using System;
using System.Globalization;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.ModelBinding.Binders;

namespace gehGassi.Web.Helper
{
    public class DateTimeModelBinder : IModelBinder
    {
        private static readonly string[] DateTimeFormats = { "yyyyMMdd'T'HHmmss.FFFFFFFK", "yyyy-MM-dd'T'HH:mm:ss.FFFFFFFK" };

        public Task BindModelAsync(ModelBindingContext bindingContext)
        {
            if (bindingContext == null)
                throw new ArgumentNullException(nameof(bindingContext));

            var stringValue = bindingContext.ValueProvider.GetValue(bindingContext.ModelName).FirstValue;

            if (bindingContext.ModelType == typeof(DateTime?) && string.IsNullOrEmpty(stringValue))
            {
                bindingContext.Result = ModelBindingResult.Success(null);
                return Task.CompletedTask;
            }
            if (bindingContext.ModelType == typeof(DateTimeOffset?) && string.IsNullOrEmpty(stringValue))
            {
                bindingContext.Result = ModelBindingResult.Success(null);
                return Task.CompletedTask;
            }
            if (bindingContext.ModelType == typeof(DateOnly?) && string.IsNullOrEmpty(stringValue))
            {
                bindingContext.Result = ModelBindingResult.Success(null);
                return Task.CompletedTask;
            }

            if (bindingContext.ModelMetadata.UnderlyingOrModelType == typeof(DateOnly))
            {
                if (DateOnly.TryParse(stringValue, null, DateTimeStyles.RoundtripKind, out var dateOnly))
                {
                    bindingContext.Result = ModelBindingResult.Success(dateOnly);
                }
                else
                {
                    ModelBindingResult.Failed();
                }
            }
            if (bindingContext.ModelMetadata.UnderlyingOrModelType == typeof(DateTimeOffset))
            {
                if (DateTimeOffset.TryParse(stringValue, null, DateTimeStyles.RoundtripKind, out var dateTimeOffset))
                {
                    bindingContext.Result = ModelBindingResult.Success(dateTimeOffset);
                }
                else
                {
                    ModelBindingResult.Failed();
                }
            }
            else if (bindingContext.ModelMetadata.UnderlyingOrModelType == typeof(DateTime))
            {
                if (DateTime.TryParse(stringValue, null, DateTimeStyles.RoundtripKind, out var date))
                {
                    bindingContext.Result = ModelBindingResult.Success(date);
                }
                else
                {
                    ModelBindingResult.Failed();
                }
            }

            return Task.CompletedTask;
        }
    }

    public class DateTimeModelBinderProvider : IModelBinderProvider
    {
        public IModelBinder GetBinder(ModelBinderProviderContext context)
        {
            if (context == null)
                throw new ArgumentNullException(nameof(context));

            if (context.Metadata.UnderlyingOrModelType == typeof(DateTime))
                return new BinderTypeModelBinder(typeof(DateTimeModelBinder));

            if (context.Metadata.UnderlyingOrModelType == typeof(DateTimeOffset))
                return new BinderTypeModelBinder(typeof(DateTimeModelBinder));

            if (context.Metadata.UnderlyingOrModelType == typeof(DateOnly))
                return new BinderTypeModelBinder(typeof(DateTimeModelBinder));

            return null;
        }
    }
}