using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.Nfc.CardEmulators;

namespace B2NFC
{
    [Service(Exported = true, Enabled = true, Permission = "android.permission.BIND_NFC_SERVICE"),
                 IntentFilter(new[] { "android.nfc.cardemulation.action.HOST_APDU_SERVICE" }, Categories = new[] { "android.intent.category.DEFAULT" }),
                 MetaData("android.nfc.cardemulation.host_apdu_service", Resource = "@xml/aid_list")]
    class ServicoPay : HostApduService
    {

        private byte[] CPPSE = new byte[] { 0x00, 0xA4, 0x04, 0x00, 0x0E };
        private byte[] CSELECT = new byte[] { 0x00, 0xA4, 0x04, 0x00, 0x07 };
        private byte[] CGPO = new byte[] { 0x80, 0xA8, 0x00, 0x00, 0x02 };
        private byte[] CGEN = new byte[] { 0x80, 0xAE, 0x80, 0x00, 0x2B };
        private byte[] CRECORD1 = new byte[] { 0x00, 0xB2, 0x01, 0x14, 0x00 };
        private byte[] CRECORD2 = new byte[] { 0x00, 0xB2, 0x01, 0x1C, 0x00 };
        private byte[] CRECORD3 = new byte[] { 0x00, 0xB2, 0x02, 0x1C, 0x00 };
        private byte[] CRECORD4 = new byte[] { 0x00, 0xB2, 0x01, 0x24, 0x00 };
        private byte[] CRECORD5 = new byte[] { 0x00, 0xB2, 0x02, 0x24, 0x00 };

        private static byte[] ISO7816_UNKNOWN_ERROR_RESPONSE ={
            (byte)0x6F, (byte)0x00
    };


        private byte[] RRECORD1 = new byte[] { 0x00 };
        private byte[] RRECORD2 = new byte[] { 0x00 };
        private byte[] RRECORD3 = new byte[] { 0x00 };
        private byte[] RRECORD4 = new byte[] { 0x00 };
        private byte[] RRECORD5 = new byte[] { 0x00 };
        public byte[] CopyByte(byte[] arr, int index, int count)
        {
            if (count < 1)
                return new byte[0];

            List<byte> Res = new List<byte>();

            for (int i = index; i < index + count; i++)
            {
                Res.Add(arr[i]);
            }

            return Res.ToArray();
        }
        public byte[] GetPPSE(byte[] apdu)
        {
            byte[] DF = CopyByte(apdu, 5, 14);
            List<byte> Return = new List<byte>() { 0x6F, 0x23, 0x84, 0x0E };
            Return.AddRange(DF);
            Return.AddRange(HexStringToByteArray("A511BF0C0E610C4F07"));
            Return.AddRange(HexStringToByteArray(cGlobal.getAID()));
            Return.AddRange(HexStringToByteArray("870101"));
            Return.AddRange(new byte[] { 0x90, 0x00 });
            return HexStringToByteArray($"6F23840E325041592E5359532E4444463031A511BF0C0E610C4F07{cGlobal.getAID()}8701019000");
        }
        public byte[] GETSelect(byte[] apdu)
        {
            byte[] AID = HexStringToByteArray(cGlobal.getAID());
            List<byte> Return = new List<byte>() { 0x6F, 0x14, 0x84, 0x07 };
            Return.AddRange(AID);
            Return.AddRange(HexStringToByteArray("A5095007"));
            Return.AddRange(HexStringToByteArray(cGlobal.getIDEN()));
            Return.AddRange(new byte[] { 0x90, 0x00 });
            return HexStringToByteArray($"6F3E8407{AID}A533500B56495341204352454449549F38189F66049F02069F03069F1A0295055F2A029A039C019F3704BF0C089F5A0500084008409000");
        }
        public byte[] GETGPO(byte[] apdu)
        {
            return HexStringToByteArray("7716820219809410080101001001010118010200200102009000");
        }
        public void ReadRecConf()
        {
            string track2 = cGlobal.TrackSelected.getTrackParser();
            string Vencimento = cGlobal.TrackSelected.getFinal().Substring(0, 4);
            string diaVencimento = "31";
            string num = cGlobal.TrackSelected.getNum();
            if (num.Length % 2 != 0)
                num += "F";
            switch (Vencimento.Substring(2, 2))
            {
                case "02":
                    diaVencimento = "29";
                    break;
                case "04":
                case "06":
                case "09":
                case "11":
                    diaVencimento = "30";
                    break;
                case "01":
                case "03":
                case "05":
                case "07":
                case "08":
                case "10":
                case "12":
                    diaVencimento = "31";
                    break;
                default:
                    break;

            }
            Vencimento += diaVencimento;
            string trackLen = (track2.Length / 2).ToString("X");
            string numLen = (num.Length / 2).ToString("X");
            RRECORD1 = HexStringToByteArray($"70819E57{trackLen}{track2}5A{numLen}{num}5F2403{Vencimento}5F25030401015F280200565F3401018C219F02069F03069F1A0295055F2A029A039C019F37049F35019F45029F4C089F34038D0C910A8A0295059F37049F4C088E0C000000000000000042031F039F0702FF009F080200029F0D0500000000009F0E0500000000009F0F0500000000009F420209789F4A01829000");
            RRECORD2 = HexStringToByteArray("7081A08F01FA9F3201039204D35241079081908BED68CB5E81B76EF8A9F6FF38168D728F11A160F78A48562F544D0BA42826C35989B4333FAC96FF7EFB34F34FD3F815A2BC0B2B8BAFD84FD99B26C96B7B35E2B080F1664A481B980FB6C41405796A0B9D5C9CDE2EF3668EBD0557D728DB3A0ABC4F87803CF28180795CE33A377E397AA8A71251D88E2B092E287BB780865C6AB9FA891F85B268D215A43C2A77C3C1D99000");
            RRECORD3 = HexStringToByteArray("70039301FF9000");
            RRECORD4 = HexStringToByteArray("70219F4701039F481A00000000000000066000000000000000000000000000000000559000");
            RRECORD5 = HexStringToByteArray("70739F46707005E297C2B7D0E80AC54C3014820F2FF7811EB95495E0F1D4A6BC120E0A8A739AC78DABCDB59ADEEDB43AC7652D83074D0D2C7B3EA53E0B1CC514D29D58AA7B91389289EB1DF96D00200D2E2EF4628F0646C0A9047C9390851BF04B7D17D430E51EDC7B2072D85367A172377B486BB19000");
        }
        public override void OnDeactivated(DeactivationReason reason)
        {

        }
        public override void OnCreate()
        {

        }
        public bool isArray(byte[] ar1, byte[] ar2, int len = 5)
        {
            return ar1[0] == ar2[0] && ar1[1] == ar2[1] && ar1[02] == ar2[02] && ar1[3] == ar2[3] && ar1[4] == ar2[4];
        }
        public override byte[] ProcessCommandApdu(byte[] commandApdu, Bundle extras)
        {
            ReadRecConf();

            byte[] returnAPDU = new byte[12];
            if (isArray(commandApdu, CPPSE))
                returnAPDU = GetPPSE(commandApdu);
            else if (isArray(commandApdu, CSELECT))
                returnAPDU = GETSelect(commandApdu);
            else if (isArray(commandApdu, CGPO))
                returnAPDU = GETGPO(commandApdu);
            else if (isArray(commandApdu, CRECORD1))
                returnAPDU = RRECORD1;
            else if (isArray(commandApdu, CRECORD2))
                returnAPDU = RRECORD2;
            else if (isArray(commandApdu, CRECORD3))
                returnAPDU = RRECORD3;
            else if (isArray(commandApdu, CRECORD4))
                returnAPDU = RRECORD4;
            else if (isArray(commandApdu, CRECORD5))
                returnAPDU = RRECORD5;
            else if (isArray(commandApdu, CGEN))
                returnAPDU = new byte[1];
            else
                returnAPDU = ISO7816_UNKNOWN_ERROR_RESPONSE;
            cGlobal.addHistory($"APDU:{ByteArrayToHexString(commandApdu)} RESPONSE: {ByteArrayToHexString(returnAPDU)}");
            return returnAPDU;

        }
        public string ByteArrayToHexString(byte[] bytes)
        {
            String s = "";
            for (int i = 0; i < bytes.Length; i++)
            {
                s += bytes[i].ToString("X2");
            }
            return s;
        }
        private byte[] HexStringToByteArray(string s)
        {
            int len = s.Length;
            if (len % 2 != 0)
            {
                s += "0";
                return HexStringToByteArray(s);
            }
            byte[] data = new byte[len / 2]; //Allocate 1 byte per 2 hex characters
            for (int i = 0; i < len; i += 2)
            {
                ushort val, val2;
                // Convert each chatacter into an unsigned integer (base-16)
                try
                {
                    val = (ushort)Convert.ToInt32(s[i].ToString() + "0", 16);
                    val2 = (ushort)Convert.ToInt32("0" + s[i + 1].ToString(), 16);
                }
                catch (Exception)
                {
                    continue;
                }

                data[i / 2] = (byte)(val + val2);
            }
            return data;
        }
        public byte[] ConcatArrays(byte[] first, params byte[][] rest)
        {
            int totalLength = first.Length;
            foreach (byte[] array in rest)
            {
                totalLength += array.Length;
            }
            byte[] result = new byte[totalLength];
            first.CopyTo(result, 0);
            int offset = first.Length;
            foreach (byte[] array in rest)
            {
                array.CopyTo(result, offset);
                offset += array.Length;
            }
            return result;
        }
    }
}