using System;
using System.Runtime.InteropServices;

namespace YOLODetectProcessLib
{
    /// <summary>
    /// cpp dll 中图像信息的数据结构
    /// </summary>
    public struct StructImageInfo
    {
        public int width;
        public int height;
        public int channel;
        public IntPtr pData;
    }

    /// <summary>
    /// cpp dll 中矩形框的数据结构
    /// </summary>
    public struct StructMyRect
    {
        public int left;
        public int top;
        public int width;
        public int height;
    }

    /// <summary>
    /// cpp dll 中提取前处理数据时所需信息的数据结构
    /// </summary>
    public struct StructExtractInfo
    {
        public int meanValueType;
        public float meanR;
        public float meanG;
        public float meanB;
        public int scaleValueType;
        public float scaleR;
        public float scaleG;
        public float scaleB;
        public int normalizationType;
        public bool reverseInputChannels;
        public int axisOrder;
    }

    /// <summary>
    /// 图像处理过程中的一些辅助的功能函数
    /// </summary>
    public class ImageUtils
    {

        #region dll import

        [DllImport(@"ImageProcessUtilsLib.dll", EntryPoint = "ResizeBilinear", CallingConvention = CallingConvention.Cdecl)]
        public static extern int ResizeBilinear(StructImageInfo origImg, ref StructImageInfo dstImg);

        [DllImport(@"ImageProcessUtilsLib.dll", EntryPoint = "FillWithPadValue", CallingConvention = CallingConvention.Cdecl)]
        public static extern int FillWithPadValue(ref StructImageInfo origImg, IntPtr padValue);

        [DllImport(@"ImageProcessUtilsLib.dll", EntryPoint = "CropRect", CallingConvention = CallingConvention.Cdecl)]
        public static extern int CropRect(StructImageInfo origImg, StructMyRect cropRect, ref StructImageInfo dstImg);

        [DllImport(@"ImageProcessUtilsLib.dll", EntryPoint = "PasteRect", CallingConvention = CallingConvention.Cdecl)]
        public static extern int PasteRect(StructImageInfo srcImg, StructMyRect pasteRect, ref StructImageInfo dstImg);

        [DllImport(@"ImageProcessUtilsLib.dll", EntryPoint = "ExtractRGB24AsGray", CallingConvention = CallingConvention.Cdecl)]
        public static extern int ExtractRGB24AsGray(StructImageInfo srcImg, IntPtr dstDataPtr, StructExtractInfo extractInfo);

        [DllImport(@"ImageProcessUtilsLib.dll", EntryPoint = "ExtractRGB24AsColor", CallingConvention = CallingConvention.Cdecl)]
        public static extern int ExtractRGB24AsColor(StructImageInfo srcImg, IntPtr dstDataPtr, StructExtractInfo extractInfo);

        #endregion


        #region public 

        public static IImage ResizeBilinearWithCpp(IImage image, int dstWidth, int dstHeight)
        {
            GCHandle hObjectOrig = GCHandle.Alloc(image.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataOrig = hObjectOrig.AddrOfPinnedObject();
            StructImageInfo origImgInfo = new StructImageInfo
            {
                width = image.Width,
                height = image.Height,
                channel = image.Channel,
                pData = pDataOrig,
            };
            RawImage resizedImg = new RawImage(new byte[dstWidth * dstHeight * image.Channel], dstWidth, dstHeight,
                image.Channel, dstWidth * image.Channel);
            GCHandle hObjectDst = GCHandle.Alloc(resizedImg.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataDst = hObjectDst.AddrOfPinnedObject();
            StructImageInfo dstImgInfo = new StructImageInfo
            {
                width = resizedImg.Width,
                height = resizedImg.Height,
                channel = resizedImg.Channel,
                pData = pDataDst,
            };
            var ret = ResizeBilinear(origImgInfo, ref dstImgInfo);
            if (hObjectOrig.IsAllocated)
            {
                hObjectOrig.Free();
            }
            if (hObjectDst.IsAllocated)
            {
                hObjectDst.Free();
            }
            if (ret != 0)
            {
                throw new Exception("Failed at calling cpp func: ResizeBilinear.(error code: " + ret + ").");
            }
            return resizedImg;
        }

        public static void FillPadValWithCpp(IImage image, byte[] padValue)
        {
            GCHandle hObjectOrig = GCHandle.Alloc(image.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataOrig = hObjectOrig.AddrOfPinnedObject();
            StructImageInfo origImgInfo = new StructImageInfo
            {
                width = image.Width,
                height = image.Height,
                channel = image.Channel,
                pData = pDataOrig,
            };
            GCHandle hObjectPadValue = GCHandle.Alloc(padValue, GCHandleType.Pinned);
            IntPtr pDataPadValue = hObjectPadValue.AddrOfPinnedObject();
            var ret = FillWithPadValue(ref origImgInfo, pDataPadValue);
            if (hObjectOrig.IsAllocated)
            {
                hObjectOrig.Free();
            }
            if (hObjectPadValue.IsAllocated)
            {
                hObjectPadValue.Free();
            }
            if (ret != 0)
            {
                throw new Exception("Failed at calling cpp func: FillWithPadValue.(error code: " + ret + ").");
            }
        }

        public static IImage CropRectWithCpp(IImage image, Rect cropRect)
        {
            GCHandle hObjectOrig = GCHandle.Alloc(image.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataOrig = hObjectOrig.AddrOfPinnedObject();
            StructImageInfo origImgInfo = new StructImageInfo
            {
                width = image.Width,
                height = image.Height,
                channel = image.Channel,
                pData = pDataOrig,
            };
            RawImage dstImage = new RawImage(new byte[cropRect.Width * cropRect.Height * image.Channel],
                cropRect.Width, cropRect.Height, image.Channel, cropRect.Width * image.Channel);
            GCHandle hObjectDst = GCHandle.Alloc(dstImage.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataDst = hObjectDst.AddrOfPinnedObject();
            StructImageInfo dstImgInfo = new StructImageInfo
            {
                width = dstImage.Width,
                height = dstImage.Height,
                channel = dstImage.Channel,
                pData = pDataDst,
            };
            StructMyRect structCropRect = new StructMyRect
            {
                left = cropRect.Left,
                top = cropRect.Top,
                width = cropRect.Width,
                height = cropRect.Height,
            };
            var ret = CropRect(origImgInfo, structCropRect, ref dstImgInfo);
            if (hObjectOrig.IsAllocated)
            {
                hObjectOrig.Free();
            }
            if (hObjectDst.IsAllocated)
            {
                hObjectDst.Free();
            }
            if (ret != 0)
            {
                throw new Exception("Failed at calling cpp func: CropRect.(error code: " + ret + ").");
            }
            return dstImage;
        }

        public static void CropRectWithCpp(IImage image, Rect cropRect, ref byte[] dstImgDataBuffer)
        {
            //  目标图像数据区尺寸是否需要改变？
            int dstChannel = image.Channel;
            int dstWidth = cropRect.Width;
            int dstHeight = cropRect.Height;
            int dstDataLen = dstWidth * dstHeight * dstChannel;
            if (dstImgDataBuffer.Length < dstDataLen)
            {
                Array.Resize(ref dstImgDataBuffer, dstDataLen);
            }
            GCHandle hObjectOrig = GCHandle.Alloc(image.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataOrig = hObjectOrig.AddrOfPinnedObject();
            StructImageInfo origImgInfo = new StructImageInfo
            {
                width = image.Width,
                height = image.Height,
                channel = image.Channel,
                pData = pDataOrig,
            };
            GCHandle hObjectDst = GCHandle.Alloc(dstImgDataBuffer, GCHandleType.Pinned);
            IntPtr pDataDst = hObjectDst.AddrOfPinnedObject();
            StructImageInfo dstImgInfo = new StructImageInfo
            {
                width = dstWidth,
                height = dstHeight,
                channel = dstChannel,
                pData = pDataDst,
            };
            StructMyRect structCropRect = new StructMyRect
            {
                left = cropRect.Left,
                top = cropRect.Top,
                width = cropRect.Width,
                height = cropRect.Height,
            };
            var ret = CropRect(origImgInfo, structCropRect, ref dstImgInfo);
            if (hObjectOrig.IsAllocated)
            {
                hObjectOrig.Free();
            }
            if (hObjectDst.IsAllocated)
            {
                hObjectDst.Free();
            }
            if (ret != 0)
            {
                throw new Exception("Failed at calling cpp func: CropRect.(error code: " + ret + ").");
            }
            return;
        }


        public static void PasteRectWithCpp(IImage dstImg, IImage srcImg, Rect pasteRect)
        {
            GCHandle hObjectSrc = GCHandle.Alloc(srcImg.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataSrc = hObjectSrc.AddrOfPinnedObject();
            StructImageInfo srcImgInfo = new StructImageInfo
            {
                width = srcImg.Width,
                height = srcImg.Height,
                channel = srcImg.Channel,
                pData = pDataSrc,
            };
            GCHandle hObjectDst = GCHandle.Alloc(dstImg.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataDst = hObjectDst.AddrOfPinnedObject();
            StructImageInfo dstImgInfo = new StructImageInfo
            {
                width = dstImg.Width,
                height = dstImg.Height,
                channel = dstImg.Channel,
                pData = pDataDst,
            };
            StructMyRect structPasteRect = new StructMyRect
            {
                left = pasteRect.Left,
                top = pasteRect.Top,
                width = pasteRect.Width,
                height = pasteRect.Height,
            };
            var ret = PasteRect(srcImgInfo, structPasteRect, ref dstImgInfo);
            if (hObjectSrc.IsAllocated)
            {
                hObjectSrc.Free();
            }
            if (hObjectDst.IsAllocated)
            {
                hObjectDst.Free();
            }
            if (ret != 0)
            {
                throw new Exception("Failed at calling cpp func: PasteRect.(error code: " + ret + ").");
            }
        }

        public static IImage ResizeBilinear(IImage image, int dstWidth, int dstHeight)
        {
            byte[] dstDataBuffer = new byte[dstWidth * dstHeight * image.Channel];
            ResizeBilinear(image, dstWidth, dstHeight, ref dstDataBuffer);
            return new RawImage(dstDataBuffer, dstWidth, dstHeight, image.Channel, dstWidth * image.Channel);
        }

        public static void FillPadVal(IImage image, byte[] padValue)
        {
            if (padValue == null)
            {
                throw new ArgumentNullException("padValue");
            }
            int channel = image.Channel;
            byte[] dataBuffer = image.DataBuffer;
            if (padValue.Length != channel)
            {
                throw new ArgumentException("padValue", "Length of the padValue should equal to Channel.");
            }
            if (dataBuffer == null)
            {
                throw new ArgumentNullException("image.DataBuffer");
            }
            int imageSize = image.Width * image.Height;
            for (int ni = 0; ni < imageSize; ni++)
            {
                Buffer.BlockCopy(padValue, 0, dataBuffer, ni * channel, channel);
            }
        }

        public static IImage CropRect(IImage image, Rect cropRect)
        {
            byte[] croppedDataBuffer = new byte[cropRect.Width * cropRect.Height * image.Channel];
            CropRect(image, cropRect, ref croppedDataBuffer);
            return new RawImage(croppedDataBuffer, cropRect.Width, cropRect.Height, image.Channel, cropRect.Width * image.Channel);
        }

        public static void PasteRect(IImage dstImg, IImage srcImg, Rect pasteRect)
        {
            int dstRectLeft = pasteRect.Left;
            int dstRectRight = pasteRect.Right;
            int dstRectTop = pasteRect.Top;
            int dstRectBottom = pasteRect.Bottom;
            int dstRectWidth = pasteRect.Width;
            int dstRectHeight = pasteRect.Height;
            int width = dstImg.Width;
            int height = dstImg.Height;
            int channel = dstImg.Channel;
            int stride = dstImg.Stride;
            byte[] dataBuffer = dstImg.DataBuffer;
            if (dstRectLeft < 0 || dstRectLeft > width - 1)
            {
                throw new ArgumentOutOfRangeException("dstRect.Left", "Left of the paste dstRect is out of the image.");
            }
            if (dstRectRight < 0 || dstRectRight > width)
            {
                throw new ArgumentOutOfRangeException("dstRect.Right", "Right of the paste dstRect is out of the image.");
            }
            if (dstRectTop < 0 || dstRectTop > height - 1)
            {
                throw new ArgumentOutOfRangeException("dstRect.Top", "Top of the paste dstRect is out of the image.");
            }
            if (dstRectBottom < 0 || dstRectBottom > height)
            {
                throw new ArgumentOutOfRangeException("dstRect.Bottom", "Right of the paste dstRect is out of the image.");
            }
            if (srcImg == null)
            {
                throw new ArgumentNullException("srcImg");
            }
            if (srcImg.Channel != channel)
            {
                throw new ArgumentException("srcImg.Channel", "The channel of srcImg should be equal to the channel of this image.");
            }
            if (srcImg.Width != dstRectWidth)
            {
                throw new ArgumentException("srcImg.Width", "The Width of srcImg should be equal to the width of the dstRect.");
            }
            if (srcImg.Height != dstRectHeight)
            {
                throw new ArgumentException("srcImg.Height", "The Height of srcImg should be equal to the height of the dstRect.");
            }
            if (dataBuffer == null)
            {
                throw new ArgumentNullException("dstImg.DataBuffer");
            }
            // 如果rect的尺寸就是整幅图的尺寸，就直接整幅图clone即可，不需要一行一行复制
            if (dstRectLeft == 0 && dstRectTop == 0 && dstRectWidth == width && dstRectHeight == height)
            {
                Buffer.BlockCopy(srcImg.DataBuffer, 0, dataBuffer, 0, width * height * channel);
                return;
            }
            byte[] srcImgDataBuffer = srcImg.DataBuffer;
            int rectRowCopyLen = dstRectWidth * channel;
            int rectCopyOffset = dstRectTop * width * channel + dstRectLeft * channel;
            int rowCopyOffset = width * channel;
            for (int nh = 0; nh < dstRectHeight; nh++)
            {
                Buffer.BlockCopy(srcImgDataBuffer, nh * rectRowCopyLen,
                    dataBuffer, rectCopyOffset + nh * rowCopyOffset, rectRowCopyLen);
            }
            return;
        }

        public static void ResizeBilinear(IImage image, int dstWidth, int dstHeight, ref byte[] dstDataBuffer)
        {
            int width = image.Width;
            int height = image.Height;
            int channel = image.Channel;
            byte[] dataBuffer = image.DataBuffer;
            int dstDataLen = dstWidth * dstHeight * channel;
            if (dstDataBuffer.Length < dstDataLen)
            {
                Array.Resize(ref dstDataBuffer, dstDataLen);
            }
            float scale_x = (float)width / dstWidth;
            float scale_y = (float)height / dstHeight;
            int dstStep = dstWidth * channel;
            int srcStep = width * channel;
            float fy, fx;
            int sy, sx;
            short[] cbufy = new short[2];
            short[] cbufx = new short[2];
            int nh, nw, nc;
            for (nh = 0; nh < dstHeight; ++nh)
            {
                fy = (float)((nh + 0.5) * scale_y - 0.5);
                sy = Convert.ToInt32(Math.Floor(fy));
                fy -= sy;
                sy = Math.Min(sy, height - 2);
                sy = Math.Max(0, sy);
                cbufy[0] = Convert.ToInt16((1 - fy) * 2048);
                cbufy[1] = Convert.ToInt16(2048 - cbufy[0]);
                for (nw = 0; nw < dstWidth; ++nw)
                {
                    fx = (float)((nw + 0.5) * scale_x - 0.5);
                    sx = Convert.ToInt16(Math.Floor(fx));
                    fx -= sx;
                    if (sx < 0)
                    {
                        fx = 0;
                        sx = 0;
                    }
                    if (sx >= width - 2)
                    {
                        fx = 0;
                        sx = width - 2;
                    }
                    cbufx[0] = Convert.ToInt16((1 - fx) * 2048);
                    cbufx[1] = Convert.ToInt16(2048 - cbufx[0]);
                    for (nc = 0; nc < channel; ++nc)
                    {
                        dstDataBuffer[nh * dstStep + nw * channel + nc] = Convert.ToByte((
                            dataBuffer[sy * srcStep + sx * channel + nc] * cbufx[0] * cbufy[0] +
                            dataBuffer[(sy + 1) * srcStep + sx * channel + nc] * cbufx[0] * cbufy[1] +
                            dataBuffer[sy * srcStep + (sx + 1) * channel + nc] * cbufx[1] * cbufy[0] +
                            dataBuffer[(sy + 1) * srcStep + (sx + 1) * channel + nc] * cbufx[1] * cbufy[1]) >> 22);
                    }
                }
            }
        }

        public static void ResizeBilinearWithCpp(IImage image, int dstWidth, int dstHeight, ref byte[] dstImgDataBuffer)
        {
            //  目标图像数据区尺寸是否需要改变？
            int dstChannel = image.Channel;
            int dstDataLen = dstWidth * dstHeight * dstChannel;
            if (dstImgDataBuffer.Length < dstDataLen)
            {
                Array.Resize(ref dstImgDataBuffer, dstDataLen);
            }
            GCHandle hObjectOrig = GCHandle.Alloc(image.DataBuffer, GCHandleType.Pinned);
            IntPtr pDataOrig = hObjectOrig.AddrOfPinnedObject();
            StructImageInfo origImgInfo = new StructImageInfo
            {
                width = image.Width,
                height = image.Height,
                channel = image.Channel,
                pData = pDataOrig,
            };
            GCHandle hObjectDst = GCHandle.Alloc(dstImgDataBuffer, GCHandleType.Pinned);
            IntPtr pDataDst = hObjectDst.AddrOfPinnedObject();
            StructImageInfo dstImgInfo = new StructImageInfo
            {
                width = dstWidth,
                height = dstHeight,
                channel = dstChannel,
                pData = pDataDst,
            };
            var ret = ResizeBilinear(origImgInfo, ref dstImgInfo);
            if (hObjectOrig.IsAllocated)
            {
                hObjectOrig.Free();
            }
            if (hObjectDst.IsAllocated)
            {
                hObjectDst.Free();
            }
            if (ret != 0)
            {
                throw new Exception("Failed at calling cpp func: ResizeBilinear.(error code: " + ret + ").");
            }
            return;
        }
        public static void CropRect(IImage image, Rect cropRect, ref byte[] dstDataBuffer)
        {
            if (cropRect.IsEmpty())
            {
                return;
            }
            int rectLeft = cropRect.Left;
            int rectRight = cropRect.Right;
            int rectTop = cropRect.Top;
            int rectBottom = cropRect.Bottom;
            int rectWidth = cropRect.Width;
            int rectHeight = cropRect.Height;
            int width = image.Width;
            int height = image.Height;
            int channel = image.Channel;
            int stride = image.Stride;
            byte[] dataBuffer = image.DataBuffer;
            if (rectLeft < 0 || rectLeft > width - 1)
            {
                throw new ArgumentOutOfRangeException("rect.Left", "Left of the crop rect is out of the image.");
            }
            if (rectRight < 0 || rectRight > width)
            {
                throw new ArgumentOutOfRangeException("rect.Right", "Right of the crop rect is out of the image.");
            }
            if (rectTop < 0 || rectTop > height - 1)
            {
                throw new ArgumentOutOfRangeException("rect.Top", "Top of the crop rect is out of the image.");
            }
            if (rectBottom < 0 || rectBottom > height)
            {
                throw new ArgumentOutOfRangeException("rect.Bottom", "Right of the crop rect is out of the image.");
            }
            // 目标图像的尺寸是否需要改变
            int dstDataLen = rectWidth * rectHeight * channel;
            if (dstDataBuffer.Length < dstDataLen)
            {
                Array.Resize(ref dstDataBuffer, dstDataLen);
            }
            // 如果rect的尺寸就是整幅图的尺寸，就直接整幅图clone即可，不需要一行一行复制
            if (rectLeft == 0 && rectTop == 0 && rectWidth == width && rectHeight == height)
            {
                Buffer.BlockCopy(dataBuffer, 0, dstDataBuffer, 0, image.DataBufferSize);
            }
            int rectRowCopyLen = rectWidth * channel;
            int rectCopyOffset = rectTop * width * channel + rectLeft * channel;
            for (int nh = 0; nh < rectHeight; nh++)
            {
                Buffer.BlockCopy(dataBuffer, rectCopyOffset + nh * stride,
                    dstDataBuffer, nh * rectRowCopyLen, rectRowCopyLen);
            }
        }


        #endregion

    }


}