From fd599d20d5a64d18c1d2cdb62870c584afbc7f63 Mon Sep 17 00:00:00 2001
From: mntone <sd8@live.jp>
Date: Sun, 9 Aug 2020 23:23:41 +0900
Subject: [PATCH] Add a feature to change placement of notifications by
 dragging.

---
 source/SylphyHorn/UI/SettingsWindow.xaml    |  12 ++-
 source/SylphyHorn/UI/SettingsWindow.xaml.cs | 113 +++++++++++++++++++-
 2 files changed, 121 insertions(+), 4 deletions(-)

diff --git a/source/SylphyHorn/UI/SettingsWindow.xaml b/source/SylphyHorn/UI/SettingsWindow.xaml
index d1f4152..0506cb0 100644
--- a/source/SylphyHorn/UI/SettingsWindow.xaml
+++ b/source/SylphyHorn/UI/SettingsWindow.xaml
@@ -360,7 +360,10 @@
 						<Canvas x:Name="CanvasRoot"
 								HorizontalAlignment="Left"
 								Width="480"
-								Height="270">
+								Height="270"
+								MouseMove="OnCanvasRootMouseMove"
+								MouseLeave="OnCanvasRootMouseLeave"
+								MouseUp="OnCanvasRootMouseUp">
 							<Canvas.Resources>
 								<Style x:Key="PreviewGridStyle"
 									   TargetType="Grid">
@@ -703,7 +706,9 @@
 								  Width="300"
 								  Height="50"
 								  Style="{StaticResource PreviewGridStyle}"
-								  Visibility="{Binding Source={x:Static serialization:Settings.General}, Path=NotificationWhenSwitchedDesktop.Value, Converter={StaticResource BooleanToVisibilityConverter}, Mode=OneWay}">
+								  Visibility="{Binding Source={x:Static serialization:Settings.General}, Path=NotificationWhenSwitchedDesktop.Value, Converter={StaticResource BooleanToVisibilityConverter}, Mode=OneWay}"
+								  MouseDown="OnPreviewRootMouseDown"
+								  Cursor="SizeAll">
 								<Border Width="300"
 										Height="50"
 										ClipToBounds="True">
@@ -741,7 +746,8 @@
 										Style="{StaticResource PreviewBorderStyle}" />
 							</Grid>
 
-							<Rectangle Fill="{Binding TaskbarBackground}"
+							<Rectangle x:Name="PreviewTaskbar"
+									   Fill="{Binding TaskbarBackground}"
 									   Style="{StaticResource PreviewTaskbarStyle}" />
 						</Canvas>
 					</StackPanel>
diff --git a/source/SylphyHorn/UI/SettingsWindow.xaml.cs b/source/SylphyHorn/UI/SettingsWindow.xaml.cs
index 92453b6..f571ecc 100644
--- a/source/SylphyHorn/UI/SettingsWindow.xaml.cs
+++ b/source/SylphyHorn/UI/SettingsWindow.xaml.cs
@@ -1,7 +1,9 @@
-using System;
+using SylphyHorn.UI.Bindings;
+using System;
 using System.ComponentModel;
 using System.Windows;
 using System.Windows.Controls;
+using System.Windows.Input;
 using WindowsDesktop;
 
 namespace SylphyHorn.UI
@@ -48,5 +50,114 @@ private void UpdatePreviewBlurImageMargin()
 				-(this.CanvasRoot.Width - previewLeft - this.PreviewRoot.Width),
 				-(this.CanvasRoot.Height - previewTop - this.PreviewRoot.Height));
 		}
+
+		#region Implement PreviewRoot dragging
+
+		private const double _snappingDeltaX = 30;
+		private const double _snappingDeltaY = 45;
+
+		private bool _isDrag = false;
+		private Point _positionOffset = new Point(0, 0);
+
+		private void OnPreviewRootMouseDown(object sender, MouseButtonEventArgs e)
+		{
+			if (e.LeftButton == MouseButtonState.Pressed)
+			{
+				this._positionOffset = e.GetPosition(this.PreviewRoot);
+				this._isDrag = true;
+			}
+		}
+
+		private void OnCanvasRootMouseMove(object sender, MouseEventArgs e)
+		{
+			if (!this._isDrag || e.LeftButton != MouseButtonState.Pressed) return;
+
+			var viewModel = this.DataContext as SettingsWindowViewModel;
+			if (viewModel == null) return;
+
+			var left = 0.0;
+			var top = 0.0;
+			var width = this.CanvasRoot.ActualWidth - this.PreviewRoot.ActualWidth;
+			var height = this.CanvasRoot.ActualHeight - this.PreviewRoot.ActualHeight;
+			switch (viewModel.PreviewTaskbarPosition)
+			{
+				case "Left":
+					left = this.PreviewTaskbar.ActualWidth;
+					break;
+
+				case "Top":
+					top = this.PreviewTaskbar.ActualHeight;
+					break;
+
+				case "Right":
+					width -= this.PreviewTaskbar.ActualWidth;
+					break;
+
+				case "Bottom":
+					height -= this.PreviewTaskbar.ActualHeight;
+					break;
+			}
+
+			var position = Point.Subtract(e.GetPosition(this.CanvasRoot), _positionOffset);
+			Canvas.SetLeft(this.PreviewRoot, Math.Max(left, Math.Min(width, position.X)));
+			Canvas.SetTop(this.PreviewRoot, Math.Max(top, Math.Min(height, position.Y)));
+
+			var halfAvaiableWidth = width * 0.5;
+			if (position.Y <= top + _snappingDeltaY)
+			{
+				if (position.X <= left + _snappingDeltaX)
+				{
+					viewModel.Placement = WindowPlacement.TopLeft;
+				}
+				else if (ContainsRange(position.X, halfAvaiableWidth, _snappingDeltaX))
+				{
+					viewModel.Placement = WindowPlacement.TopCenter;
+				}
+				else if (position.X >= width - _snappingDeltaX)
+				{
+					viewModel.Placement = WindowPlacement.TopRight;
+				}
+			}
+			else if (ContainsRange(position.Y, height * 0.5, _snappingDeltaY))
+			{
+				viewModel.Placement = WindowPlacement.Center;
+			}
+			else if (position.Y >= height - _snappingDeltaY)
+			{
+				if (position.X <= left + _snappingDeltaX)
+				{
+					viewModel.Placement = WindowPlacement.BottomLeft;
+				}
+				else if (ContainsRange(position.X, halfAvaiableWidth, _snappingDeltaX))
+				{
+					viewModel.Placement = WindowPlacement.BottomCenter;
+				}
+				else if (position.X >= width - _snappingDeltaX)
+				{
+					viewModel.Placement = WindowPlacement.BottomRight;
+				}
+			}
+		}
+
+		private void OnCanvasRootMouseUp(object sender, MouseButtonEventArgs e)
+			=> this.ResetDragState();
+
+		private void OnCanvasRootMouseLeave(object sender, MouseEventArgs e)
+			=> this.ResetDragState();
+
+		private void ResetDragState()
+		{
+			if (this._isDrag)
+			{
+				this.PreviewRoot.ClearValue(Canvas.LeftProperty);
+				this.PreviewRoot.ClearValue(Canvas.TopProperty);
+				this._isDrag = false;
+			}
+		}
+
+		private static bool ContainsRange(double current, double length, double delta)
+			=> current >= length - delta && current <= length + delta;
+
+		#endregion
 	}
 }