

namespace SMBLibrary
{
    /// <summary>
    /// [MS-DTYP] ACL (Access Control List)
    /// </summary>
    public class ACL : List<ACE>
    {
        public const int FixedLength = 8;

        public byte AclRevision;
        public byte Sbz1;
        // ushort AclSize;
        // ushort AceCount;
        public ushort Sbz2;

        public ACL()
        {
            AclRevision = 0x02;
        }

        public ACL(byte[] buffer, int offset)
        {
            AclRevision = ByteReader.ReadByte(buffer, offset + 0);
            Sbz1 = ByteReader.ReadByte(buffer, offset + 1);
            ushort aclSize = LittleEndianConverter.ToUInt16(buffer, offset + 2);
            ushort aceCount = LittleEndianConverter.ToUInt16(buffer, offset + 4);
            Sbz2 = LittleEndianConverter.ToUInt16(buffer, offset + 6);

            offset += 8;
            for (int index = 0; index < aceCount; index++)
            {
                ACE ace = ACE.GetAce(buffer, offset);
                this.Add(ace);
                offset += ace.Length;
            }
        }

        public void WriteBytes(byte[] buffer, ref int offset)
        {
            ByteWriter.WriteByte(buffer, ref offset, AclRevision);
            ByteWriter.WriteByte(buffer, ref offset, Sbz1);
            LittleEndianWriter.WriteUInt16(buffer, ref offset, (ushort)Length);
            LittleEndianWriter.WriteUInt16(buffer, ref offset, (ushort)Count);
            LittleEndianWriter.WriteUInt16(buffer, ref offset, Sbz2);
            foreach (ACE ace in this)
            {
                ace.WriteBytes(buffer, ref offset);
            }
        }

        public int Length
        {
            get
            {
                int length = FixedLength;
                foreach (ACE ace in this)
                {
                    length += ace.Length;
                }
                return length;
            }
        }
    }
}