using System;

using System.Text;

using System.Text.Json.Nodes;

using System.Collections.Generic;

using Nethereum.Util;

using Nethereum.Signer;

using Nethereum.Hex.HexConvertors.Extensions;

using Newtonsoft.Json;

using System.Linq;

​

namespace SigningAddress

{

    public class Data

    {

        public int NewAccountID { get; set; }

​

        public string? PubKey { get; set; }

​

        public bool IsETH { get; set; }

​

        public int UserID { get; set; }

​

        public int NodeID { get; set; }

​

        public DateTime CreatedByUser { get; set; }

    }

​

    public class Program

    {

        public static byte[] StringToByteArray(string hex)

        {

            return Enumerable.Range(0, hex.Length).Where(x => x % 2 == 0).Select(x => Convert.ToByte(hex.Substring(x, 2), 16)).ToArray();

        }

​

        public static void Main()

        {

            Console.OutputEncoding = System.Text.Encoding.UTF8;

            string jsonString = @"{""NewAccountID"":5,""PubKey"":""BCT4ALtlDp9SkeQaN9SsLm2rcnhC8IAAwFqHbOYiR2U2vRusCalc2WTyvYjfzcVEv6zWXV+4WDXqgcwSCjVrUNo="",""IsETH"":true,""UserID"":4,""NodeID"":1,""CreatedByUser"":""2022-07-19T02:31:42.4757528Z""}";

            JsonNode dataNode = JsonNode.Parse(jsonString)!;

            Data? dataObject = JsonConvert.DeserializeObject<Data>(jsonString);

            Console.WriteLine($"Object: {jsonString}");

            //This sample demonstrates how to sign a message with a private key 

            //and validate the signer later on by recovering the address of the signature.

            //Given an address with a private key

            var address = "0xd864e8c9Eb1525a759503F03aCF03149d344E671";

            var privateKey = "0xfaa4bff60e5aca00877a3511da0c56f4caa3047e1987df5879ce4ed3a8c373ea";

            Console.WriteLine($"Address {address} with private key: {privateKey}");

            //And a message to sign

            // var messageToSign = "teste";

            // var messageToSign = Encoding.UTF8.GetString(Encoding.Default.GetBytes(dataNode!.ToJsonString()));

            // var messageToSign = jsonString;

            var messageToSign = JsonConvert.SerializeObject(dataObject);

            // var messageToSign = "wee test message 18/09/2017 02:55PM";

            //Message to be sign

            Console.WriteLine($"Message to be sign: {messageToSign})");

            Console.WriteLine($"Test between serialization and static string: {String.Compare(jsonString, messageToSign)}");

            //We can create an Ethereum signer. 

            //Note: the EthereumSigner is a specialised signer for messages that prefixes the messages with "x19Ethereum Signed Message:"

            var signer = new EthereumMessageSigner();

            //To sign a text message we UTF8 encoded it (byte array) first and then sign it

            var signature = signer.EncodeUTF8AndSign(messageToSign, new EthECKey(privateKey));

            Console.WriteLine($"Signature: {signature}");

            // Convert to base64

            var signatureBase64 = System.Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(signature.Substring(2)));

            Console.WriteLine($"Signature in base64: {signatureBase64}");

            //To recover the address of the signer of a text message 

            //we first UTF8 encoded it (byte array) and then using the Elliptic Curve recovery we get the address.

            var addressRecovered = signer.EncodeUTF8AndEcRecover(messageToSign, signature);

            //We can validate the signature if the address matches

            Console.WriteLine($"Address recovered: {addressRecovered}");

            // Implementation from Example - Client

            var privKey4 = new Nethereum.Signer.EthECKey(StringToByteArray(privateKey.Substring(2)), true);

            var sign = privKey4.Sign(Encoding.UTF8.GetBytes("teste e teste"));

            var signByte = sign.ToDER();

            Console.WriteLine($"The signByte data in base64: {Convert.ToBase64String(signByte)}");

            // public key from privKey4 - Extracted using typescript code

            var publicKeyNC = "0x0424f800bb650e9f5291e41a37d4ac2e6dab727842f08000c05a876ce622476536bd1bac09a95cd964f2bd88dfcdc544bfacd65d5fb85835ea81cc120a356b50da";

            // var newpubkey = new Nethereum.Signer.EthECKey(StringToByteArray(publicKeyNC.Substring(2)), false);

            var newpubkey = new Nethereum.Signer.EthECKey(publicKeyNC.HexToByteArray(), false);

            var signx = new Nethereum.Signer.EthECDSASignature(signByte);

            var contbytes = Encoding.UTF8.GetBytes("teste e teste");

            var test = newpubkey.Verify(contbytes, signx);

            Console.WriteLine($"The result from Verify: {test}");

            // Converting a signature string to EthECDSASignature

            // https://github.com/Nethereum/Nethereum/blob/f6acc6260129f2893647aad94a6b75104db1ff09/src/Nethereum.Signer/MessageSigner.cs#L79

            var ecdsaSignature = MessageSigner.ExtractEcdsaSignature(signature);

            var ecdsaSignatureByte = ecdsaSignature.ToDER();

            Console.WriteLine($"The signByte data in base64: {Convert.ToBase64String(ecdsaSignatureByte)}");

            var ethereumMessageSigner = new EthereumMessageSigner();

            var hashMessage100 = ethereumMessageSigner.HashPrefixedMessage(Encoding.UTF8.GetBytes(messageToSign));

            var ecdaSignature100 = MessageSigner.ExtractEcdsaSignature(signature);

            var publicAddress100 = EthECKey.RecoverFromSignature(ecdaSignature100, hashMessage100).GetPublicAddress();

            var pubKey100 = EthECKey.RecoverFromSignature(ecdaSignature100, hashMessage100).GetPubKey();

            Console.WriteLine($"Public Address: {publicAddress100}");

            Console.WriteLine($"Public Key: {Convert.ToHexString(pubKey100)}");

            // Verifying the signature using the pubkey from privatekey

            var signx1 = new Nethereum.Signer.EthECDSASignature(ecdsaSignatureByte);

            var contbytes1 = ethereumMessageSigner.HashPrefixedMessage(Encoding.UTF8.GetBytes(messageToSign));

            Console.WriteLine($"Message to be sign using base64: {Convert.ToBase64String(Encoding.UTF8.GetBytes(messageToSign))}");

            var test1 = newpubkey.Verify(contbytes1, signx1);

            Console.WriteLine($"The result from Verify: {test1}");

        }

    }

}