#region Copyright notice and license

// Copyright 2015, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#endregion

using System;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Grpc.Core;
using Grpc.Core.Internal;
using Grpc.Core.Utils;
using NUnit.Framework;

namespace Grpc.Core.Tests
{
    /// <summary>
    /// Tests for Deadline support.
    /// </summary>
    public class TimeoutsTest
    {
        const string Host = "localhost";
        const string ServiceName = "tests.Test";

        static readonly Method<string, string> TestMethod = new Method<string, string>(
            MethodType.Unary,
            ServiceName,
            "Test",
            Marshallers.StringMarshaller,
            Marshallers.StringMarshaller);

        static readonly ServerServiceDefinition ServiceDefinition = ServerServiceDefinition.CreateBuilder(ServiceName)
            .AddMethod(TestMethod, TestMethodHandler)
            .Build();

        // provides a way how to retrieve an out-of-band result value from server handler
        static TaskCompletionSource<string> stringFromServerHandlerTcs;

        Server server;
        Channel channel;

        [SetUp]
        public void Init()
        {
            server = new Server
            {
                Services = { ServiceDefinition },
                Ports = { { Host, ServerPort.PickUnused, ServerCredentials.Insecure } }
            };
            server.Start();
            channel = new Channel(Host, server.Ports.Single().BoundPort, Credentials.Insecure);

            stringFromServerHandlerTcs = new TaskCompletionSource<string>();
        }

        [TearDown]
        public void Cleanup()
        {
            channel.Dispose();
            server.ShutdownAsync().Wait();
        }

        [TestFixtureTearDown]
        public void CleanupClass()
        {
            GrpcEnvironment.Shutdown();
        }

        [Test]
        public void InfiniteDeadline()
        {
            // no deadline specified, check server sees infinite deadline
            var callDetails = new CallInvocationDetails<string, string>(channel, TestMethod, new CallOptions());
            Assert.AreEqual("DATETIME_MAXVALUE", Calls.BlockingUnaryCall(callDetails, "RETURN_DEADLINE"));

            // DateTime.MaxValue deadline specified, check server sees infinite deadline
            var callDetails2 = new CallInvocationDetails<string, string>(channel, TestMethod, new CallOptions());
            Assert.AreEqual("DATETIME_MAXVALUE", Calls.BlockingUnaryCall(callDetails2, "RETURN_DEADLINE"));
        }

        [Test]
        public void DeadlineTransferredToServer()
        {
            var remainingTimeClient = TimeSpan.FromDays(7);
            var deadline = DateTime.UtcNow + remainingTimeClient;
            Thread.Sleep(1000);
            var callDetails = new CallInvocationDetails<string, string>(channel, TestMethod, new CallOptions(deadline: deadline));

            var serverDeadlineTicksString = Calls.BlockingUnaryCall(callDetails, "RETURN_DEADLINE");
            var serverDeadline = new DateTime(long.Parse(serverDeadlineTicksString), DateTimeKind.Utc);

            // A fairly relaxed check that the deadline set by client and deadline seen by server
            // are in agreement. C core takes care of the work with transferring deadline over the wire,
            // so we don't need an exact check here.
            Assert.IsTrue(Math.Abs((deadline - serverDeadline).TotalMilliseconds) < 5000);
        }

        [Test]
        public void DeadlineInThePast()
        {
            var callDetails = new CallInvocationDetails<string, string>(channel, TestMethod, new CallOptions(deadline: DateTime.MinValue));

            try
            {
                Calls.BlockingUnaryCall(callDetails, "TIMEOUT");
                Assert.Fail();
            }
            catch (RpcException e)
            {
                // We can't guarantee the status code always DeadlineExceeded. See issue #2685.
                Assert.Contains(e.Status.StatusCode, new[] { StatusCode.DeadlineExceeded, StatusCode.Internal });
            }
        }

        [Test]
        public void DeadlineExceededStatusOnTimeout()
        {
            var deadline = DateTime.UtcNow.Add(TimeSpan.FromSeconds(5));
            var callDetails = new CallInvocationDetails<string, string>(channel, TestMethod, new CallOptions(deadline: deadline));

            try
            {
                Calls.BlockingUnaryCall(callDetails, "TIMEOUT");
                Assert.Fail();
            }
            catch (RpcException e)
            {
                // We can't guarantee the status code always DeadlineExceeded. See issue #2685.
                Assert.Contains(e.Status.StatusCode, new[] { StatusCode.DeadlineExceeded, StatusCode.Internal });
            }
        }

        [Test]
        public void ServerReceivesCancellationOnTimeout()
        {
            var deadline = DateTime.UtcNow.Add(TimeSpan.FromSeconds(5));
            var callDetails = new CallInvocationDetails<string, string>(channel, TestMethod, new CallOptions(deadline: deadline));

            try
            {
                Calls.BlockingUnaryCall(callDetails, "CHECK_CANCELLATION_RECEIVED");
                Assert.Fail();
            }
            catch (RpcException e)
            {
                // We can't guarantee the status code is always DeadlineExceeded. See issue #2685.
                Assert.Contains(e.Status.StatusCode, new[] { StatusCode.DeadlineExceeded, StatusCode.Internal });
            }
            Assert.AreEqual("CANCELLED", stringFromServerHandlerTcs.Task.Result);
        }
            
        private static async Task<string> TestMethodHandler(string request, ServerCallContext context)
        {
            if (request == "TIMEOUT")
            {
                await Task.Delay(60000);
                return "";
            }

            if (request == "RETURN_DEADLINE")
            {
                if (context.Deadline == DateTime.MaxValue)
                {
                    return "DATETIME_MAXVALUE";
                }

                return context.Deadline.Ticks.ToString();
            }

            if (request == "CHECK_CANCELLATION_RECEIVED")
            {
                // wait until cancellation token is fired.
                var tcs = new TaskCompletionSource<object>();
                context.CancellationToken.Register(() => { tcs.SetResult(null); });
                await tcs.Task;
                stringFromServerHandlerTcs.SetResult("CANCELLED");
                return "";
            }

            return "";
        }
    }
}