using OxyPlot;
using System;
using System.Collections.Generic;
using System.Diagnostics.Eventing.Reader;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace TeamAAS_VP.Controls
{
    /// <summary>
    /// PictureDisplayControl.xaml 的交互逻辑
    /// </summary>
    public partial class PictureDisplayControl : UserControl
    {
        private bool _startMove;
        private Point _start;
        private bool _isFirst = true;

        public PictureDisplayControl()
        {
            InitializeComponent();
            Loaded+=(s, e) =>
            {
                FitImageToControl();
            };
        }

        public BitmapSource Image
        {
            get { return (BitmapSource)GetValue(ImageProperty); }
            set { SetValue(ImageProperty, value);
                if (value != null)
                {
                    FitImageToControl();
                }
                //if (_isFirst && value!=null)
                //{
                //    FitImageToControl();
                //    _isFirst = false;
                //}
            }
        }

        // Using a DependencyProperty as the backing store for MyProperty.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty ImageProperty =
            DependencyProperty.Register("Image", typeof(BitmapSource), typeof(PictureDisplayControl), new PropertyMetadata(null, new PropertyChangedCallback(ImageValueChanged)));

        private static void ImageValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            PictureDisplayControl obj = (PictureDisplayControl)d;
            if (obj != null)
            {
                obj.Update(e.NewValue as BitmapSource);
            }
        }

        private void Update(BitmapSource bitmap)
        {
            App.Current.Dispatcher.Invoke(() =>
            {
                if (bitmap != null)
                {
                    this.Img.Source = bitmap;
                    FitImageToControl();
                }
                else
                {
                    this.Img.Source = bitmap;
                }
            });
        }

        private void Viewbox_MouseWheel(object sender, MouseWheelEventArgs e)
        {
            var centerPt = e.GetPosition(Box);
            ChangSize(e.Delta > 0, Box, centerPt.X, centerPt.Y);
            e.Handled = true; //避免缩放时同时影响滚动条;
        }

        private void Viewbox_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            if (Box.IsMouseCaptured) return;
            Box.CaptureMouse();
            _start = e.MouseDevice.GetPosition(Sv);
            e.Handled = true;
            _startMove = true;
        }

        private void Viewbox_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            Box.ReleaseMouseCapture();
            _startMove = false;
        }

        private void Viewbox_PreviewMouseMove(object sender, MouseEventArgs e)
        {
            if (!Box.IsMouseCaptured || !_startMove) return;
            var point = e.MouseDevice.GetPosition(Sv);
            var m = Box.RenderTransform.Value;
            //计算x偏移量 
            m.OffsetX = m.OffsetX + point.X - _start.X;
            //计算y偏移量
            m.OffsetY = m.OffsetY + point.Y - _start.Y;
            Box.RenderTransform = new MatrixTransform(m);
            //给鼠标起点和图片临时位置重新赋值
            _start = point;
        }

        private void ChangSize(bool big, FrameworkElement ctrl, double centerX, double centerY)
        {
            var m = ((MatrixTransform)ctrl.RenderTransform).Matrix;
            if (big)
            {
                m.ScaleAtPrepend(1.1, 1.1, centerX, centerY);
            }
            else
            {
                m.ScaleAtPrepend(1 / 1.1, 1 / 1.1, centerX, centerY);
            }
            ctrl.RenderTransform = new MatrixTransform(m);
        }

        private void FitImageToControl()
        {
            if (Image==null)
            {
                return;  
            }
            var imageWidth = Image.PixelWidth;
            var imageHeight = Image.PixelHeight;
            var controlWidth = this.ActualWidth;
            var controlHeight = this.ActualHeight;

            double scaleX = controlWidth / imageWidth;
            double scaleY = controlHeight / imageHeight;
            double scale = Math.Min(scaleX, scaleY);

            var m = new Matrix();
            m.Scale(scale, scale);
            m.Translate((controlWidth - imageWidth * scale) / 2, (controlHeight - imageHeight * scale) / 2);
            Box.RenderTransform = new MatrixTransform(m);
        }
    }
}