using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Shapes;
using System.Windows.Threading;

namespace DocTools.WPF
{
    /// <summary>
    /// WaitingSpinner.xaml 的交互逻辑
    /// </summary>
    public partial class WaitingSpinner : UserControl
    {
        #region Private Variables

        private readonly DispatcherTimer _animationTimer;

        #endregion Private Variables

        #region Constructor

        public WaitingSpinner()
        {
            InitializeComponent();
            // 每40 ms 转一下
            _animationTimer = new DispatcherTimer(DispatcherPriority.Normal, Dispatcher) { Interval = new TimeSpan(0, 0, 0, 0, 80) };
            Visibility = Visibility.Collapsed;
        }

        #endregion Constructor

        private void Start()
        {
            _animationTimer.Tick += HandleAnimationTick;
            _animationTimer.Start();
        }

        private void Stop()
        {
            _animationTimer.Stop();
            _animationTimer.Tick -= HandleAnimationTick;
        }

        private void HandleAnimationTick(object sender, EventArgs e)
        {
            SpinnerRotate.Angle = (SpinnerRotate.Angle + 36) % 360;
        }

        private void OnCanvasLoaded(object sender, RoutedEventArgs e)
        {
            SpinnerRotate.CenterX = (float)0.5 * CanvasSpinner.Width;
            SpinnerRotate.CenterY = (float)0.5 * CanvasSpinner.Height;

            const double offset = Math.PI;
            const double step = Math.PI * 2 / 10.0;

            SetPosition(C0, offset, 0.0, step);
            SetPosition(C1, offset, 1.0, step);
            SetPosition(C2, offset, 2.0, step);
            SetPosition(C3, offset, 3.0, step);
            SetPosition(C4, offset, 4.0, step);
            SetPosition(C5, offset, 5.0, step);
            SetPosition(C6, offset, 6.0, step);
            SetPosition(C7, offset, 7.0, step);
            SetPosition(C8, offset, 8.0, step);
        }

        private void SetPosition(Ellipse ellipse, double offset, double posOffSet, double step)
        {
            ellipse.SetValue(Canvas.LeftProperty, CanvasSpinner.Width * 0.5 + Math.Sin(offset + posOffSet * step) * CanvasSpinner.Width * 0.4 - 0.5 * ellipse.Width);
            ellipse.SetValue(Canvas.TopProperty, CanvasSpinner.Width * 0.5 + Math.Cos(offset + posOffSet * step) * CanvasSpinner.Width * 0.4 - 0.5 * ellipse.Width);
        }

        private void OnCanvasUnLoaded(object sender, RoutedEventArgs e)
        {
            Stop();
        }

        /// <summary>
        /// Start the waiting animation
        /// </summary>
        public void StartWaiting()
        {
            Visibility = Visibility.Visible;
            Start();
        }

        /// <summary>
        /// Stop the waiting animation
        /// </summary>
        public void StopWaiting()
        {
            Stop();
            Visibility = Visibility.Collapsed;
        }
    }
}