// 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.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Microsoft.Extensions.Options;
using Xunit;

namespace Microsoft.Extensions.DependencyInjection
{
    // Integration tests for extension methods on IHealthCheckBuilder
    //
    // We test the longest overload of each 'family' of Add...Check methods, since they chain to each other.
    public class HealthChecksBuilderTest
    {
        [Fact]
        public void AddCheck_Instance()
        {
            // Arrange
            var instance = new DelegateHealthCheck((_) =>
            {
                return Task.FromResult(HealthCheckResult.Healthy());
            });

            var services = CreateServices();
            services.AddHealthChecks().AddCheck("test", failureStatus: HealthStatus.Degraded,tags: new[] { "tag", }, instance: instance);

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Degraded, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);
            Assert.Same(instance, registration.Factory(serviceProvider));
        }

        [Fact]
        public void AddCheck_T_TypeActivated()
        {
            // Arrange
            var services = CreateServices();
            services.AddHealthChecks().AddCheck<TestHealthCheck>("test", failureStatus: HealthStatus.Degraded, tags: new[] { "tag", });

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Degraded, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);
            Assert.IsType<TestHealthCheck>(registration.Factory(serviceProvider));
        }

        [Fact]
        public void AddCheck_T_Service()
        {
            // Arrange
            var instance = new TestHealthCheck();

            var services = CreateServices();
            services.AddSingleton(instance);
            services.AddHealthChecks().AddCheck<TestHealthCheck>("test", failureStatus: HealthStatus.Degraded, tags: new[] { "tag", });

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Degraded, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);
            Assert.Same(instance, registration.Factory(serviceProvider));
        }

        [Fact]
        public void AddTypeActivatedCheck()
        {
            // Arrange
            var services = CreateServices();
            services
                .AddHealthChecks()
                .AddTypeActivatedCheck<TestHealthCheckWithArgs>("test", failureStatus: HealthStatus.Degraded, tags: new[] { "tag", }, args: new object[] { 5, "hi", });

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Degraded, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);

            var check = Assert.IsType<TestHealthCheckWithArgs>(registration.Factory(serviceProvider));
            Assert.Equal(5, check.I);
            Assert.Equal("hi", check.S);
        }

        [Fact]
        public void AddDelegateCheck_NoArg()
        {
            // Arrange
            var services = CreateServices();
            services.AddHealthChecks().AddCheck("test", tags: new[] { "tag", }, check: () =>
            {
                return HealthCheckResult.Healthy();
            });

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Unhealthy, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);
            Assert.IsType<DelegateHealthCheck>(registration.Factory(serviceProvider));
        }

        [Fact]
        public void AddDelegateCheck_CancellationToken()
        {
            // Arrange
            var services = CreateServices();
            services.AddHealthChecks().AddCheck("test", (_) =>
            {
                return HealthCheckResult.Degraded();
            }, tags: new[] { "tag", });

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Unhealthy, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);
            Assert.IsType<DelegateHealthCheck>(registration.Factory(serviceProvider));
        }

        [Fact]
        public void AddAsyncDelegateCheck_NoArg()
        {
            // Arrange
            var services = CreateServices();
            services.AddHealthChecks().AddAsyncCheck("test", () =>
            {
                return Task.FromResult(HealthCheckResult.Healthy());
            }, tags: new[] { "tag", });

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Unhealthy, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);
            Assert.IsType<DelegateHealthCheck>(registration.Factory(serviceProvider));
        }

        [Fact]
        public void AddAsyncDelegateCheck_CancellationToken()
        {
            // Arrange
            var services = CreateServices();
            services.AddHealthChecks().AddAsyncCheck("test", (_) =>
            {
                return Task.FromResult(HealthCheckResult.Unhealthy());
            }, tags: new[] { "tag", });

            var serviceProvider = services.BuildServiceProvider();

            // Act
            var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>().Value;

            // Assert
            var registration = Assert.Single(options.Registrations);
            Assert.Equal("test", registration.Name);
            Assert.Equal(HealthStatus.Unhealthy, registration.FailureStatus);
            Assert.Equal<string>(new[] { "tag", }, registration.Tags);
            Assert.IsType<DelegateHealthCheck>(registration.Factory(serviceProvider));
        }

        [Fact]
        public void ChecksCanBeRegisteredInMultipleCallsToAddHealthChecks()
        {
            var services = new ServiceCollection();
            services
                .AddHealthChecks()
                .AddAsyncCheck("Foo", () => Task.FromResult(HealthCheckResult.Healthy()));
            services
                .AddHealthChecks()
                .AddAsyncCheck("Bar", () => Task.FromResult(HealthCheckResult.Healthy()));

            // Act
            var options = services.BuildServiceProvider().GetRequiredService<IOptions<HealthCheckServiceOptions>>();

            // Assert
            Assert.Collection(
                options.Value.Registrations,
                actual => Assert.Equal("Foo", actual.Name),
                actual => Assert.Equal("Bar", actual.Name));
        }

        private IServiceCollection CreateServices()
        {
            var services = new ServiceCollection();
            services.AddLogging();
            services.AddOptions();
            return services;
        }

        private class TestHealthCheck : IHealthCheck
        {
            public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
            {
                throw new System.NotImplementedException();
            }
        }

        private class TestHealthCheckWithArgs : IHealthCheck
        {
            public TestHealthCheckWithArgs(int i, string s)
            {
                I = i;
                S = s;
            }

            public int I { get; set; }

            public string S { get; set; }

            public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
            {
                throw new System.NotImplementedException();
            }
        }
    }
}