/*
This file is part of PacketDotNet

PacketDotNet 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 3 of the License, or
(at your option) any later version.

PacketDotNet 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 PacketDotNet.  If not, see <http://www.gnu.org/licenses/>.
*/
/*
 *  Copyright 2010 Chris Morgan <chmorgan@gmail.com>
 */
using System;
using System.Collections.Generic;
using System.Text;
using PacketDotNet.Utils;
using MiscUtil.Conversion;

namespace PacketDotNet
{
    /// <summary>
    /// PPP packet
    /// See http://en.wikipedia.org/wiki/Point-to-Point_Protocol
    /// </summary>
    public class PPPPacket : Packet
    {
        // NOTE: No need to warn about lack of use, the compiler won't
        //       put any calls to 'log' here but we need 'log' to exist to compile
#pragma warning disable 0169, 0649
        private static readonly ILogInactive log;
#pragma warning restore 0169, 0649

        /// <summary>
        /// See http://www.iana.org/assignments/ppp-numbers
        /// </summary>
        public PPPProtocol Protocol
        {
            get
            {
                return (PPPProtocol)EndianBitConverter.Big.ToUInt16(header.Bytes,
                                                      header.Offset + PPPFields.ProtocolPosition);
            }

            set
            {
                var val = (UInt16)value;
                EndianBitConverter.Big.CopyBytes(val,
                                                 header.Bytes,
                                                 header.Offset + PPPFields.ProtocolPosition);
            }
        }

        /// <summary>
        /// Construct a new PPPPacket from source and destination mac addresses
        /// </summary>
        public PPPPacket(PPPoECode Code,
                     UInt16 SessionId)
        {
            log.Debug("");

            // allocate memory for this packet
            int offset = 0;
            int length = PPPFields.HeaderLength;
            var headerBytes = new byte[length];
            header = new ByteArraySegment(headerBytes, offset, length);

            // setup some typical values and default values
            this.Protocol = PPPProtocol.Padding;
        }

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="bas">
        /// A <see cref="ByteArraySegment"/>
        /// </param>
        public PPPPacket(ByteArraySegment bas)
        {
            log.Debug("");

            // slice off the header portion as our header
            header = new ByteArraySegment(bas);
            RandomUtils.EnsurePacketLength(this, PPPFields.HeaderLength, header.Length);
            header.Length = PPPFields.HeaderLength;

            // parse the encapsulated bytes
            payloadPacketOrData = ParseEncapsulatedBytes(header, Protocol);
        }

        internal static PacketOrByteArraySegment ParseEncapsulatedBytes(ByteArraySegment Header,
                                                                        PPPProtocol Protocol)
        {
            // slice off the payload
            var payload = Header.EncapsulatedBytes();

            log.DebugFormat("payload: {0}", payload);

            var payloadPacketOrData = new PacketOrByteArraySegment();

            switch(Protocol)
            {
            case PPPProtocol.IPv4:
                payloadPacketOrData.ThePacket = new IPv4Packet(payload);
                break;
            case PPPProtocol.IPv6:
                payloadPacketOrData.ThePacket = new IPv6Packet(payload);
                break;
            default:
                throw new System.NotImplementedException("Protocol of " + Protocol + " is not implemented");
            }

            return payloadPacketOrData;
        }

        /// <summary> Fetch ascii escape sequence of the color associated with this packet type.</summary>
        public override System.String Color
        {
            get
            {
                return AnsiEscapeSequences.DarkGray;
            }
        }

        /// <summary cref="Packet.ToString(StringOutputType)" />
        public override string ToString(StringOutputType outputFormat)
        {
            var buffer = new StringBuilder();
            string color = "";
            string colorEscape = "";

            if(outputFormat == StringOutputType.Colored || outputFormat == StringOutputType.VerboseColored)
            {
                color = Color;
                colorEscape = AnsiEscapeSequences.Reset;
            }

            if(outputFormat == StringOutputType.Normal || outputFormat == StringOutputType.Colored)
            {
                // build the output string
                buffer.AppendFormat("{0}[PPPPacket: Protocol={2}]{1}",
                    color,
                    colorEscape,
                    Protocol);
            }

            if(outputFormat == StringOutputType.Verbose || outputFormat == StringOutputType.VerboseColored)
            {
                // collect the properties and their value
                Dictionary<string,string> properties = new Dictionary<string,string>();
                properties.Add("protocol", Protocol.ToString() + " (0x" + Protocol.ToString("x") + ")");

                // calculate the padding needed to right-justify the property names
                int padLength = Utils.RandomUtils.LongestStringLength(new List<string>(properties.Keys));

                // build the output string
                buffer.AppendLine("PPP:  ******* PPP - \"Point-to-Point Protocol\" - offset=? length=" + TotalPacketLength);
                buffer.AppendLine("PPP:");
                foreach(var property in properties)
                {
                    buffer.AppendLine("PPP: " + property.Key.PadLeft(padLength) + " = " + property.Value);
                }
                buffer.AppendLine("PPP:");
            }

            // append the base output
            buffer.Append(base.ToString(outputFormat));

            return buffer.ToString();
        }

        /// <summary>
        /// Returns the encapsulated PPPPacket of the Packet p or null if
        /// there is no encapsulated packet
        /// </summary>
        /// <param name="p">
        /// A <see cref="Packet"/>
        /// </param>
        /// <returns>
        /// A <see cref="PPPPacket"/>
        /// </returns>
        [Obsolete("Use Packet.Extract() instead")]
        public static PPPPacket GetEncapsulated(Packet p)
        {
            if(p is EthernetPacket)
            {
                var payload = p.PayloadPacket;
                if(payload is PPPoEPacket)
                {
                    return (PPPPacket)payload.PayloadPacket;

                }
            }

            return null;
        }

        /// <summary>
        /// Generate a random PPPoEPacket
        /// </summary>
        /// <returns>
        /// A <see cref="PPPoEPacket"/>
        /// </returns>
        public static PPPoEPacket RandomPacket()
        {
            throw new System.NotImplementedException();
        }
    }
}