using ProjectBulldozer.Exceptions;  
namespace ProjectBulldozer.Generics
{
    internal class SetGeneric<T> where T : class
    {
        private readonly List<T?> _places;
        public int Count => _places.Count;
        /// Максимальное количество объектов в списке
        private readonly int _maxCount;
        public SetGeneric(int count)
        {
            _maxCount = count;
            _places = new List<T?>(count);
        }
        /// Добавление объекта в набор
        public bool Insert(T tract)
        {
            return Insert(tract, 0);
        }
        public bool Insert(T tract, int position)
        {
            if (position < 0 || position >= _maxCount)
            {
                throw new BulldozerNotFoundException(position);
            }
            if (Count >= _maxCount)
            {
                throw new StorageOverflowException(_maxCount);
            }
            _places.Insert(position, tract);
            return true;
        }
        public bool Remove(int position)
        {
            if (position < 0 || position >= _maxCount)
            {
                return false;
            }
            if (_places[position] == null)
            {
                throw new BulldozerNotFoundException(position);
            }
            _places[position] = null;
            return true;
        }
        public T? this[int position]
        {
            get
            {
                if (position < 0 || position >= Count) return null;
                return _places[position];
            }
            set
            {
                if (position < 0 || position >= Count || Count == _maxCount) return;
                _places.Insert(position, value);
            }
        }
        public IEnumerable<T?> GetTractors(int? maxTracts = null)
        {
            for (int i = 0; i < _places.Count; ++i)
            {
                yield return _places[i];
                if (maxTracts.HasValue && i == maxTracts.Value)
                {
                    yield break;
                }
            }
        }
    }
}