using System;
using System.Windows.Controls;
using System.Windows.Media.Animation;
using System.Windows;

namespace MultiTerm.Wpf.Behaviours;

/// <summary>
/// Smoothens <see cref="ProgressBar"/> by adding an animation for each change of value.
/// Inspired by https://stackoverflow.com/questions/14485818/how-to-update-a-progress-bar-so-it-increases-smoothly
/// </summary>
public class ProgressBarSmoother
{
    public static double GetSmoothValue(DependencyObject obj)
    {
        return (double)obj.GetValue(SmoothValueProperty);
    }

    public static void SetSmoothValue(DependencyObject obj, double value)
    {
        obj.SetValue(SmoothValueProperty, value);
    }

    public static readonly DependencyProperty SmoothValueProperty =
        DependencyProperty.RegisterAttached(
            "SmoothValue", 
            typeof(double), 
            typeof(ProgressBarSmoother), 
            new PropertyMetadata(0.0, Changing));

    private static void Changing(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        // guard wrong type
        if(d is not ProgressBar progressBar) { return; }

        var anim = new DoubleAnimation((double)e.OldValue, (double)e.NewValue, new TimeSpan(0, 0, 0, 0, 250));
        progressBar.BeginAnimation(ProgressBar.ValueProperty, anim, HandoffBehavior.Compose);
    }
}