Initial endpoint configuration with authentication

src/WebApi/Common/ValidatorExtensions.cs

@@ -0,0 +1,94 @@
+using FluentValidation;
+using FluentValidation.Results;
+using Microsoft.Extensions.Options;
+
+namespace Vegasco.WebApi.Common;
+
+public static class ValidatorExtensions
+{
+	/// <summary>
+	/// Asynchronously validates an instance of <typeparamref name="T"/> against all <see cref="IValidator{T}"/> instances in <paramref name="validators"/>.
+	/// </summary>
+	/// <typeparam name="T"></typeparam>
+	/// <param name="validators"></param>
+	/// <param name="instance"></param>
+	/// <returns>The failed validation results.</returns>
+	public static async Task<List<ValidationResult>> ValidateAllAsync<T>(this IEnumerable<IValidator<T>> validators, T instance)
+	{
+		var validationTasks = validators
+			.Select(validator => validator.ValidateAsync(instance))
+			.ToList();
+
+		await Task.WhenAll(validationTasks);
+
+		List<ValidationResult> failedValidations = validationTasks
+			.Select(x => x.Result)
+			.Where(x => !x.IsValid)
+			.ToList();
+
+		return failedValidations;
+	}
+
+	public static Dictionary<string, string[]> ToCombinedDictionary(this IEnumerable<ValidationResult> validationResults)
+	{
+		// Use a hash set to avoid duplicate error messages.
+		Dictionary<string, HashSet<string>> combinedErrors = [];
+
+		foreach (var error in validationResults.SelectMany(x => x.Errors))
+		{
+			if (!combinedErrors.TryGetValue(error.PropertyName, out HashSet<string>? value))
+			{
+				value = ([error.ErrorMessage]);
+				combinedErrors[error.PropertyName] = value;
+				continue;
+			}
+
+			value.Add(error.ErrorMessage);
+		}
+
+		return combinedErrors.ToDictionary(x => x.Key, x => x.Value.ToArray());
+	}
+
+	public static OptionsBuilder<T> ValidateFluently<T>(this OptionsBuilder<T> builder)
+		where T : class
+	{
+		builder.Services.AddTransient<IValidateOptions<T>>(serviceProvider =>
+		{
+			var validators = serviceProvider.GetServices<IValidator<T>>() ?? [];
+			return new FluentValidationOptions<T>(builder.Name, validators);
+		});
+		return builder;
+	}
+}
+
+internal class FluentValidationOptions<TOptions> : IValidateOptions<TOptions>
+	where TOptions : class
+{
+	private readonly IEnumerable<IValidator<TOptions>> _validators;
+
+	public string? Name { get; set; }
+
+	public FluentValidationOptions(string? name, IEnumerable<IValidator<TOptions>> validators)
+	{
+		Name = name;
+		_validators = validators;
+	}
+
+	public ValidateOptionsResult Validate(string? name, TOptions options)
+	{
+		if (name is not null && name != Name)
+		{
+			return ValidateOptionsResult.Skip;
+		}
+
+		ArgumentNullException.ThrowIfNull(options);
+
+		var failedValidations = _validators.ValidateAllAsync(options).Result;
+		if (failedValidations.Count == 0)
+		{
+			return ValidateOptionsResult.Success;
+		}
+
+		return ValidateOptionsResult.Fail(failedValidations.SelectMany(x => x.Errors.Select(x => x.ErrorMessage)));
+	}
+}