using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls;
using System.Windows.Threading;
using System.Windows.Media.Imaging;
using System.Drawing;
using System.Drawing.Imaging;
using YOLODetectProcessLib;

namespace YOLODetectDemo
{
    public class Roi
    {
        public Rect BoundBox { get; set; }
        public System.Windows.Media.Brush Color { get; set; }
        public string LabelName { get; set; }
    }

    public class MyTransform
    {
        public double Scale { get; set; }

        public double OffsetX { get; set; }

        public double OffsetY { get; set; }

        public MyTransform(double scale, double offsetX, double offsetY)
        {
            Scale = scale;
            OffsetX = offsetX;
            OffsetY = offsetY;
        }

        public System.Windows.Point Transform(System.Windows.Point point)
        {
            double x = OffsetX + Scale * point.X;
            double y = OffsetY + Scale * point.Y;
            return new System.Windows.Point(x, y);
        }

        public System.Windows.Rect Transform(System.Windows.Rect rect)
        {
            double left = OffsetX + Scale * rect.Left;
            double top = OffsetY + Scale * rect.Top;
            double width = Scale * rect.Width;
            double height = Scale * rect.Height;
            return new System.Windows.Rect(left, top, width, height);
        }

    }


    /// <summary>
    /// ImageCanvas.xaml 的交互逻辑
    /// </summary>
    public partial class ImageCanvas : UserControl
    {

        #region private

        private Bitmap _image;
        private List<Roi> _rois;
        private volatile bool _enableAI;
        private volatile bool _showContour;
        private volatile bool _showSize;
        private MyTransform _transform;

        #endregion


        #region properties

        public Bitmap Image { get => _image; }

        #endregion

        #region 用户界面响应

        private void CanvasSizeChanged(object sender, System.Windows.SizeChangedEventArgs e)
        {
            UpdateTransforms();
        }


        #endregion


        #region public

        public ImageCanvas()
        {
            InitializeComponent();
        }

        public void SetShowParams(bool enableAI)
        {
            _enableAI = enableAI;
            if (_rois != null)
            {
                for (int ni = 0; ni < _rois.Count; ni++)
                {
                    DrawRoiInCanvas(_rois[ni], ni.ToString());
                }
            }
        }

        public void UpdateImage(Bitmap image)
        {
            _image = image.Clone(new Rectangle(0, 0, image.Width, image.Height), image.PixelFormat);
            // 更新缩放比例
            UpdateTransforms();
            // 更新图像显示
            var bitmapImage = BitmapToBitmapImage(image);
            Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() =>
            {
                ImageShow.Source = bitmapImage;
            }));
        }

        #endregion


        #region private

        private void RemoveRoiInCanvas(string roiName)
        {
            // 文字
            string textName = "Text_" + roiName;
            System.Windows.Controls.TextBlock textExist = RoiCanvas.FindName(textName) as System.Windows.Controls.TextBlock;
            if (textExist != null)
            {
                RoiCanvas.Children.Remove(textExist);
                RoiCanvas.UnregisterName(textName);
            }

        }

        private void DrawRoiInCanvas(Roi roi, string roiName)
        {
            if (_transform == null)
            {
                return;
            }
            // 已有则删除
            RemoveRoiInCanvas(roiName);

            // 不启用AI，则直接退出
            if (!_enableAI)
            {
                return;
            }

            // 将Roi的序号写在左上角
            var pointLT = new System.Windows.Point(roi.BoundBox.Left, roi.BoundBox.Top);
            var transPointLT = _transform.Transform(pointLT);
            var textLeft = transPointLT.X - 16;
            var textTop = transPointLT.Y;
            TextBlock text = new TextBlock();
            text.Text = roiName;
            text.FontSize = 16;
            text.FontWeight = System.Windows.FontWeights.Bold;
            text.Foreground = roi.Color;
            text.VerticalAlignment = System.Windows.VerticalAlignment.Top;
            Canvas.SetLeft(text, textLeft);
            Canvas.SetTop(text, textTop);

            RoiCanvas.Children.Add(text);
            string textName = "Text_" + roiName;
            RoiCanvas.RegisterName(textName, text);

        }

        private BitmapImage BitmapToBitmapImage(Bitmap img)
        {
            BitmapImage bmpimg = new BitmapImage();
            using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
            {
                img.Save(ms, ImageFormat.Png);
                bmpimg.BeginInit();
                bmpimg.StreamSource = ms;
                bmpimg.CacheOption = BitmapCacheOption.OnLoad;
                bmpimg.EndInit();
                bmpimg.Freeze();
                ms.Dispose();
            }
            return bmpimg;
        }

        private void UpdateTransforms()
        {
            if (_image != null)
            {
                // 使图片保持长宽比例，居中显示，需要平移和缩放
                var imgWidth = _image.Width;
                var imgHeight = _image.Height;
                var canvasWidth = RoiCanvas.ActualWidth;
                var canvasHeight = RoiCanvas.ActualHeight;
                var scaleX = canvasWidth / imgWidth;
                var scaleY = canvasHeight / imgHeight;
                var scale = scaleX < scaleY ? scaleX : scaleY;
                double offsetX, offsetY;
                if (Math.Abs(scale - scaleX) < 0.0001)
                {
                    offsetY = 0.5 * (scaleY - scale) * imgHeight;
                    offsetX = 0;
                }
                else
                {
                    offsetX = 0.5 * (scaleX - scale) * imgWidth;
                    offsetY = 0;
                }
                _transform = new MyTransform(scale, offsetX, offsetY);
            }
        }
        #endregion
    }

}