request/src/request.validation/DispatchingValidator.cs

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

using System.Collections.Concurrent;
using System.Reflection.Metadata;

[assembly: MetadataUpdateHandler(typeof(Geekeey.Request.Validation.DispatchingValidator))]

namespace Geekeey.Request.Validation;

internal sealed partial class DispatchingValidator : IValidator
{
	private static readonly ConcurrentDictionary<Type, ValidatorInvoker> ValidatorsHandlers = new();

	private readonly IServiceProvider _serviceProvider;

	public DispatchingValidator(IServiceProvider serviceProvider)
	{
		_serviceProvider = serviceProvider;
	}

	public static void ClearCache(Type[]? _)
	{
		ValidatorsHandlers.Clear();
	}

	public Validation Validate(ValidationContext context)
	{
		ArgumentNullException.ThrowIfNull(context);

		if (context.Instance is null)
		{
			return new Validation([]);
		}

		var handler = ValidatorsHandlers.GetOrAdd(context.Instance.GetType(), static key =>
		{
			var type = typeof(ValidatorInvoker<>).MakeGenericType(key);
			return (ValidatorInvoker)Activator.CreateInstance(type)!;
		});

		return handler.Validate(context, _serviceProvider);
	}
}