using StgSharp.Math;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.Graphics
{
    public class Image
    {
        [StructLayout(LayoutKind.Sequential)]
        internal struct ImageInfo
        {
            internal int width;
            internal int height;
            internal int channel;
            internal IntPtr pixelPtr;
        }

        internal byte[] pixelArray;
        internal ImageInfo info;

        public int Width { get => info.width; }
        public int Height { get => info.height; }
        public int Channel { get => info.channel; }

        internal Image(ImageInfo information)
        {
            info = information;
            int length = info.width * info.height * info.channel;
            pixelArray = new byte[length];
            Marshal.Copy(
                source: info.pixelPtr,
                destination: pixelArray,
                startIndex: 0,
                length: length
                );
        }

        internal byte[] PixelArray
        {
            get
            {
                if (pixelArray == null)
                {
                    pixelArray = new byte[info.width * info.height * info.channel];
                    Marshal.Copy(source: info.pixelPtr, destination: pixelArray,
                        startIndex: 0, length: info.width * info.height * info.channel);
                    Marshal.FreeHGlobal(info.pixelPtr);
                }
                return pixelArray;
            }
        }

        public unsafe Image()
        {
#if NET5_0_OR_GREATER
            Unsafe.SkipInit(out pixelArray);
#endif
            info = new ImageInfo();
        }

        ~Image()
        {
            Marshal.FreeHGlobal(info.pixelPtr);
        }

    }


}