using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Identity;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace UnitTests.AspNetCore.Utilities
{
	[TestClass]
	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
	public class PasswordHelperTests
	{
		[TestMethod]
		public void ShouldReturnNullHashWhenNullProvided()
		{
			// arrange
			string password = null;

			// act
			string hash = PasswordHelper.HashPassword(password);

			// assert
			Assert.IsNull(hash);
		}

		[TestMethod]
		public void ShouldReturnEmptyHashWhenSpacesProvided()
		{
			// arrange
			string password = "        ";

			// act
			string hash = PasswordHelper.HashPassword(password);

			// assert
			Assert.AreEqual("", hash);
		}

		[TestMethod]
		public void ShouldReturnHashWhenTextProvided()
		{
			// arrange
			string password = "password";

			// act
			string hash = PasswordHelper.HashPassword(password);

			// assert
			Assert.IsTrue(!string.IsNullOrWhiteSpace(hash));
		}

		[TestMethod]
		public void ShouldReturnFalseOnNullPassword()
		{
			// arrange
			string password = null;
			string hash = PasswordHelper.HashPassword(password);

			// act
			bool isValid = PasswordHelper.VerifyPassword(password, hash, out bool rehashNeeded);

			// assert
			Assert.IsFalse(isValid);
			Assert.IsFalse(rehashNeeded);
		}

		[TestMethod]
		public void ShouldReturnFalseOnEmptyPassword()
		{
			// arrange
			string password = "   ";
			string hash = PasswordHelper.HashPassword(password);

			// act
			bool isValid = PasswordHelper.VerifyPassword(password, hash, out bool rehashNeeded);

			// assert
			Assert.IsFalse(isValid);
			Assert.IsFalse(rehashNeeded);
		}

		[TestMethod]
		public void ShouldReturnFalseOnNullHash()
		{
			// arrange
			string password = "password";
			string hash = null;

			// act
			bool isValid = PasswordHelper.VerifyPassword(password, hash, out bool rehashNeeded);

			// assert
			Assert.IsFalse(isValid);
			Assert.IsFalse(rehashNeeded);
		}

		[TestMethod]
		public void ShouldReturnFalseOnEmptyHash()
		{
			// arrange
			string password = "password";
			string hash = "";

			// act
			bool isValid = PasswordHelper.VerifyPassword(password, hash, out bool rehashNeeded);

			// assert
			Assert.IsFalse(isValid);
			Assert.IsFalse(rehashNeeded);
		}

		[TestMethod]
		public void ShouldReturnTrueOnSuccess()
		{
			// arrange
			string password = "password";
			string hash = PasswordHelper.HashPassword(password);

			// act
			bool isValid = PasswordHelper.VerifyPassword(password, hash, out bool rehashNeeded);

			// assert
			Assert.IsTrue(isValid);
			Assert.IsFalse(rehashNeeded);
		}

		[TestMethod]
		public void ShouldReturnFalseOnError()
		{
			// arrange
			string password = "pass";
			string hash = PasswordHelper.HashPassword(password + "word");

			// act
			bool isValid = PasswordHelper.VerifyPassword(password, hash, out bool rehashNeeded);

			// assert
			Assert.IsFalse(isValid);
			Assert.IsFalse(rehashNeeded);
		}

		[TestMethod]
		public void ShouldReturnTrueWithRehash()
		{
			// arrange
			var devHasher = new PasswordHasher<object>();
			var field = devHasher.GetType().GetField("_compatibilityMode", BindingFlags.NonPublic | BindingFlags.Instance);
			field.SetValue(devHasher, PasswordHasherCompatibilityMode.IdentityV2);

			string password = "password";
			string hash = devHasher.HashPassword(null, password);

			// act
			bool isValid = PasswordHelper.VerifyPassword(password, hash, out bool rehashNeeded);

			// assert
			Assert.IsTrue(isValid);
			Assert.IsTrue(rehashNeeded);
		}
	}
}