using System;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Net.Mime;
using System.Threading;
using System.Threading.Tasks;

using Microsoft.VisualStudio.TestTools.UnitTesting;
using Newtonsoft.Json;

using Tgstation.Server.Api;
using Tgstation.Server.Api.Models;
using Tgstation.Server.Api.Models.Request;
using Tgstation.Server.Api.Models.Response;
using Tgstation.Server.Api.Rights;
using Tgstation.Server.Client;
using Tgstation.Server.Host.Controllers;

namespace Tgstation.Server.Tests.Live
{
	sealed class InstanceManagerTest
	{
		public const string TestInstanceName = "IntegrationTestInstance";

		readonly IRestServerClient serverClient;
		readonly IInstanceManagerClient instanceManagerClient;
		readonly IUsersClient usersClient;
		readonly string testRootPath;

		public InstanceManagerTest(IRestServerClient serverClient, string testRootPath)
		{
			this.serverClient = serverClient ?? throw new ArgumentNullException(nameof(serverClient));
			instanceManagerClient = serverClient.Instances;
			usersClient = serverClient.Users;
			this.testRootPath = testRootPath ?? throw new ArgumentNullException(nameof(testRootPath));
		}

		public async Task<InstanceResponse> CreateTestInstance(string name, CancellationToken cancellationToken)
		{
			var instance = await CreateTestInstanceStub(name, cancellationToken);
			return await instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = instance.Id,
				Online = true,
				ConfigurationType = ConfigurationType.HostWrite
			}, cancellationToken);
		}

		ValueTask<InstanceResponse> CreateTestInstanceStub(string name, CancellationToken cancellationToken) => instanceManagerClient.CreateOrAttach(new InstanceCreateRequest
		{
			Name = name,
			Path = Path.Combine(testRootPath, $"Instance-{name}"),
			Online = true,
			ChatBotLimit = 2
		}, cancellationToken);

		static TRequestType FromResponse<TRequestType>(InstanceResponse response) where TRequestType : Api.Models.Instance, new() => new()
		{
			Id = response.Id,
			Path = response.Path,
			AutoUpdateInterval = response.AutoUpdateInterval,
			ChatBotLimit = response.ChatBotLimit,
			ConfigurationType = response.ConfigurationType,
			Name = response.Name,
			Online = response.Online
		};

		public async Task RunPreTest(CancellationToken cancellationToken)
		{
			var firstTest = await CreateTestInstanceStub(TestInstanceName, cancellationToken);
			//instances always start offline
			Assert.AreEqual(false, firstTest.Online);
			//check it exists
			Assert.IsTrue(Directory.Exists(firstTest.Path));

			var firstClient = instanceManagerClient.CreateClient(firstTest);
			await ApiAssert.ThrowsExactly<ConflictException, JobResponse>(() => firstClient.DreamDaemon.Start(cancellationToken), ErrorCode.InstanceOffline);

			//cant create instances in existent directories
			var testNonEmpty = Path.Combine(testRootPath, Guid.NewGuid().ToString());
			Directory.CreateDirectory(testNonEmpty);
			var testFile = Path.Combine(testNonEmpty, "asdf");
			await File.WriteAllBytesAsync(testFile, Array.Empty<byte>(), cancellationToken);
			await ApiAssert.ThrowsExactly<ConflictException, InstanceResponse>(() => instanceManagerClient.CreateOrAttach(new InstanceCreateRequest
			{
				Path = testNonEmpty,
				Name = "NonEmptyTest"
			}, cancellationToken), ErrorCode.InstanceAtExistingPath);

			//check it works for truly empty directories
			File.Delete(testFile);
			var secondTry = await instanceManagerClient.CreateOrAttach(new InstanceCreateRequest
			{
				Path = Path.Combine(testRootPath, Guid.NewGuid().ToString()),
				Name = "NonEmptyTest"
			}, cancellationToken);

			await ApiAssert.ThrowsExactly<ConflictException, InstanceResponse>(() => instanceManagerClient.CreateOrAttach(FromResponse<InstanceCreateRequest>(firstTest), cancellationToken), ErrorCode.InstanceAtConflictingPath);
			Assert.IsTrue(Directory.Exists(firstTest.Path));

			//can't create instances in installation directory
			await ApiAssert.ThrowsExactly<ConflictException, InstanceResponse>(() => instanceManagerClient.CreateOrAttach(new InstanceCreateRequest
			{
				Path = "./A/Local/Path",
				Name = "NoInstallDirTest"
			}, cancellationToken), ErrorCode.InstanceAtConflictingPath);

			//can't create instances as children of other instances
			await ApiAssert.ThrowsExactly<ConflictException, InstanceResponse>(() => instanceManagerClient.CreateOrAttach(new InstanceCreateRequest
			{
				Path = Path.Combine(firstTest.Path, "subdir"),
				Name = "NoOtherInstanceDirTest"
			}, cancellationToken), ErrorCode.InstanceAtConflictingPath);
			Assert.IsTrue(Directory.Exists(firstTest.Path));

			//can't move to existent directories
			await ApiAssert.ThrowsExactly<ConflictException, InstanceResponse>(() => instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				Path = testNonEmpty
			}, cancellationToken), ErrorCode.InstanceAtExistingPath);

			await ApiAssert.ThrowsExactly<ConflictException>(() => instanceManagerClient.GrantPermissions(new InstanceUpdateRequest
			{
				Id = 3482974,
			}, cancellationToken), ErrorCode.ResourceNotPresent);

			// test can't create instance outside of whitelist
			await ApiAssert.ThrowsExactly<ApiConflictException, InstanceResponse>(() => instanceManagerClient.CreateOrAttach(new InstanceCreateRequest
			{
				Name = "TestInstanceOutsideOfWhitelist",
				Path = Path.Combine(testRootPath, "..", Guid.NewGuid().ToString()),
				Online = true,
				ChatBotLimit = 1
			}, cancellationToken), ErrorCode.InstanceNotAtWhitelistedPath);

			//test basic move
			Directory.Delete(testNonEmpty);
			var initialPath = firstTest.Path;
			firstTest = await instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				Path = testNonEmpty
			}, cancellationToken);

			Assert.IsNotNull(firstTest.MoveJob);

			do
			{
				firstTest = await instanceManagerClient.GetId(firstTest, cancellationToken);
				await Task.Delay(TimeSpan.FromSeconds(1), cancellationToken);
			} while (firstTest.MoveJob != null);
			Assert.IsTrue(Directory.Exists(firstTest.Path));

			//online it for real for component tests
			firstTest.Online = true;
			firstTest.ConfigurationType = ConfigurationType.HostWrite;
			firstTest = await instanceManagerClient.Update(FromResponse<InstanceUpdateRequest>(firstTest), cancellationToken);
			Assert.AreEqual(true, firstTest.Online);
			Assert.AreEqual(ConfigurationType.HostWrite, firstTest.ConfigurationType);
			Assert.IsTrue(Directory.Exists(firstTest.Path));

			// a couple data validation checks
			// check setting both fails
			await ApiAssert.ThrowsExactly<ApiConflictException, InstanceResponse>(() => instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				AutoUpdateInterval = 9999,
				AutoUpdateCron = "0 0 0 1 1 *"
			}, cancellationToken), ErrorCode.ModelValidationFailure);

			// check bad crons fail
			await ApiAssert.ThrowsExactly<ApiConflictException, InstanceResponse>(() => instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				AutoUpdateCron = "not a cron"
			}, cancellationToken), ErrorCode.ModelValidationFailure);

			// regression check
			var updated = await instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				AutoUpdateInterval = 9999,
			}, cancellationToken);

			Assert.AreEqual(String.Empty, updated.AutoUpdateCron);
			Assert.AreEqual(9999U, updated.AutoUpdateInterval);

			// check regular 6-part crons succeed
			updated = await instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				AutoUpdateCron = "0 0 0 1 1 *"
			}, cancellationToken);

			Assert.AreEqual("0 0 0 1 1 *", updated.AutoUpdateCron);
			Assert.AreEqual(0U, updated.AutoUpdateInterval);

			//can't move online instance
			await ApiAssert.ThrowsExactly<ConflictException, InstanceResponse>(() => instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				Path = initialPath
			}, cancellationToken), ErrorCode.InstanceRelocateOnline);
			Assert.IsTrue(Directory.Exists(firstTest.Path));

			await RegressionTest1256(cancellationToken);
			firstTest = await instanceManagerClient.Update(new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				Online = false,
			}, cancellationToken);

			Assert.AreEqual(false, firstTest.Online);
			await instanceManagerClient.Detach(firstTest, cancellationToken);
		}

		async Task RegressionTest1256(CancellationToken cancellationToken)
		{
			var allInstances = await instanceManagerClient.List(null, cancellationToken);
			Assert.IsTrue(allInstances.Count <= 6, "Need less than or 6 instances at this point");

			for (var I = allInstances.Count; I < 6; ++I)
				await instanceManagerClient.CreateOrAttach(new InstanceCreateRequest
				{
					Name = $"RegressionTest1256-{I}",
					Path = Path.Combine(testRootPath, Guid.NewGuid().ToString()),
				}, cancellationToken);

			var url = serverClient.Url;
			var token = serverClient.Token.Bearer;
			// check that 400s are returned appropriately
			using var httpClient = new HttpClient();
			using var request = new HttpRequestMessage(HttpMethod.Get, string.Concat(url.ToString(), Routes.ListRoute(Routes.InstanceManager).AsSpan(1), "?pageSize=2"));
			request.Headers.Accept.Clear();
			request.Headers.UserAgent.Add(new ProductInfoHeaderValue("RegressionTest1256", "1.0.0"));
			request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue(MediaTypeNames.Application.Json));
			request.Headers.Add(ApiHeaders.ApiVersionHeader, "Tgstation.Server.Api/" + ApiHeaders.Version);
			request.Headers.Authorization = new AuthenticationHeaderValue(ApiHeaders.BearerAuthenticationScheme, token);
			using var response = await httpClient.SendAsync(request, cancellationToken);
			response.EnsureSuccessStatusCode();

			var json = await response.Content.ReadAsStringAsync(cancellationToken);
			var paginated = JsonConvert.DeserializeObject<PaginatedResponse<InstanceResponse>>(json);

			Assert.AreEqual(2, paginated.PageSize);
			Assert.AreEqual(3, paginated.TotalPages);
		}

		public async Task RunPostTest(Api.Models.Instance instance, CancellationToken cancellationToken)
		{
			var instances = await instanceManagerClient.List(null, cancellationToken);
			var firstTest = instances.Single(x => x.Name == instance.Name);
			var instanceClient = instanceManagerClient.CreateClient(firstTest);

			Assert.IsTrue(firstTest.Accessible);

			//can regain permissions on instance without instance user
			var ourInstanceUser = await instanceClient.PermissionSets.Read(cancellationToken);
			await instanceClient.PermissionSets.Delete(ourInstanceUser, cancellationToken);

			firstTest = await instanceManagerClient.GetId(firstTest, cancellationToken);
			Assert.IsFalse(firstTest.Accessible);

			await ApiAssert.ThrowsExactly<InsufficientPermissionsException, InstancePermissionSetResponse>(() => instanceClient.PermissionSets.Read(cancellationToken));

			await instanceManagerClient.GrantPermissions(new InstanceUpdateRequest
			{
				Id = firstTest.Id
			}, cancellationToken);

			firstTest = await instanceManagerClient.GetId(firstTest, cancellationToken);
			Assert.IsTrue(firstTest.Accessible);

			ourInstanceUser = await instanceClient.PermissionSets.Read(cancellationToken);

			Assert.AreEqual(RightsHelper.AllRights<DreamDaemonRights>(), ourInstanceUser.DreamDaemonRights.Value);

			//can't detach online instance
			await ApiAssert.ThrowsExactly<ConflictException>(() => instanceManagerClient.Detach(firstTest, cancellationToken), ErrorCode.InstanceDetachOnline);

			firstTest.Online = false;
			firstTest = await instanceManagerClient.Update(FromResponse<InstanceUpdateRequest>(firstTest), cancellationToken);

			await instanceManagerClient.Detach(firstTest, cancellationToken);

			var attachPath = Path.Combine(firstTest.Path, InstanceController.InstanceAttachFileName);
			Assert.IsTrue(File.Exists(attachPath));

			//can recreate detached instance
			firstTest = await instanceManagerClient.CreateOrAttach(FromResponse<InstanceCreateRequest>(firstTest), cancellationToken);

			// Test updating only with SetChatBotLimit works
			var current = await usersClient.Read(cancellationToken);
			var update = new UserUpdateRequest
			{
				Id = current.Id,
				PermissionSet = new PermissionSet
				{
					InstanceManagerRights = InstanceManagerRights.SetChatBotLimit,
					AdministrationRights = RightsHelper.AllRights<AdministrationRights>()
				}
			};
			await usersClient.Update(update, cancellationToken);
			var update2 = new InstanceUpdateRequest
			{
				Id = firstTest.Id,
				ChatBotLimit = 77
			};
			var newThing = await instanceManagerClient.Update(update2, cancellationToken);

			update.PermissionSet.InstanceManagerRights |= InstanceManagerRights.Delete | InstanceManagerRights.Create | InstanceManagerRights.List;
			await usersClient.Update(update, cancellationToken);

			//but only if the attach file exists
			await instanceManagerClient.Detach(firstTest, cancellationToken);
			File.Delete(attachPath);
			await ApiAssert.ThrowsExactly<ConflictException, InstanceResponse>(() => instanceManagerClient.CreateOrAttach(FromResponse<InstanceCreateRequest>(firstTest), cancellationToken), ErrorCode.InstanceAtExistingPath);
		}
	}
}