using NUnit.Framework;
using ServiceShared.Crypto;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace ServiceOutsideTests.Crypto
{
    public class Curve25519
    {
        [Test]
        public void SharedKeys()
        {
            KeyPair aliceKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();
            KeyPair bobKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();
            byte[] aliceSharedKey = aliceKey.GetSharedKey(bobKey.PublicKey);
            byte[] bobSharedKey = bobKey.GetSharedKey(aliceKey.PublicKey);

            Assert.AreEqual(aliceSharedKey, bobSharedKey);
        }


        [Test]
        public void AliceSendsToBob()
        {
            KeyPair aliceKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();
            KeyPair bobKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();

            byte[] aliceSharedKey = aliceKey.GetSharedKey(bobKey.PublicKey);
            byte[] bobSharedKey = bobKey.GetSharedKey(aliceKey.PublicKey);

            string key = "a dasdas djakl jdklas jdlkjakldhsajkdhsakdhkajhdkjgahkdgsagdas gdj sadag jdsaj gdg jasdagj dgsa gdsa dsga dgsja gdjagdgasj gjhdga gdja";
            string input = "Hello World";
            string encrypted = ServiceShared.Crypto.AES.Encrypt(input, aliceSharedKey);
            string decrypted = ServiceShared.Crypto.AES.Decrypt(encrypted, bobSharedKey);
            Assert.AreEqual(input, decrypted);
        }

        [Test]
        public void BobSendsToAlice()
        {
            KeyPair aliceKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();
            KeyPair bobKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();

            byte[] aliceSharedKey = aliceKey.GetSharedKey(bobKey.PublicKey);
            byte[] bobSharedKey = bobKey.GetSharedKey(aliceKey.PublicKey);

            string key = "a dasdas djakl jdklas jdlkjakldhsajkdhsakdhkajhdkjgahkdgsagdas gdj sadag jdsaj gdg jasdagj dgsa gdsa dsga dgsja gdjagdgasj gjhdga gdja";
            string input = "Hello World";
            string encrypted = ServiceShared.Crypto.AES.Encrypt(input, bobSharedKey);
            string decrypted = ServiceShared.Crypto.AES.Decrypt(encrypted, aliceSharedKey);
            Assert.AreEqual(input, decrypted);
        }

        [Test]
        public void EncryptDecrypt()
        {
            KeyPair aliceKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();
            KeyPair bobKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();

            byte[] aliceSharedKey = aliceKey.GetSharedKey(bobKey.PublicKey);
            byte[] bobSharedKey = bobKey.GetSharedKey(aliceKey.PublicKey);

            for (int i = 0; i < 1000; i++)
            {
                int KeySize = new Random().Next(1, 4096);
                byte[] random = new byte[KeySize];
                RandomNumberGenerator.Fill(random);
                

                if(i%2 == 0)
                {
                    string input = Encoding.UTF8.GetString(random);
                    string encrypted = ServiceShared.Crypto.AES.Encrypt(input, aliceSharedKey);
                    string decrypted = ServiceShared.Crypto.AES.Decrypt(encrypted, bobSharedKey);
                    Assert.AreEqual(input, decrypted);
                }
                else
                {
                    string input = Encoding.UTF8.GetString(random);
                    string encrypted = ServiceShared.Crypto.AES.Encrypt(input, bobSharedKey);
                    string decrypted = ServiceShared.Crypto.AES.Decrypt(encrypted, aliceSharedKey);
                    Assert.AreEqual(input, decrypted);
                }
            }
        }

        [Test]
        public void BobVerifiesAlicasSignature()
        {
            KeyPair aliceKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();
            KeyPair bobKey = ServiceShared.Crypto.Curve25519.GenerateKeyPair();
            string message = "a dasdas djakl jdklas jdlkjakldhsajkdhsakdhkajhdkjgahkdgsagdas gdj sadag jdsaj gdg jasdagj dgsa gdsa dsga dgsja gdjagdgasj gjhdga gdjaa dasdas djakl jdklas jdlkjakldhsajkdhsakdhk";
            string aliceSignature = aliceKey.GetSignature(message);
            Assert.IsTrue(bobKey.VerifySignature(message, aliceSignature, aliceKey.SigningPublicKey));
        }

        [Test]
        public void FixedKeys()
        {
            byte[] bobDefinedPrivateKey = Convert.FromBase64String("sl+zJ6XehkmHhr9GUgdtNGItpBrWy2y9zqUNkxQ+2nc=");
            byte[] bobPrivate = ServiceShared.Crypto.Curve25519.ClampPrivateKey(bobDefinedPrivateKey);     
            byte[] bobPublic = ServiceShared.Crypto.Curve25519.GetPublicKey(bobPrivate);

            string alicePublicKeyBase64 = "Q6eZkHPevsEB7cpoMRQ4TY0ggjdB4etV+X6aOqqeymc=";

            byte[] alicePublicKey = Convert.FromBase64String(alicePublicKeyBase64);
            byte[] bobSharedSecret = ServiceShared.Crypto.Curve25519.GetSharedSecret(bobPrivate, alicePublicKey);

            string bobSharedSecretBase64 = Convert.ToBase64String(bobSharedSecret);
            byte[] bobSharedKey = HKDF.DeriveKey(HashAlgorithmName.SHA512, bobSharedSecret, 32);
            string bobSharedKeyBase64 = Convert.ToBase64String(bobSharedKey);
           

            string bobSecretMessage = "XhK7GpN6JqbFgSl4h2J6kjpwEi+aFGzTPDehrdF/qvEupBUHYPJI9zOWPhbWBi4IZ2i9";
            string bobSecretMessageDecrypted = ServiceShared.Crypto.AES.Decrypt(bobSecretMessage, bobSharedKey);

            Console.WriteLine("Bob Private Key: " + Convert.ToBase64String(bobPrivate));
            Console.WriteLine("Bob Public Key: " + Convert.ToBase64String(bobPublic));

            Console.WriteLine("Alice Public Key: " + Convert.ToBase64String(alicePublicKey));
            Console.WriteLine("Bob Shared Secret: " + Convert.ToBase64String(bobSharedSecret));
            Console.WriteLine("Bob Shared Key(Base64): " + Convert.ToBase64String(bobSharedKey));
            Console.WriteLine("Bob Shared Key(ASCII): " + Encoding.ASCII.GetString(bobSharedKey));
            Console.WriteLine("Bob Secret Message(Clearly): " + bobSecretMessageDecrypted);
            Console.WriteLine("Alice HMAC: " + ServiceShared.Crypto.SHA512.HMAC(bobSecretMessage, bobSharedKey));
            Assert.IsTrue(ServiceShared.Crypto.SHA512.isValidAuthenticationCode(ServiceShared.Crypto.SHA512.HMAC(bobSecretMessage, bobSharedKey), bobSecretMessage, bobSharedKey));
        }

        [Test]
        public void VerifyFixedSignature()
        {
            string strPrivateKey = "+jkrpn+/3akv6I1AubmC4SX/+ivUNtuOwSynX56lKbw=";
            string strPublicKey = "XNeY4FNb9GvGP2UA4Qm3luwM5fGmuE1uBESHSoV6DK4=";
   

            byte[] privateKey = Convert.FromBase64String(strPrivateKey);
            byte[] publicKey = Convert.FromBase64String(strPublicKey);

            byte[] message = Encoding.UTF8.GetBytes("Signature Message");

            byte[] signature = ServiceShared.Crypto.Ed25519.Signature(message, privateKey, publicKey);

            string base64Signature = "4KVCEjEqGajal6LsUOeOeA6NobyPmo0fiRiyCGQ3IcMZtAVUZjOfrkbOubtvL66ARNP5EnrWXHWtP6PpyqeGCg=="; // Convert.ToBase64String(signature);
            byte[] signatureBytes = Convert.FromBase64String(base64Signature);

            bool verified = ServiceShared.Crypto.Ed25519.CheckValid(signatureBytes, message, publicKey);

            Assert.IsTrue(verified);
        }
    }
}