using System;
using Microsoft.SPOT;

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

namespace CPF
{
    class IModem
    {
        public enum returnCode : int
        {
            none = 0,
            CSQ,
            SBDWT,
            SBDIX,
        }
       
        public static SerialPort iModemPort = new SerialPort("COM2", 19200, Parity.None, 8, StopBits.One);

        private static object iModemLock = new object();

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

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

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

            iModemPort.DiscardInBuffer();
            iModemPort.DiscardOutBuffer();
            iModemPort.DataReceived += new SerialDataReceivedEventHandler(iModemDataReceived);
        }

        private static byte[] txBytes = new byte[1024];

        private const string a3laCSQ = "AT+CSQ\r";
        public static void sendCSQ()
        {
            //Debug.Print("Sending CSQ");
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(a3laCSQ), txBytes, a3laCSQ.Length);
            qS.returnCode = (int)returnCode.CSQ;
            iModemPort.Write(txBytes, 0, a3laCSQ.Length);
        }


        private static StringBuilder sbTemp = new StringBuilder(1024);
        public static void sendSBDWT(byte[] inBytes)
        {
            sbTemp.Clear();
            sbTemp.Append(UTF8Encoding.UTF8.GetChars(inBytes));
            Debug.Print("SBDWT string = " + sbTemp.ToString());
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(sbTemp.ToString()), txBytes, sbTemp.Length);
            qS.returnCode = (int)returnCode.SBDWT;
            iModemPort.Write(txBytes, 0, sbTemp.Length);
        }

        private static StringBuilder sbSBDIX = new StringBuilder("AT+SBDIX\r");
        public static void sendSBDIX()
        {
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(sbSBDIX.ToString()), txBytes, sbSBDIX.Length);
            qS.returnCode = (int)returnCode.SBDIX;
            iModemPort.Write(txBytes, 0, sbTemp.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 iModemDataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            bytesToRead = iModemPort.BytesToRead;

            try
            {
                iModemPort.Read(bytesRead, 0, bytesToRead);
            }
            catch
            {
                Debug.Print("Iridium Modem 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("iModem Message = " + sbTemp.ToString());

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

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