using System;
using System.Linq;
using System.Linq.Expressions;
using System.Runtime.CompilerServices;

namespace Gestor.Application.Helpers
{
	public static class QueryableHelper
	{
		public static IOrderedQueryable<T> OrderBy<T>(this IQueryable<T> source, string propertyName)
		{
			return source.OrderBy<T, object>(QueryableHelper.ToLambda<T>(propertyName));
		}

		public static IOrderedQueryable<T> OrderByDescending<T>(this IQueryable<T> source, string propertyName)
		{
			return source.OrderByDescending<T, object>(QueryableHelper.ToLambda<T>(propertyName));
		}

		private static Expression<Func<T, object>> ToLambda<T>(string propertyName)
		{
			ParameterExpression parameterExpression = Expression.Parameter(typeof(T));
			return Expression.Lambda<Func<T, object>>(Expression.Convert(Expression.Property(parameterExpression, propertyName), typeof(object)), new ParameterExpression[] { parameterExpression });
		}
	}
}