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;
  using System.Collections.Generic;
  using System.Linq;
  using OpenRA.Graphics;
  using OpenRA.Mods.Common.Orders;
  using OpenRA.Mods.RA.Activities;
  using OpenRA.Traits;
  
  namespace OpenRA.Mods.RA.Traits
  {
  	public class MinelayerInfo : ITraitInfo
  	{
  		[ActorReference] public readonly string Mine = "minv";
  		[ActorReference] public readonly HashSet<string> RearmBuildings = new HashSet<string> { "fix" };
  
  		public readonly string AmmoPoolName = "primary";
  
  		public readonly float MinefieldDepth = 1.5f;
  
  		public object Create(ActorInitializer init) { return new Minelayer(init.Self); }
  	}
  
  	public class Minelayer : IIssueOrder, IResolveOrder, IPostRenderSelection, ISync
  	{
  		/* TODO: [Sync] when sync can cope with arrays! */
  		public CPos[] Minefield = null;
  		readonly Actor self;
  		readonly Sprite tile;
  		[Sync] CPos minefieldStart;
  
  		public Minelayer(Actor self)
  		{
  			this.self = self;
  
  			var tileset = self.World.TileSet.Id.ToLowerInvariant();
  			tile = self.World.Map.SequenceProvider.GetSequence("overlay", "build-valid-{0}".F(tileset)).GetSprite(0);
  		}
  
  		public IEnumerable<IOrderTargeter> Orders
  		{
  			get
  			{
  				yield return new BeginMinefieldOrderTargeter();
  				yield return new DeployOrderTargeter("PlaceMine", 5);
  			}
  		}
  
  		public Order IssueOrder(Actor self, IOrderTargeter order, Target target, bool queued)
  		{
  			switch (order.OrderID)
  			{
  				case "BeginMinefield":
  					var start = self.World.Map.CellContaining(target.CenterPosition);
  					self.World.OrderGenerator = new MinefieldOrderGenerator(self, start);
  					return new Order("BeginMinefield", self, false) { TargetLocation = start };
  				case "PlaceMine":
  					return new Order("PlaceMine", self, false) { TargetLocation = self.Location };
  				default:
  					return null;
  			}
  		}
  
  		public void ResolveOrder(Actor self, Order order)
  		{
  			if (order.OrderString == "BeginMinefield")
  				minefieldStart = order.TargetLocation;
  
  			if (order.OrderString == "PlaceMine")
  			{
  				minefieldStart = order.TargetLocation;
  				Minefield = new CPos[] { order.TargetLocation };
  				self.CancelActivity();
  				self.QueueActivity(new LayMines(self));
  			}
  
  			if (order.OrderString == "PlaceMinefield")
  			{
  				var movement = self.Trait<IPositionable>();
  
  				Minefield = GetMinefieldCells(minefieldStart, order.TargetLocation,
  					self.Info.TraitInfo<MinelayerInfo>().MinefieldDepth)
  					.Where(p => movement.CanEnterCell(p, null, false)).ToArray();
  
  				self.CancelActivity();
  				self.QueueActivity(new LayMines(self));
  			}
  		}
  
  		static IEnumerable<CPos> GetMinefieldCells(CPos start, CPos end, float depth)
  		{
  			var mins = CPos.Min(start, end);
  			var maxs = CPos.Max(start, end);
  
  			/* TODO: proper endcaps, if anyone cares (which won't happen unless depth is large) */
  
  			var p = end - start;
  			var q = new float2(p.Y, -p.X);
  			q = (start != end) ? (1 / q.Length) * q : new float2(1, 0);
  			var c = -float2.Dot(q, new float2(start.X, start.Y));
  
  			/* return all points such that |ax + by + c| < depth */
  
  			for (var i = mins.X; i <= maxs.X; i++)
  				for (var j = mins.Y; j <= maxs.Y; j++)
  					if (Math.Abs(q.X * i + q.Y * j + c) < depth)
  						yield return new CPos(i, j);
  		}
  
  		public IEnumerable<IRenderable> RenderAfterWorld(WorldRenderer wr)
  		{
  			if (self.Owner != self.World.LocalPlayer || Minefield == null)
  				yield break;
  
  			var pal = wr.Palette("terrain");
  			foreach (var c in Minefield)
  				yield return new SpriteRenderable(tile, self.World.Map.CenterOfCell(c),
  					WVec.Zero, -511, pal, 1f, true);
  		}
  
  		class MinefieldOrderGenerator : IOrderGenerator
  		{
  			readonly Actor minelayer;
  			readonly CPos minefieldStart;
  			readonly Sprite tileOk;
  			readonly Sprite tileBlocked;
  
  			public MinefieldOrderGenerator(Actor self, CPos xy)
  			{
  				minelayer = self;
  				minefieldStart = xy;
  
  				var tileset = self.World.TileSet.Id.ToLowerInvariant();
  				tileOk = self.World.Map.SequenceProvider.GetSequence("overlay", "build-valid-{0}".F(tileset)).GetSprite(0);
  				tileBlocked = self.World.Map.SequenceProvider.GetSequence("overlay", "build-invalid").GetSprite(0);
  			}
  
  			public IEnumerable<Order> Order(World world, CPos cell, int2 worldPixel, MouseInput mi)
  			{
  				if (mi.Button == Game.Settings.Game.MouseButtonPreference.Cancel)
  				{
  					world.CancelInputMode();
  					yield break;
  				}
  
  				var underCursor = world.ScreenMap.ActorsAt(mi)
  					.Where(a => !world.FogObscures(a))
  					.MaxByOrDefault(a => a.Info.HasTraitInfo<SelectableInfo>()
  						? a.Info.TraitInfo<SelectableInfo>().Priority : int.MinValue);
  
  				if (mi.Button == Game.Settings.Game.MouseButtonPreference.Action && underCursor == null)
  				{
  					minelayer.World.CancelInputMode();
  					yield return new Order("PlaceMinefield", minelayer, false) { TargetLocation = cell };
  				}
  			}
  
  			public void Tick(World world)
  			{
  				if (!minelayer.IsInWorld || minelayer.IsDead)
  					world.CancelInputMode();
  			}
  
  			CPos lastMousePos;
  			public IEnumerable<IRenderable> Render(WorldRenderer wr, World world) { yield break; }
  			public IEnumerable<IRenderable> RenderAfterWorld(WorldRenderer wr, World world)
  			{
  				if (!minelayer.IsInWorld)
  					yield break;
  
  				var movement = minelayer.Trait<IPositionable>();
  				var minefield = GetMinefieldCells(minefieldStart, lastMousePos,
  					minelayer.Info.TraitInfo<MinelayerInfo>().MinefieldDepth);
  
  				var pal = wr.Palette("terrain");
  				foreach (var c in minefield)
  				{
  					var tile = movement.CanEnterCell(c, null, false) ? tileOk : tileBlocked;
  					yield return new SpriteRenderable(tile, world.Map.CenterOfCell(c),
  						WVec.Zero, -511, pal, 1f, true);
  				}
  			}
  
  			public string GetCursor(World world, CPos cell, int2 worldPixel, MouseInput mi)
  			{
  				lastMousePos = cell; return "ability";	/* TODO */
  			}
  		}
  
  		class BeginMinefieldOrderTargeter : IOrderTargeter
  		{
  			public string OrderID { get { return "BeginMinefield"; } }
  			public int OrderPriority { get { return 5; } }
  			public bool OverrideSelection { get { return true; } }
  
  			public bool CanTarget(Actor self, Target target, List<Actor> othersAtTarget, ref TargetModifiers modifiers, ref string cursor)
  			{
  				if (target.Type != TargetType.Terrain)
  					return false;
  
  				var location = self.World.Map.CellContaining(target.CenterPosition);
  				if (!self.World.Map.Contains(location))
  					return false;
  
  				cursor = "ability";
  
gt: 				IsQueued = modifiers.HasModifier(TargetModifiers.ForceQueue);