using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DoubleDeckerbus.Generic
{
    internal class SetGeneric<T>
        where T : class
    {
        private readonly List<T?> _places;
        public int Count => _places.Count;
        private readonly int _maxCount;
        public SetGeneric(int count)
        {
            _maxCount = count;
            _places = new List<T?>(count);
        }
        public int Insert(T bus)
        {
            _places.Insert(0, bus);                                                     //0
            return 0;
        }
        public bool Insert(T bus, int position)
        {
            if (position < 0 || position >= Count || Count >= _maxCount)
            {
                return false;
            }
            _places.Insert(position, bus);
            return true;
        }
        public bool Remove(int position)
        {
            if (position < 0 || position >= Count)
            {
                return false;
            }
            _places.RemoveAt(position);
            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?> GetBus(int? maxBus = null)
        {
            for (int i = 0; i < _places.Count; ++i)
            {
                yield return _places[i];
                if (maxBus.HasValue && i == maxBus.Value)
                {
                    yield break;
                }
            }
        }
    }
}