using System;
using System.Windows.Controls.Primitives;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows;
using System.Windows.Shapes;
using Brushes = System.Windows.Media.Brushes;
using Size = System.Windows.Size;
using EGC = ExtendedGrid.Microsoft.Windows.Controls;
using System.Diagnostics;

namespace MECF.Framework.UI.Client.DataGridTransform.DataGrid.Microsoft.Windows.Controls.Primitives
{
    public class DataGridCellDragToFillAdorner : Adorner
    {
        public event EventHandler<DragStartedEventArgs> OnDragStart;
        public event EventHandler<DragCompletedEventArgs> OnDragCompleted;
        public event EventHandler<DragDeltaEventArgs> OnDragDelta;

        private readonly Brush _defaultBrush;
        private readonly VisualCollection _adornerVisuals;
        private readonly Thumb _thumb2;
        private readonly Rectangle _rec;
        private readonly Rectangle _recShadow;
        private Rect _lastBoundRect;

        #region Constructors

        public DataGridCellDragToFillAdorner(UIElement adornedElement, Size originCellSize) : base(adornedElement)
        {
            _lastBoundRect = new Rect(0, 0, originCellSize.Width, originCellSize.Height);

            _adornerVisuals = new VisualCollection(this);
            _defaultBrush = Brushes.ForestGreen;

            _thumb2 = new Thumb();
            
            _rec = new Rectangle()
            {
                StrokeThickness = 2
            };

            _recShadow = new Rectangle()
            {
                StrokeThickness = 2,
                StrokeDashArray = { 1, 1 },
                Opacity = 0.5,
                Visibility = Visibility.Hidden
            };

            _thumb2.DragStarted += Thumb2OnDragStarted;
            _thumb2.DragDelta += Thumb2_DragDelta;
            _thumb2.DragCompleted += Thumb2OnDragCompleted;

            _adornerVisuals.Add(_rec);
            _adornerVisuals.Add(_recShadow);
            _adornerVisuals.Add(_thumb2);
        }

        protected override void OnInitialized(EventArgs e)
        {
            base.OnInitialized(e);
            
            LoadDefaultThumbStyle();
            LoadDefaultBorderStyle();
        }

        #endregion

        #region Properties

        protected override int VisualChildrenCount => _adornerVisuals.Count;

        internal int StartCellIndex { get; private set; }

        internal int EndCellIndex { get; private set; }

        #endregion

        #region Dps

        public static readonly DependencyProperty ThumbStyleProperty = DependencyProperty.Register(
            nameof(ThumbStyle), typeof(Style), typeof(DataGridCellDragToFillAdorner), 
            new PropertyMetadata(default(Style), ThumbStyleChangedCallback));

        private static void ThumbStyleChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (d is DataGridCellDragToFillAdorner adr && e.NewValue is Style s)
                adr.SetThumbStyle(s);
        }

        public Style ThumbStyle
        {
            get => (Style)GetValue(ThumbStyleProperty);
            set => SetValue(ThumbStyleProperty, value);
        }

        public static readonly DependencyProperty BorderColorProperty = DependencyProperty.Register(
            nameof(BorderColorBrush), typeof(Brush), typeof(DataGridCellDragToFillAdorner), 
            new PropertyMetadata(default(Brush), BorderColorPropertyChangedCallback));

        private static void BorderColorPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (d is DataGridCellDragToFillAdorner adr && e.NewValue is Brush b)
            {
                adr.SetBorderBrush(b);
            }
        }

        public Brush BorderColorBrush
        {
            get => (Brush)GetValue(BorderColorProperty);
            set => SetValue(BorderColorProperty, value);
        }

        #endregion

        #region Methods

        protected override Visual GetVisualChild(int index)
        {
            return _adornerVisuals[index];
        }

        protected override Size ArrangeOverride(Size finalSize)
        {
            /*_rec.Arrange(_lastBoundRect);
            _thumb2.Arrange(new Rect(_lastBoundRect.Width - 5, _lastBoundRect.Height + _lastBoundRect.Y - 5, 10, 10));*/
            _rec.Arrange(new Rect(0, 0, finalSize.Width, finalSize.Height));
            //_recShadow.Arrange(new Rect(0, 0, finalSize.Width, finalSize.Height));
            _thumb2.Arrange(new Rect(finalSize.Width - 5, finalSize.Height - 5, 10, 10));

            return base.ArrangeOverride(finalSize);
        }

        private void SetThumbStyle(Style style)
        {
            if (style != null && style.TargetType == typeof(Thumb))
                _thumb2.Style = style;
            else
            {
                // Load default style
                LoadDefaultThumbStyle();
            }
        }

        private void SetBorderBrush(Brush brush)
        {
            if (brush != null)
            {
                _rec.Stroke = brush;
                _recShadow.Stroke = brush;
            }
            else
            {
                LoadDefaultBorderStyle();
            }
        }

        private void LoadDefaultThumbStyle()
        {
            var brush = _defaultBrush;
            if (BorderColorBrush != null)
                brush = BorderColorBrush;
                
            _thumb2.Width = 10;
            _thumb2.Height = 10;
            _thumb2.Background = brush;
            _thumb2.BorderThickness = new Thickness(0);
        }

        private void LoadDefaultBorderStyle()
        {
            var brush = _defaultBrush;
            if (BorderColorBrush != null)
                brush = BorderColorBrush;

            _rec.Stroke = brush;
            _recShadow.Stroke = brush;
        }

        /// <summary>
        /// 绘制选择范围的虚线框。
        /// </summary>
        /// <param name="boundRect"></param>
        /// <param name="startCellIndex"></param>
        /// <param name="endCellIndex"></param>
        internal void ArrangeSelectionBound(Rect boundRect, int startCellIndex, int endCellIndex)
        {
            _lastBoundRect.X = boundRect.X;
            _lastBoundRect.Y = boundRect.Y;
            _lastBoundRect.Width = boundRect.Width;
            _lastBoundRect.Height = boundRect.Height;
            _recShadow.Arrange(_lastBoundRect);
            StartCellIndex = startCellIndex;
            EndCellIndex = endCellIndex;

            //Debug.WriteLine($"Adorner Bound: {_lastBoundRect}", "Adorner");
        }

        /// <summary>
        /// 获取拖动选择的范围。
        /// </summary>
        /// <returns></returns>
        internal Rect GetSelectionBound()
        {
            return _lastBoundRect;
        }

        /// <summary>
        /// 取消填充操作。
        /// </summary>
        internal void Cancel()
        {
            if (_thumb2.IsDragging)
                _thumb2.CancelDrag();
        }

        #endregion

        #region Event Handlers

        private void Thumb2OnDragStarted(object sender, DragStartedEventArgs e)
        {
            _recShadow.Visibility = Visibility.Visible;
            OnDragStart?.Invoke(this, e);
        }

        private void Thumb2OnDragCompleted(object sender, DragCompletedEventArgs e)
        {
            _recShadow.Visibility = Visibility.Hidden;

            if (!e.Canceled)
            {
                _rec.Arrange(_lastBoundRect);
                _recShadow.Arrange(_lastBoundRect);
                _thumb2.Arrange(new Rect(_lastBoundRect.Width - 5, _lastBoundRect.Height + _lastBoundRect.Y - 5, 10, 10));

                OnDragCompleted?.Invoke(this, e);
            }
        }

        private void Thumb2_DragDelta(object sender, DragDeltaEventArgs e)
        {
            OnDragDelta?.Invoke(this, e);
        }

        #endregion
    }
}