using System.Reflection;
using FluentValidation;
using Microsoft.Extensions.DependencyInjection;
using PnvPanel.Application.Common.Behaviors;
using PnvPanel.Application.Common.Messaging;

namespace PnvPanel.Application;

/// <summary>
/// Точка регистрации сервисов слоя Application: собственный CQRS-диспетчер (ISender),
/// хендлеры/валидаторы (авто-сканирование сборки) и pipeline behaviors — в порядке выполнения.
/// </summary>
public static class DependencyInjection
{
    public static IServiceCollection AddApplication(this IServiceCollection services)
    {
        var assembly = typeof(DependencyInjection).Assembly;

        services.AddScoped<ISender, Sender>();

        RegisterClosedGeneric(services, assembly, typeof(ICommandHandler<,>));
        RegisterClosedGeneric(services, assembly, typeof(IQueryHandler<,>));
        RegisterClosedGeneric(services, assembly, typeof(IValidator<>));

        // Порядок важен: Logging (снаружи) -> Validation -> RequireActivation -> UnitOfWork (ближе к хендлеру).
        services.AddScoped(typeof(IPipelineBehavior<,>), typeof(LoggingBehavior<,>));
        services.AddScoped(typeof(IPipelineBehavior<,>), typeof(ValidationBehavior<,>));
        services.AddScoped(typeof(IPipelineBehavior<,>), typeof(RequireActivationBehavior<,>));
        services.AddScoped(typeof(IPipelineBehavior<,>), typeof(UnitOfWorkBehavior<,>));

        return services;
    }

    private static void RegisterClosedGeneric(IServiceCollection services, Assembly assembly, Type openInterface)
    {
        var implementations = assembly.GetTypes()
            .Where(t => t is { IsClass: true, IsAbstract: false })
            .SelectMany(t => t.GetInterfaces()
                .Where(i => i.IsGenericType && i.GetGenericTypeDefinition() == openInterface)
                .Select(i => (Service: i, Implementation: t)));

        foreach (var (service, implementation) in implementations)
            services.AddScoped(service, implementation);
    }
}