context: #region Copyright & License Information
  /*
   * Copyright 2007-2015 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. For more information,
   * see COPYING.
   */
  #endregion
  
  using System.Collections.Generic;
  using System.Drawing;
  using System.Linq;
  using OpenRA.Graphics;
  using OpenRA.Mods.Common.Graphics;
  using OpenRA.Mods.Common.Traits;
  using OpenRA.Mods.RA.Activities;
  
  namespace OpenRA.Mods.RA.Traits
  {
  	class ChronoshiftPowerInfo : SupportPowerInfo
  	{
  		[Desc("Target actor selection radius in cells.")]
  		public readonly int Range = 1;
  
  		[Desc("Seconds until returning after teleportation.")]
  		public readonly int Duration = 30;
  
  		public readonly bool KillCargo = true;
  
  		public override object Create(ActorInitializer init) { return new ChronoshiftPower(init.Self, this); }
  	}
  
  	class ChronoshiftPower : SupportPower
  	{
  		public ChronoshiftPower(Actor self, ChronoshiftPowerInfo info) : base(self, info) { }
  
  		public override void SelectTarget(Actor self, string order, SupportPowerManager manager)
  		{
  			Game.Sound.PlayToPlayer(manager.Self.Owner, Info.SelectTargetSound);
  			self.World.OrderGenerator = new SelectChronoshiftTarget(Self.World, order, manager, this);
  		}
  
  		public override void Activate(Actor self, Order order, SupportPowerManager manager)
  		{
  			base.Activate(self, order, manager);
  
  			foreach (var target in UnitsInRange(order.ExtraLocation))
  			{
  				var cs = target.Trait<Chronoshiftable>();
  				var targetCell = target.Location + (order.TargetLocation - order.ExtraLocation);
  				var cpi = Info as ChronoshiftPowerInfo;
  
  				if (self.Owner.Shroud.IsExplored(targetCell) && cs.CanChronoshiftTo(target, targetCell))
  					cs.Teleport(target, targetCell, cpi.Duration * 25, cpi.KillCargo, self);
  			}
  		}
  
  		public IEnumerable<Actor> UnitsInRange(CPos xy)
  		{
  			var range = ((ChronoshiftPowerInfo)Info).Range;
  			var tiles = Self.World.Map.FindTilesInCircle(xy, range);
  			var units = new HashSet<Actor>();
  			foreach (var t in tiles)
  				units.UnionWith(Self.World.ActorMap.GetActorsAt(t));
  
  			return units.Where(a => a.Info.HasTraitInfo<ChronoshiftableInfo>() &&
  				!a.TraitsImplementing<IPreventsTeleport>().Any(condition => condition.PreventsTeleport(a)));
  		}
  
  		public bool SimilarTerrain(CPos xy, CPos sourceLocation)
  		{
  			if (!Self.Owner.Shroud.IsExplored(xy))
  				return false;
  
  			var range = ((ChronoshiftPowerInfo)Info).Range;
  			var sourceTiles = Self.World.Map.FindTilesInCircle(xy, range);
  			var destTiles = Self.World.Map.FindTilesInCircle(sourceLocation, range);
  
  			using (var se = sourceTiles.GetEnumerator())
  			using (var de = destTiles.GetEnumerator())
  				while (se.MoveNext() && de.MoveNext())
  				{
  					var a = se.Current;
  					var b = de.Current;
  
  					if (!Self.Owner.Shroud.IsExplored(a) || !Self.Owner.Shroud.IsExplored(b))
  						return false;
  
  					if (Self.World.Map.GetTerrainIndex(a) != Self.World.Map.GetTerrainIndex(b))
  						return false;
  				}
  
  			return true;
  		}
  
  		class SelectChronoshiftTarget : IOrderGenerator
  		{
  			readonly ChronoshiftPower power;
  			readonly int range;
  			readonly Sprite tile;
  			readonly SupportPowerManager manager;
  			readonly string order;
  
  			public SelectChronoshiftTarget(World world, string order, SupportPowerManager manager, ChronoshiftPower power)
  			{
  				// Clear selection if using Left-Click Orders
  				if (Game.Settings.Game.UseClassicMouseStyle)
  					manager.Self.World.Selection.Clear();
  
  				this.manager = manager;
  				this.order = order;
  				this.power = power;
  				this.range = ((ChronoshiftPowerInfo)power.Info).Range;
  				tile = world.Map.SequenceProvider.GetSequence("overlay", "target-select").GetSprite(0);
  			}
  
  			public IEnumerable<Order> Order(World world, CPos xy, MouseInput mi)
  			{
  				world.CancelInputMode();
  				if (mi.Button == MouseButton.Left)
  					world.OrderGenerator = new SelectDestination(world, order, manager, power, xy);
  
  				yield break;
  			}
  
  			public void Tick(World world)
  			{
  				// Cancel the OG if we can't use the power
  				if (!manager.Powers.ContainsKey(order))
  					world.CancelInputMode();
  			}
  
  			public IEnumerable<IRenderable> RenderAfterWorld(WorldRenderer wr, World world)
  			{
  				var xy = wr.Viewport.ViewToWorld(Viewport.LastMousePos);
  				var targetUnits = power.UnitsInRange(xy).Where(a => !world.FogObscures(a));
  
  				foreach (var unit in targetUnits)
  					if (manager.Self.Owner.CanTargetActor(unit))
  						yield return new SelectionBoxRenderable(unit, Color.Red);
  			}
  
  			public IEnumerable<IRenderable> Render(WorldRenderer wr, World world)
  			{
  				var xy = wr.Viewport.ViewToWorld(Viewport.LastMousePos);
  				var tiles = world.Map.FindTilesInCircle(xy, range);
  				var pal = wr.Palette("terrain");
  				foreach (var t in tiles)
  					yield return new SpriteRenderable(tile, wr.World.Map.CenterOfCell(t), WVec.Zero, -511, pal, 1f, true);
  			}
  
  			public string GetCursor(World world, CPos xy, MouseInput mi)
  			{
  				return "chrono-select";
  			}
  		}
  
  		class SelectDestination : IOrderGenerator
  		{
  			readonly ChronoshiftPower power;
  			readonly CPos sourceLocation;
  			readonly int range;
  			readonly Sprite validTile, invalidTile, sourceTile;
  			readonly SupportPowerManager manager;
  			readonly string order;
  
  			public SelectDestination(World world, string order, SupportPowerManager manager, ChronoshiftPower power, CPos sourceLocation)
  			{
  				this.manager = manager;
  				this.order = order;
  				this.power = power;
  				this.sourceLocation = sourceLocation;
  				this.range = ((ChronoshiftPowerInfo)power.Info).Range;
  
  				var tileset = manager.Self.World.TileSet.Id.ToLowerInvariant();
  				validTile = world.Map.SequenceProvider.GetSequence("overlay", "target-valid-{0}".F(tileset)).GetSprite(0);
  				invalidTile = world.Map.SequenceProvider.GetSequence("overlay", "target-invalid").GetSprite(0);
  				sourceTile = world.Map.SequenceProvider.GetSequence("overlay", "target-select").GetSprite(0);
  			}
  
  			public IEnumerable<Order> Order(World world, CPos xy, MouseInput mi)
  			{
  				if (mi.Button == MouseButton.Right)
  				{
  					world.CancelInputMode();
  					yield break;
  				}
  
  				var ret = OrderInner(xy).FirstOrDefault();
  				if (ret == null)
  					yield break;
  
  				world.CancelInputMode();
  				yield return ret;
  			}
  
  			IEnumerable<Order> OrderInner(CPos xy)
  			{
  				// Cannot chronoshift into unexplored location
  				if (IsValidTarget(xy))
  					yield return new Order(order, manager.Self, false)
  					{
  						TargetLocation = xy,
  						ExtraLocation = sourceLocation,
  						SuppressVisualFeedback = true
  					};
  			}
  
  			public void Tick(World world)
  			{
  				// Cancel the OG if we can't use the power
  				if (!manager.Powers.ContainsKey(order))
  					world.CancelInputMode();
  			}
  
  			public IEnumerable<IRenderable> RenderAfterWorld(WorldRenderer wr, World world)
  			{
  				foreach (var unit in power.UnitsInRange(sourceLocation))
  					if (manager.Self.Owner.CanTargetActor(unit))
  						yield return new SelectionBoxRenderable(unit, Color.Red);
  			}
  
  			public IEnumerable<IRenderable> Render(WorldRenderer wr, World world)
  			{
  				var xy = wr.Viewport.ViewToWorld(Viewport.LastMousePos);
  				var pal = wr.Palette("terrain");
  
  				// Source tiles
  				foreach (var t in world.Map.FindTilesInCircle(sourceLocation, range))
  					yield return new SpriteRenderable(sourceTile, wr.World.Map.CenterOfCell(t), WVec.Zero, -511, pal, 1f, true);
  
  				// Destination tiles
  				foreach (var t in world.Map.FindTilesInCircle(xy, range))
  					yield return new SpriteRenderable(sourceTile, wr.World.Map.CenterOfCell(t), WVec.Zero, -511, pal, 1f, true);
  
  				// Unit previews
  				foreach (var unit in power.UnitsInRange(sourceLocation))
  				{
  					var offset = world.Map.CenterOfCell(xy) - world.Map.CenterOfCell(sourceLocation);
  					if (manager.Self.Owner.CanTargetActor(unit))
  						foreach (var r in unit.Render(wr))
  							yield return r.OffsetBy(offset);
  				}
  
  				// Unit tiles
  				foreach (var unit in power.UnitsInRange(sourceLocation))
  				{
  					if (manager.Self.Owner.CanTargetActor(unit))
  					{
  						var targetCell = unit.Location + (xy - sourceLocation);
  						var canEnter = manager.Self.Owner.Shroud.IsExplored(targetCell) &&
  							unit.Trait<Chronoshiftable>().CanChronoshiftTo(unit, targetCell);
  
gt: 						var tile = canEnter ? validTile : invalidTile;