Ground work for Wino Calendar. (#475)

Wino Calendar abstractions.

Wino.Calendar/Controls/WinoCalendarFlipView.cs

@@ -0,0 +1,91 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using CommunityToolkit.WinUI;
+using Windows.UI.Xaml.Controls;
+using Wino.Core.Domain.Models.Calendar;
+using Wino.Core.MenuItems;
+
+namespace Wino.Calendar.Controls
+{
+    public class WinoCalendarFlipView : CustomCalendarFlipView
+    {
+        public event EventHandler<WinoDayTimelineCanvas> ActiveTimelineCanvasChanged;
+
+        public WinoCalendarFlipView()
+        {
+            SelectionChanged += CalendarDisplayRangeChanged;
+        }
+
+        private async void CalendarDisplayRangeChanged(object sender, SelectionChangedEventArgs e)
+        {
+            if (SelectedIndex < 0)
+                ActiveTimelineCanvasChanged?.Invoke(this, null);
+            else
+            {
+                // TODO: Refactor this mechanism by listening to PrepareContainerForItemOverride and Loaded events together.
+                while (ContainerFromIndex(SelectedIndex) == null)
+                {
+                    await Task.Delay(250);
+                }
+
+                if (ContainerFromIndex(SelectedIndex) is FlipViewItem flipViewItem)
+                {
+                    var canvas = flipViewItem.FindDescendant<WinoDayTimelineCanvas>();
+                    ActiveTimelineCanvasChanged?.Invoke(this, canvas);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Navigates to the specified date in the calendar.
+        /// </summary>
+        /// <param name="dateTime">Date to navigate.</param>
+        public async void NavigateToDay(DateTime dateTime)
+        {
+            // Find the day range that contains the date.
+            var dayRange = GetItemsSource()?.FirstOrDefault(a => a.CalendarDays.Any(b => b.RepresentingDate.Date == dateTime.Date));
+
+            if (dayRange != null)
+            {
+                var navigationItemIndex = GetItemsSource().IndexOf(dayRange);
+
+                if (Math.Abs(navigationItemIndex - SelectedIndex) > 4)
+                {
+                    // Difference between dates are high.
+                    // No need to animate this much, just go without animating.
+
+                    SelectedIndex = navigationItemIndex;
+                }
+                else
+                {
+                    // Until we reach the day in the flip, simulate next-prev button clicks.
+                    // This will make sure the FlipView animations are triggered.
+                    // Setting SelectedIndex directly doesn't trigger the animations.
+
+                    while (SelectedIndex != navigationItemIndex)
+                    {
+                        if (SelectedIndex > navigationItemIndex)
+                        {
+                            GoPreviousFlip();
+                        }
+                        else
+                        {
+                            GoNextFlip();
+                        }
+                    }
+                }
+            }
+        }
+
+
+        public void NavigateHour(TimeSpan hourTimeSpan)
+        {
+            // Total height of the FlipViewItem is the same as vertical ScrollViewer to position day headers.
+            // Find the day range that contains the hour.
+        }
+
+        private ObservableRangeCollection<DayRangeRenderModel> GetItemsSource()
+            => ItemsSource as ObservableRangeCollection<DayRangeRenderModel>;
+    }
+}