using FluentValidation;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Prefab.Handler;
using Prefab.Handler.Decorators;

namespace Prefab;

/// <summary>
/// Provides extension methods for registering core Prefab services with the dependency injection container.
/// </summary>
public static class Config
{
    /// <summary>
    /// Adds Prefab handler pipeline services and decorators to the specified service collection.
    /// </summary>
    /// <remarks>This method registers the default handler pipeline decorators and invoker required for
    /// Prefab. Decorators are added in the order of execution, similar to ASP.NET Core middleware.</remarks>
    /// <param name="services">The service collection to which the Prefab services will be added. Cannot be null.</param>
    /// <param name="configuration">The application configuration used to configure Prefab services. Cannot be null.</param>
    /// <returns>The same instance of <see cref="IServiceCollection"/> that was provided, to support method chaining.</returns>
    public static IServiceCollection AddPrefab(this IServiceCollection services, IConfiguration configuration)
    {
        services.AddHttpContextAccessor();
        services.AddScoped<IHandlerContextAccessor, HandlerContextAccessor>();

        // Default decorators for handler pipeline. Place in order of execution, same way as .NET Core middleware does.
        services.AddScoped<IHandlerDecorator, HandlerContextDecorator>();
        services.AddScoped<IHandlerDecorator, ValidationDecorator>();
        services.AddScoped<IHandlerDecorator, LoggingDecorator>();

        services.AddScoped<HandlerInvoker>();

        services.Scan(scan => scan
            .FromApplicationDependencies(assembly => assembly.GetName().Name?.StartsWith(nameof(Prefab)) == true)
            .AddClasses(classes => classes.AssignableTo(typeof(IValidator<>)), publicOnly: false)
                .AsImplementedInterfaces()
                .WithScopedLifetime());

        return services;
    }

    /// <summary>
    /// Scans Prefab assemblies for handler implementations and registers them with the dependency injection container.
    /// </summary>
    /// <remarks>Call this after all Prefab modules are loaded so Scrutor can discover handlers defined within them.</remarks>
    public static IServiceCollection AddPrefabHandlers(this IServiceCollection services)
    {
        services.Scan(scan => scan
            .FromApplicationDependencies(assembly => assembly.GetName().Name?.StartsWith(nameof(Prefab)) == true)
            .AddClasses(classes => classes.AssignableTo(typeof(IHandler<,>)), publicOnly: false)
                .AsImplementedInterfaces()
                .WithScopedLifetime()
            .AddClasses(classes => classes.AssignableTo(typeof(IHandler<>)), publicOnly: false)
                .AsImplementedInterfaces()
                .WithScopedLifetime());

        return services;
    }
}