using System;
using System.Diagnostics;
using System.IO;
using System.Reflection;
using System.Security.Cryptography;
using System.Text.RegularExpressions;
using AMWD.Common.Tests.Utils;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace AMWD.Common.Tests.Utilities
{
	[TestClass]
	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
	public class CryptographyHelperTests
	{
		private string keyFile;
		private CryptographyHelper cryptoHelper;

		[TestInitialize]
		public void Initialize()
		{
			keyFile = Path.GetTempFileName();
			cryptoHelper = new CryptographyHelper(keyFile);
		}

		[TestCleanup]
		public void Cleanup()
		{
			File.Delete(keyFile);
		}

		#region Static

		#region Encryption

		#region AES

		[TestMethod]
		public void ShouldEncryptAesWithoutSalt()   // required to test the encryption itself
		{
			// arrange
			using var disposable = CryptographyHelperSaltMock.Create(0);

			byte[] bytes = new byte[] { 0xaf, 0xfe };
			string str = "ABC";
			string password1 = "P@ssw0rd!";
			string password2 = "P@ssw0rd";

			byte[] expectedBytes = new byte[] { 0x7c, 0x7b, 0x77, 0x56, 0x91, 0x1a, 0xd9, 0xc0, 0x72, 0x70, 0x36, 0x88, 0x9f, 0xb4, 0xb5, 0xbc };

			// act
			byte[] cipherBytes1 = CryptographyHelper.AesEncrypt(bytes, password1);
			string cipherStr1 = CryptographyHelper.AesEncrypt(str, password1);
			byte[] cipherBytes2 = CryptographyHelper.AesEncrypt(bytes, password2);
			string cipherStr2 = CryptographyHelper.AesEncrypt(str, password2);

			// assert
			CollectionAssert.AreEqual(expectedBytes, cipherBytes1);
			Assert.AreEqual("ueLuhFNpCuYmx8v3hczHtg==", cipherStr1);

			CollectionAssert.AreNotEqual(expectedBytes, cipherBytes2);
			Assert.AreNotEqual("ueLuhFNpCuYmx8v3hczHtg==", cipherStr2);
		}

		[TestMethod]
		public void ShouldDecryptAesWithoutSalt()   // required to test the decryption itself
		{
			// arrange
			using var disposable = CryptographyHelperSaltMock.Create(0);

			string cipherStr = "ueLuhFNpCuYmx8v3hczHtg==";
			byte[] cipherBytes = new byte[] { 0x7c, 0x7b, 0x77, 0x56, 0x91, 0x1a, 0xd9, 0xc0, 0x72, 0x70, 0x36, 0x88, 0x9f, 0xb4, 0xb5, 0xbc };

			string password1 = "P@ssw0rd!";
			string password2 = "P@ssw0rd";

			byte[] expectedBytes = new byte[] { 0xaf, 0xfe };

			// act
			byte[] plainBytes1 = CryptographyHelper.AesDecrypt(cipherBytes, password1);
			string plainStr1 = CryptographyHelper.AesDecrypt(cipherStr, password1);

			try
			{
				CryptographyHelper.AesDecrypt(cipherBytes, password2);
				Assert.Fail();
			}
			catch (CryptographicException)
			{ }

			try
			{
				CryptographyHelper.AesDecrypt(cipherStr, password2);
				Assert.Fail();
			}
			catch (CryptographicException)
			{ }

			// assert
			CollectionAssert.AreEqual(expectedBytes, plainBytes1);
			Assert.AreEqual("ABC", plainStr1);
		}

		[TestMethod]
		public void ShouldEncryptDecryptAesBytes()
		{
			// arrange
			byte[] plain = new byte[] { 0xaf, 0xfe };
			string password = "P@ssw0rd!";

			// act
			byte[] cipher1 = CryptographyHelper.AesEncrypt(plain, password);
			byte[] cipher2 = CryptographyHelper.AesEncrypt(plain, password);

			byte[] plain1 = CryptographyHelper.AesDecrypt(cipher1, password);
			byte[] plain2 = CryptographyHelper.AesDecrypt(cipher2, password);

			// assert
			CollectionAssert.AreNotEqual(cipher1, cipher2);
			Assert.AreEqual(24, cipher1.Length);
			Assert.AreEqual(24, cipher2.Length);
			CollectionAssert.AreEqual(plain, plain1);
			CollectionAssert.AreEqual(plain, plain2);
		}

		[TestMethod]
		public void ShouldEncryptDecryptAesString()
		{
			// arrange
			string plain = "ABC";
			string password = "P@ssw0rd!";

			// act
			string cipher1 = CryptographyHelper.AesEncrypt(plain, password);
			string cipher2 = CryptographyHelper.AesEncrypt(plain, password);

			string plain1 = CryptographyHelper.AesDecrypt(cipher1, password);
			string plain2 = CryptographyHelper.AesDecrypt(cipher2, password);

			// assert
			Assert.AreNotEqual(cipher1, cipher2);
			Assert.AreEqual(32, cipher1.Length);
			Assert.AreEqual(32, cipher2.Length);
			Assert.AreEqual(plain, plain1);
			Assert.AreEqual(plain, plain2);
		}

		#endregion AES

		#region TripleDES

		[TestMethod]
		public void ShouldEncryptTdesWithoutSalt()   // required to test the encryption itself
		{
			// arrange
			using var disposable = CryptographyHelperSaltMock.Create(0);

			byte[] bytes = new byte[] { 0xaf, 0xfe };
			string str = "ABC";
			string password1 = "P@ssw0rd!";
			string password2 = "P@ssw0rd";

			byte[] expectedBytes = new byte[] { 0xbf, 0x59, 0x1f, 0x48, 0x69, 0xab, 0x18, 0xc7 };

			// act
			byte[] cipherBytes1 = CryptographyHelper.TripleDesEncrypt(bytes, password1);
			string cipherStr1 = CryptographyHelper.TripleDesEncrypt(str, password1);
			byte[] cipherBytes2 = CryptographyHelper.TripleDesEncrypt(bytes, password2);
			string cipherStr2 = CryptographyHelper.TripleDesEncrypt(str, password2);

			// assert
			CollectionAssert.AreEqual(expectedBytes, cipherBytes1);
			Assert.AreEqual("1l74soBuuEI=", cipherStr1);

			CollectionAssert.AreNotEqual(expectedBytes, cipherBytes2);
			Assert.AreNotEqual("1l74soBuuEI=", cipherStr2);
		}

		[TestMethod]
		public void ShouldDecryptTdesWithoutSalt()   // required to test the decryption itself
		{
			// arrange
			using var disposable = CryptographyHelperSaltMock.Create(0);

			string cipherStr = "1l74soBuuEI=";
			byte[] cipherBytes = new byte[] { 0xbf, 0x59, 0x1f, 0x48, 0x69, 0xab, 0x18, 0xc7 };

			string password1 = "P@ssw0rd!";
			string password2 = "P@ssw0rd";

			byte[] expectedBytes = new byte[] { 0xaf, 0xfe };

			// act
			byte[] plainBytes1 = CryptographyHelper.TripleDesDecrypt(cipherBytes, password1);
			string plainStr1 = CryptographyHelper.TripleDesDecrypt(cipherStr, password1);

			try
			{
				CryptographyHelper.TripleDesDecrypt(cipherBytes, password2);
				Assert.Fail();
			}
			catch (CryptographicException)
			{ }

			try
			{
				CryptographyHelper.TripleDesDecrypt(cipherStr, password2);
				Assert.Fail();
			}
			catch (CryptographicException)
			{ }

			// assert
			CollectionAssert.AreEqual(expectedBytes, plainBytes1);
			Assert.AreEqual("ABC", plainStr1);
		}

		[TestMethod]
		public void ShouldEncryptDecryptTdesBytes()
		{
			// arrange
			byte[] plain = new byte[] { 0xaf, 0xfe };
			string password = "P@ssw0rd!";

			// act
			byte[] cipher1 = CryptographyHelper.TripleDesEncrypt(plain, password);
			byte[] cipher2 = CryptographyHelper.TripleDesEncrypt(plain, password);

			byte[] plain1 = CryptographyHelper.TripleDesDecrypt(cipher1, password);
			byte[] plain2 = CryptographyHelper.TripleDesDecrypt(cipher2, password);

			// assert
			CollectionAssert.AreNotEqual(cipher1, cipher2);
			Assert.AreEqual(16, cipher1.Length);
			Assert.AreEqual(16, cipher2.Length);
			CollectionAssert.AreEqual(plain, plain1);
			CollectionAssert.AreEqual(plain, plain2);
		}

		[TestMethod]
		public void ShouldEncryptDecryptTdesString()
		{
			// arrange
			string plain = "ABC";
			string password = "P@ssw0rd!";

			// act
			string cipher1 = CryptographyHelper.TripleDesEncrypt(plain, password);
			string cipher2 = CryptographyHelper.TripleDesEncrypt(plain, password);

			string plain1 = CryptographyHelper.TripleDesDecrypt(cipher1, password);
			string plain2 = CryptographyHelper.TripleDesDecrypt(cipher2, password);

			// assert
			Assert.AreNotEqual(cipher1, cipher2);
			Assert.AreEqual(24, cipher1.Length);
			Assert.AreEqual(24, cipher2.Length);
			Assert.AreEqual(plain, plain1);
			Assert.AreEqual(plain, plain2);
		}

		#endregion TripleDES

		#endregion Encryption

		#region Hash

		[TestMethod]
		public void ShouldReturnMd5Hash()
		{
			// arrange
			string text = "Hello World!";
			byte[] bytes = new byte[] { 0xde, 0xad, 0xbe, 0xef };
			string fileName = Path.GetTempFileName();

			// act
			string textHash = CryptographyHelper.Md5(text);
			string bytesHash = CryptographyHelper.Md5(bytes);

			File.WriteAllText(fileName, text);
			string fileHash = CryptographyHelper.Md5File(fileName);
			File.Delete(fileName);

			// assert
			Assert.AreEqual("ed076287532e86365e841e92bfc50d8c", textHash);
			Assert.AreEqual("2f249230a8e7c2bf6005ccd2679259ec", bytesHash);
			Assert.AreEqual("ed076287532e86365e841e92bfc50d8c", fileHash);
		}

		[TestMethod]
		public void ShouldReturnSha1Hash()
		{
			// arrange
			string text = "Hello World!";
			byte[] bytes = new byte[] { 0xde, 0xad, 0xbe, 0xef };
			string fileName = Path.GetTempFileName();

			// act
			string textHash = CryptographyHelper.Sha1(text);
			string bytesHash = CryptographyHelper.Sha1(bytes);

			File.WriteAllText(fileName, text);
			string fileHash = CryptographyHelper.Sha1File(fileName);
			File.Delete(fileName);

			// assert
			Assert.AreEqual("2ef7bde608ce5404e97d5f042f95f89f1c232871", textHash);
			Assert.AreEqual("d78f8bb992a56a597f6c7a1fb918bb78271367eb", bytesHash);
			Assert.AreEqual("2ef7bde608ce5404e97d5f042f95f89f1c232871", fileHash);
		}

		[TestMethod]
		public void ShouldReturnSha256Hash()
		{
			// arrange
			string text = "Hello World!";
			byte[] bytes = new byte[] { 0xde, 0xad, 0xbe, 0xef };
			string fileName = Path.GetTempFileName();

			// act
			string textHash = CryptographyHelper.Sha256(text);
			string bytesHash = CryptographyHelper.Sha256(bytes);

			File.WriteAllText(fileName, text);
			string fileHash = CryptographyHelper.Sha256File(fileName);
			File.Delete(fileName);

			// assert
			Assert.AreEqual("7f83b1657ff1fc53b92dc18148a1d65dfc2d4b1fa3d677284addd200126d9069", textHash);
			Assert.AreEqual("5f78c33274e43fa9de5659265c1d917e25c03722dcb0b8d27db8d5feaa813953", bytesHash);
			Assert.AreEqual("7f83b1657ff1fc53b92dc18148a1d65dfc2d4b1fa3d677284addd200126d9069", fileHash);
		}

		[TestMethod]
		public void ShouldReturnSha512Hash()
		{
			// arrange
			string text = "Hello World!";
			byte[] bytes = new byte[] { 0xde, 0xad, 0xbe, 0xef };
			string fileName = Path.GetTempFileName();

			// act
			string textHash = CryptographyHelper.Sha512(text);
			string bytesHash = CryptographyHelper.Sha512(bytes);

			File.WriteAllText(fileName, text);
			string fileHash = CryptographyHelper.Sha512File(fileName);
			File.Delete(fileName);

			// assert
			Assert.AreEqual("861844d6704e8573fec34d967e20bcfef3d424cf48be04e6dc08f2bd58c729743371015ead891cc3cf1c9d34b49264b510751b1ff9e537937bc46b5d6ff4ecc8", textHash);
			Assert.AreEqual("1284b2d521535196f22175d5f558104220a6ad7680e78b49fa6f20e57ea7b185d71ec1edb137e70eba528dedb141f5d2f8bb53149d262932b27cf41fed96aa7f", bytesHash);
			Assert.AreEqual("861844d6704e8573fec34d967e20bcfef3d424cf48be04e6dc08f2bd58c729743371015ead891cc3cf1c9d34b49264b510751b1ff9e537937bc46b5d6ff4ecc8", fileHash);
		}

		#endregion Hash

		#region Random

		[TestMethod]
		public void ShouldReturnRandomBytes()
		{
			// arrange
			int length1 = 12;
			int length2 = 12;
			int length3 = 42;

			// act
			byte[] bytes1 = CryptographyHelper.GetRandomBytes(length1);
			byte[] bytes2 = CryptographyHelper.GetRandomBytes(length2);
			byte[] bytes3 = CryptographyHelper.GetRandomBytes(length3);

			// assert
			Assert.AreEqual(length1, bytes1.Length);
			Assert.AreEqual(length2, bytes2.Length);
			Assert.AreEqual(length3, bytes3.Length);

			Assert.IsTrue(bytes1.Length == bytes2.Length);
			CollectionAssert.AreNotEqual(bytes1, bytes2);
		}

		[TestMethod]
		public void ShouldReturnRandomString()
		{
			// arrange
			int length1 = 12;
			int length2 = 12;
			int length3 = 42;

			// act
			string str1 = CryptographyHelper.GetRandomString(length1);
			string str2 = CryptographyHelper.GetRandomString(length2);
			string str3 = CryptographyHelper.GetRandomString(length3);

			// assert
			Assert.AreEqual(length1, str1.Length);
			Assert.AreEqual(length2, str2.Length);
			Assert.AreEqual(length3, str3.Length);

			Assert.IsTrue(str1.Length == str2.Length);
			Assert.IsFalse(str1 == str2);
		}

		[TestMethod]
		public void ShouldReturnRandomStringWithPool()
		{
			// arrange
			int length = 12;
			string pool = "0123456789abcdef";

			// act
			string str1 = CryptographyHelper.GetRandomString(length, pool);
			string str2 = CryptographyHelper.GetRandomString(length, pool);

			// assert
			Assert.AreEqual(length, str1.Length);
			Assert.AreEqual(length, str2.Length);
			Assert.IsFalse(str1 == str2);
			Assert.IsFalse(Regex.IsMatch(str1, "[^0-9a-f]"));
			Assert.IsFalse(Regex.IsMatch(str2, "[^0-9a-f]"));
		}

		#endregion Random

		#region Secure probing

		[TestMethod]
		public void ShouldTakeSameTimeToCompareString()
		{
			// arrange
			string str1 = "Hello World!";
			string str2 = "Hello World!";
			string str3 = "Hallo World!";
			string str4 = "Hello World?";
			string nullStr = null;
			string strLen = "Hello World";

			var sw = new Stopwatch();

			// act
			bool nullCompare = CryptographyHelper.SecureEquals(nullStr, str1);
			bool lenCompare = CryptographyHelper.SecureEquals(strLen, str1);

			sw.Start();
			bool compare1 = CryptographyHelper.SecureEquals(str1, str2);
			long time1 = sw.ElapsedMilliseconds;

			bool compare2 = CryptographyHelper.SecureEquals(str1, str3);
			long time2 = sw.ElapsedMilliseconds;

			bool compare3 = CryptographyHelper.SecureEquals(str1, str4);
			long time3 = sw.ElapsedMilliseconds;
			sw.Stop();

			// assert
			Assert.IsFalse(nullCompare);
			Assert.IsFalse(lenCompare);
			Assert.IsTrue(compare1);
			Assert.IsFalse(compare2);
			Assert.IsFalse(compare3);

			Assert.AreEqual(time1, time2);
			Assert.AreEqual(time1, time3);
			Assert.AreEqual(time2, time3);
		}

		[TestMethod]
		public void ShouldTakeSameTimeToCompareBytes()
		{
			// arrange
			byte[] bytes1 = CryptographyHelper.GetRandomBytes(200);
			byte[] bytes2 = new byte[bytes1.Length];
			byte[] bytes3 = new byte[bytes1.Length];
			byte[] bytes4 = new byte[bytes1.Length];
			byte[] nullBytes = null;
			byte[] lenBytes = new byte[bytes1.Length + 1];

			Array.Copy(bytes1, bytes2, bytes1.Length);
			Array.Copy(bytes1, bytes3, bytes1.Length);
			Array.Copy(bytes1, bytes4, bytes1.Length);

			bytes3[10] = (byte)(bytes1[10] + 1);
			bytes4[190] = (byte)(bytes1[190] + 1);

			var sw = new Stopwatch();

			// act
			bool nullCompare = CryptographyHelper.SecureEquals(nullBytes, bytes1);
			bool lenCompare = CryptographyHelper.SecureEquals(lenBytes, bytes1);

			sw.Start();
			bool compare1 = CryptographyHelper.SecureEquals(bytes1, bytes2);
			long time1 = sw.ElapsedMilliseconds;

			bool compare2 = CryptographyHelper.SecureEquals(bytes1, bytes3);
			long time2 = sw.ElapsedMilliseconds;

			bool compare3 = CryptographyHelper.SecureEquals(bytes1, bytes4);
			long time3 = sw.ElapsedMilliseconds;
			sw.Stop();

			// assert
			Assert.IsFalse(nullCompare);
			Assert.IsFalse(lenCompare);
			Assert.IsTrue(compare1);
			Assert.IsFalse(compare2);
			Assert.IsFalse(compare3);

			Assert.AreEqual(time1, time2);
			Assert.AreEqual(time1, time3);
			Assert.AreEqual(time2, time3);
		}

		#endregion Secure probing

		#endregion Static

		#region Instance

		[TestMethod]
		public void ShouldCreateDefaultFile()
		{
			// arrange
			string executingAssemblyDir = AppContext.BaseDirectory;
			string filePath = Path.Combine(executingAssemblyDir, "crypto.key");

			// act
			bool fileExistsBefore = File.Exists(filePath);
			var helper = new CryptographyHelper();
			bool fileExistsAfter = File.Exists(filePath);
			string content = fileExistsAfter ? File.ReadAllText(filePath) : null;
			File.Delete(filePath);

			// assert
			Assert.IsFalse(fileExistsBefore);
			Assert.IsNotNull(helper);
			Assert.IsTrue(fileExistsAfter);
			Assert.IsTrue(!string.IsNullOrWhiteSpace(content));
		}


		[TestMethod]
		public void ShouldEncryptAesUsingKeyFile()
		{
			// arrange
			string str = "Hello World!";
			byte[] bytes = CryptographyHelper.GetRandomBytes(32);

			string password = File.ReadAllText(keyFile);

			// act
			string cipherStr = cryptoHelper.EncryptAes(str);
			byte[] cipherBytes = cryptoHelper.EncryptAes(bytes);

			string plainStr = CryptographyHelper.AesDecrypt(cipherStr, password);
			byte[] plainBytes = CryptographyHelper.AesDecrypt(cipherBytes, password);

			// assert
			Assert.AreNotEqual(str, cipherStr);
			Assert.AreEqual(str, plainStr);
			CollectionAssert.AreNotEqual(bytes, cipherBytes);
			CollectionAssert.AreEqual(bytes, plainBytes);
		}

		[TestMethod]
		public void ShouldDecryptAesUsingKeyFile()
		{
			// arrange
			string str = "Hello World!";
			byte[] bytes = CryptographyHelper.GetRandomBytes(32);

			string password = File.ReadAllText(keyFile);

			// act
			string cipherStr = CryptographyHelper.AesEncrypt(str, password);
			byte[] cipherBytes = CryptographyHelper.AesEncrypt(bytes, password);

			string plainStr = cryptoHelper.DecryptAes(cipherStr);
			byte[] plainBytes = cryptoHelper.DecryptAes(cipherBytes);

			// assert
			Assert.AreNotEqual(str, cipherStr);
			Assert.AreEqual(str, plainStr);
			CollectionAssert.AreNotEqual(bytes, cipherBytes);
			CollectionAssert.AreEqual(bytes, plainBytes);
		}

		[TestMethod]
		public void ShouldEncryptTdesUsingKeyFile()
		{
			// arrange
			string str = "Hello World!";
			byte[] bytes = CryptographyHelper.GetRandomBytes(32);

			string password = File.ReadAllText(keyFile);

			// act
			string cipherStr = cryptoHelper.EncryptTripleDes(str);
			byte[] cipherBytes = cryptoHelper.EncryptTripleDes(bytes);

			string plainStr = CryptographyHelper.TripleDesDecrypt(cipherStr, password);
			byte[] plainBytes = CryptographyHelper.TripleDesDecrypt(cipherBytes, password);

			// assert
			Assert.AreNotEqual(str, cipherStr);
			Assert.AreEqual(str, plainStr);
			CollectionAssert.AreNotEqual(bytes, cipherBytes);
			CollectionAssert.AreEqual(bytes, plainBytes);
		}

		[TestMethod]
		public void ShouldDecryptTdesUsingKeyFile()
		{
			// arrange
			string str = "Hello World!";
			byte[] bytes = CryptographyHelper.GetRandomBytes(32);

			string password = File.ReadAllText(keyFile);

			// act
			string cipherStr = CryptographyHelper.TripleDesEncrypt(str, password);
			byte[] cipherBytes = CryptographyHelper.TripleDesEncrypt(bytes, password);

			string plainStr = cryptoHelper.DecryptTripleDes(cipherStr);
			byte[] plainBytes = cryptoHelper.DecryptTripleDes(cipherBytes);

			// assert
			Assert.AreNotEqual(str, cipherStr);
			Assert.AreEqual(str, plainStr);
			CollectionAssert.AreNotEqual(bytes, cipherBytes);
			CollectionAssert.AreEqual(bytes, plainBytes);
		}

		#endregion Instance
	}
}