using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Threading;

namespace Wpf_AiSportsMicrospace.MyUserControl
{
    /// <summary>
    /// CoverFlowControl.xaml 的交互逻辑
    /// </summary>
    public partial class CoverFlowControl : UserControl
    {// 新增事件：进度条完成
        public event Action<CoverFlowItem>? ProgressCompleted;
        public ObservableCollection<CoverFlowItem> Images { get; set; } = new ObservableCollection<CoverFlowItem>();
        private int _selectedIndex = 0;
        private bool _isAnimating;
        private int _pendingSlideSteps;

        private const double CardWidth = 346;
        private const double CardHeight = 534;
        private const double CardGap = 30;          // 卡片之间水平间距
        private const double SlideDurationMs = 420; // 动画时长

        public int SelectedIndex
        {
            get => _selectedIndex;
            set
            {
                if (Images.Count == 0) return;

                if (value < 0) _selectedIndex = Images.Count - 1;
                else if (value >= Images.Count) _selectedIndex = 0;
                else _selectedIndex = value;

                UpdateSelectionFlags();
                RefreshCards(instant: true);

                // 启动进度条动画
                //var current = Images[_selectedIndex];
                //StartProgress(current);
            }

        }

        public CoverFlowControl()
        {
            InitializeComponent();
            DataContext = this;
            Loaded += CoverFlowControl_Loaded;

            //var timer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(5) };
            //timer.Tick += (s, e) =>
            //{
            //    if (Images.Count == 0) return;
            //    var current = Images[_selectedIndex];
            //    if (current.Progress < 1)
            //        current.Progress += 0.01; // 调整速度
            //};
            //timer.Start();
        }
        private EventHandler? _renderHandler;

        private CoverFlowItem? _currentItem;

        private void CoverFlowControl_Loaded(object sender, RoutedEventArgs e)
        {
            if (Images.Count > 0)
            {
                UpdateSelectionFlags();
                RefreshCards(instant: true);
            }

            CarouselCanvas.Focus();
            Keyboard.Focus(CarouselCanvas);
        }

        /// <summary>
        /// 针对当前选中项启动进度条动画
        /// </summary>
        public void StartSelectedProgress()
        {
            if (SelectedIndex >= 0 && SelectedIndex < Images.Count)
            {
                var current = Images[SelectedIndex];
                if (current.Progress >= 1) return; // 已完成，直接返回，不再启动
                StartProgress(current);
            }
        }
        public void CancelSelectedProgress()
        {
            if (SelectedIndex >= 0 && SelectedIndex < Images.Count)
            {
                var current = Images[SelectedIndex];

                // 停止动画/计时
                StopProgress();

                // 清零当前的进度值
                current.Progress = 0;
            }
        }
        public void StartProgress(CoverFlowItem item)
        {
            StopProgress();

            _currentItem = item;
            item.Progress = 0;

            _renderHandler = (s, e) =>
            {
                if (_currentItem.Progress < 1)
                {
                    _currentItem.Progress += 0.01; // 控制速度
                }
                else
                {
                    ProgressCompleted?.Invoke(_currentItem);
                    // 停止动画
                    StopProgress();
                }
            };

            CompositionTarget.Rendering += _renderHandler;
        }

        private void StopProgress()

        {
            if (_renderHandler != null)
            {
                CompositionTarget.Rendering -= _renderHandler;
                _renderHandler = null;
            }

            if (_currentItem != null)
            {
                _currentItem.Progress = 0;
                _currentItem = null;
            }
        }
        private void UpdateSelectionFlags()
        {
            for (int i = 0; i < Images.Count; i++)
                Images[i].IsSelected = i == _selectedIndex;
        }

        private int WrapIndex(int index)
        {
            if (Images.Count == 0) return 0;
            var m = index % Images.Count;
            if (m < 0) m += Images.Count;
            return m;
        }

        private double SlotDistance => CardWidth + CardGap;

        private double XFarLeft => 0;
        private double XLeft => SlotDistance;
        private double XCenter => SlotDistance * 2;
        private double XRight => SlotDistance * 3;
        private double XFarRight => SlotDistance * 4;
        private double XOffLeft => -SlotDistance;
        private double XOffRight => SlotDistance * 5;

        private void SetCard(ContentPresenter card, CoverFlowItem? item, double left, double opacity = 1)
        {
            card.Content = item;
            Canvas.SetLeft(card, left);
            Canvas.SetTop(card, 0);
            card.Opacity = opacity;
        }

        private void RefreshCards(bool instant)
        {
            if (Images.Count == 0) return;

            var farLeft = Images[WrapIndex(_selectedIndex - 2)];
            var left = Images[WrapIndex(_selectedIndex - 1)];
            var center = Images[WrapIndex(_selectedIndex)];
            var right = Images[WrapIndex(_selectedIndex + 1)];
            var farRight = Images[WrapIndex(_selectedIndex + 2)];

            SetCard(CardFarLeft, farLeft, XFarLeft, 1);
            SetCard(CardLeft, left, XLeft, 1);
            SetCard(CardCenter, center, XCenter, 1);
            SetCard(CardRight, right, XRight, 1);
            SetCard(CardFarRight, farRight, XFarRight, 1);

            // spare stays hidden offscreen
            SetCard(CardSpare, null, XOffRight, 0);

            if (!instant)
                return;
        }

        private void Carousel_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
        {
            if (e.Delta < 0) SlideLeft();
            else if (e.Delta > 0) SlideRight();
            e.Handled = true;
        }

        private void Carousel_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Right || e.Key == Key.Down)
            {
                SlideLeft();
                e.Handled = true;
            }
            else if (e.Key == Key.Left || e.Key == Key.Up)
            {
                SlideRight();
                e.Handled = true;
            }
        }

        private void CardLeft_Click(object sender, MouseButtonEventArgs e)
        {
            RequestSlide(-1);
        }

        private void CardRight_Click(object sender, MouseButtonEventArgs e)
        {
            RequestSlide(+1);
        }

        private void CardFarLeft_Click(object sender, MouseButtonEventArgs e)
        {
            RequestSlide(-2);
        }

        private void CardFarRight_Click(object sender, MouseButtonEventArgs e)
        {
            RequestSlide(+2);
        }

        private void CardCenter_Click(object sender, MouseButtonEventArgs e)
        {
            // center click: treat as selecting current (already selected)
        }

        private void RequestSlide(int steps)
        {
            if (Images.Count == 0) return;
            if (steps == 0) return;

            _pendingSlideSteps += steps;
            TryRunNextSlide();
        }

        private void TryRunNextSlide()
        {
            if (_isAnimating) return;
            if (_pendingSlideSteps == 0) return;

            if (_pendingSlideSteps > 0)
            {
                _pendingSlideSteps--;
                AnimateLeftOne();
            }
            else
            {
                _pendingSlideSteps++;
                AnimateRightOne();
            }
        }

        private void AnimateLeftOne()
        {
            if (_isAnimating) return;
            if (Images.Count == 0) return;

            _isAnimating = true;
            StopProgress();

            var newSelected = WrapIndex(_selectedIndex + 1);
            var incomingFarRight = Images[WrapIndex(newSelected + 2)];

            // Prepare spare entering from the right (to far-right slot)
            SetCard(CardSpare, incomingFarRight, XOffRight, 1);

            var sb = new Storyboard { FillBehavior = FillBehavior.Stop };
            var ease = new CubicEase { EasingMode = EasingMode.EaseOut };
            var dur = TimeSpan.FromMilliseconds(SlideDurationMs);

            void AddMove(FrameworkElement fe, double toX)
            {
                var anim = new DoubleAnimation
                {
                    To = toX,
                    Duration = new Duration(dur),
                    EasingFunction = ease
                };
                Storyboard.SetTarget(anim, fe);
                Storyboard.SetTargetProperty(anim, new PropertyPath("(Canvas.Left)"));
                sb.Children.Add(anim);
            }

            void AddFade(FrameworkElement fe, double toOpacity)
            {
                var anim = new DoubleAnimation
                {
                    To = toOpacity,
                    Duration = new Duration(dur),
                    EasingFunction = ease
                };
                Storyboard.SetTarget(anim, fe);
                Storyboard.SetTargetProperty(anim, new PropertyPath("Opacity"));
                sb.Children.Add(anim);
            }

            // Far-left card slides out to left and fades
            AddMove(CardFarLeft, XOffLeft);
            AddFade(CardFarLeft, 0);

            // Shift others left by one slot, spare enters to far-right
            AddMove(CardLeft, XFarLeft);
            AddMove(CardCenter, XLeft);
            AddMove(CardRight, XCenter);
            AddMove(CardFarRight, XRight);
            AddMove(CardSpare, XFarRight);

            sb.Completed += (_, _) =>
            {
                _selectedIndex = newSelected;
                UpdateSelectionFlags();

                // After shift left:
                // new FarLeft = old Left
                // new Left = old Center
                // new Center = old Right
                // new Right = old FarRight
                // new FarRight = old Spare
                var oldFarLeftContent = (CoverFlowItem?)CardFarLeft.Content;
                var oldLeftContent = (CoverFlowItem?)CardLeft.Content;
                var oldCenterContent = (CoverFlowItem?)CardCenter.Content;
                var oldRightContent = (CoverFlowItem?)CardRight.Content;
                var oldFarRightContent = (CoverFlowItem?)CardFarRight.Content;
                var oldSpareContent = (CoverFlowItem?)CardSpare.Content;

                SetCard(CardFarLeft, oldLeftContent, XFarLeft, 1);
                SetCard(CardLeft, oldCenterContent, XLeft, 1);
                SetCard(CardCenter, oldRightContent, XCenter, 1);
                SetCard(CardRight, oldFarRightContent, XRight, 1);
                SetCard(CardFarRight, oldSpareContent, XFarRight, 1);

                SetCard(CardSpare, null, XOffRight, 0);

                _isAnimating = false;
                TryRunNextSlide();
            };

            sb.Begin(this, true);
        }

        private void AnimateRightOne()
        {
            if (_isAnimating) return;
            if (Images.Count == 0) return;

            _isAnimating = true;
            StopProgress();

            var newSelected = WrapIndex(_selectedIndex - 1);
            var incomingFarLeft = Images[WrapIndex(newSelected - 2)];

            // Prepare spare entering from the left (to far-left slot)
            SetCard(CardSpare, incomingFarLeft, XOffLeft, 1);

            var sb = new Storyboard { FillBehavior = FillBehavior.Stop };
            var ease = new CubicEase { EasingMode = EasingMode.EaseOut };
            var dur = TimeSpan.FromMilliseconds(SlideDurationMs);

            void AddMove(FrameworkElement fe, double toX)
            {
                var anim = new DoubleAnimation
                {
                    To = toX,
                    Duration = new Duration(dur),
                    EasingFunction = ease
                };
                Storyboard.SetTarget(anim, fe);
                Storyboard.SetTargetProperty(anim, new PropertyPath("(Canvas.Left)"));
                sb.Children.Add(anim);
            }

            void AddFade(FrameworkElement fe, double toOpacity)
            {
                var anim = new DoubleAnimation
                {
                    To = toOpacity,
                    Duration = new Duration(dur),
                    EasingFunction = ease
                };
                Storyboard.SetTarget(anim, fe);
                Storyboard.SetTargetProperty(anim, new PropertyPath("Opacity"));
                sb.Children.Add(anim);
            }

            // Far-right card slides out to right and fades
            AddMove(CardFarRight, XOffRight);
            AddFade(CardFarRight, 0);

            // Shift others right by one slot, spare enters to far-left
            AddMove(CardRight, XFarRight);
            AddMove(CardCenter, XRight);
            AddMove(CardLeft, XCenter);
            AddMove(CardFarLeft, XLeft);
            AddMove(CardSpare, XFarLeft);

            sb.Completed += (_, _) =>
            {
                _selectedIndex = newSelected;
                UpdateSelectionFlags();

                var oldFarLeftContent = (CoverFlowItem?)CardFarLeft.Content;
                var oldLeftContent = (CoverFlowItem?)CardLeft.Content;
                var oldCenterContent = (CoverFlowItem?)CardCenter.Content;
                var oldRightContent = (CoverFlowItem?)CardRight.Content;
                var oldFarRightContent = (CoverFlowItem?)CardFarRight.Content;
                var oldSpareContent = (CoverFlowItem?)CardSpare.Content;

                // After shift right:
                // new FarRight = old Right
                // new Right = old Center
                // new Center = old Left
                // new Left = old FarLeft
                // new FarLeft = old Spare
                SetCard(CardFarRight, oldRightContent, XFarRight, 1);
                SetCard(CardRight, oldCenterContent, XRight, 1);
                SetCard(CardCenter, oldLeftContent, XCenter, 1);
                SetCard(CardLeft, oldFarLeftContent, XLeft, 1);
                SetCard(CardFarLeft, oldSpareContent, XFarLeft, 1);

                SetCard(CardSpare, null, XOffRight, 0);

                _isAnimating = false;
                TryRunNextSlide();
            };

            sb.Begin(this, true);
        }


        public void SlideLeft()
        {
            RequestSlide(+1);
        }
        public void SlideRight()
        {
            RequestSlide(-1);
        }
    }
}