using System.Reflection;
using Microsoft.OpenApi.Models;
using Swashbuckle.AspNetCore.SwaggerGen;

namespace LearningOfficer.OA.Mobile.Api.Filters
{
    public class NullableParameterFilter : IParameterFilter
    {
        public void Apply(OpenApiParameter parameter, ParameterFilterContext context)
        {
            if (context.ApiParameterDescription.Type is null)
                return;

            if (Nullable.GetUnderlyingType(context.ApiParameterDescription.Type) != null)
            {
                parameter.Schema.Nullable = true;
            }
            else if (context.ApiParameterDescription.Type.IsClass || context.ApiParameterDescription.Type.IsInterface)
            {
                
                var nullableAttribute = context.ParameterInfo?.GetCustomAttribute<System.Runtime.CompilerServices.NullableAttribute>();
                if (nullableAttribute != null || context.ApiParameterDescription.Type.FullName?.Contains("System.Nullable") == true)
                {
                    parameter.Schema.Nullable = true;
                }
            }
        }
    }
}