using System.Threading.Tasks;
using FluentValidation;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;

namespace Svrnty.CQRS.MinimalApi;

public class ValidationFilter<T> : IEndpointFilter where T : class
{
    public const string ValidatedObjectKey = "ValidatedObject";

    public async ValueTask<object?> InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
    {
        // Deserialize the request body
        var obj = await context.HttpContext.Request.ReadFromJsonAsync<T>(context.HttpContext.RequestAborted);

        if (obj == null)
            return Results.BadRequest("Invalid request payload");

        // Store the deserialized object for the lambda to retrieve
        context.HttpContext.Items[ValidatedObjectKey] = obj;

        // Validate if validator is registered
        var validator = context.HttpContext.RequestServices.GetService<IValidator<T>>();
        if (validator != null)
        {
            var validationResult = await validator.ValidateAsync(obj, context.HttpContext.RequestAborted);

            if (!validationResult.IsValid)
            {
                return Results.ValidationProblem(validationResult.ToDictionary());
            }
        }

        return await next(context);
    }
}