Make WinRT/UWP platform classes more maintainable (#652)

* Split Platform.cs into partial classes

* Split the NavigationPageRenderer into partial classes for easier maintenance

* Simplify GetCommandBarAsync, remove unneeded comments

* Correct broken GetCommandBarAsync method

* Fix OSX build

1 files changed, 211 insertions, 0 deletions

diff --git a/Xamarin.Forms.Platform.WinRT/PlatformWinRT.cs b/Xamarin.Forms.Platform.WinRT/PlatformWinRT.cs
new file mode 100644
index 00000000..5e11c8d8
--- /dev/null
+++ b/Xamarin.Forms.Platform.WinRT/PlatformWinRT.cs
@@ -0,0 +1,211 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Windows.UI;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Controls.Primitives;
+using Windows.UI.Xaml.Media;
+using Windows.UI.Xaml.Media.Animation;
+
+namespace Xamarin.Forms.Platform.WinRT
+{
+	public abstract partial class Platform
+	{
+		CommandBar AddOpenMasterButton(CommandBar commandBar)
+		{
+			if (!_toolbarTracker.HaveMasterDetail)
+			{
+				return commandBar;
+			}
+
+			if (commandBar == null)
+			{
+				commandBar = CreateCommandBar();
+			}
+
+			Page target = _toolbarTracker.Target;
+			var mdp = target as MasterDetailPage;
+			while (mdp == null)
+			{
+				var container = target as IPageContainer<Page>;
+				if (container == null)
+				{
+					break;
+				}
+
+				target = container.CurrentPage;
+				mdp = container.CurrentPage as MasterDetailPage;
+			}
+
+			if (mdp == null || !mdp.ShouldShowToolbarButton())
+			{
+				return commandBar;
+			}
+
+			var openMaster = new AppBarButton { DataContext = mdp };
+			openMaster.SetBinding(AppBarButton.LabelProperty, "Master.Title");
+			openMaster.SetBinding(AppBarButton.IconProperty, "Master.Icon", _fileImageSourcePathConverter);
+			openMaster.Click += (s, a) => { mdp.IsPresented = !mdp.IsPresented; };
+
+			commandBar.PrimaryCommands.Add(openMaster);
+
+			return commandBar;
+		}
+
+		CommandBar CreateCommandBar()
+		{
+			var commandBar = new CommandBar();
+			_page.BottomAppBar = commandBar;
+			return commandBar;
+		}
+
+		void UpdateBounds()
+		{
+			_bounds = new Rectangle(0, 0, _page.ActualWidth, _page.ActualHeight);
+		}
+
+		Task<CommandBar> GetCommandBarAsync()
+		{
+			return Task.FromResult(_page.BottomAppBar as CommandBar);
+		}
+
+		void ClearCommandBar()
+		{
+			_page.BottomAppBar = null;
+		}
+
+		void OnPageActionSheet(Page sender, ActionSheetArguments options)
+		{
+			var finalArguments = new List<string>();
+			if (options.Destruction != null)
+				finalArguments.Add(options.Destruction);
+			if (options.Buttons != null)
+				finalArguments.AddRange(options.Buttons);
+			if (options.Cancel != null)
+				finalArguments.Add(options.Cancel);
+
+			var list = new Windows.UI.Xaml.Controls.ListView
+			{
+				Style = (Windows.UI.Xaml.Style)Windows.UI.Xaml.Application.Current.Resources["ActionSheetList"],
+				ItemsSource = finalArguments,
+				IsItemClickEnabled = true
+			};
+
+			list.ItemClick += (s, e) =>
+			{
+				_currentActionSheet.IsOpen = false;
+				options.SetResult((string)e.ClickedItem);
+			};
+
+			_actionSheetOptions = options;
+
+			Size size = Device.Info.ScaledScreenSize;
+
+			var stack = new StackPanel
+			{
+				MinWidth = 100,
+				Children =
+				{
+					new TextBlock
+					{
+						Text = options.Title ?? string.Empty,
+						Style = (Windows.UI.Xaml.Style)Windows.UI.Xaml.Application.Current.Resources["TitleTextBlockStyle"],
+						Margin = new Windows.UI.Xaml.Thickness(0, 0, 0, 10),
+						Visibility = options.Title != null ? Visibility.Visible : Visibility.Collapsed
+					},
+					list
+				}
+			};
+
+			var border = new Border
+			{
+				Child = stack,
+				BorderBrush = new SolidColorBrush(Colors.White),
+				BorderThickness = new Windows.UI.Xaml.Thickness(1),
+				Padding = new Windows.UI.Xaml.Thickness(15),
+				Background = (Brush)Windows.UI.Xaml.Application.Current.Resources["AppBarBackgroundThemeBrush"]
+			};
+
+			Windows.UI.Xaml.Controls.Grid.SetRow(border, 1);
+			Windows.UI.Xaml.Controls.Grid.SetColumn(border, 1);
+
+			var container = new Windows.UI.Xaml.Controls.Grid
+			{
+				RowDefinitions =
+				{
+					new Windows.UI.Xaml.Controls.RowDefinition { Height = new Windows.UI.Xaml.GridLength(1, Windows.UI.Xaml.GridUnitType.Star) },
+					new Windows.UI.Xaml.Controls.RowDefinition { Height = new Windows.UI.Xaml.GridLength(0, Windows.UI.Xaml.GridUnitType.Auto) },
+					new Windows.UI.Xaml.Controls.RowDefinition { Height = new Windows.UI.Xaml.GridLength(1, Windows.UI.Xaml.GridUnitType.Star) }
+				},
+				ColumnDefinitions =
+				{
+					new Windows.UI.Xaml.Controls.ColumnDefinition { Width = new Windows.UI.Xaml.GridLength(1, Windows.UI.Xaml.GridUnitType.Star) },
+					new Windows.UI.Xaml.Controls.ColumnDefinition { Width = new Windows.UI.Xaml.GridLength(0, Windows.UI.Xaml.GridUnitType.Auto) },
+					new Windows.UI.Xaml.Controls.ColumnDefinition { Width = new Windows.UI.Xaml.GridLength(1, Windows.UI.Xaml.GridUnitType.Star) }
+				},
+				Height = size.Height,
+				Width = size.Width,
+				Children = { border }
+			};
+
+			var bgPopup = new Popup { Child = new Canvas { Width = size.Width, Height = size.Height, Background = new SolidColorBrush(new Windows.UI.Color { A = 128, R = 0, G = 0, B = 0 }) } };
+
+			bgPopup.IsOpen = true;
+
+			_currentActionSheet = new Popup { ChildTransitions = new TransitionCollection { new PopupThemeTransition() }, IsLightDismissEnabled = true, Child = container };
+
+			_currentActionSheet.Closed += (s, e) =>
+			{
+				bgPopup.IsOpen = false;
+				CancelActionSheet();
+			};
+
+			if (Device.Idiom == TargetIdiom.Phone)
+			{
+				double height = _page.ActualHeight;
+				stack.Height = height;
+				stack.Width = size.Width;
+				border.BorderThickness = new Windows.UI.Xaml.Thickness(0);
+
+				_currentActionSheet.Height = height;
+				_currentActionSheet.VerticalOffset = size.Height - height;
+			}
+
+			_currentActionSheet.IsOpen = true;
+		}
+
+		internal async Task UpdateToolbarItems()
+		{
+			CommandBar commandBar = await GetCommandBarAsync();
+			if (commandBar != null)
+			{
+				commandBar.PrimaryCommands.Clear();
+				commandBar.SecondaryCommands.Clear();
+			}
+
+			commandBar = AddOpenMasterButton(commandBar);
+
+			foreach (ToolbarItem item in _toolbarTracker.ToolbarItems.OrderBy(ti => ti.Priority))
+			{
+				if (commandBar == null)
+					commandBar = CreateCommandBar();
+
+				var button = new AppBarButton();
+				button.SetBinding(AppBarButton.LabelProperty, "Text");
+				button.SetBinding(AppBarButton.IconProperty, "Icon", _fileImageSourcePathConverter);
+				button.Command = new MenuItemCommand(item);
+				button.DataContext = item;
+
+				ToolbarItemOrder order = item.Order == ToolbarItemOrder.Default ? ToolbarItemOrder.Primary : item.Order;
+				if (order == ToolbarItemOrder.Primary)
+					commandBar.PrimaryCommands.Add(button);
+				else
+					commandBar.SecondaryCommands.Add(button);
+			}
+
+			if (commandBar?.PrimaryCommands.Count + commandBar?.SecondaryCommands.Count == 0)
+				ClearCommandBar();
+		}
+	}
+}