using System.Reflection;

namespace YLErp.Helpers
{
    public static class ReflectionHelper
    {
        /// <summary>
        /// 用于找出属性值为double.nan的对象
        /// 以帮助EF保存时能够避免出错
        /// </summary>
        [System.Diagnostics.Conditional("DEBUG")]
        public static void CheckNanValue<T>(IEnumerable<T> objs) where T : class
        {
            CheckNanValue2(objs);
        }

        /// <summary>
        /// 远程调试的时候使用，程序内不要调用
        /// </summary>
        public static void CheckNanValue2<T>(IEnumerable<T> objs) where T : class
        {
            if (objs is null)
            {
                throw new ArgumentNullException(nameof(objs));
            }

            var props = typeof(T).GetTypeInfo().GetProperties(BindingFlags.Instance | BindingFlags.Public)
                .Where(n => n.CanRead && (n.PropertyType == typeof(double) || n.PropertyType == typeof(double?))).ToArray();

            foreach (var obj in objs)
            {
                foreach (var p in props)
                {
                    var dobj = p.GetValue(obj);

                    if (dobj == null)
                    {
                        continue;
                    }

                    double dd;

                    if (dobj is double?)
                    {
                        dd = ((double?)dobj).Value;
                    }
                    else
                    {
                        dd = (double)dobj;
                    }

                    if (double.IsNaN(dd))
                    {
                        throw new Exception("找到一个NaN:" + p.Name);
                    }
                }
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="t"></param>
        public static bool IsNullableType(Type t)
        {
            if (t is null)
            {
                throw new ArgumentNullException(nameof(t));
            }
            return t.GetTypeInfo().IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>);
        }
    }
}