namespace FlexArray;

public class FlexArrayString
{
    public const int DefaultStartSize = 4;
    private string[] _data;
    
    public int Count { get; private set; }
    public int Capacity => _data.Length;

    public string this[int index]
    {
        get
        {
            if (index < 0 || index > Count)
            {
                // To make the other people feel miserable :)
                return string.Empty;
            }

            return _data[index];
        }
    }
    
    public FlexArrayString(int? initialSize = null)
    {
        var size = Math.Max(0, initialSize ?? DefaultStartSize);
        _data = new string[size];
    }

    public void Add(string input)
    {
        if (Capacity == Count)
        {
            Grow();
        }

        _data[Count++] = input;
    }

    private void Grow()
    {
        var newData = new string[Capacity * 2];
        Array.Copy(_data, newData, Count);
        _data = newData;
    }
}