//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="Image.cs"
//     Project: StgSharp
//     AuthorGroup: Nitload Space
//     Copyright (c) Nitload Space. All rights reserved.
//     
//     Permission is hereby granted, free of charge, to any person 
//     obtaining a copy of this software and associated documentation 
//     files (the “Software”), to deal in the Software without restriction, 
//     including without limitation the rights to use, copy, modify, merge,
//     publish, distribute, sublicense, and/or sell copies of the Software, 
//     and to permit persons to whom the Software is furnished to do so, 
//     subject to the following conditions:
//     
//     The above copyright notice and 
//     this permission notice shall be included in all copies 
//     or substantial portions of the Software.
//     
//     THE SOFTWARE IS PROVIDED “AS IS”, 
//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//     
//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
using StgSharp.Data;
using StgSharp.Graphics.GL;
using StgSharp.Math;

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

namespace StgSharp.Graphics
{
    public class Image : ISSDSerializable, IImageProvider
    {
        internal byte[] data;
        internal ImageInfo info;

        internal Image(ImageInfo information)
        {
            info = information;
            data = Array.Empty<byte>();
            //int length = info.width * info.height * info.channel;
        }

        public ref byte[] DataStream
        {
            get => ref data;
        }

        public unsafe Image()
        {
            info = new ImageInfo();
        }

        public ImageChannel Channel => info.Channel;
        public int ChannelCount => info.ChannelCount;
        public int Height => info.Height;

        public (int width, int height) Size
        {
            get => (info.Width, info.Height);
        }

        public SerializableTypeCode SSDTypeCode => SerializableTypeCode.PixelImage;
        public int Width => info.Width;

        public static unsafe Image FromFile(string route, ImageLoader loader)
        {
            Image ret = new Image();
            fixed (ImageInfo* iptr = &ret.info)
            {
                InternalIO.InternalLoadImage(route, iptr, loader);
            }
            return ret;
        }

        public static Image FromMemory((int width, int height) size, int channelCount, byte[] stream)
        {
            ImageInfo _info = new ImageInfo
            {
                Height = size.height,
                Width = size.width,
                ChannelCount = channelCount,
                StreamPtr = IntPtr.Zero
            };
            Image ret = new Image(_info);
            ret.data = stream;
            return ret;
        }

        public glArrayHandle GetArrayHandle()
        {
            if ((data == Array.Empty<byte>()) || (data == null))
            {
                this.GetBytes();
                return new glArrayHandle(data);
            }
            return new glArrayHandle(data);
        }

        public unsafe byte[] GetBytes()
        {
            if (data == null)
            {
                int size = Width * Height * ChannelCount;
                data = new byte[size];
                int i = 0;
                fixed (byte* bptr = data)
                {
                    byte* pptr = bptr;
                    for (; i < size; i += 16)
                    {
                        *(M128*)(pptr + i) = *(M128*)(info.StreamPtr + i);
                    }
                    for (; i < size; i++)
                    {
                        *(pptr + i) = *(byte*)(info.StreamPtr + i);
                    }
                }
                fixed (ImageInfo* pptr = &info)
                {
                    InternalIO.InternalUnloadImage(pptr);
                }
                info.StreamPtr = IntPtr.Zero;
            }
            return data;
        }

        public void FromBytes(byte[] stream)
        {

        }

        public Image ProvideImage()
        {
            throw new NotImplementedException();
        }

        ~Image()
        {
            if (info.StreamPtr != IntPtr.Zero)
            {
                //   Marshal.FreeHGlobal(info.StreamPtr);
            }
        }

    }

    [StructLayout(LayoutKind.Sequential)]
    internal struct ImageInfo
    {

        private ImageChannel channel;
        private int channelCount;
        private int height;
        private int width;
        private IntPtr pixelPtr;

        public ImageChannel Channel
        {
            get => channel;
            set
            {
                channel = value;
                switch (channel)
                {
                    case ImageChannel.SingleColor:
                        channelCount = 1; break;
                    case ImageChannel.DoubleColor:
                        channelCount = 2; break;
                    case ImageChannel.FullColor:
                        channelCount = 3; break;
                    case ImageChannel.WithAlphaChannel:
                        channelCount = 4; break;
                    default:
                        throw new InvalidCastException("Unknown color channel decoding setting.");
                }
            }
        }

        public int ChannelCount
        {
            get => channelCount;
            set
            {
                channelCount = value;
                switch (channelCount)
                {
                    case 1:
                        channel = ImageChannel.SingleColor; break;
                    case 2:
                        channel = ImageChannel.DoubleColor; break;
                    case 3:
                        channel = ImageChannel.FullColor; break;
                    case 4:
                        channel = ImageChannel.WithAlphaChannel; break;
                    default:
                        throw new InvalidCastException("Unknown color channel decoding setting.");
                }
            }
        }

        public int Height
        {
            get => height;
            set => height = value;
        }

        public IntPtr StreamPtr
        {
            get => pixelPtr;
            internal set => pixelPtr = value;
        }

        public int StreamSize
        {
            get => width * height * channelCount;
        }

        public int Width
        {
            get => width;
            set => width = value;
        }

        public override string ToString()
        {
            return $"{channel}\t{width}\t{height}\t{(ulong)StreamPtr}";
        }

    }

    public enum ImageChannel : uint
    {
        SingleColor = GLconst.RED,
        DoubleColor = GLconst.RG,
        FullColor = GLconst.RGB,
        WithAlphaChannel = GLconst.RGBA,
    }


}