using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace Future.Contract
{
    public sealed class DrawerAdorner : Adorner
    {
        private VisualCollection mVisuals;
        private Border mRoot;
        private AdornerLayer? mLayer;
        private Size mSize;
        private bool mIsShowed = false;
        private bool mIsClosed = false;
        private Func<bool> mApplyCloseCallback;

        public DrawerAdorner(UIElement adornedElement) : base(adornedElement)
        {
            mVisuals = new VisualCollection(this);
            mRoot = new Border();
            mVisuals.Add(mRoot);

            this.mLayer = AdornerLayer.GetAdornerLayer(adornedElement);
            //注意：开场动画必须在此处执行
            this.Loaded += (ss, ee) => this.StartAnimationIn();
            //this.Unloaded += (ss, ee) => this.StartAnimationOut();
        }

        protected override int VisualChildrenCount => mVisuals.Count;

        protected override Visual GetVisualChild(int index) => mVisuals[index];

        protected override Size ArrangeOverride(Size finalSize)
        {
            mSize = finalSize;
            mRoot.Arrange(new Rect(new Point(), finalSize));

            return finalSize;
        }
#pragma warning disable CS0628 // 在密封类型中声明了新的保护成员
        protected void SetHandleVisibility(Visibility visibility)
#pragma warning restore CS0628 // 在密封类型中声明了新的保护成员
        {
            if (this.mRoot.Child != null && this.mRoot.Child is DrawerTemplate)
            {
                DrawerTemplate template = this.mRoot.Child as DrawerTemplate;
                template.HandleVisibility = visibility;
            }
        }
        public void ShowWithTemplate(DrawerTemplate? template, FrameworkElement view, string title, Func<bool>? applyCloseCallback = null)
        {
            if (template == null && view == null) return;
            view?.ClearValue(FrameworkElement.WidthProperty);
            view?.ClearValue(FrameworkElement.HeightProperty);
            this.mApplyCloseCallback = applyCloseCallback;
            if (template != null)
            {
                this.mRoot.Child = template;
                template.Title = title;
                template.Content = view;
                template.ApplyCloseDrawer += () => this.Close();
            }
            else this.mRoot.Child = view;

            //隐藏同一个目标上最上层的相同装饰器的半透明区域(注意：需要防止这个逻辑执行2次)
            var adorners = this.mLayer?.GetAdorners(this.AdornedElement);
            if (adorners != null && !this.mIsShowed)//保证即使更换显示内容也不会重复处理关闭按钮的隐藏
            {
                for (int i = adorners.Length - 1; i >= 0; i--)
                    if (adorners[i] is DrawerAdorner)
                    {
                        ((DrawerAdorner)adorners[i]).SetHandleVisibility(Visibility.Collapsed);
                        break;
                    }
            }
            if (!this.mIsShowed) this.mLayer?.Add(this);//完成显示工作
            //注意：入场动画在OnLoad事件的响应时调用
            this.mIsShowed = true;
            this.mIsClosed = false;
        }

        public static DrawerAdorner ShowInVisual(UIElement adornedElement, DrawerTemplate? template, FrameworkElement view, string title, Func<bool>? applyCloseCallback = null)
        {
            DrawerAdorner drawer = new DrawerAdorner(adornedElement);
            drawer.ShowWithTemplate(template?.Clone(), view, title, applyCloseCallback);
            //drawer.ShowWithTemplate(template, view, title, applyCloseCallback);
            return drawer;
        }

        public static DrawerAdorner ShowInTarget(string targetName, DrawerTemplate? template, FrameworkElement view, string title, Func<bool>? applyCloseCallback = null)
        {
            if (LayerOwners.ContainsKey(targetName))
                return ShowInVisual(LayerOwners[targetName], template, view, title, applyCloseCallback);
            else return null;
        }

        public void ShowOnlyView(FrameworkElement view) => this.ShowWithTemplate(null, view, null, null);

        public static DrawerAdorner ShowView(UIElement adornedElement, FrameworkElement view)
        {
            DrawerAdorner drawer = new DrawerAdorner(adornedElement);
            drawer.ShowOnlyView(view);
            return drawer;
        }

        public void CloseDrawer()
        {
            //强制清空请求关闭委托
            this.mApplyCloseCallback = null;
            this.Close();
        }

        private async void Close()
        {
            if (this.mIsClosed) return;//如果已经关闭了就不要重复执行了，会导致层叠问题
            var sign = this.mApplyCloseCallback?.Invoke();
            if (sign == false) return;

            #region   关闭动画；注意：不能单独封装为函数使用，否则会因为“异步”执行造成动画失效；如果单独封装成函数则需要将“装饰器”卸载操作一同封装
            float seconds = 0.3f;
            var sb = new Storyboard();
            //var offset = mRoot?.ActualWidth ?? 0;
            //var animation = new ThicknessAnimation
            //{
            //    Duration = new Duration(TimeSpan.FromSeconds(seconds)),
            //    From = new Thickness(0),
            //    To = new Thickness(-offset, 0, offset, 0),
            //};
            var animation = BuildAnimation(seconds, true);
            Storyboard.SetTargetProperty(animation, new PropertyPath("Margin"));
            sb.Children.Add(animation);
            sb.Begin(mRoot);
            await Task.Delay((int)(seconds * 1000));
            #endregion

            //开始卸载装饰器
            this.SetHandleVisibility(Visibility.Collapsed);
            this.mRoot.Child = null;    //清除模板视图的引用
            this.mLayer?.Remove(this);  //完成关闭装饰器工作
            //显示同一个目标上最上层的相同装饰器的半透明区域
            var adorners = this.mLayer?.GetAdorners(this.AdornedElement);
            if (adorners != null)
            {
                for (int i = adorners.Length - 1; i >= 0; i--)
                    if (adorners[i] is DrawerAdorner)
                    {
                        ((DrawerAdorner)adorners[i]).SetHandleVisibility(Visibility.Visible);
                        break;
                    }
            }
            this.mIsClosed = true;
            this.mIsShowed = false;
        }
        private ThicknessAnimation BuildAnimation(float seconds = 0.3f, bool inOrOut = false)
        {
            var wOffset = mRoot?.ActualWidth ?? 0;
            var hOffset = mRoot?.ActualHeight ?? 0;

            Thickness from = new Thickness(-wOffset, 0, wOffset, 0);
            Thickness to = new Thickness(0);

            DrawerTemplate template = this.mRoot?.Child as DrawerTemplate;
            if (template != null)
            {
                switch (template.Dock)
                {
                    case Dock.Top:
                        from = new Thickness(0, -hOffset, 0, hOffset);
                        break;
                    case Dock.Bottom:
                        from = new Thickness(0, hOffset, 0, -hOffset);
                        break;
                    case Dock.Right:
                        from = new Thickness(wOffset, 0, -wOffset, 0);
                        break;
                    default: break;
                }
            }

            //如果是退出动画则需要对调From与To两个节点
            if (inOrOut)
            {
                Thickness thickness = from;
                from = to;
                to = thickness;
            }

            return new ThicknessAnimation()
            {
                Duration = new Duration(TimeSpan.FromSeconds(seconds)),
                From = from,
                To = to
            };
        }
        private async void StartAnimationIn(float seconds = 0.3f)
        {
            var sb = new Storyboard();
            //var offset = mRoot?.ActualWidth ?? 0;
            //var animation = new ThicknessAnimation
            //{
            //    Duration = new Duration(TimeSpan.FromSeconds(seconds)),
            //    From = new Thickness(-offset, 0, offset, 0),
            //    To = new Thickness(0)
            //};
            var animation = BuildAnimation(seconds);
            Storyboard.SetTargetProperty(animation, new PropertyPath("Margin"));
            sb.Children.Add(animation);
            sb.Begin(mRoot);
            await Task.Delay((int)(seconds * 1000));
        }
        private async void StartAnimationOut(float seconds = 0.3f)
        {
            var sb = new Storyboard();
            var offset = mRoot?.ActualWidth ?? 0;
            var animation = new ThicknessAnimation
            {
                Duration = new Duration(TimeSpan.FromSeconds(seconds)),
                From = new Thickness(0),
                To = new Thickness(-offset, 0, offset, 0),
            };
            Storyboard.SetTargetProperty(animation, new PropertyPath("Margin"));
            sb.Children.Add(animation);
            sb.Begin(mRoot);
            await Task.Delay((int)(seconds * 1000));

            this.mRoot.Child = null;
            this.mLayer?.Remove(this);//完成关闭工作
            //显示同一个目标上最上层的相同装饰器的半透明区域
            var adorners = this.mLayer?.GetAdorners(this.AdornedElement);
            if (adorners != null)
            {
                for (int i = adorners.Length - 1; i >= 0; i--)
                    if (adorners[i] is DrawerAdorner)
                    {
                        ((DrawerAdorner)adorners[i]).SetHandleVisibility(Visibility.Visible);
                        break;
                    }
            }
        }
        #region   依赖属性
        private static Dictionary<string, UIElement> LayerOwners = new Dictionary<string, UIElement>();
        public static string GetLayerName(DependencyObject obj)
        {
            return (string)obj.GetValue(LayerNameProperty);
        }
        public static void SetLayerName(DependencyObject obj, string value)
        {
            obj.SetValue(LayerNameProperty, value);
        }
        // Using a DependencyProperty as the backing store for LayerName.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty LayerNameProperty =
            DependencyProperty.RegisterAttached("LayerName", typeof(string), typeof(DrawerAdorner), new PropertyMetadata(null, (s, e) =>
            {
                //将抽屉拥有者注册到静态区
                var layerOwner = s as UIElement;
                if (s == null) return;
                if (e.OldValue != null && LayerOwners.ContainsKey((string)e.OldValue))
                    LayerOwners.Remove((string)e.OldValue);
                if (e.NewValue != null && layerOwner != null)
                {
                    if (LayerOwners.ContainsKey((string)e.NewValue))
                        LayerOwners.Remove((string)e.NewValue);

                    LayerOwners.Add((string)e.NewValue, layerOwner);

                    DependencyObject d = s;
                    while (d != null)
                    {
                        if (d is Window) break;
                        var f = d as FrameworkElement;
                        if (f != null && f is not Window) d = f.Parent;
                    }
                    if (d is Window)
                    {
                        Window w = (Window)d;
                        w.Unloaded += (ss, ee) =>
                        LayerOwners.Remove((string)e.NewValue);
                    }
                }
            }));
        #endregion
    }
}