context: #region Copyright & License Information
  /*
   * Copyright 2007-2014 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;
  using System.Collections.Generic;
  using System.Drawing;
  using System.Linq;
  using OpenRA.Mods.RA.Activities;
  using OpenRA.Primitives;
  using OpenRA.Traits;
  
  namespace OpenRA.Mods.RA.Move
  {
  	[Flags]
  	public enum CellConditions
  	{
  		None = 0,
  		TransientActors,
  		BlockedByMovers,
  		All = TransientActors | BlockedByMovers
  	};
  
  	[Desc("Unit is able to move.")]
  	public class MobileInfo : ITraitInfo, IOccupySpaceInfo, IFacingInfo, IMoveInfo, UsesInit<FacingInit>, UsesInit<LocationInit>, UsesInit<SubCellInit>
  	{
  		[FieldLoader.LoadUsing("LoadSpeeds")]
  		[Desc("Set Water: 0 for ground units and lower the value on rough terrain.")]
  		public readonly Dictionary<string, TerrainInfo> TerrainSpeeds;
  
  		[Desc("e.g. crate, wall, infantry")]
  		public readonly string[] Crushes = { };
  
  		public readonly int WaitAverage = 5;
  
  		public readonly int WaitSpread = 2;
  
  		public readonly int InitialFacing = 128;
  
  		[Desc("Rate of Turning")]
  		public readonly int ROT = 255;
  
  		public readonly int Speed = 1;
  
  		public readonly bool OnRails = false;
  
  		[Desc("Allow multiple (infantry) units in one cell.")]
  		public readonly bool SharesCell = false;
  
  		[Desc("Can the actor be ordered to move in to shroud?")]
  		public readonly bool MoveIntoShroud = true;
  
  		public virtual object Create(ActorInitializer init) { return new Mobile(init, this); }
  
  		static object LoadSpeeds(MiniYaml y)
  		{
  			var ret = new Dictionary<string, TerrainInfo>();
  			foreach (var t in y.ToDictionary()["TerrainSpeeds"].Nodes)
  			{
  				var speed = FieldLoader.GetValue<decimal>("speed", t.Value.Value);
  				var nodesDict = t.Value.ToDictionary();
  				var cost = nodesDict.ContainsKey("PathingCost")
  					? FieldLoader.GetValue<int>("cost", nodesDict["PathingCost"].Value)
  					: (int)(10000 / speed);
  				ret.Add(t.Key, new TerrainInfo(speed, cost));
  			}
  
  			return ret;
  		}
  
  		TerrainInfo[] LoadTilesetSpeeds(TileSet tileSet)
  		{
  			var info = new TerrainInfo[tileSet.TerrainInfo.Length];
  			for (var i = 0; i < info.Length; i++)
  				info[i] = TerrainInfo.Impassable;
  
  			foreach (var kvp in TerrainSpeeds)
  			{
  				byte index;
  				if (tileSet.TryGetTerrainIndex(kvp.Key, out index))
  					info[index] = kvp.Value;
  			}
  
  			return info;
  		}
  
  		public class TerrainInfo
  		{
  			public static readonly TerrainInfo Impassable = new TerrainInfo();
  
  			public readonly int Cost;
  			public readonly decimal Speed;
  
  			public TerrainInfo()
  			{
  				Cost = int.MaxValue;
  				Speed = 0;
  			}
  
  			public TerrainInfo(decimal speed, int cost)
  			{
  				Speed = speed;
  				Cost = cost;
  			}
  		}
  
  		public readonly Cache<TileSet, TerrainInfo[]> TilesetTerrainInfo;
  		public readonly Cache<TileSet, int> TilesetMovementClass;
  
  		public MobileInfo()
  		{
  			TilesetTerrainInfo = new Cache<TileSet, TerrainInfo[]>(LoadTilesetSpeeds);
  			TilesetMovementClass = new Cache<TileSet, int>(CalculateTilesetMovementClass);
  		}
  
  		public int MovementCostForCell(World world, CPos cell)
  		{
  			if (!world.Map.Contains(cell))
  				return int.MaxValue;
  
  			var index = world.Map.GetTerrainIndex(cell);
  			if (index == byte.MaxValue)
  				return int.MaxValue;
  
  			return TilesetTerrainInfo[world.TileSet][index].Cost;
  		}
  
  		public int CalculateTilesetMovementClass(TileSet tileset)
  		{
  			/* collect our ability to cross *all* terraintypes, in a bitvector */
  			return TilesetTerrainInfo[tileset].Select(ti => ti.Cost < int.MaxValue).ToBits();
  		}
  
  		public int GetMovementClass(TileSet tileset)
  		{
  			return TilesetMovementClass[tileset];
  		}
  
  		static bool IsMovingInMyDirection(Actor self, Actor other)
  		{
  			if (!other.IsMoving()) return false;
  			if (self == null) return true;
  
  			var selfMobile = self.TraitOrDefault<Mobile>();
  			if (selfMobile == null) return false;
  
  			var otherMobile = other.TraitOrDefault<Mobile>();
  			if (otherMobile == null) return false;
  
  			// Sign of dot-product indicates (roughly) if vectors are facing in same or opposite directions:
  			var dp = CVec.Dot((selfMobile.toCell - self.Location), (otherMobile.toCell - other.Location));
  			if (dp <= 0) return false;
  
  			return true;
  		}
  
  		public bool CanEnterCell(World world, Actor self, CPos cell, Actor ignoreActor = null, CellConditions check = CellConditions.All)
  		{
  			if (MovementCostForCell(world, cell) == int.MaxValue)
  				return false;
  
  			if (SharesCell && world.ActorMap.HasFreeSubCell(cell))
  				return true;
  
  			if (check.HasFlag(CellConditions.TransientActors))
  			{
  				var canIgnoreMovingAllies = self != null && !check.HasFlag(CellConditions.BlockedByMovers);
  				var needsCellExclusively = self == null || Crushes == null || !Crushes.Any();
  				foreach(var a in world.ActorMap.GetUnitsAt(cell))
  				{
  					if (a == ignoreActor)
  						continue;
  
  					// Neutral/enemy units are blockers. Allied units that are moving are not blockers.
  					if (canIgnoreMovingAllies && self.Owner.Stances[a.Owner] == Stance.Ally && IsMovingInMyDirection(self, a)) continue;
  					
  					// Non-sharable unit can enter a cell with shareable units only if it can crush all of them.
  					if (needsCellExclusively)
  						return false;
  					var crushables = a.TraitsImplementing<ICrushable>();
  					if (!crushables.Any())
  						return false;
  					foreach (var crushable in crushables)
  						if (!crushable.CrushableBy(Crushes, self.Owner))
  							return false;
  				}
  			}
  
  			return true;
  		}
  
  		public SubCell GetAvailableSubCell(World world, Actor self, CPos cell, SubCell preferredSubCell = SubCell.Any, Actor ignoreActor = null, CellConditions check = CellConditions.All)
  		{
  			if (MovementCostForCell(world, cell) == int.MaxValue)
  				return SubCell.Invalid;
  
  			if (check.HasFlag(CellConditions.TransientActors))
  			{
  				var canIgnoreMovingAllies = self != null && !check.HasFlag(CellConditions.BlockedByMovers);
  				var needsCellExclusively = self == null || Crushes == null || !Crushes.Any();
  
  				Func<Actor, bool> checkTransient = a =>
  				{
  					if (a == ignoreActor)
  						return false;
  
  					// Neutral/enemy units are blockers. Allied units that are moving are not blockers.
  					if (canIgnoreMovingAllies && self.Owner.Stances[a.Owner] == Stance.Ally && IsMovingInMyDirection(self, a))
  						return false;
  					
  					// Non-sharable unit can enter a cell with shareable units only if it can crush all of them.
  					if (needsCellExclusively)
  						return true;
  					var crushables = a.TraitsImplementing<ICrushable>();
  					if (!crushables.Any())
  						return true;
  					foreach (var crushable in crushables)
  						if (!crushable.CrushableBy(Crushes, self.Owner))
  							return true;
  
  					return false;
  				};
  
  				if (!SharesCell)
  					return world.ActorMap.AnyUnitsAt(cell, SubCell.FullCell, checkTransient) ? SubCell.Invalid : SubCell.FullCell;
  
  				return world.ActorMap.FreeSubCell(cell, preferredSubCell, checkTransient);
  			}
  
  			if (!SharesCell)
  				return world.ActorMap.AnyUnitsAt(cell, SubCell.FullCell)? SubCell.Invalid : SubCell.FullCell;
  
  			return world.ActorMap.FreeSubCell(cell, preferredSubCell);
  		}
  
  		public int GetInitialFacing() { return InitialFacing; }
  	}
  
  	public class Mobile : IIssueOrder, IResolveOrder, IOrderVoice, IPositionable, IMove, IFacing, ISync, INotifyAddedToWorld, INotifyRemovedFromWorld, INotifyBlockingMove
  	{
  		public readonly Actor self;
  		public readonly MobileInfo Info;
  		public bool IsMoving { get; set; }
  
  		int __facing;
  		CPos __fromCell, __toCell;
  		public SubCell fromSubCell, toSubCell;
  
  		//int __altitude;
  
  		[Sync] public int Facing
  		{
  			get { return __facing; }
  			set { __facing = value; }
  		}
  
  		public int ROT { get { return Info.ROT; } }
  
  		[Sync] public WPos CenterPosition { get; private set; }
  		[Sync] public CPos fromCell { get { return __fromCell; } }
  		[Sync] public CPos toCell { get { return __toCell; } }
  
  		[Sync] public int PathHash;	// written by Move.EvalPath, to temporarily debug this crap.
  
  		public void SetLocation(CPos from, SubCell fromSub, CPos to, SubCell toSub)
  		{
  			if (fromCell == from && toCell == to && fromSubCell == fromSub && toSubCell == toSub)
  				return;
  
  			RemoveInfluence();
  			__fromCell = from;
  			__toCell = to;
  			fromSubCell = fromSub;
  			toSubCell = toSub;
  			AddInfluence();
  		}
  
  		const int avgTicksBeforePathing = 5;
  		const int spreadTicksBeforePathing = 5;
  		internal int ticksBeforePathing = 0;
  
  		public Mobile(ActorInitializer init, MobileInfo info)
  		{
  			this.self = init.self;
  			this.Info = info;
  
  			toSubCell = fromSubCell = info.SharesCell ? init.world.Map.DefaultSubCell : SubCell.FullCell;
  			if (init.Contains<SubCellInit>())
  			{
  				this.fromSubCell = this.toSubCell = init.Get<SubCellInit, SubCell>();
  			}
  
  			if (init.Contains<LocationInit>())
  			{
  				this.__fromCell = this.__toCell = init.Get<LocationInit, CPos>();
  				SetVisualPosition(self, init.world.Map.CenterOfSubCell(fromCell, fromSubCell));
  			}
  
  			this.Facing = init.Contains<FacingInit>() ? init.Get<FacingInit, int>() : info.InitialFacing;
  
  			// Sets the visual position to WPos accuracy
  			// Use LocationInit if you want to insert the actor into the ActorMap!
  			if (init.Contains<CenterPositionInit>())
  				SetVisualPosition(self, init.Get<CenterPositionInit, WPos>());
  		}
  
  		// Returns a valid sub-cell
  		public SubCell GetValidSubCell(SubCell preferred = SubCell.Any)
  		{
  			// Try same sub-cell
  			if (preferred == SubCell.Any)
  				preferred = fromSubCell;
  
  			// Fix sub-cell assignment
  			if (Info.SharesCell)
  			{
  				if (preferred <= SubCell.FullCell)
  					return self.World.Map.DefaultSubCell;
  			}
  			else
  			{
  				if (preferred != SubCell.FullCell)
  					return SubCell.FullCell;
  			}
  			return preferred;
  		}
  
  		public void SetPosition(Actor self, CPos cell, SubCell subCell = SubCell.Any)
  		{
  			subCell = GetValidSubCell(subCell);
  			SetLocation(cell, subCell, cell, subCell);
  			SetVisualPosition(self, self.World.Map.CenterOfSubCell(cell, subCell));
  			FinishedMoving(self);
  		}
  
  		public void SetPosition(Actor self, WPos pos)
  		{
  			var cell = self.World.Map.CellContaining(pos);
  			SetLocation(cell, fromSubCell, cell, fromSubCell);
  			SetVisualPosition(self, pos);
  			FinishedMoving(self);
  		}
  
  		public void SetVisualPosition(Actor self, WPos pos)
  		{
  			CenterPosition = pos;
  			if (self.IsInWorld)
  			{
  				self.World.ScreenMap.Update(self);
  				self.World.ActorMap.UpdatePosition(self, this);
  			}
  		}
  
  		public void AddedToWorld(Actor self)
  		{
  			self.World.ActorMap.AddInfluence(self, this);
  			self.World.ActorMap.AddPosition(self, this);
  			self.World.ScreenMap.Add(self);
  		}
  
  		public void RemovedFromWorld(Actor self)
  		{
  			self.World.ActorMap.RemoveInfluence(self, this);
  			self.World.ActorMap.RemovePosition(self, this);
  			self.World.ScreenMap.Remove(self);
  		}
  
  		public IEnumerable<IOrderTargeter> Orders { get { yield return new MoveOrderTargeter(self, Info); } }
  
  		// Note: Returns a valid order even if the unit can't move to the target
  		public Order IssueOrder(Actor self, IOrderTargeter order, Target target, bool queued)
  		{
  			if (order is MoveOrderTargeter)
  			{
  				if (Info.OnRails)
  					return null;
  
  				return new Order("Move", self, queued) { TargetLocation = self.World.Map.CellContaining(target.CenterPosition) };
  			}
  			return null;
  		}
  
  		public CPos NearestMoveableCell(CPos target)
  		{
  			// Limit search to a radius of 10 tiles
  			return NearestMoveableCell(target, 1, 10);
  		}
  
  		public CPos NearestMoveableCell(CPos target, int minRange, int maxRange)
  		{
  			if (CanEnterCell(target))
  				return target;
  
  			foreach (var tile in self.World.Map.FindTilesInAnnulus(target, minRange, maxRange))
  				if (CanEnterCell(tile))
  					return tile;
  
  			// Couldn't find a cell
  			return target;
  		}
  
  		public CPos NearestCell(CPos target, Func<CPos, bool> check, int minRange, int maxRange)
  		{
  			if (check(target))
  				return target;
  
  			foreach (var tile in self.World.Map.FindTilesInAnnulus(target, minRange, maxRange))
  				if (check(tile))
  					return tile;
  
  			// Couldn't find a cell
  			return target;
  		}
  
  		void PerformMoveInner(Actor self, CPos targetLocation, bool queued)
  		{
  			var currentLocation = NearestMoveableCell(targetLocation);
  
  			if (!CanEnterCell(currentLocation))
  			{
  				if (queued) self.CancelActivity();
  				return;
  			}
  
  			if (!queued) self.CancelActivity();
  
  			ticksBeforePathing = avgTicksBeforePathing + self.World.SharedRandom.Next(-spreadTicksBeforePathing, spreadTicksBeforePathing);
  
  			self.QueueActivity(new Move(self, currentLocation, 8));
  
  			self.SetTargetLine(Target.FromCell(self.World, currentLocation), Color.Green);
  		}
  
  		protected void PerformMove(Actor self, CPos targetLocation, bool queued)
  		{
  			if (queued)
  				self.QueueActivity(new CallFunc(() => PerformMoveInner(self, targetLocation, true)));
  			else
  				PerformMoveInner(self, targetLocation, false);
  		}
  
  		public void ResolveOrder(Actor self, Order order)
  		{
  			if (order.OrderString == "Move")
  			{
  				if (!Info.MoveIntoShroud && !self.Owner.Shroud.IsExplored(order.TargetLocation))
  					return;
  
  				PerformMove(self, self.World.Map.Clamp(order.TargetLocation),
  					order.Queued && !self.IsIdle);
  			}
  
  			if (order.OrderString == "Stop")
  				self.CancelActivity();
  
  			if (order.OrderString == "Scatter")
  				Nudge(self, self, true);
  		}
  
  		public string VoicePhraseForOrder(Actor self, Order order)
  		{
  			switch (order.OrderString)
  			{
  				case "Move":
  				case "Scatter":
  				case "Stop":
  					return "Move";
  				default:
  					return null;
  			}
  		}
  
  		public CPos TopLeft { get { return toCell; } }
  
  		public IEnumerable<Pair<CPos, SubCell>> OccupiedCells()
  		{
  			if (fromCell == toCell)
  				yield return Pair.New(fromCell, fromSubCell);
  			else if (CanEnterCell(toCell))
  				yield return Pair.New(toCell, toSubCell);
  			else
  			{
  				yield return Pair.New(fromCell, fromSubCell);
  				yield return Pair.New(toCell, toSubCell);
  			}
  		}
  
  		public bool IsLeavingCell(CPos location, SubCell subCell = SubCell.Any)
  		{
  			return toCell != location && __fromCell == location
  				&& (subCell == SubCell.Any || fromSubCell == subCell || subCell == SubCell.FullCell || fromSubCell == SubCell.FullCell);
  		}
  
  		public SubCell GetAvailableSubCell(CPos a, SubCell preferredSubCell = SubCell.Any, Actor ignoreActor = null, bool checkTransientActors = true)
  		{
  			return Info.GetAvailableSubCell(self.World, self, a, preferredSubCell, ignoreActor, checkTransientActors? CellConditions.All : CellConditions.None);
  		}
  
  		public bool CanEnterCell(CPos cell, Actor ignoreActor = null, bool checkTransientActors = true)
  		{
  			return Info.CanEnterCell(self.World, self, cell, ignoreActor, checkTransientActors ? CellConditions.All : CellConditions.BlockedByMovers);
  		}
  
  		public void EnteringCell(Actor self)
  		{
  			var crushables = self.World.ActorMap.GetUnitsAt(toCell).Where(a => a != self)
  				.SelectMany(a => a.TraitsImplementing<ICrushable>().Where(b => b.CrushableBy(Info.Crushes, self.Owner)));
  			foreach (var crushable in crushables)
  				crushable.WarnCrush(self);
  		}
  
  		public void FinishedMoving(Actor self)
  		{
  			var crushables = self.World.ActorMap.GetUnitsAt(toCell).Where(a => a != self)
  				.SelectMany(a => a.TraitsImplementing<ICrushable>().Where(c => c.CrushableBy(Info.Crushes, self.Owner)));
  			foreach (var crushable in crushables)
  				crushable.OnCrush(self);
  		}
  
  		public int MovementSpeedForCell(Actor self, CPos cell)
  		{
  			var index = self.World.Map.GetTerrainIndex(cell);
  			if (index == byte.MaxValue)
  				return 0;
  
  			// TODO: Convert to integers
  			var speed = Info.TilesetTerrainInfo[self.World.TileSet][index].Speed;
  			if (speed == decimal.Zero)
  				return 0;
  
  			speed *= Info.Speed;
  			foreach (var t in self.TraitsImplementing<ISpeedModifier>())
  				speed *= t.GetSpeedModifier() / 100m;
  
  			return (int)(speed / 100);
  		}
  
  		public void AddInfluence()
  		{
  			if (self.IsInWorld)
  				self.World.ActorMap.AddInfluence(self, this);
  		}
  
  		public void RemoveInfluence()
  		{
  			if (self.IsInWorld)
  				self.World.ActorMap.RemoveInfluence(self, this);
  		}
  
  		public void Nudge(Actor self, Actor nudger, bool force)
  		{
  			/* initial fairly braindead implementation. */
  			if (!force && self.Owner.Stances[nudger.Owner] != Stance.Ally)
  				return;		/* don't allow ourselves to be pushed around
  							 * by the enemy! */
  
  			if (!force && !self.IsIdle)
  				return;		/* don't nudge if we're busy doing something! */
  
  			// pick an adjacent available cell.
  			var availCells = new List<CPos>();
  			var notStupidCells = new List<CPos>();
  
  			for (var i = -1; i < 2; i++)
  				for (var j = -1; j < 2; j++)
  				{
  					var p = toCell + new CVec(i, j);
  					if (CanEnterCell(p))
  						availCells.Add(p);
  					else
  						if (p != nudger.Location && p != toCell)
  							notStupidCells.Add(p);
  				}
  
  			var moveTo = availCells.Any() ? availCells.Random(self.World.SharedRandom) :
  				notStupidCells.Any() ? notStupidCells.Random(self.World.SharedRandom) : (CPos?)null;
  
  			if (moveTo.HasValue)
  			{
  				self.CancelActivity();
  				self.SetTargetLine(Target.FromCell(self.World, moveTo.Value), Color.Green, false);
  				self.QueueActivity(new Move(self, moveTo.Value, 0));
  
  				Log.Write("debug", "OnNudge #{0} from {1} to {2}",
  					self.ActorID, self.Location, moveTo.Value);
  			}
  			else
  				Log.Write("debug", "OnNudge #{0} refuses at {1}",
  					self.ActorID, self.Location);
  		}
  
  		class MoveOrderTargeter : IOrderTargeter
  		{
  			readonly MobileInfo unitType;
  			readonly bool rejectMove;
  
  			public MoveOrderTargeter(Actor self, MobileInfo unitType)
  			{
  				this.unitType = unitType;
  				this.rejectMove = !self.AcceptsOrder("Move");
  			}
  
  			public string OrderID { get { return "Move"; } }
  			public int OrderPriority { get { return 4; } }
  			public bool IsQueued { get; protected set; }
  
  			public bool CanTarget(Actor self, Target target, List<Actor> othersAtTarget, TargetModifiers modifiers, ref string cursor)
  			{
  				if (rejectMove || !target.IsValidFor(self))
  					return false;
  
  				var location = self.World.Map.CellContaining(target.CenterPosition);
  				IsQueued = modifiers.HasModifier(TargetModifiers.ForceQueue);
  
  				var explored = self.Owner.Shroud.IsExplored(location);
  
gt: 				cursor = self.World.Map.Contains(location) ?