internal static IEnumerable <Menu> Subtract(IEnumerable <Menu> first, IEnumerable <Menu> second)
{
var result = new List <Menu>();
if (second == null)
{
if (first != null)
{
result.AddRange(first.Select(item => item.Clone()));
}
}
else
{
if (first != null)
{
var dicForbidenMenus = second.ToDictionary(item => item.Id);
foreach (var item in first)
{
if (dicForbidenMenus.ContainsKey(item.Id))
{
var menu = Menu.Subtract(item, dicForbidenMenus[item.Id]);
if (menu != null && !menu.IsEmpty)
{
result.Add(menu);
}
}
else
{
result.Add(item.Clone());
}
}
}
}
return(result);
}
