using System.Text;

namespace OpenCvSharp.Internal.Vectors;

/// <summary> 
/// </summary>
public class VectorOfString : DisposableCvObject, IStdVector<string?>
{
    /// <summary>
    /// Constructor
    /// </summary>
    public VectorOfString()
    {
        ptr = NativeMethods.vector_string_new1();
    }

    /// <summary>
    /// Constructor
    /// </summary>
    /// <param name="size"></param>
    public VectorOfString(nuint size)
    {
        if (size < 0)
            throw new ArgumentOutOfRangeException(nameof(size));
        ptr = NativeMethods.vector_string_new2(size);
    }

    /// <summary>
    /// Releases unmanaged resources
    /// </summary>
    protected override void DisposeUnmanaged()
    {
        NativeMethods.vector_string_delete(ptr);
        base.DisposeUnmanaged();
    }

    /// <summary>
    /// vector.size()
    /// </summary>
    public int Size
    {
        get
        {
            var res = NativeMethods.vector_string_getSize(ptr);
            GC.KeepAlive(this);
            return (int)res;
        }
    }

    /// <summary>
    /// Converts std::vector to managed array
    /// </summary>
    /// <returns></returns>
    public string[] ToArray()
    {
        var size = Size;
        if (size == 0)
            return Array.Empty<string>();

        var ret = new string[size];
        var cStringPointers = new IntPtr[size];
        var stringLengths = new int[size];

        NativeMethods.vector_string_getElements(ptr, cStringPointers, stringLengths);

        for (var i = 0; i < size; i++)
        {
            unsafe
            {
                ret[i] = Encoding.UTF8.GetString((byte*) cStringPointers[i], stringLengths[i]);
            }
        }

        GC.KeepAlive(cStringPointers);
        GC.KeepAlive(stringLengths);
        GC.KeepAlive(this);
        return ret;
    }
}