using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Input;

using System.Windows.Threading;



namespace Microsoft.Research.DynamicDataDisplay.Charts.Navigation

{

    public sealed class LongOperationsIndicator : IPlotterElement

    {

        public LongOperationsIndicator()

        {

            timer.Tick += new EventHandler(timer_Tick);

        }



        private void timer_Tick(object sender, EventArgs e)

        {

            UpdateWaitIndicator();

            timer.Stop();

        }



        #region IPlotterElement Members



        void IPlotterElement.OnPlotterAttached(Plotter plotter)

        {

            this.plotter = plotter;

        }



        void IPlotterElement.OnPlotterDetaching(Plotter plotter)

        {

            this.plotter = null;

        }



        private Plotter plotter;

        Plotter IPlotterElement.Plotter

        {

            get { return plotter; }

        }



        #endregion



        #region LongOperationRunning



        public static void BeginLongOperation(DependencyObject obj)

        {

            obj.SetValue(LongOperationRunningProperty, true);

        }



        public static void EndLongOperation(DependencyObject obj)

        {

            obj.SetValue(LongOperationRunningProperty, false);

        }



        public static bool GetLongOperationRunning(DependencyObject obj)

        {

            return (bool)obj.GetValue(LongOperationRunningProperty);

        }



        public static void SetLongOperationRunning(DependencyObject obj, bool value)

        {

            obj.SetValue(LongOperationRunningProperty, value);

        }



        public static readonly DependencyProperty LongOperationRunningProperty = DependencyProperty.RegisterAttached(

          "LongOperationRunning",

          typeof(bool),

          typeof(LongOperationsIndicator),

          new FrameworkPropertyMetadata(false, OnLongOperationRunningChanged));



        private static void OnLongOperationRunningChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)

        {

            Plotter plotter = null;

            IPlotterElement element = d as IPlotterElement;

            if (element == null)

            {

                plotter = Plotter.GetPlotter(d);

            }

            else

            {

                plotter = element.Plotter;

            }



            if (plotter != null)

            {

                var indicator = plotter.Children.OfType<LongOperationsIndicator>().FirstOrDefault();

                if (indicator != null)

                {

                    indicator.OnLongOperationRunningChanged(element, (bool)e.NewValue);

                }

            }

        }



        UIElement indicator = LoadIndicator();



        private static UIElement LoadIndicator()

        {

            var resources = (ResourceDictionary)Application.LoadComponent(new Uri("/DynamicDataDisplay;component/Charts/Navigation/LongOperationsIndicatorResources.xaml", UriKind.Relative));

            UIElement indicator = (UIElement)resources["Indicator"];

            return indicator;

        }



        private readonly DispatcherTimer timer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(100) };

        private int operationsCounter = 0;

        private void OnLongOperationRunningChanged(IPlotterElement element, bool longOperationRunning)

        {

            int change = longOperationRunning ? +1 : -1;

            operationsCounter += change;



            if (plotter == null) return;



            if (operationsCounter == 1)

            {

                timer.Start();

            }

            else if (operationsCounter == 0)

            {

                timer.Stop();

                UpdateWaitIndicator();

            }

        }



        private void UpdateWaitIndicator()

        {

            if (operationsCounter == 1)

            {

                if (!plotter.MainCanvas.Children.Contains(indicator))

                {

                    plotter.MainCanvas.Children.Add(indicator);

                }

                plotter.Cursor = Cursors.Wait;

            }

            else if (operationsCounter == 0)

            {

                plotter.MainCanvas.Children.Remove(indicator);

                plotter.ClearValue(Plotter.CursorProperty);

            }

        }



        #endregion // end of LongOperationRunning

    }

}