using System;
using Microsoft.SPOT;

using System.Threading;
using System.IO.Ports;
using System.Text;

namespace CPF
{
    public static class EVK7GPS
    {
        public static SerialPort evk7Port = new SerialPort("COM5", 19200, Parity.None, 8, StopBits.One);

        private static object evk7Lock = new object();

        private static StructQueue.qStruct qS = new StructQueue.qStruct();

        public static void init()
        {
            qS.byteArray = new byte[StructQueue.qRecordWidth];

            evk7Port.ReadTimeout = 5000;
            evk7Port.Open();

            evk7Port.DiscardInBuffer();
            evk7Port.DiscardOutBuffer();
            evk7Port.DataReceived += new SerialDataReceivedEventHandler(evk7DataReceived);
        }

        private static byte[] txBytes = new byte[64];
        private const string evk7PUBXCmd = "$PUBX,00*33\r\n";
        public static void getPUBX()
        {
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(evk7PUBXCmd), txBytes, evk7PUBXCmd.Length);
            evk7Port.Write(txBytes, 0, evk7PUBXCmd.Length);
        }

        private static byte LF = 10;
        private static byte[] bytesRead = new byte[2048];
        private static byte[] messageBytes = new byte[2048];
        private static int bytesToRead;
        private static int messageIndex = 0;

        private static void evk7DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            bytesToRead = evk7Port.BytesToRead;

            try
            {
                evk7Port.Read(bytesRead, 0, bytesToRead);
            }
            catch
            {
                Debug.Print("EVK7 GPS Read Exception");          //TODO do something smarter here
            }

            for (int i = 0; i < bytesToRead; i++)
            {
                messageBytes[messageIndex] = bytesRead[i];
                if (messageBytes[messageIndex] == LF)
                {
                    qS.timeStamp = DateTime.Now;
                    qS.state = Program.CPFState;

                    //sbTemp.Clear();
                    //sbTemp.Append(UTF8Encoding.UTF8.GetChars(messageBytes, 0, messageIndex - 1));
                    //Debug.Print("EVK7 Message = " + sbTemp.ToString());

                    Array.Clear(qS.byteArray, 0, qS.byteArray.Length);
                    Array.Copy(messageBytes, qS.byteArray, messageIndex + 1);
                    qS.qRecordType = StructQueue.QRecordType.EVK7;
                    lock (evk7Lock) { Program.sQueue.Enqueue(qS); }

                    messageIndex = 0;
                    Array.Clear(messageBytes, 0, messageBytes.Length);
                }
                else
                {
                    messageIndex = messageIndex + 1;
                }
            }
        }
    }
}