using System;
using Microsoft.SPOT;

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


namespace CPF
{
    class IModem
    {
        public enum ReturnCodes : int
        {
            none = 0,
            CSQ,
            SBDWT,
            SBDIX,
        }
        public static int returnCode;

        public static SerialPort iModemPort = new SerialPort("COM2", 19200, Parity.None, 8, StopBits.One);

        private static object iModemLock = new object();

        public static void init()
        {
            Array.Clear(messageBytes, 0, messageBytes.Length);
            Array.Clear(bytesRead, 0, bytesRead.Length);

            qS.byteArray = new byte[StructQueue.byteArrayWidth];

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

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

            sendD0();
            Thread.Sleep(1000);
            sendK0();
            Thread.Sleep(1000);
            sendSBDD2();
            Thread.Sleep(1000);
        }

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

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

        private const string a3laD0 = "AT&D0\r";
        public static void sendD0()
        {
            //Debug.Print(DateTime.Now + " Sending D0");
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(a3laD0), txBytes, a3laD0.Length);
            iModemPort.Write(txBytes, 0, a3laD0.Length);
        }

        private const string a3laK0 = "AT&K0\r";
        public static void sendK0()
        {
            //Debug.Print(DateTime.Now + " Sending K0");
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(a3laK0), txBytes, a3laK0.Length);
            iModemPort.Write(txBytes, 0, a3laK0.Length);
        }

        private static byte[] sbdwtHeader = new byte[9] { (byte)65, (byte)84, (byte)43, (byte)83, (byte)66, (byte)68, (byte)87, (byte)84, (byte)13 };            // AT+SBDWT

        private static readonly StringBuilder sbTemp = new StringBuilder(1024);
        public static void sendSBDWT(byte[] inBytes)
        {
            //Debug.Print(DateTime.Now + " Sending SBDWT");
            iModemPort.Write(sbdwtHeader, 0, sbdwtHeader.Length);
            Thread.Sleep(2000);
            sbTemp.Clear();
            sbTemp.Append(UTF8Encoding.UTF8.GetChars(inBytes));
            //Debug.Print(DateTime.Now + " Sending:" + sbTemp.ToString());
            iModemPort.Write(inBytes, 0, Array.IndexOf(inBytes, 0));
        }

        private static readonly StringBuilder sbSBDD2 = new StringBuilder("AT+SBDD2\r");
        public static void sendSBDD2()
        {
            //Debug.Print(DateTime.Now + " Sending SBDD2");
            iModemPort.Write(UTF8Encoding.UTF8.GetBytes(sbSBDD2.ToString()), 0, sbSBDD2.Length);
        }

        private static readonly StringBuilder sbSBDI = new StringBuilder("AT+SBDI\r");
        public static void sendSBDI()
        {
            //Debug.Print(DateTime.Now + " Sending SBDI");
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(sbSBDI.ToString()), txBytes, sbSBDI.Length);
            iModemPort.Write(txBytes, 0, sbSBDI.Length);
        }

        private static readonly StringBuilder sbSBDIX = new StringBuilder("AT+SBDIX\r");
        public static void sendSBDIX()
        {
            //Debug.Print(DateTime.Now + " Sending SBDIX");
            Array.Clear(txBytes, 0, txBytes.Length);
            Array.Copy(UTF8Encoding.UTF8.GetBytes(sbSBDI.ToString()), txBytes, sbSBDI.Length);
            iModemPort.Write(txBytes, 0, sbSBDI.Length);
        }

        public static void parseSQ(byte[] inBytes)
        {
            if ((inBytes[0] == 43) && (inBytes[1] == 67) && (inBytes[2] == 83) && (inBytes[3] == 81))
                Program.signalQuality = (int)inBytes[5] - 48;
        }

        private static byte LF = 10;
        private static byte[] bytesRead = new byte[2048];
        public static byte[] messageBytes = new byte[2048];
        private static int bytesToRead;
        private static int messageIndex = 0;
        private static StructQueue.qStruct qS = new StructQueue.qStruct();
        private static Object IModemLock = new Object();

        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(DateTime.Now + " 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);
                    returnCode = 0;
                }
                else
                {
                    messageIndex = messageIndex + 1;
                }
            }
        }
    }
}