// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Ignitor;
using Microsoft.AspNetCore.Components.E2ETest.Infrastructure.ServerFixtures;
using Microsoft.AspNetCore.SignalR.Client;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Testing;
using Xunit;

namespace Microsoft.AspNetCore.Components.E2ETest.ServerExecutionTests
{
    public class ComponentHubReliabilityTest : IClassFixture<AspNetSiteServerFixture>, IDisposable
    {
        private static readonly TimeSpan DefaultLatencyTimeout = TimeSpan.FromMilliseconds(500);
        private readonly AspNetSiteServerFixture _serverFixture;

        public ComponentHubReliabilityTest(AspNetSiteServerFixture serverFixture)
        {
            serverFixture.BuildWebHostMethod = TestServer.Program.BuildWebHost;
            _serverFixture = serverFixture;
            CreateDefaultConfiguration();
        }

        public BlazorClient Client { get; set; }

        private IList<Batch> Batches { get; set; } = new List<Batch>();
        private IList<string> Errors { get; set; } = new List<string>();
        private IList<LogMessage> Logs { get; set; } = new List<LogMessage>();

        public TestSink TestSink { get; set; }

        private void CreateDefaultConfiguration()
        {
            Client = new BlazorClient() { DefaultLatencyTimeout = DefaultLatencyTimeout };
            Client.RenderBatchReceived += (id, data) => Batches.Add(new Batch(id, data));
            Client.OnCircuitError += (error) => Errors.Add(error);

            _  = _serverFixture.RootUri; // this is needed for the side-effects of getting the URI.
            TestSink = _serverFixture.Host.Services.GetRequiredService<TestSink>();
            TestSink.MessageLogged += LogMessages;
        }

        private void LogMessages(WriteContext context) => Logs.Add(new LogMessage(context.LogLevel, context.Message, context.Exception));

        [Fact]
        public async Task CannotStartMultipleCircuits()
        {
            // Arrange
            var expectedError = "The circuit host '.*?' has already been initialized.";
            var rootUri = _serverFixture.RootUri;
            var baseUri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(baseUri, prerendered: false), "Couldn't connect to the app");
            Assert.Single(Batches);

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync(
                "StartCircuit",
                baseUri,
                baseUri + "/home"));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Matches(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
        }

        [Fact]
        public async Task CannotStartCircuitWithNullData()
        {
            // Arrange
            var expectedError = "The uris provided are invalid.";
            var rootUri = _serverFixture.RootUri;
            var uri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(uri, prerendered: false, connectAutomatically: false), "Couldn't connect to the app");

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync("StartCircuit", null, null));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Matches(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
        }

        [Fact]
        public async Task CannotStartCircuitWithInvalidUris()
        {
            // Arrange
            var expectedError = "The uris provided are invalid.";
            var rootUri = _serverFixture.RootUri;
            var uri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(uri, prerendered: false, connectAutomatically: false), "Couldn't connect to the app");

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync("StartCircuit", uri.AbsoluteUri, "/foo"));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Matches(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
        }

        // This is a hand-chosen example of something that will cause an exception in creating the circuit host.
        // We want to test this case so that we know what happens when creating the circuit host blows up.
        [Fact]
        public async Task StartCircuitCausesInitializationError()
        {
            // Arrange
            var expectedError = "The circuit failed to initialize.";
            var rootUri = _serverFixture.RootUri;
            var uri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(uri, prerendered: false, connectAutomatically: false), "Couldn't connect to the app");

            // Act
            //
            // These are valid URIs by the BaseUri doesn't contain the Uri - so it fails to initialize.
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync("StartCircuit", uri, "http://example.com"), TimeSpan.FromHours(1));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Matches(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
        }

        [Fact]
        public async Task CannotInvokeJSInteropBeforeInitialization()
        {
            // Arrange
            var expectedError = "Circuit not initialized.";
            var rootUri = _serverFixture.RootUri;
            var baseUri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(baseUri, prerendered: false, connectAutomatically: false));
            Assert.Empty(Batches);

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync(
                "BeginInvokeDotNetFromJS",
                "",
                "",
                "",
                0,
                ""));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Equal(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
            Assert.Contains(Logs, l => (l.LogLevel, l.Message) == (LogLevel.Debug, "Call to 'BeginInvokeDotNetFromJS' received before the circuit host initialization"));
        }

        [Fact]
        public async Task CannotInvokeJSInteropCallbackCompletionsBeforeInitialization()
        {
            // Arrange
            var expectedError = "Circuit not initialized.";
            var rootUri = _serverFixture.RootUri;
            var baseUri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(baseUri, prerendered: false, connectAutomatically: false));
            Assert.Empty(Batches);

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync(
                "EndInvokeJSFromDotNet",
                3,
                true,
                "[]"));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Equal(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
            Assert.Contains(Logs, l => (l.LogLevel, l.Message) == (LogLevel.Debug, "Call to 'EndInvokeJSFromDotNet' received before the circuit host initialization"));
        }

        [Fact]
        public async Task CannotDispatchBrowserEventsBeforeInitialization()
        {
            // Arrange
            var expectedError = "Circuit not initialized.";
            var rootUri = _serverFixture.RootUri;
            var baseUri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(baseUri, prerendered: false, connectAutomatically: false));
            Assert.Empty(Batches);

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync(
                "DispatchBrowserEvent",
                "",
                ""));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Equal(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
            Assert.Contains(Logs, l => (l.LogLevel, l.Message) == (LogLevel.Debug, "Call to 'DispatchBrowserEvent' received before the circuit host initialization"));
        }

        [Fact]
        public async Task CannotInvokeOnRenderCompletedInitialization()
        {
            // Arrange
            var expectedError = "Circuit not initialized.";
            var rootUri = _serverFixture.RootUri;
            var baseUri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(baseUri, prerendered: false, connectAutomatically: false));
            Assert.Empty(Batches);

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync(
                "OnRenderCompleted",
                5,
                null));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Equal(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
            Assert.Contains(Logs, l => (l.LogLevel, l.Message) == (LogLevel.Debug, "Call to 'OnRenderCompleted' received before the circuit host initialization"));
        }

        [Fact]
        public async Task CannotInvokeOnLocationChangedBeforeInitialization()
        {
            // Arrange
            var expectedError = "Circuit not initialized.";
            var rootUri = _serverFixture.RootUri;
            var baseUri = new Uri(rootUri, "/subdir");
            Assert.True(await Client.ConnectAsync(baseUri, prerendered: false, connectAutomatically: false));
            Assert.Empty(Batches);

            // Act
            await Client.ExpectCircuitError(() => Client.HubConnection.SendAsync(
                "OnLocationChanged",
                baseUri.AbsoluteUri,
                false));

            // Assert
            var actualError = Assert.Single(Errors);
            Assert.Equal(expectedError, actualError);
            Assert.DoesNotContain(Logs, l => l.LogLevel > LogLevel.Information);
            Assert.Contains(Logs, l => (l.LogLevel, l.Message) == (LogLevel.Debug, "Call to 'OnLocationChanged' received before the circuit host initialization"));
        }

        public void Dispose()
        {
            TestSink.MessageLogged -= LogMessages;
        }

        private class LogMessage
        {
            public LogMessage(LogLevel logLevel, string message, Exception exception)
            {
                LogLevel = logLevel;
                Message = message;
                Exception = exception;
            }

            public LogLevel LogLevel { get; set; }
            public string Message { get; set; }
            public Exception Exception { get; set; }
        }

        private class Batch
        {
            public Batch(int id, byte [] data)
            {
                Id = id;
                Data = data;
            }

            public int Id { get; }
            public byte[] Data { get; }
        }
    }
}