using GFramework.Core.Abstractions.Logging;
using GFramework.Core.Architectures;
using GFramework.Core.Ioc;
using GFramework.Core.Logging;
using GFramework.Cqrs.Abstractions.Cqrs;
using GFramework.Cqrs.Tests.Logging;

namespace GFramework.Cqrs.Tests.Cqrs;

/// <summary>
///     验证 CQRS 处理器自动注册在顺序与容错层面的可观察行为。
/// </summary>
[TestFixture]
internal sealed class CqrsHandlerRegistrarTests
{
    private MicrosoftDiContainer? _container;
    private ArchitectureContext? _context;

    /// <summary>
    ///     初始化测试容器并重置共享状态。
    /// </summary>
    [SetUp]
    public void SetUp()
    {
        LoggerFactoryResolver.Provider = new ConsoleLoggerFactoryProvider();
        DeterministicNotificationHandlerState.Reset();

        _container = new MicrosoftDiContainer();
        CqrsTestRuntime.RegisterHandlers(
            _container,
            typeof(CqrsHandlerRegistrarTests).Assembly);

        _container.Freeze();
        _context = new ArchitectureContext(_container);
        ClearRegistrarCaches();
    }

    /// <summary>
    ///     清理测试过程中创建的上下文与共享状态。
    /// </summary>
    [TearDown]
    public void TearDown()
    {
        _context = null;
        _container = null;
        DeterministicNotificationHandlerState.Reset();
        ClearRegistrarCaches();
    }

    /// <summary>
    ///     验证自动扫描到的通知处理器会按稳定名称顺序执行，而不是依赖反射枚举顺序。
    /// </summary>
    [Test]
    public async Task PublishAsync_Should_Run_Notification_Handlers_In_Deterministic_Name_Order()
    {
        await _context!.PublishAsync(new DeterministicOrderNotification());

        Assert.That(
            DeterministicNotificationHandlerState.InvocationOrder,
            Is.EqualTo(
            [
                nameof(AlphaDeterministicNotificationHandler),
                nameof(ZetaDeterministicNotificationHandler)
            ]));
    }

    /// <summary>
    ///     验证部分类型加载失败时仍能保留可加载类型，并记录诊断日志。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Register_Loadable_Types_And_Log_Warnings_When_Assembly_Load_Partially_Fails()
    {
        var originalProvider = LoggerFactoryResolver.Provider;
        var capturingProvider = new CapturingLoggerFactoryProvider(LogLevel.Warning);
        var reflectionTypeLoadException = new ReflectionTypeLoadException(
            [typeof(AlphaDeterministicNotificationHandler), null],
            [new TypeLoadException("Missing optional dependency for registrar test.")]);
        var partiallyLoadableAssembly = new Mock<Assembly>();
        partiallyLoadableAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.PartiallyLoadableAssembly, Version=1.0.0.0");
        partiallyLoadableAssembly
            .Setup(static assembly => assembly.GetTypes())
            .Throws(reflectionTypeLoadException);

        LoggerFactoryResolver.Provider = capturingProvider;
        try
        {
            var container = new MicrosoftDiContainer();
            CqrsTestRuntime.RegisterHandlers(container, partiallyLoadableAssembly.Object);
            container.Freeze();

            var handlers = container.GetAll<INotificationHandler<DeterministicOrderNotification>>();
            var warningLogs = capturingProvider.Loggers
                .SelectMany(static logger => logger.Logs)
                .Where(static log => log.Level == LogLevel.Warning)
                .ToList();

            Assert.Multiple(() =>
            {
                Assert.That(
                    handlers.Select(static handler => handler.GetType()),
                    Is.EqualTo([typeof(AlphaDeterministicNotificationHandler)]));
                Assert.That(warningLogs.Count, Is.GreaterThanOrEqualTo(2));
                Assert.That(
                    warningLogs.Any(log => log.Message.Contains("partially failed", StringComparison.Ordinal)),
                    Is.True);
                Assert.That(
                    warningLogs.Any(log =>
                        log.Message.Contains("Missing optional dependency", StringComparison.Ordinal)),
                    Is.True);
            });
        }
        finally
        {
            LoggerFactoryResolver.Provider = originalProvider;
        }
    }

    /// <summary>
    ///     验证当程序集提供源码生成的注册器时，运行时会优先使用该注册器而不是反射扫描类型列表。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Use_Generated_Registry_When_Available()
    {
        var generatedAssembly = new Mock<Assembly>();
        generatedAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.GeneratedRegistryAssembly, Version=1.0.0.0");
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsHandlerRegistryAttribute), false))
            .Returns([new CqrsHandlerRegistryAttribute(typeof(GeneratedNotificationHandlerRegistry))]);

        var container = new MicrosoftDiContainer();
        CqrsTestRuntime.RegisterHandlers(container, generatedAssembly.Object);
        container.Freeze();

        var handlers = container.GetAll<INotificationHandler<GeneratedRegistryNotification>>();

        Assert.That(
            handlers.Select(static handler => handler.GetType()),
            Is.EqualTo([typeof(GeneratedRegistryNotificationHandler)]));
    }

    /// <summary>
    ///     验证 generated registry 使用私有无参构造器时，运行时仍可激活它并完成处理器注册。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Activate_Generated_Registry_With_Private_Parameterless_Constructor()
    {
        var generatedAssembly = new Mock<Assembly>();
        generatedAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.PrivateGeneratedRegistryAssembly, Version=1.0.0.0");
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsHandlerRegistryAttribute), false))
            .Returns([new CqrsHandlerRegistryAttribute(typeof(PrivateConstructorNotificationHandlerRegistry))]);

        var container = new MicrosoftDiContainer();
        CqrsTestRuntime.RegisterHandlers(container, generatedAssembly.Object);
        container.Freeze();

        var handlers = container.GetAll<INotificationHandler<GeneratedRegistryNotification>>();

        Assert.That(
            handlers.Select(static handler => handler.GetType()),
            Is.EqualTo([typeof(GeneratedRegistryNotificationHandler)]));
    }

    /// <summary>
    ///     验证当生成注册器元数据损坏时，运行时会记录告警并回退到反射扫描路径。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Fall_Back_To_Reflection_When_Generated_Registry_Is_Invalid()
    {
        var originalProvider = LoggerFactoryResolver.Provider;
        var capturingProvider = new CapturingLoggerFactoryProvider(LogLevel.Warning);
        var generatedAssembly = new Mock<Assembly>();
        generatedAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.InvalidGeneratedRegistryAssembly, Version=1.0.0.0");
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsHandlerRegistryAttribute), false))
            .Returns([new CqrsHandlerRegistryAttribute(typeof(string))]);
        generatedAssembly
            .Setup(static assembly => assembly.GetTypes())
            .Returns([typeof(AlphaDeterministicNotificationHandler)]);

        LoggerFactoryResolver.Provider = capturingProvider;
        try
        {
            var container = new MicrosoftDiContainer();
            CqrsTestRuntime.RegisterHandlers(container, generatedAssembly.Object);
            container.Freeze();

            var handlers = container.GetAll<INotificationHandler<DeterministicOrderNotification>>();
            var warningLogs = capturingProvider.Loggers
                .SelectMany(static logger => logger.Logs)
                .Where(static log => log.Level == LogLevel.Warning)
                .ToList();

            Assert.Multiple(() =>
            {
                Assert.That(
                    handlers.Select(static handler => handler.GetType()),
                    Is.EqualTo([typeof(AlphaDeterministicNotificationHandler)]));
                Assert.That(
                    warningLogs.Any(log =>
                        log.Message.Contains("does not implement", StringComparison.Ordinal)),
                    Is.True);
            });
        }
        finally
        {
            LoggerFactoryResolver.Provider = originalProvider;
        }
    }

    /// <summary>
    ///     验证当生成注册器提供精确 fallback 类型名时，运行时会定向补扫剩余 handlers，
    ///     而不是重新枚举整个程序集的类型列表。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Use_Targeted_Type_Lookups_For_Reflection_Fallback_Without_Duplicates()
    {
        var generatedAssembly = new Mock<Assembly>();
        generatedAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.PartialGeneratedRegistryAssembly, Version=1.0.0.0");
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsHandlerRegistryAttribute), false))
            .Returns([new CqrsHandlerRegistryAttribute(typeof(PartialGeneratedNotificationHandlerRegistry))]);
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsReflectionFallbackAttribute), false))
            .Returns(
            [
                new CqrsReflectionFallbackAttribute(
                    ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.FullName!)
            ]);
        generatedAssembly
            .Setup(static assembly => assembly.GetType(
                ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.FullName!,
                false,
                false))
            .Returns(ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType);

        var container = new MicrosoftDiContainer();
        CqrsTestRuntime.RegisterHandlers(container, generatedAssembly.Object);

        var registrations = container.GetServicesUnsafe
            .Where(static descriptor =>
                descriptor.ServiceType == typeof(INotificationHandler<GeneratedRegistryNotification>) &&
                descriptor.ImplementationType is not null)
            .Select(static descriptor => descriptor.ImplementationType!)
            .ToList();

        Assert.That(
            registrations,
            Is.EqualTo(
            [
                typeof(GeneratedRegistryNotificationHandler),
                ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType
            ]));

        generatedAssembly.Verify(
            static assembly => assembly.GetType(
                ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.FullName!,
                false,
                false),
            Times.Once);
        generatedAssembly.Verify(static assembly => assembly.GetTypes(), Times.Never);
    }

    /// <summary>
    ///     验证手写 fallback metadata 直接提供 handler 类型时，运行时会复用这些类型，
    ///     而不会再通过程序集名称查找或整程序集扫描补齐映射。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Use_Direct_Fallback_Types_Without_GetType_Or_GetTypes()
    {
        var generatedAssembly = new Mock<Assembly>();
        generatedAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns(ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.Assembly.FullName);
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsHandlerRegistryAttribute), false))
            .Returns([new CqrsHandlerRegistryAttribute(typeof(PartialGeneratedNotificationHandlerRegistry))]);
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsReflectionFallbackAttribute), false))
            .Returns(
            [
                new CqrsReflectionFallbackAttribute(
                    ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType)
            ]);

        var container = new MicrosoftDiContainer();
        CqrsTestRuntime.RegisterHandlers(container, generatedAssembly.Object);

        var registrations = container.GetServicesUnsafe
            .Where(static descriptor =>
                descriptor.ServiceType == typeof(INotificationHandler<GeneratedRegistryNotification>) &&
                descriptor.ImplementationType is not null)
            .Select(static descriptor => descriptor.ImplementationType!)
            .ToList();

        Assert.That(
            registrations,
            Is.EqualTo(
            [
                typeof(GeneratedRegistryNotificationHandler),
                ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType
            ]));

        generatedAssembly.Verify(
            static assembly => assembly.GetType(
                ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.FullName!,
                false,
                false),
            Times.Never);
        generatedAssembly.Verify(static assembly => assembly.GetTypes(), Times.Never);
    }

    /// <summary>
    ///     验证同一程序集对象重复接入多个容器时，会复用已解析的 registry / fallback 元数据，
    ///     而不是重复读取程序集级 attribute 或重复执行 type-name lookup。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Cache_Assembly_Metadata_Across_Containers()
    {
        var generatedAssembly = new Mock<Assembly>();
        generatedAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.CachedMetadataAssembly, Version=1.0.0.0");
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsHandlerRegistryAttribute), false))
            .Returns([new CqrsHandlerRegistryAttribute(typeof(PartialGeneratedNotificationHandlerRegistry))]);
        generatedAssembly
            .Setup(static assembly => assembly.GetCustomAttributes(typeof(CqrsReflectionFallbackAttribute), false))
            .Returns(
            [
                new CqrsReflectionFallbackAttribute(
                    ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.FullName!)
            ]);
        generatedAssembly
            .Setup(static assembly => assembly.GetType(
                ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.FullName!,
                false,
                false))
            .Returns(ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType);

        var firstContainer = new MicrosoftDiContainer();
        var secondContainer = new MicrosoftDiContainer();

        CqrsTestRuntime.RegisterHandlers(firstContainer, generatedAssembly.Object);
        CqrsTestRuntime.RegisterHandlers(secondContainer, generatedAssembly.Object);
        firstContainer.Freeze();
        secondContainer.Freeze();

        var firstRegistrations = firstContainer.GetAll<INotificationHandler<GeneratedRegistryNotification>>()
            .Select(static handler => handler.GetType())
            .ToArray();
        var secondRegistrations = secondContainer.GetAll<INotificationHandler<GeneratedRegistryNotification>>()
            .Select(static handler => handler.GetType())
            .ToArray();

        Assert.Multiple(() =>
        {
            Assert.That(
                firstRegistrations,
                Is.EqualTo(
                [
                    typeof(GeneratedRegistryNotificationHandler),
                    ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType
                ]));
            Assert.That(
                secondRegistrations,
                Is.EqualTo(
                [
                    typeof(GeneratedRegistryNotificationHandler),
                    ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType
                ]));
        });

        generatedAssembly.Verify(
            static assembly => assembly.GetCustomAttributes(typeof(CqrsHandlerRegistryAttribute), false),
            Times.Once);
        generatedAssembly.Verify(
            static assembly => assembly.GetCustomAttributes(typeof(CqrsReflectionFallbackAttribute), false),
            Times.Once);
        generatedAssembly.Verify(
            static assembly => assembly.GetType(
                ReflectionFallbackNotificationContainer.ReflectionOnlyHandlerType.FullName!,
                false,
                false),
            Times.Once);
    }

    /// <summary>
    ///     验证同一程序集对象在未命中 generated registry 时，会复用首次扫描得到的可加载类型列表，
    ///     而不是为每个容器重复执行整程序集 <c>GetTypes()</c>。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Cache_Loadable_Types_Across_Containers()
    {
        var reflectionTypeLoadException = new ReflectionTypeLoadException(
            [typeof(AlphaDeterministicNotificationHandler), null],
            [new TypeLoadException("Cached loadable-type probe.")]);
        var partiallyLoadableAssembly = new Mock<Assembly>();
        partiallyLoadableAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.CachedLoadableTypesAssembly, Version=1.0.0.0");
        partiallyLoadableAssembly
            .Setup(static assembly => assembly.GetTypes())
            .Throws(reflectionTypeLoadException);

        var firstContainer = new MicrosoftDiContainer();
        var secondContainer = new MicrosoftDiContainer();

        CqrsTestRuntime.RegisterHandlers(firstContainer, partiallyLoadableAssembly.Object);
        CqrsTestRuntime.RegisterHandlers(secondContainer, partiallyLoadableAssembly.Object);
        firstContainer.Freeze();
        secondContainer.Freeze();

        Assert.Multiple(() =>
        {
            Assert.That(
                firstContainer.GetAll<INotificationHandler<DeterministicOrderNotification>>()
                    .Select(static handler => handler.GetType())
                    .ToArray(),
                Is.EqualTo([typeof(AlphaDeterministicNotificationHandler)]));
            Assert.That(
                secondContainer.GetAll<INotificationHandler<DeterministicOrderNotification>>()
                    .Select(static handler => handler.GetType())
                    .ToArray(),
                Is.EqualTo([typeof(AlphaDeterministicNotificationHandler)]));
        });

        partiallyLoadableAssembly.Verify(static assembly => assembly.GetTypes(), Times.Once);
    }

    /// <summary>
    ///     验证同一 handler 类型跨容器重复注册时，会复用已筛选的 supported handler interface 列表，
    ///     而不是为每个容器重新执行接口反射分析。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Cache_Supported_Handler_Interfaces_Across_Containers()
    {
        var supportedHandlerInterfacesCache = GetRegistrarCacheField("SupportedHandlerInterfacesCache");
        var firstHandlerType = typeof(AlphaDeterministicNotificationHandler);
        var secondHandlerType = typeof(ZetaDeterministicNotificationHandler);
        var handlerAssembly = new Mock<Assembly>();
        handlerAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.CachedHandlerInterfacesAssembly, Version=1.0.0.0");
        handlerAssembly
            .Setup(static assembly => assembly.GetTypes())
            .Returns([firstHandlerType, secondHandlerType]);

        Assert.Multiple(() =>
        {
            Assert.That(GetSingleKeyCacheValue(supportedHandlerInterfacesCache, firstHandlerType), Is.Null);
            Assert.That(GetSingleKeyCacheValue(supportedHandlerInterfacesCache, secondHandlerType), Is.Null);
        });

        var firstContainer = new MicrosoftDiContainer();
        var secondContainer = new MicrosoftDiContainer();

        CqrsTestRuntime.RegisterHandlers(firstContainer, handlerAssembly.Object);
        var firstHandlerInterfaces =
            GetSingleKeyCacheValue(supportedHandlerInterfacesCache, firstHandlerType);
        var secondHandlerInterfaces =
            GetSingleKeyCacheValue(supportedHandlerInterfacesCache, secondHandlerType);

        CqrsTestRuntime.RegisterHandlers(secondContainer, handlerAssembly.Object);

        Assert.Multiple(() =>
        {
            Assert.That(firstHandlerInterfaces, Is.Not.Null);
            Assert.That(secondHandlerInterfaces, Is.Not.Null);
            Assert.That(
                GetSingleKeyCacheValue(supportedHandlerInterfacesCache, firstHandlerType),
                Is.SameAs(firstHandlerInterfaces));
            Assert.That(
                GetSingleKeyCacheValue(supportedHandlerInterfacesCache, secondHandlerType),
                Is.SameAs(secondHandlerInterfaces));
        });

        handlerAssembly.Verify(static assembly => assembly.GetTypes(), Times.Once);
    }

    /// <summary>
    ///     验证当程序集枚举结果包含重复 handler 类型时，registrar 仍只会写入一份 handler 映射。
    /// </summary>
    [Test]
    public void RegisterHandlers_Should_Skip_Duplicate_Handler_Mappings_When_Assembly_Returns_Duplicate_Types()
    {
        var handlerType = typeof(AlphaDeterministicNotificationHandler);
        var handlerAssembly = new Mock<Assembly>();
        handlerAssembly
            .SetupGet(static assembly => assembly.FullName)
            .Returns("GFramework.Core.Tests.Cqrs.DuplicateHandlerMappingsAssembly, Version=1.0.0.0");
        handlerAssembly
            .Setup(static assembly => assembly.GetTypes())
            .Returns([handlerType, handlerType]);

        var container = new MicrosoftDiContainer();
        CqrsTestRuntime.RegisterHandlers(container, handlerAssembly.Object);

        var registrations = container.GetServicesUnsafe
            .Where(static descriptor =>
                descriptor.ServiceType == typeof(INotificationHandler<DeterministicOrderNotification>) &&
                descriptor.ImplementationType == typeof(AlphaDeterministicNotificationHandler))
            .ToArray();

        Assert.That(registrations, Has.Length.EqualTo(1));
    }

    /// <summary>
    ///     清空本测试依赖的 registrar 静态缓存，避免跨用例共享进程级状态导致断言漂移。
    /// </summary>
    private static void ClearRegistrarCaches()
    {
        ClearCache(GetRegistrarCacheField("AssemblyMetadataCache"));
        ClearCache(GetRegistrarCacheField("RegistryActivationMetadataCache"));
        ClearCache(GetRegistrarCacheField("LoadableTypesCache"));
        ClearCache(GetRegistrarCacheField("SupportedHandlerInterfacesCache"));
    }

    /// <summary>
    ///     通过反射读取 registrar 的静态缓存对象。
    /// </summary>
    private static object GetRegistrarCacheField(string fieldName)
    {
        var registrarType = GetRegistrarType();
        var field = registrarType.GetField(
            fieldName,
            BindingFlags.NonPublic | BindingFlags.Static);

        Assert.That(field, Is.Not.Null, $"Missing registrar cache field {fieldName}.");

        return field!.GetValue(null)
               ?? throw new InvalidOperationException(
                   $"Registrar cache field {fieldName} returned null.");
    }

    /// <summary>
    ///     清空指定缓存对象。
    /// </summary>
    private static void ClearCache(object cache)
    {
        _ = InvokeInstanceMethod(cache, "Clear");
    }

    /// <summary>
    ///     读取单键缓存中当前保存的对象。
    /// </summary>
    private static object? GetSingleKeyCacheValue(object cache, Type key)
    {
        return InvokeInstanceMethod(cache, "GetValueOrDefaultForTesting", key);
    }

    /// <summary>
    ///     调用缓存对象上的实例方法。
    /// </summary>
    private static object? InvokeInstanceMethod(object target, string methodName, params object[] arguments)
    {
        var method = target.GetType().GetMethod(
            methodName,
            BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);

        Assert.That(method, Is.Not.Null, $"Missing cache method {target.GetType().FullName}.{methodName}.");

        return method!.Invoke(target, arguments);
    }

    /// <summary>
    ///     获取 CQRS handler registrar 运行时类型。
    /// </summary>
    private static Type GetRegistrarType()
    {
        return typeof(CqrsReflectionFallbackAttribute).Assembly
            .GetType("GFramework.Cqrs.Internal.CqrsHandlerRegistrar", throwOnError: true)!;
    }
}

/// <summary>
///     记录确定性通知处理器的实际执行顺序。
/// </summary>
internal static class DeterministicNotificationHandlerState
{
    /// <summary>
    ///     获取当前测试中的通知处理器执行顺序。
    /// </summary>
    public static List<string> InvocationOrder { get; } = [];

    /// <summary>
    ///     重置共享的执行顺序状态。
    /// </summary>
    public static void Reset()
    {
        InvocationOrder.Clear();
    }
}

/// <summary>
///     用于验证同一通知的多个处理器是否按稳定顺序执行。
/// </summary>
internal sealed record DeterministicOrderNotification : INotification;

/// <summary>
///     故意放在 Alpha 之前声明，用于验证注册器不会依赖源码声明顺序。
/// </summary>
internal sealed class ZetaDeterministicNotificationHandler : INotificationHandler<DeterministicOrderNotification>
{
    /// <summary>
    ///     记录当前处理器已执行。
    /// </summary>
    /// <param name="notification">通知实例。</param>
    /// <param name="cancellationToken">取消令牌。</param>
    /// <returns>已完成任务。</returns>
    public ValueTask Handle(DeterministicOrderNotification notification, CancellationToken cancellationToken)
    {
        DeterministicNotificationHandlerState.InvocationOrder.Add(nameof(ZetaDeterministicNotificationHandler));
        return ValueTask.CompletedTask;
    }
}

/// <summary>
///     名称排序上应先于 Zeta 处理器执行的通知处理器。
/// </summary>
internal sealed class AlphaDeterministicNotificationHandler : INotificationHandler<DeterministicOrderNotification>
{
    /// <summary>
    ///     记录当前处理器已执行。
    /// </summary>
    /// <param name="notification">通知实例。</param>
    /// <param name="cancellationToken">取消令牌。</param>
    /// <returns>已完成任务。</returns>
    public ValueTask Handle(DeterministicOrderNotification notification, CancellationToken cancellationToken)
    {
        DeterministicNotificationHandlerState.InvocationOrder.Add(nameof(AlphaDeterministicNotificationHandler));
        return ValueTask.CompletedTask;
    }
}

/// <summary>
///     为 CQRS 注册测试捕获真实启动路径中创建的日志记录器。
/// </summary>
/// <remarks>
///     处理器注册入口会分别为测试运行时、容器和注册器创建日志器。
///     该提供程序统一保留这些测试日志器，以便断言警告是否经由公开入口真正发出。
/// </remarks>
internal sealed class CapturingLoggerFactoryProvider : ILoggerFactoryProvider
{
    private readonly List<TestLogger> _loggers = [];

    /// <summary>
    ///     使用指定的最小日志级别初始化一个新的捕获型日志工厂提供程序。
    /// </summary>
    /// <param name="minLevel">要应用到新建测试日志器的最小日志级别。</param>
    public CapturingLoggerFactoryProvider(LogLevel minLevel = LogLevel.Info)
    {
        MinLevel = minLevel;
    }

    /// <summary>
    ///     获取通过当前提供程序创建的全部测试日志器。
    /// </summary>
    public IReadOnlyList<TestLogger> Loggers => _loggers;

    /// <summary>
    ///     获取或设置新建测试日志器的最小日志级别。
    /// </summary>
    public LogLevel MinLevel { get; set; }

    /// <summary>
    ///     创建一个测试日志器并将其纳入捕获集合。
    /// </summary>
    /// <param name="name">日志记录器名称。</param>
    /// <returns>用于后续断言的测试日志器。</returns>
    public ILogger CreateLogger(string name)
    {
        var logger = new TestLogger(name, MinLevel);
        _loggers.Add(logger);
        return logger;
    }
}

/// <summary>
///     用于验证生成注册器路径的通知消息。
/// </summary>
internal sealed record GeneratedRegistryNotification : INotification;

/// <summary>
///     由模拟的源码生成注册器显式注册的通知处理器。
/// </summary>
internal sealed class GeneratedRegistryNotificationHandler : INotificationHandler<GeneratedRegistryNotification>
{
    /// <summary>
    ///     处理生成注册器测试中的通知。
    /// </summary>
    /// <param name="notification">通知实例。</param>
    /// <param name="cancellationToken">取消令牌。</param>
    /// <returns>已完成任务。</returns>
    public ValueTask Handle(GeneratedRegistryNotification notification, CancellationToken cancellationToken)
    {
        return ValueTask.CompletedTask;
    }
}

/// <summary>
///     模拟源码生成器为某个程序集生成的 CQRS 处理器注册器。
/// </summary>
internal sealed class GeneratedNotificationHandlerRegistry : ICqrsHandlerRegistry
{
    /// <summary>
    ///     将测试通知处理器注册到目标服务集合。
    /// </summary>
    /// <param name="services">承载处理器映射的服务集合。</param>
    /// <param name="logger">用于记录注册诊断的日志器。</param>
    public void Register(IServiceCollection services, ILogger logger)
    {
        ArgumentNullException.ThrowIfNull(services);
        ArgumentNullException.ThrowIfNull(logger);

        services.AddTransient(
            typeof(INotificationHandler<GeneratedRegistryNotification>),
            typeof(GeneratedRegistryNotificationHandler));
        logger.Debug(
            $"Registered CQRS handler {typeof(GeneratedRegistryNotificationHandler).FullName} as {typeof(INotificationHandler<GeneratedRegistryNotification>).FullName}.");
    }
}

/// <summary>
///     用于验证“生成注册器 + reflection fallback”组合路径的私有嵌套处理器容器。
/// </summary>
internal sealed class ReflectionFallbackNotificationContainer
{
    /// <summary>
    ///     获取仅能通过反射补扫接入的私有嵌套处理器类型。
    /// </summary>
    public static Type ReflectionOnlyHandlerType => typeof(ReflectionOnlyGeneratedRegistryNotificationHandler);

    private sealed class ReflectionOnlyGeneratedRegistryNotificationHandler
        : INotificationHandler<GeneratedRegistryNotification>
    {
        /// <summary>
        ///     处理测试通知。
        /// </summary>
        /// <param name="notification">通知实例。</param>
        /// <param name="cancellationToken">取消令牌。</param>
        /// <returns>已完成任务。</returns>
        public ValueTask Handle(GeneratedRegistryNotification notification, CancellationToken cancellationToken)
        {
            return ValueTask.CompletedTask;
        }
    }
}

/// <summary>
///     模拟局部生成注册器场景中，仅注册“可由生成代码直接引用”的那部分 handlers。
/// </summary>
internal sealed class PartialGeneratedNotificationHandlerRegistry : ICqrsHandlerRegistry
{
    /// <summary>
    ///     将生成路径可见的通知处理器注册到目标服务集合。
    /// </summary>
    /// <param name="services">承载处理器映射的服务集合。</param>
    /// <param name="logger">用于记录注册诊断的日志器。</param>
    public void Register(IServiceCollection services, ILogger logger)
    {
        ArgumentNullException.ThrowIfNull(services);
        ArgumentNullException.ThrowIfNull(logger);

        services.AddTransient(
            typeof(INotificationHandler<GeneratedRegistryNotification>),
            typeof(GeneratedRegistryNotificationHandler));
        logger.Debug(
            $"Registered CQRS handler {typeof(GeneratedRegistryNotificationHandler).FullName} as {typeof(INotificationHandler<GeneratedRegistryNotification>).FullName}.");
    }
}

/// <summary>
///     模拟生成注册器使用私有无参构造器的场景，验证运行时仍可通过缓存工厂激活它。
/// </summary>
internal sealed class PrivateConstructorNotificationHandlerRegistry : ICqrsHandlerRegistry
{
    /// <summary>
    ///     初始化一个新的私有生成注册器实例。
    /// </summary>
    private PrivateConstructorNotificationHandlerRegistry()
    {
    }

    /// <summary>
    ///     将测试通知处理器注册到目标服务集合。
    /// </summary>
    /// <param name="services">承载处理器映射的服务集合。</param>
    /// <param name="logger">用于记录注册诊断的日志器。</param>
    public void Register(IServiceCollection services, ILogger logger)
    {
        ArgumentNullException.ThrowIfNull(services);
        ArgumentNullException.ThrowIfNull(logger);

        services.AddTransient(
            typeof(INotificationHandler<GeneratedRegistryNotification>),
            typeof(GeneratedRegistryNotificationHandler));
        logger.Debug(
            $"Registered CQRS handler {typeof(GeneratedRegistryNotificationHandler).FullName} as {typeof(INotificationHandler<GeneratedRegistryNotification>).FullName}.");
    }
}