using LibrarySDR.Enums;
using LibrarySDR.Flags;
using System;
using System.Collections;
using System.Globalization;
using System.Text;
using static LibrarySDR.Helpers.BinaryHexHelper;

namespace LibrarySDR.Requests
{
    public class TextSDSRequest
    {
        private static int sendingReference = 0;
        public static int SendingReference
        {
            get
            {
                // rest counter to value 0 after max value inside a byte
                if (sendingReference > 255)
                    sendingReference = 0;

                return sendingReference;
            }
        }

        private static PDUType PduType = PDUType.DATA_REQ_RESP;
        private static ProtocolIdentifier protocolIdentifier = ProtocolIdentifier.SimpleTextWithoutSDSTL;

        private Int64 sourceISSI;
        public Int64 SourceISSI { get { return sourceISSI; } }

        private Int64 destinationISSI;
        public Int64 DestinationISSI { get { return destinationISSI; } }


        private ProtocolIdentifier pi;
        public ProtocolIdentifier ProtocolIdentifier { get { return pi; } }

        private Int16 messageReference;
        public Int16 MessageRefence { get { return messageReference;  } }

        private Int16 areaSelection;
        public Int16 AreaSelection { get { return areaSelection; } }

        private Int16 validityPeriod;
        public Int16 ValidityPeriod { get { return validityPeriod; } }


        private Int64 forwardAddress;
        public Int64 ForwardAddress { get { return forwardAddress; } }

        private Int16 flags;
        public Int16 Flags { get { return flags; } }

        private DataFlag dataFlag;
        public DataFlag DataFlags { get { return dataFlag; } }

        private Int16 lengthBits;
        public Int16 LengthBits { get { return lengthBits; } }

        private Int16 lengthBytes;
        public Int16 LengthBytes { get { return lengthBytes; } }

        private Int16 textEncoding;
        public Int16 TextEncoding { get { return textEncoding; } }

        private String message;
        public String Message { get { return message; } }


        private String hexMessage;
        public String HexMessage { get { return hexMessage; } }

        private static Int64 transactionId = 1;
        public static Int64 TransactionId
        {
            get
            {
                return transactionId++;
            }
        }

        public static Int32 EncodingType = 26;

        public TextSDSRequest(string hexSimpleTextSDSReceived)
        {
            String resp = hexSimpleTextSDSReceived;
            int i = 0;
            int prevIdx = 0;
            
            // get source SSI (32 bits = 4 byte = 8 hex characters)
            String hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 4*2));
            Int64.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out sourceISSI);

            // get destination SSI (32 bits = 4 byte = 8 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 4*2));
            Int64.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out destinationISSI);

            // get protocol identifier (8 bits = 1 byte = 2 hex characters)
            Int16 pi = 0;
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 2));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out pi);
            this.pi = (ProtocolIdentifier)pi;

            // get message reference (8 bits = 1 byte = 2 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 2));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out messageReference);

            // get area selection (8 bits = 1 byte = 2 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 2));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out areaSelection);

            // get validity period (8 bits = 1 byte = 2 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 2));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out validityPeriod);

            // get forward address (32 bits = 4 byte = 8 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 4 * 2));
            Int64.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out forwardAddress);

            // get flags (8 bits = 1 byte = 2 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 2));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out flags);

            // parse the data flag
            dataFlag = new DataFlag(flags);

            // get length bits (16 bits = 2 byte = 4 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 4));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out lengthBits);

            // get length bytes (16 bits = 2 byte = 4 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 4));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out lengthBytes);

            // get encoding (8 bits = 1 byte = 2 hex characters)
            hex = LittleToBigEndianHexString(resp.Substring(i = i + prevIdx, prevIdx = 2));
            Int16.TryParse(hex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out textEncoding);

            hexMessage = resp.Substring(i = i + prevIdx); // LittleToBigEndianHexString(resp.Substring(i = i + prevIdx));

             
            for (int w = 0; w < hexMessage.Length /2; w++)
                message += (char)Convert.ToInt16(hexMessage.Substring(w * 2, 2), 16);

            ;
        }

       
        public static String GetInstance(Int64 sourceISSI, Int64 destinationISSI, String text, bool isConfirmationReq)
        {

            //text = "\u0006\u0006G\u0006D\u0006\u0006H\u00063\u0006G\u0006D\u0006";
            //text = "\u70B9\u83DC";

            StringBuilder sb = new StringBuilder("");

            // PDU Type (8 bits)
            sb.Append(GetBits((int)PduType, 8));

            // Source ISSI (32 bits)
            sb.Append(GetBits(sourceISSI, 32));

            // Destination ISSI (32 bits)
            sb.Append(GetBits(destinationISSI, 32));

            // Protocol Identifier (8 bits)
            sb.Append(GetBits(0x82, 8));

            // Message reference (8 bits) - ignored for Simple Text)
            ++sendingReference;
            sb.Append(GetBits(SendingReference, 8));

            // Area selection (8 bits) - unused
            sb.Append(GetBits(0x00, 8));

            // Validity period (8 bits) - unused
            sb.Append(GetBits(0x00, 8));

            // Forward Address (32 bits) - ignored for Simple Text
            sb.Append(GetBits(0x00, 32));

            // Flags (8 bits) 
            sb.Append(GetBits(isConfirmationReq ? 0x40 : 0x00, 8));


            // Length in bites (16 bits) + the encoding one
            sb.Append(GetBits((text.Length * 2 + 1) * 8 , 16));

            // Length in bytes (16 bits) + the encoding one
            sb.Append(GetBits(text.Length * 2 + 1, 16));

            // Encoding (8 bits) - Latin-1
            sb.Append(GetBits(EncodingType, 8));

            // Text message
            if (EncodingType == 1)
                sb.Append(GetBits(text, Encoding.Unicode));
            else
            {
                /*
                byte[] bytesUtf16 = Encoding.Unicode.GetBytes(text);
                String btit = ToBitString(new BitArray(bytesUtf16));

                sb.Append(btit);*/

                for (int i = 0; i < text.Length; i++)
                {
                    int unicode = text[i];

                    
                    string convertedUtf16 = GetEscapeSequence(text[i]);


                    BitArray b3 = new BitArray(StringToByteArrayFastest(convertedUtf16.Substring(2, 2)));
                    //BitArray b2 = new BitArray(StringToByteArrayFastest(convertedUtf16.Substring(2, 1)));
                    //BitArray b1 = new BitArray(StringToByteArrayFastest(convertedUtf16.Substring(1, 1)));
                    BitArray b0 = new BitArray(StringToByteArrayFastest(convertedUtf16.Substring(0, 2)));
                    String btit = ToBitString(new BitArray(b0), Endian.BIG);

                    sb.Append(btit.Substring(4, 4));
                    sb.Append(btit.Substring(0, 4));
                    //btit = ToBitString(new BitArray(b2));
                    //sb.Append(btit);
                    //btit = ToBitString(new BitArray(b1));
                    //sb.Append(btit);
                    btit = ToBitString(new BitArray(b3), Endian.BIG);
                    sb.Append(btit.Substring(4, 4));
                    sb.Append(btit.Substring(0, 4));

                    /*
                    byte[] bytesUtf16 = Encoding.Unicode.GetBytes(convertedUtf16);
                    String btit = ToBitString(new BitArray(bytesUtf16));
                    sb.Append(btit);
                    

                    byte[]  bytesUtf16 = Encoding.Unicode.GetBytes(convertedUtf16.Substring(2, 2));
                    String btit = ToBitString(new BitArray(bytesUtf16));
                    sb.Append(btit);
                    
                    bytesUtf16 = Encoding.Unicode.GetBytes(convertedUtf16.Substring(0,2));
                    btit = ToBitString(new BitArray(bytesUtf16));
                    sb.Append(btit);
                    */


                    /*
                    for (int w = 0; w < convertedUtf16.Length; w++)
                    {
                        Int16 unicodeVal = Int16.Parse(convertedUtf16[w] + "", NumberStyles.HexNumber);
                        //string convertedUtf16 = Encoding.Unicode.GetString(text[i]);

                        sb.Append(GetBits(unicodeVal, 8));
                    }*/
                }
            }

            /*
            // Transaction Id 
            sb.Append(GetBits(TransactionId, 32));

            // Gw Report
            sb.Append(GetBits(0x01, 8));*/

            // get the header with the length
            String header = Header.GetHeaderBinary(sb.ToString().Length / 8);

            // add header in front of the request
            return BinaryStringToHexString($"{header}{sb.ToString()}", Padding.RIGHT);
        }

        public static byte[] GetBytes(Int64 sourceISSI, Int64 destinationISSI, String text, bool isConfirmationReq)
        {
            String res = GetInstance(sourceISSI, destinationISSI, text, isConfirmationReq);

            byte[] response = new byte[res.Length / 2];

            for (int i = 0; i < res.Length / 2; i++)
                response[i] = (byte)Convert.ToInt16(res.Substring(i * 2, 2), 16);

            return response;
        }
    }
}