context: #region Copyright & License Information
  /*
   * Copyright 2007-2021 The OpenRA Developers (see AUTHORS)
   * This file is part of OpenRA, which is free software. It is made
   * available to you under the terms of the GNU General Public License
   * as published by the Free Software Foundation, either version 3 of
   * the License, or (at your option) any later version. For more
   * information, see COPYING.
   */
  #endregion
  
  using System.Collections.Generic;
  using System.Linq;
  using OpenRA.Graphics;
  using OpenRA.Mods.Common.Traits;
  using OpenRA.Orders;
  using OpenRA.Primitives;
  using OpenRA.Traits;
  using OpenRA.Widgets;
  
  namespace OpenRA.Mods.Common.Widgets
  {
  	public class WorldInteractionControllerWidget : Widget
  	{
  		protected readonly World World;
  		readonly WorldRenderer worldRenderer;
  		readonly Color normalSelectionColor;
  		readonly Color altSelectionColor;
  		readonly Color ctrlSelectionColor;
  
  		public readonly string ClickSound = ChromeMetrics.Get<string>("ClickSound");
  		public readonly string ClickDisabledSound = ChromeMetrics.Get<string>("ClickDisabledSound");
  
  		int2 dragStart, mousePos;
  		bool isDragging = false;
  
  		bool IsValidDragbox => isDragging && (dragStart - mousePos).Length > Game.Settings.Game.SelectionDeadzone;
  
  		[ObjectCreator.UseCtor]
  		public WorldInteractionControllerWidget(World world, WorldRenderer worldRenderer)
  		{
  			World = world;
  			this.worldRenderer = worldRenderer;
  			if (!ChromeMetrics.TryGet("AltSelectionColor", out altSelectionColor))
  				altSelectionColor = Color.White;
  
  			if (!ChromeMetrics.TryGet("CtrlSelectionColor", out ctrlSelectionColor))
  				ctrlSelectionColor = Color.White;
  
  			if (!ChromeMetrics.TryGet("NormalSelectionColor", out normalSelectionColor))
  				normalSelectionColor = Color.White;
  		}
  
  		public override void Draw()
  		{
  			var modifiers = Game.GetModifierKeys();
  			IEnumerable<Actor> rollover;
  			if (IsValidDragbox)
  			{
  				var a = worldRenderer.Viewport.WorldToViewPx(dragStart);
  				var b = worldRenderer.Viewport.WorldToViewPx(mousePos);
  
  				var color = normalSelectionColor;
  				if (modifiers.HasFlag(Modifiers.Alt) && !modifiers.HasFlag(Modifiers.Ctrl))
  					color = altSelectionColor;
  				else if (modifiers.HasFlag(Modifiers.Ctrl) && !modifiers.HasFlag(Modifiers.Alt))
  					color = ctrlSelectionColor;
  
  				Game.Renderer.RgbaColorRenderer.DrawRect(a, b, 1, color);
  
  				// Render actors in the dragbox
  				rollover = SelectionUtils.SelectActorsInBoxWithDeadzone(World, dragStart, mousePos, modifiers);
  			}
  			else
  			{
  				// Render actors under the mouse pointer
  				rollover = SelectionUtils.SelectActorsInBoxWithDeadzone(World, mousePos, mousePos, modifiers);
  			}
  
  			worldRenderer.World.Selection.SetRollover(rollover);
  		}
  
  		public override bool HandleMouseInput(MouseInput mi)
  		{
  			mousePos = worldRenderer.Viewport.ViewToWorldPx(mi.Location);
  
  			var useClassicMouseStyle = Game.Settings.Game.UseClassicMouseStyle;
  
  			var multiClick = mi.MultiTapCount >= 2;
  
  			if (!(World.OrderGenerator is UnitOrderGenerator uog))
  			{
  				ApplyOrders(World, mi);
  				isDragging = false;
  				YieldMouseFocus(mi);
  				return true;
  			}
  
  			if (mi.Button == MouseButton.Left && mi.Event == MouseInputEvent.Down)
  			{
  				if (!TakeMouseFocus(mi))
  					return false;
  
  				dragStart = mousePos;
  				isDragging = true;
  			}
  
  			if (mi.Button == MouseButton.Left && mi.Event == MouseInputEvent.Up)
  			{
  				if (useClassicMouseStyle && HasMouseFocus)
  				{
  					if (!IsValidDragbox && World.Selection.Actors.Any() && !multiClick && uog.InputOverridesSelection(World, mousePos, mi))
  					{
  						// Order units instead of selecting
  						ApplyOrders(World, mi);
  						isDragging = false;
  						YieldMouseFocus(mi);
  						return true;
  					}
  				}
  
  				if (multiClick)
  				{
  					var unit = World.ScreenMap.ActorsAtMouse(mousePos)
  						.WithHighestSelectionPriority(mousePos, mi.Modifiers);
  
  					var eligiblePlayers = SelectionUtils.GetPlayersToIncludeInSelection(World);
  
  					if (unit != null && eligiblePlayers.Contains(unit.Owner))
  					{
  						var s = unit.TraitOrDefault<ISelectable>();
  						if (s != null)
  						{
  							// Select actors on the screen that have the same selection class as the actor under the mouse cursor
  							var newSelection = SelectionUtils.SelectActorsOnScreen(World, worldRenderer, new HashSet<string> { s.Class }, eligiblePlayers);
  
  							World.Selection.Combine(World, newSelection, true, false);
  						}
  					}
  				}
  				else
  				{
  					/* The block below does three things:
  					// 1. Allows actor selection using a selection box regardless of input mode.
  					// 2. Allows actor deselection with a single click in the default input mode (UnitOrderGenerator).
  					// 3. Prevents units from getting deselected when exiting input modes (eg. AttackMove or Guard).
  					//
  					// We cannot check for UnitOrderGenerator here since it's the default order generator that gets activated in
  					// World.CancelInputMode. If we did check it, actor de-selection would not be possible by just clicking somewhere,
  					// only by dragging an empty selection box.
  					*/
  					if (isDragging && (uog.ClearSelectionOnLeftClick || IsValidDragbox))
  					{
  						var newSelection = SelectionUtils.SelectActorsInBoxWithDeadzone(World, dragStart, mousePos, mi.Modifiers);
  						World.Selection.Combine(World, newSelection, mi.Modifiers.HasModifier(Modifiers.Shift), dragStart == mousePos);
  					}
  				}
  
  				World.CancelInputMode();
  
  				isDragging = false;
  				YieldMouseFocus(mi);
  			}
  
  			if (mi.Button == MouseButton.Right && mi.Event == MouseInputEvent.Up)
  			{
  				// Don't do anything while selecting
  				if (!IsValidDragbox)
  				{
  					if (useClassicMouseStyle)
  						World.Selection.Clear();
  
  					ApplyOrders(World, mi);
  				}
  			}
  
  			return true;
  		}
  
  		void ApplyOrders(World world, MouseInput mi)
  		{
  			if (world.OrderGenerator == null)
  				return;
  
  			var cell = worldRenderer.Viewport.ViewToWorld(mi.Location);
  			var worldPixel = worldRenderer.Viewport.ViewToWorldPx(mi.Location);
  			var orders = world.OrderGenerator.Order(world, cell, worldPixel, mi).ToArray();
  			world.PlayVoiceForOrders(orders);
  
  			var flashed = false;
  			foreach (var o in orders)
  			{
  				if (o == null)
  					continue;
  
  				if (!flashed && !o.SuppressVisualFeedback)
  				{
  					var visualTarget = o.VisualFeedbackTarget.Type != TargetType.Invalid ? o.VisualFeedbackTarget : o.Target;
  
  					foreach (var notifyOrderIssued in world.WorldActor.TraitsImplementing<INotifyOrderIssued>())
  						flashed = notifyOrderIssued.OrderIssued(world, visualTarget);
  				}
  
  				world.IssueOrder(o);
  			}
  		}
  
  		public override string GetCursor(int2 screenPos)
  		{
  
gt: 			return Sync.RunUnsynced(World, () =>