// Copyright (c) The Geekeey Authors
// SPDX-License-Identifier: EUPL-1.2

using Microsoft.Extensions.DependencyInjection;

namespace Geekeey.Request.Validation;

/// <summary>
/// Provides extension methods for configuring and registering validator services in the <see cref="IServiceCollection"/>.
/// </summary>
public static class ServiceCollectionExtensions
{
	/// <summary>
	/// Adds validator services to the specified <see cref="IServiceCollection"/>.
	/// </summary>
	/// <param name="services">The service collection to which the validator services will be added.</param>
	/// <returns>An instance of <see cref="IValidatorBuilder"/> to configure the validator registrations.</returns>
	public static IValidatorBuilder AddValidation(this IServiceCollection services)
	{
		ArgumentNullException.ThrowIfNull(services);

		services.AddOptions<ValidationOptions>();
		services.AddTransient<IValidator, DispatchingValidator>();

		return new ValidatorBuilder(services);
	}

	/// <summary>
	/// Adds validator services to the specified <see cref="IServiceCollection"/>
	/// and configures them using the provided <see cref="Action{T}"/>.
	/// </summary>
	/// <param name="services">The service collection to which the validator services will be added.</param>
	/// <param name="configure">A delegate to configure the validator builder.</param>
	/// <returns>The service collection with the validator services added.</returns>
	public static IServiceCollection AddValidation(this IServiceCollection services, Action<IValidatorBuilder> configure)
	{
		ArgumentNullException.ThrowIfNull(services);
		ArgumentNullException.ThrowIfNull(configure);

		configure(services.AddValidation());

		return services;
	}

	private sealed class ValidatorBuilder(IServiceCollection services) : IValidatorBuilder
	{
		public IServiceCollection Services { get; } = services;
	}
}