using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Collections;
using System.Collections.Specialized;
using System.IO;

namespace IvyBus
{
    /// <summary>
    /// Description résumée de IvyStream.
    /// </summary>
    internal class IvyTCPStreamV3 : NetworkStream, IvyProtocol
    {
        StreamReader input;
        StreamWriter output;
        IvyProtocol receiver;

        /// the protocol separator
        internal const char ARG_START = '\x02';
        internal const char ARG_END = '\x03';
        internal const char MSG_END = '\n';

        internal IvyTCPStreamV3(Socket socket, IvyProtocol _receiver) : base ( socket )
        {
            output = new StreamWriter(this, Ivy.ivyEncoding);
            output.NewLine = MSG_END.ToString();
            input = new StreamReader(this, Ivy.ivyEncoding);
            receiver = _receiver;
        }
        /* the protocol magic numbers */
        internal enum MessageType : ushort
        {
            Bye = 0,			/* end of the peer */
            AddRegexp = 1,		/* the peer adds a regexp */
            Msg = 2,			/* the peer sends a message */
            Error = 3,			/* error message */
            DelBinding = 4,		/* the peer removes one of his regex */ // OLD DelRegexp rename to DelBinding
            EndRegexp = 5,		/* no more regexp in the handshake */
            StartRegexp = 6,	/* avoid race condition in concurrent connexions */
            DirectMsg = 7,		/* the peer sends a direct message */
            Die = 8,			/* the peer wants us to quit */
            Ping = 9,			/* checks the presence of the other */
            Pong = 10,			/* checks the presence of the other */
        };

        /*
         * message Syntax:
         * this is text formated message 'type id STX ARG0 {[ETX] ARG1 [ETX] ARGn}\n'
         * 
         * message Format:
                MessageType, id , length, string 
         */
        
        private void sendMsg(MessageType msgType, ushort msgId, string msgData)
        {
                  // IOException Should be traited upstairs
                output.Write((ushort)msgType);
                output.Write(' ');
                output.Write(msgId);
                output.Write(ARG_START);
                output.Write(msgData);
                output.Write(MSG_END);
                output.Flush();
        
        }
        void IvyProtocol.TokenStartRegexp(ushort port, string appName)
        {
            sendMsg(MessageType.StartRegexp, port, appName);
        }
        void IvyProtocol.TokenEndRegexp()
        {
            sendMsg(MessageType.EndRegexp, 0, "");
        }
        void IvyProtocol.TokenApplicationId(ushort priority, string appId)
        {
           // NOt implemented in this protocol version
        }

        void IvyProtocol.TokenAddBinding(BindingType type, ushort id, string expression)
        {
            switch (type)
            {
                case BindingType.Regexp:
                    sendMsg(MessageType.AddRegexp, id, expression); /* perhaps we should perform some checking here */
                    break;
                case BindingType.Simple:
                    // NO Simple Binding in this protocol
                    break;
            }
        }

        void IvyProtocol.TokenDelBinding(ushort id)
        {
            sendMsg(MessageType.DelBinding, id, "");
        }

        void IvyProtocol.TokenDirectMsg(ushort id, string message)
        {
            sendMsg(MessageType.DirectMsg, id, message);
        }
        void IvyProtocol.TokenPong(string s)
        {
            sendMsg(MessageType.Pong, 0, s);
        }
        void IvyProtocol.TokenPing(string s)
        {
            sendMsg(MessageType.Ping, 0, s);
        }

        void IvyProtocol.TokenBye(ushort id, string message)
        {
            sendMsg(MessageType.Bye, id, message);
        }

        void IvyProtocol.TokenDie(ushort id, string message)
        {
            sendMsg(MessageType.Die, id, message);
        }

        void IvyProtocol.TokenMsg(ushort key, string[] args)
        {
            string delimiter = "" + ARG_END;
            string data = string.Join(delimiter, args);
            // a bad protocol implementation in C add a delimiter to the end of each arg
            // we must add a delimiter to the end
            data += delimiter;
            sendMsg(MessageType.Msg, key, data);
        }

        void IvyProtocol.TokenError(ushort key, string arg)
        {
            sendMsg(MessageType.Msg, key, arg);
        }

        private ushort DeserializeShort()
        {
            int read;
            ushort ret = 0;
            char digit;
            // this will eat next non digit char ie space
            do
            {
                read = input.Read();
                if (read < 0)
                    throw new EndOfStreamException();
                digit = (char)read;
                if (Char.IsDigit(digit))
                    ret = (ushort)(ret * 10 + (digit - 0x30));
            } while (Char.IsDigit(digit));
            return ret;
        }
        private string DeserializeString(char sep)
        {
            int read;
            char car;
            StringBuilder str = new StringBuilder();
            // this will eat next non separator char
            do
            {
                read = input.Read();
                if (read < 0) 
                    throw new EndOfStreamException();
                car = (char)read;
                if (car != sep ) str.Append(car);
            } while (car != sep);
            return str.ToString();
        }

        bool IvyProtocol.receiveMsg()
        {
            MessageType msgType = MessageType.Die;
            ushort msgId = 0;
            string msgData = null;

            try
            {
                msgType = (MessageType)DeserializeShort();
                msgId = DeserializeShort();
                msgData = DeserializeString(MSG_END);

                switch (msgType)
                {
                    case MessageType.Die:
                        receiver.TokenDie(msgId, msgData);
                        break;

                    case MessageType.Bye:
                        receiver.TokenBye(msgId, msgData);
                        break;

                    case MessageType.AddRegexp:    
                        receiver.TokenAddBinding(BindingType.Regexp, msgId, msgData);
                        break;

                    case MessageType.DelBinding:
                        receiver.TokenDelBinding(msgId);
                        break;

                    case MessageType.EndRegexp:
                        receiver.TokenEndRegexp();
                        break;

                    case MessageType.Msg:
                        // a bad protocol implementation in C add a delimiter to the end of each arg
                        // we must remove a delimiter to the end
                        if ( msgData.Length > 0 )
                            msgData = msgData.Remove(msgData.Length - 1,1);
                        receiver.TokenMsg(msgId, msgData.Split( ARG_END ));
                        break;

                    case MessageType.Pong:
                        receiver.TokenPong(msgData);
                        break;

                    case MessageType.Ping:
                        receiver.TokenPing(msgData);
                        break;

                    case MessageType.Error:
                        receiver.TokenError(msgId, msgData);
                        break;

                    case MessageType.StartRegexp:
                        receiver.TokenStartRegexp(msgId, msgData);
                        break;

                    case MessageType.DirectMsg:
                        receiver.TokenDirectMsg(msgId, msgData);
                        break;
                    default:
                        throw new IvyException("protocol error, unknown message type " + msgType);

                }



            }
            catch (EndOfStreamException)
            {
                return false;
            }
            catch (FormatException)
            {
                throw new IvyException("protocol error on msgType");
            }


            return true;
        }

    }
}