using System;
using System.ComponentModel.DataAnnotations;
using System.Linq.Expressions;
using System.Reflection;

namespace Infrastructure.Extensions
{
    public static class ExpressionExtensions
    {
        public static string GetPropertyName(this Expression<Func<object, object>> expression)
        {
            if (expression is null)
            {
                throw new ArgumentNullException(nameof(expression));
            }
            return (expression.Body as MemberExpression).Member.Name;
        }

        public static string MemberName<T, V>(this Expression<Func<T, V>> expression)
        {
            var memberExpression = expression.Body as MemberExpression;
            if (memberExpression == null)
                throw new InvalidOperationException("Expression must be a member expression");

            return memberExpression.Member.Name;
        }

        public static string GetDisplayAttributeValue<T>(this Expression<Func<T, object>> expression)
        {
            if (expression is null)
            {
                throw new ArgumentNullException(nameof(expression));
            }
            var memberExpression = expression.Body as MemberExpression;

            var displayAttribute = memberExpression.Member.GetCustomAttribute<DisplayAttribute>();
            return displayAttribute == null ? memberExpression.Member.Name : displayAttribute.Name;
        }
    }
}