namespace Prac7Meow
{
    internal class DynamicContainer<Meow>
    {
        private Meow[] _data;
        private int _count;
        private int _capacity;

        public int Count => _count;
        public int Capacity => _capacity;

        public DynamicContainer(int initCap)
        {
            if (initCap < 1) initCap = 2;

            _capacity = Utils.NearPow(initCap);
            _data = new Meow[_capacity];
            _count = 0;
        }

        private void Expand()
        {
            _capacity = (_capacity <= 0) ? 2 : _capacity * 2;

            Meow[] data = new Meow[_capacity];

            for (int i = 0; i < _count; i++) data[i] = _data[i];

            _data = data;
        }

        private void EnsureCapacity(int needed)
        {
            if (needed <= _capacity) return;

            while (_capacity < needed) Expand();
        }

        public void Add(Meow item)
        {
            EnsureCapacity(_count + 1);
            _data[_count++] = item;
        }

        public void Insert(int index, Meow item)
        {
            if (index < 0 || index > _count) 
                throw new ArgumentOutOfRangeException(nameof(index), $"Index {index} out of range [0..{_count}]");

            EnsureCapacity(_count + 1);

            for (int i = _count; i > index; i--) _data[i] = _data[i - 1];

            _data[index] = item;
            _count++;
        }

        public void RemoveAt(int index)
        {
            if (index < 0 || index >= _count)
                throw new ArgumentOutOfRangeException(nameof(index), $"Index {index} out of range [0..{_count - 1}]");

            for (int i = index; i < _count - 1; i++) _data[i] = _data[i + 1];

            _data[_count - 1] = default!;
            _count--;
        }

        public void Clear()
        {
            for (int i = 0; i < _count; i++)
                _data[i] = default!;

            _count = 0;
        }

        public Meow this[int index]
        {
            get
            {
                if (index < 0 || index >= _count)
                    throw new ArgumentOutOfRangeException(nameof(index), $"Index {index} out of range [0..{_count - 1}]");

                return _data[index];
            }
            set
            {
                if (index < 0 || index >= _count)
                    throw new ArgumentOutOfRangeException(nameof(index), $"Index {index} out of range [0..{_count - 1}]");

                _data[index] = value;
            }
        }
    }
}