using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Security.Claims;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using AMWD.Common.AspNetCore.BasicAuthentication;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Primitives;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;

namespace UnitTests.AspNetCore.BasicAuthentication
{
	[TestClass]
	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
	public class BasicAuthenticationMiddlewareTests
	{
		private Dictionary<string, string> requestHeaders;

		private Dictionary<string, string> responseHeadersCallback;
		private int responseStatusCodeCallback;

		private string validatorRealm;
		private ClaimsPrincipal validatorResponse;
		private List<(string username, string password, IPAddress ipAddr)> validatorCallback;

		[TestInitialize]
		public void InitializeTests()
		{
			requestHeaders = new Dictionary<string, string>();

			responseHeadersCallback = new Dictionary<string, string>();
			responseStatusCodeCallback = 0;

			validatorRealm = null;
			validatorResponse = null;
			validatorCallback = new List<(string username, string password, IPAddress ipAddr)>();
		}

		[TestMethod]
		public async Task ShouldAllowAccess()
		{
			// arrange
			string username = "user";
			string password = "pass:word";

			requestHeaders.Add("Authorization", $"Basic {Convert.ToBase64String(Encoding.UTF8.GetBytes($"{username}:{password}"))}");
			validatorResponse = new ClaimsPrincipal();

			var middleware = GetMiddleware();
			var context = GetContext();

			// act
			await middleware.InvokeAsync(context);

			// assert
			Assert.AreEqual(0, responseStatusCodeCallback); // not triggered
			Assert.AreEqual(0, responseHeadersCallback.Count);
			Assert.AreEqual(1, validatorCallback.Count);

			Assert.AreEqual(username, validatorCallback.First().username);
			Assert.AreEqual(password, validatorCallback.First().password);
			Assert.AreEqual(IPAddress.Loopback, validatorCallback.First().ipAddr);
		}

		[TestMethod]
		public async Task ShouldDenyMissingHeader()
		{
			// arrange
			var middleware = GetMiddleware();
			var context = GetContext();

			// act
			await middleware.InvokeAsync(context);

			// assert
			Assert.AreEqual(401, responseStatusCodeCallback);

			Assert.AreEqual(0, validatorCallback.Count);

			Assert.AreEqual(1, responseHeadersCallback.Count);
			Assert.AreEqual("WWW-Authenticate", responseHeadersCallback.Keys.First());
			Assert.AreEqual("Basic", responseHeadersCallback.Values.First());
		}

		[TestMethod]
		public async Task ShouldDenyNoResult()
		{
			// arrange
			string username = "user";
			string password = "pw";

			validatorRealm = "TEST";
			var remote = IPAddress.Parse("1.2.3.4");

			requestHeaders.Add("Authorization", $"Basic {Convert.ToBase64String(Encoding.UTF8.GetBytes($"{username}:{password}"))}");

			var middleware = GetMiddleware();
			var context = GetContext(remote);

			// act
			await middleware.InvokeAsync(context);

			// assert
			Assert.AreEqual(401, responseStatusCodeCallback);

			Assert.AreEqual(1, responseHeadersCallback.Count);
			Assert.AreEqual("WWW-Authenticate", responseHeadersCallback.Keys.First());
			Assert.AreEqual($"Basic realm=\"{validatorRealm}\"", responseHeadersCallback.Values.First());

			Assert.AreEqual(1, validatorCallback.Count);
			Assert.AreEqual(username, validatorCallback.First().username);
			Assert.AreEqual(password, validatorCallback.First().password);
			Assert.AreEqual(remote, validatorCallback.First().ipAddr);
		}

		[TestMethod]
		public async Task ShouldBreakOnException()
		{
			// arrange
			string username = "user";

			requestHeaders.Add("Authorization", $"Basic {Convert.ToBase64String(Encoding.UTF8.GetBytes($"{username}"))}");

			var middleware = GetMiddleware();
			var context = GetContext();

			// act
			await middleware.InvokeAsync(context);

			// assert
			Assert.AreEqual(500, responseStatusCodeCallback);
		}

		private BasicAuthenticationMiddleware GetMiddleware()
		{
			var nextMock = new Mock<RequestDelegate>();
			var validatorMock = new Mock<IBasicAuthenticationValidator>();
			validatorMock
				.Setup(v => v.Realm)
				.Returns(validatorRealm);
			validatorMock
				.Setup(v => v.ValidateAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IPAddress>(), It.IsAny<CancellationToken>()))
				.Callback<string, string, IPAddress, CancellationToken>((username, password, ipAddress, _) => validatorCallback.Add((username, password, ipAddress)))
				.ReturnsAsync(validatorResponse);

			return new BasicAuthenticationMiddleware(nextMock.Object, validatorMock.Object);
		}

		private HttpContext GetContext(IPAddress remote = null)
		{
			// Request
			var requestHeaderMock = new Mock<IHeaderDictionary>();
			foreach (var header in requestHeaders)
			{
				requestHeaderMock
					.Setup(h => h.ContainsKey(header.Key))
					.Returns(true);
				requestHeaderMock
					.Setup(h => h[header.Key])
					.Returns(header.Value);
			}

			var requestMock = new Mock<HttpRequest>();
			requestMock
				.Setup(r => r.Headers)
				.Returns(requestHeaderMock.Object);

			// Response
			var responseHeaderMock = new Mock<IHeaderDictionary>();
			responseHeaderMock
				.SetupSet(h => h[It.IsAny<string>()] = It.IsAny<StringValues>())
				.Callback<string, StringValues>((key, value) => responseHeadersCallback[key] = value);

			var responseMock = new Mock<HttpResponse>();
			responseMock
				.Setup(r => r.Headers)
				.Returns(responseHeaderMock.Object);
			responseMock
				.SetupSet(r => r.StatusCode = It.IsAny<int>())
				.Callback<int>((code) => responseStatusCodeCallback = code);

			// Connection
			var connectionInfoMock = new Mock<ConnectionInfo>();
			connectionInfoMock
				.Setup(ci => ci.LocalIpAddress)
				.Returns(IPAddress.Loopback);
			connectionInfoMock
				.Setup(ci => ci.RemoteIpAddress)
				.Returns(remote ?? IPAddress.Loopback);

			// Request Services
			var requestServicesMock = new Mock<IServiceProvider>();

			var contextMock = new Mock<HttpContext>();
			contextMock
				.Setup(c => c.Request)
				.Returns(requestMock.Object);
			contextMock
				.Setup(c => c.Response)
				.Returns(responseMock.Object);
			contextMock
				.Setup(c => c.Connection)
				.Returns(connectionInfoMock.Object);
			contextMock
				.Setup(c => c.RequestServices)
				.Returns(requestServicesMock.Object);
			contextMock
				.Setup(c => c.RequestAborted)
				.Returns(CancellationToken.None);

			return contextMock.Object;
		}
	}
}