using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using MQTTnet.Client;
using MQTTnet.Client.Connecting;
using MQTTnet.Client.Options;
using MQTTnet.Diagnostics;
using MQTTnet.Extensions.ManagedClient;
using MQTTnet.Server;
using MQTTnet.Tests.Mockups;

namespace MQTTnet.Tests
{
    [TestClass]
    public class ManagedMqttClient_Tests
    {
        [TestMethod]
        public async Task Drop_New_Messages_On_Full_Queue()
        {
            var factory = new MqttFactory();
            var managedClient = factory.CreateManagedMqttClient();
            try
            {
                var clientOptions = new ManagedMqttClientOptionsBuilder()
                    .WithMaxPendingMessages(5)
                    .WithPendingMessagesOverflowStrategy(MqttPendingMessagesOverflowStrategy.DropNewMessage);

                clientOptions.WithClientOptions(o => o.WithTcpServer("localhost"));

                await managedClient.StartAsync(clientOptions.Build());

                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "1" });
                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "2" });
                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "3" });
                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "4" });
                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "5" });

                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "6" });
                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "7" });
                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "8" });

                Assert.AreEqual(5, managedClient.PendingApplicationMessagesCount);
            }
            finally
            {
                await managedClient.StopAsync();
            }
        }

        [TestMethod]
        public async Task ManagedClients_Will_Message_Send()
        {
            using (var testEnvironment = new TestEnvironment())
            {
                var receivedMessagesCount = 0;

                var factory = new MqttFactory();

                await testEnvironment.StartServerAsync();

                var willMessage = new MqttApplicationMessageBuilder().WithTopic("My/last/will").WithAtMostOnceQoS().Build();
                var clientOptions = new MqttClientOptionsBuilder()
                    .WithTcpServer("localhost", testEnvironment.ServerPort)
                    .WithWillMessage(willMessage);
                var dyingClient = testEnvironment.CreateClient();
                var dyingManagedClient = new ManagedMqttClient(dyingClient, testEnvironment.ClientLogger.CreateChildLogger());
                await dyingManagedClient.StartAsync(new ManagedMqttClientOptionsBuilder()
                    .WithClientOptions(clientOptions)
                    .Build());

                var recievingClient = await testEnvironment.ConnectClientAsync();
                await recievingClient.SubscribeAsync("My/last/will");

                recievingClient.UseApplicationMessageReceivedHandler(context => Interlocked.Increment(ref receivedMessagesCount));

                dyingManagedClient.Dispose();

                await Task.Delay(1000);

                Assert.AreEqual(1, receivedMessagesCount);
            }
        }

        [TestMethod]
        public async Task Start_Stop()
        {
            using (var testEnvironment = new TestEnvironment())
            {
                var factory = new MqttFactory();

                var server = await testEnvironment.StartServerAsync();

                var managedClient = new ManagedMqttClient(testEnvironment.CreateClient(), new MqttNetLogger().CreateChildLogger());
                var clientOptions = new MqttClientOptionsBuilder()
                    .WithTcpServer("localhost", testEnvironment.ServerPort);

                TaskCompletionSource<bool> connected = new TaskCompletionSource<bool>();
                managedClient.ConnectedHandler = new MqttClientConnectedHandlerDelegate(e => { connected.SetResult(true);});

                await managedClient.StartAsync(new ManagedMqttClientOptionsBuilder()
                    .WithClientOptions(clientOptions)
                    .Build());

                await connected.Task;

                await managedClient.StopAsync();

                Assert.AreEqual(0, (await server.GetClientStatusAsync()).Count);
            }
        }
        
        [TestMethod]
        public async Task Storage_Queue_Drains()
        {
            using (var testEnvironment = new TestEnvironment())
            {
                testEnvironment.IgnoreClientLogErrors = true;
                testEnvironment.IgnoreServerLogErrors = true;

                var factory = new MqttFactory();

                var server = await testEnvironment.StartServerAsync();

                var managedClient = new ManagedMqttClient(testEnvironment.CreateClient(), new MqttNetLogger().CreateChildLogger());
                var clientOptions = new MqttClientOptionsBuilder()
                    .WithTcpServer("localhost", testEnvironment.ServerPort);
                var storage = new ManagedMqttClientTestStorage();

                TaskCompletionSource<bool> connected = new TaskCompletionSource<bool>();
                managedClient.ConnectedHandler = new MqttClientConnectedHandlerDelegate(e =>
                {
                    managedClient.ConnectedHandler = null;
                    connected.SetResult(true);
                });

                await managedClient.StartAsync(new ManagedMqttClientOptionsBuilder()
                    .WithClientOptions(clientOptions)
                    .WithStorage(storage)
                    .WithAutoReconnectDelay(System.TimeSpan.FromSeconds(5))
                    .Build());

                await connected.Task;

                await testEnvironment.Server.StopAsync();

                await managedClient.PublishAsync(new MqttApplicationMessage { Topic = "1" });

                //Message should have been added to the storage queue in PublishAsync,
                //and we are awaiting PublishAsync, so the message should already be
                //in storage at this point (i.e. no waiting).
                Assert.AreEqual(1, storage.GetMessageCount());

                connected = new TaskCompletionSource<bool>();
                managedClient.ConnectedHandler = new MqttClientConnectedHandlerDelegate(e =>
                {
                    managedClient.ConnectedHandler = null;
                    connected.SetResult(true);
                });

                await testEnvironment.Server.StartAsync(new MqttServerOptionsBuilder()
                    .WithDefaultEndpointPort(testEnvironment.ServerPort).Build());

                await connected.Task;

                //Wait 500ms here so the client has time to publish the queued message
                await Task.Delay(500);

                Assert.AreEqual(0, storage.GetMessageCount());

                await managedClient.StopAsync();
            }
        }
    }
    
    public class ManagedMqttClientTestStorage : IManagedMqttClientStorage
    {
        private IList<ManagedMqttApplicationMessage> _messages = null;

        public Task<IList<ManagedMqttApplicationMessage>> LoadQueuedMessagesAsync()
        {
            if (_messages == null)
            {
                _messages = new List<ManagedMqttApplicationMessage>();
            }
            return Task.FromResult(_messages);
        }

        public Task SaveQueuedMessagesAsync(IList<ManagedMqttApplicationMessage> messages)
        {
            _messages = messages;
            return Task.FromResult(0);
        }

        public int GetMessageCount()
        {
            return _messages.Count;
        }
    }
}