Index: ps/trunk/binaries/data/mods/public/gui/session/input.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/input.js	(revision 23829)
+++ ps/trunk/binaries/data/mods/public/gui/session/input.js	(revision 23830)
@@ -1,1655 +1,1659 @@
 const SDL_BUTTON_LEFT = 1;
 const SDL_BUTTON_MIDDLE = 2;
 const SDL_BUTTON_RIGHT = 3;
 const SDLK_LEFTBRACKET = 91;
 const SDLK_RIGHTBRACKET = 93;
 const SDLK_RSHIFT = 303;
 const SDLK_LSHIFT = 304;
 const SDLK_RCTRL = 305;
 const SDLK_LCTRL = 306;
 const SDLK_RALT = 307;
 const SDLK_LALT = 308;
 // TODO: these constants should be defined somewhere else instead, in
 // case any other code wants to use them too
 
 const ACTION_NONE = 0;
 const ACTION_GARRISON = 1;
 const ACTION_REPAIR = 2;
 const ACTION_GUARD = 3;
 const ACTION_PATROL = 4;
 var preSelectedAction = ACTION_NONE;
 
 const INPUT_NORMAL = 0;
 const INPUT_SELECTING = 1;
 const INPUT_BANDBOXING = 2;
 const INPUT_BUILDING_PLACEMENT = 3;
 const INPUT_BUILDING_CLICK = 4;
 const INPUT_BUILDING_DRAG = 5;
 const INPUT_BATCHTRAINING = 6;
 const INPUT_PRESELECTEDACTION = 7;
 const INPUT_BUILDING_WALL_CLICK = 8;
 const INPUT_BUILDING_WALL_PATHING = 9;
 const INPUT_UNIT_POSITION_START = 10;
 const INPUT_UNIT_POSITION = 11;
 
 var inputState = INPUT_NORMAL;
 
 const INVALID_ENTITY = 0;
 
 var mouseX = 0;
 var mouseY = 0;
 var mouseIsOverObject = false;
 
 /**
  * Containing the ingame position which span the line.
  */
 var g_FreehandSelection_InputLine = [];
 
 /**
  * Minimum squared distance when a mouse move is called a drag.
  */
 const g_FreehandSelection_ResolutionInputLineSquared = 1;
 
 /**
  * Minimum length a dragged line should have to use the freehand selection.
  */
 const g_FreehandSelection_MinLengthOfLine = 8;
 
 /**
  * To start the freehandSelection function you need a minimum number of units.
  * Minimum must be 2, for better performance you could set it higher.
  */
 const g_FreehandSelection_MinNumberOfUnits = 2;
 
 /**
  * Number of pixels the mouse can move before the action is considered a drag.
  */
 const g_MaxDragDelta = 4;
 
 /**
  * Used for remembering mouse coordinates at start of drag operations.
  */
 var g_DragStart;
 
 /**
  * Store the clicked entity on mousedown or mouseup for single/double/triple clicks to select entities.
  * If any mousedown or mouseup of a sequence of clicks lands on a unit,
  * that unit will be selected, which makes it easier to click on moving units.
  */
 var clickedEntity = INVALID_ENTITY;
 
 // Same double-click behaviour for hotkey presses
 const doublePressTime = 500;
 var doublePressTimer = 0;
 var prevHotkey = 0;
 
 function updateCursorAndTooltip()
 {
 	var cursorSet = false;
 	var tooltipSet = false;
 	var informationTooltip = Engine.GetGUIObjectByName("informationTooltip");
 	if (!mouseIsOverObject && (inputState == INPUT_NORMAL || inputState == INPUT_PRESELECTEDACTION) || g_MiniMapPanel.isMouseOverMiniMap())
 	{
 		let action = determineAction(mouseX, mouseY, g_MiniMapPanel.isMouseOverMiniMap());
 		if (action)
 		{
 			if (action.cursor)
 			{
 				Engine.SetCursor(action.cursor);
 				cursorSet = true;
 			}
 			if (action.tooltip)
 			{
 				tooltipSet = true;
 				informationTooltip.caption = action.tooltip;
 				informationTooltip.hidden = false;
 			}
 		}
 	}
 
 	if (!cursorSet)
 		Engine.ResetCursor();
 
 	if (!tooltipSet)
 		informationTooltip.hidden = true;
 
 	var placementTooltip = Engine.GetGUIObjectByName("placementTooltip");
 	if (placementSupport.tooltipMessage)
 		placementTooltip.sprite = placementSupport.tooltipError ? "BackgroundErrorTooltip" : "BackgroundInformationTooltip";
 
 	placementTooltip.caption = placementSupport.tooltipMessage || "";
 	placementTooltip.hidden = !placementSupport.tooltipMessage;
 }
 
 function updateBuildingPlacementPreview()
 {
 	// The preview should be recomputed every turn, so that it responds to obstructions/fog/etc moving underneath it, or
 	// in the case of the wall previews, in response to new tower foundations getting constructed for it to snap to.
 	// See onSimulationUpdate in session.js.
 
 	if (placementSupport.mode === "building")
 	{
 		if (placementSupport.template && placementSupport.position)
 		{
 			var result = Engine.GuiInterfaceCall("SetBuildingPlacementPreview", {
 				"template": placementSupport.template,
 				"x": placementSupport.position.x,
 				"z": placementSupport.position.z,
 				"angle": placementSupport.angle,
 				"actorSeed": placementSupport.actorSeed
 			});
 
 			// Show placement info tooltip if invalid position
 			placementSupport.tooltipError = !result.success;
 			placementSupport.tooltipMessage = "";
 
 			if (!result.success)
 			{
 				if (result.message && result.parameters)
 				{
 					var message = result.message;
 					if (result.translateMessage)
 						if (result.pluralMessage)
 							message = translatePlural(result.message, result.pluralMessage, result.pluralCount);
 						else
 							message = translate(message);
 					var parameters = result.parameters;
 					if (result.translateParameters)
 						translateObjectKeys(parameters, result.translateParameters);
 					placementSupport.tooltipMessage = sprintf(message, parameters);
 				}
 				return false;
 			}
 
 			if (placementSupport.attack && placementSupport.attack.Ranged)
 			{
 				// Structure can be placed here, and has an attack.
 				// Show the range advantage in the tooltip.
 				var cmd = {
 					"x": placementSupport.position.x,
 					"z": placementSupport.position.z,
 					"range": placementSupport.attack.Ranged.maxRange,
 					"elevationBonus": placementSupport.attack.Ranged.elevationBonus,
 				};
 				var averageRange = Math.round(Engine.GuiInterfaceCall("GetAverageRangeForBuildings", cmd) - cmd.range);
 				var range = Math.round(cmd.range);
 				placementSupport.tooltipMessage = sprintf(translatePlural("Basic range: %(range)s meter", "Basic range: %(range)s meters", range), { "range": range }) + "\n" +
 					sprintf(translatePlural("Average bonus range: %(range)s meter", "Average bonus range: %(range)s meters", averageRange), { "range": averageRange });
 			}
 			return true;
 		}
 	}
 	else if (placementSupport.mode === "wall")
 	{
 		if (placementSupport.wallSet && placementSupport.position)
 		{
 			// Fetch an updated list of snapping candidate entities
 			placementSupport.wallSnapEntities = Engine.PickSimilarPlayerEntities(
 				placementSupport.wallSet.templates.tower,
 				placementSupport.wallSnapEntitiesIncludeOffscreen,
 				true, // require exact template match
 				true  // include foundations
 			);
 
 			return Engine.GuiInterfaceCall("SetWallPlacementPreview", {
 				"wallSet": placementSupport.wallSet,
 				"start": placementSupport.position,
 				"end": placementSupport.wallEndPosition,
 				"snapEntities": placementSupport.wallSnapEntities,	// snapping entities (towers) for starting a wall segment
 			});
 		}
 	}
 
 	return false;
 }
 
 /**
  * Determine the context-sensitive action that should be performed when the mouse is at (x,y)
  */
 function determineAction(x, y, fromMiniMap)
 {
 	let selection = g_Selection.toList();
 	if (!selection.length)
 	{
 		preSelectedAction = ACTION_NONE;
 		return undefined;
 	}
 
 	// If the selection doesn't exist, no action.
 	let entState = GetEntityState(selection[0]);
 	if (!entState)
 		return undefined;
 
 	// If the selection isn't friendly units, no action.
 	if (!selection.every(ownsEntity) &&
 	    !(g_SimState.players[g_ViewedPlayer] &&
 	      g_SimState.players[g_ViewedPlayer].controlsAll))
 		return undefined;
 
 	let target;
 	if (!fromMiniMap)
 	{
 		let ent = Engine.PickEntityAtPoint(x, y);
 		if (ent != INVALID_ENTITY)
 			target = ent;
 	}
 
 	// Decide between the following ordered actions,
 	// if two actions are possible, the first one is taken
 	// thus the most specific should appear first.
 
 	let actionInfo = undefined;
 	if (preSelectedAction != ACTION_NONE)
 	{
 		for (let action of g_UnitActionsSortedKeys)
 			if (g_UnitActions[action].preSelectedActionCheck)
 			{
 				let r = g_UnitActions[action].preSelectedActionCheck(target, selection);
 				if (r)
 					return r;
 			}
 
 		return { "type": "none", "cursor": "", "target": target };
 	}
 
 	for (let action of g_UnitActionsSortedKeys)
 		if (g_UnitActions[action].hotkeyActionCheck)
 		{
 			let r = g_UnitActions[action].hotkeyActionCheck(target, selection);
 			if (r)
 				return r;
 		}
 
 	for (let action of g_UnitActionsSortedKeys)
 		if (g_UnitActions[action].actionCheck)
 		{
 			let r = g_UnitActions[action].actionCheck(target, selection);
 			if (r)
 				return r;
 		}
 
 	return { "type": "none", "cursor": "", "target": target };
 }
 
 function ownsEntity(ent)
 {
 	let entState = GetEntityState(ent);
 	return entState && entState.player == g_ViewedPlayer;
 }
 
 function isSnapToEdgesEnabled()
 {
 	let config = Engine.ConfigDB_GetValue("user", "gui.session.snaptoedges");
 	let hotkeyPressed = Engine.HotkeyIsPressed("session.snaptoedges");
 	return hotkeyPressed == (config == "disabled");
 }
 
 function tryPlaceBuilding(queued)
 {
 	if (placementSupport.mode !== "building")
 	{
 		error("tryPlaceBuilding expected 'building', got '" + placementSupport.mode + "'");
 		return false;
 	}
 
 	if (!updateBuildingPlacementPreview())
 	{
 		// invalid location - don't build it
 		// TODO: play a sound?
 		return false;
 	}
 
-	var selection = g_Selection.toList();
+	let selection = Engine.HotkeyIsPressed("session.orderone") &&
+		popOneFromSelection({ "type": "construct", "target": placementSupport }) || g_Selection.toList();
 
 	Engine.PostNetworkCommand({
 		"type": "construct",
 		"template": placementSupport.template,
 		"x": placementSupport.position.x,
 		"z": placementSupport.position.z,
 		"angle": placementSupport.angle,
 		"actorSeed": placementSupport.actorSeed,
 		"entities": selection,
 		"autorepair": true,
 		"autocontinue": true,
 		"queued": queued
 	});
 	Engine.GuiInterfaceCall("PlaySound", { "name": "order_build", "entity": selection[0] });
 
-	if (!queued)
+	if (!queued || !g_Selection.toList().length)
 		placementSupport.Reset();
 	else
 		placementSupport.RandomizeActorSeed();
 
 	return true;
 }
 
 function tryPlaceWall(queued)
 {
 	if (placementSupport.mode !== "wall")
 	{
 		error("tryPlaceWall expected 'wall', got '" + placementSupport.mode + "'");
 		return false;
 	}
 
-	var wallPlacementInfo = updateBuildingPlacementPreview(); // entities making up the wall (wall segments, towers, ...)
-	if (!(wallPlacementInfo === false || typeof(wallPlacementInfo) === "object"))
+	let wallPlacementInfo = updateBuildingPlacementPreview(); // entities making up the wall (wall segments, towers, ...)
+	if (!(wallPlacementInfo === false || typeof wallPlacementInfo === "object"))
 	{
 		error("Invalid updateBuildingPlacementPreview return value: " + uneval(wallPlacementInfo));
 		return false;
 	}
 
 	if (!wallPlacementInfo)
 		return false;
 
-	var selection = g_Selection.toList();
-	var cmd = {
+	let selection = Engine.HotkeyIsPressed("session.orderone") &&
+		popOneFromSelection({ "type": "construct", "target": placementSupport }) || g_Selection.toList();
+
+	let cmd = {
 		"type": "construct-wall",
 		"autorepair": true,
 		"autocontinue": true,
 		"queued": queued,
 		"entities": selection,
 		"wallSet": placementSupport.wallSet,
 		"pieces": wallPlacementInfo.pieces,
 		"startSnappedEntity": wallPlacementInfo.startSnappedEnt,
 		"endSnappedEntity": wallPlacementInfo.endSnappedEnt,
 	};
 
 	// make sure that there's at least one non-tower entity getting built, to prevent silly edge cases where the start and end
 	// point are too close together for the algorithm to place a wall segment inbetween, and only the towers are being previewed
 	// (this is somewhat non-ideal and hardcode-ish)
-	var hasWallSegment = false;
+	let hasWallSegment = false;
 	for (let piece of cmd.pieces)
 	{
 		if (piece.template != cmd.wallSet.templates.tower) // TODO: hardcode-ish :(
 		{
 			hasWallSegment = true;
 			break;
 		}
 	}
 
 	if (hasWallSegment)
 	{
 		Engine.PostNetworkCommand(cmd);
 		Engine.GuiInterfaceCall("PlaySound", { "name": "order_build", "entity": selection[0] });
 	}
 
 	return true;
 }
 
 /**
  * Updates the bandbox object with new positions and visibility.
  * @returns {array} The coordinates of the vertices of the bandbox.
  */
 function updateBandbox(bandbox, ev, hidden)
 {
 	let scale = +Engine.ConfigDB_GetValue("user", "gui.scale");
 	let vMin = Vector2D.min(g_DragStart, ev);
 	let vMax = Vector2D.max(g_DragStart, ev);
 
 	bandbox.size = new GUISize(vMin.x / scale, vMin.y / scale, vMax.x / scale, vMax.y / scale);
 	bandbox.hidden = hidden;
 
 	return [vMin.x, vMin.y, vMax.x, vMax.y];
 }
 
 // Define some useful unit filters for getPreferredEntities
 var unitFilters = {
 	"isUnit": entity => {
 		var entState = GetEntityState(entity);
 		return entState && hasClass(entState, "Unit");
 	},
 	"isDefensive": entity => {
 		var entState = GetEntityState(entity);
 		return entState && hasClass(entState, "Defensive");
 	},
 	"isMilitary": entity => {
 		var entState = GetEntityState(entity);
 		return entState &&
 			g_MilitaryTypes.some(c => hasClass(entState, c));
 	},
 	"isNonMilitary": entity => {
 		var entState = GetEntityState(entity);
 		return entState &&
 			hasClass(entState, "Unit") &&
 			!g_MilitaryTypes.some(c => hasClass(entState, c));
 	},
 	"isIdle": entity => {
 		var entState = GetEntityState(entity);
 
 		return entState &&
 			hasClass(entState, "Unit") &&
 			entState.unitAI &&
 			entState.unitAI.isIdle &&
 			!hasClass(entState, "Domestic");
 	},
 	"isWounded": entity => {
 		let entState = GetEntityState(entity);
 		return entState &&
 			hasClass(entState, "Unit") &&
 			entState.maxHitpoints &&
 			100 * entState.hitpoints <= entState.maxHitpoints * Engine.ConfigDB_GetValue("user", "gui.session.woundedunithotkeythreshold");
 	},
 	"isAnything": entity => {
 		return true;
 	}
 };
 
 // Choose, inside a list of entities, which ones will be selected.
 // We may use several entity filters, until one returns at least one element.
 function getPreferredEntities(ents)
 {
 	// Default filters
 	var filters = [unitFilters.isUnit, unitFilters.isDefensive, unitFilters.isAnything];
 
 	// Handle hotkeys
 	if (Engine.HotkeyIsPressed("selection.militaryonly"))
 		filters = [unitFilters.isMilitary];
 	if (Engine.HotkeyIsPressed("selection.nonmilitaryonly"))
 		filters = [unitFilters.isNonMilitary];
 	if (Engine.HotkeyIsPressed("selection.idleonly"))
 		filters = [unitFilters.isIdle];
 	if (Engine.HotkeyIsPressed("selection.woundedonly"))
 		filters = [unitFilters.isWounded];
 
 	var preferredEnts = [];
 	for (var i = 0; i < filters.length; ++i)
 	{
 		preferredEnts = ents.filter(filters[i]);
 		if (preferredEnts.length)
 			break;
 	}
 	return preferredEnts;
 }
 
 function handleInputBeforeGui(ev, hoveredObject)
 {
 	if (GetSimState().cinemaPlaying)
 		return false;
 
 	// Capture mouse position so we can use it for displaying cursors,
 	// and key states
 	switch (ev.type)
 	{
 	case "mousebuttonup":
 	case "mousebuttondown":
 	case "mousemotion":
 		mouseX = ev.x;
 		mouseY = ev.y;
 		break;
 	}
 
 	// Remember whether the mouse is over a GUI object or not
 	mouseIsOverObject = (hoveredObject != null);
 
 	// Close the menu when interacting with the game world
 	if (!mouseIsOverObject && (ev.type =="mousebuttonup" || ev.type == "mousebuttondown")
 		&& (ev.button == SDL_BUTTON_LEFT || ev.button == SDL_BUTTON_RIGHT))
 		g_Menu.close();
 
 	// State-machine processing:
 	//
 	// (This is for states which should override the normal GUI processing - events will
 	// be processed here before being passed on, and propagation will stop if this function
 	// returns true)
 	//
 	// TODO: it'd probably be nice to have a better state-machine system, with guaranteed
 	// entry/exit functions, since this is a bit broken now
 
 	switch (inputState)
 	{
 	case INPUT_BANDBOXING:
 		var bandbox = Engine.GetGUIObjectByName("bandbox");
 		switch (ev.type)
 		{
 		case "mousemotion":
 			var rect = updateBandbox(bandbox, ev, false);
 
 			var ents = Engine.PickPlayerEntitiesInRect(rect[0], rect[1], rect[2], rect[3], g_ViewedPlayer);
 			var preferredEntities = getPreferredEntities(ents);
 			g_Selection.setHighlightList(preferredEntities);
 
 			return false;
 
 		case "mousebuttonup":
 			if (ev.button == SDL_BUTTON_LEFT)
 			{
 				var rect = updateBandbox(bandbox, ev, true);
 
 				// Get list of entities limited to preferred entities
 				var ents = getPreferredEntities(Engine.PickPlayerEntitiesInRect(rect[0], rect[1], rect[2], rect[3], g_ViewedPlayer));
 
 				// Remove the bandbox hover highlighting
 				g_Selection.setHighlightList([]);
 
 				// Update the list of selected units
 				if (Engine.HotkeyIsPressed("selection.add"))
 				{
 					g_Selection.addList(ents);
 				}
 				else if (Engine.HotkeyIsPressed("selection.remove"))
 				{
 					g_Selection.removeList(ents);
 				}
 				else
 				{
 					g_Selection.reset();
 					g_Selection.addList(ents);
 				}
 
 				inputState = INPUT_NORMAL;
 				return true;
 			}
 			else if (ev.button == SDL_BUTTON_RIGHT)
 			{
 				// Cancel selection
 				bandbox.hidden = true;
 
 				g_Selection.setHighlightList([]);
 
 				inputState = INPUT_NORMAL;
 				return true;
 			}
 			break;
 		}
 		break;
 
 	case INPUT_UNIT_POSITION:
 		switch (ev.type)
 		{
 		case "mousemotion":
 			return positionUnitsFreehandSelectionMouseMove(ev);
 		case "mousebuttonup":
 			return positionUnitsFreehandSelectionMouseUp(ev);
 		}
 		break;
 
 	case INPUT_BUILDING_CLICK:
 		switch (ev.type)
 		{
 		case "mousemotion":
 			// If the mouse moved far enough from the original click location,
 			// then switch to drag-orientation mode
 			let maxDragDelta = 16;
 			if (g_DragStart.distanceTo(ev) >= maxDragDelta)
 			{
 				inputState = INPUT_BUILDING_DRAG;
 				return false;
 			}
 			break;
 
 		case "mousebuttonup":
 			if (ev.button == SDL_BUTTON_LEFT)
 			{
 				// If shift is down, let the player continue placing another of the same building
 				var queued = Engine.HotkeyIsPressed("session.queue");
 				if (tryPlaceBuilding(queued))
 				{
-					if (queued)
+					if (queued && g_Selection.toList().length)
 						inputState = INPUT_BUILDING_PLACEMENT;
 					else
 						inputState = INPUT_NORMAL;
 				}
 				else
 				{
 					inputState = INPUT_BUILDING_PLACEMENT;
 				}
 				return true;
 			}
 			break;
 
 		case "mousebuttondown":
 			if (ev.button == SDL_BUTTON_RIGHT)
 			{
 				// Cancel building
 				placementSupport.Reset();
 				inputState = INPUT_NORMAL;
 				return true;
 			}
 			break;
 		}
 		break;
 
 	case INPUT_BUILDING_WALL_CLICK:
 		// User is mid-click in choosing a starting point for building a wall. The build process can still be cancelled at this point
 		// by right-clicking; releasing the left mouse button will 'register' the starting point and commence endpoint choosing mode.
 		switch (ev.type)
 		{
 		case "mousebuttonup":
 			if (ev.button === SDL_BUTTON_LEFT)
 			{
 				inputState = INPUT_BUILDING_WALL_PATHING;
 				return true;
 			}
 			break;
 
 		case "mousebuttondown":
 			if (ev.button == SDL_BUTTON_RIGHT)
 			{
 				// Cancel building
 				placementSupport.Reset();
 				updateBuildingPlacementPreview();
 
 				inputState = INPUT_NORMAL;
 				return true;
 			}
 			break;
 		}
 		break;
 
 	case INPUT_BUILDING_WALL_PATHING:
 		// User has chosen a starting point for constructing the wall, and is now looking to set the endpoint.
 		// Right-clicking cancels wall building mode, left-clicking sets the endpoint and builds the wall and returns to
 		// normal input mode. Optionally, shift + left-clicking does not return to normal input, and instead allows the
 		// user to continue building walls.
 		switch (ev.type)
 		{
 			case "mousemotion":
 				placementSupport.wallEndPosition = Engine.GetTerrainAtScreenPoint(ev.x, ev.y);
 
 				// Update the structure placement preview, and by extension, the list of snapping candidate entities for both (!)
 				// the ending point and the starting point to snap to.
 				//
 				// TODO: Note that here, we need to fetch all similar entities, including any offscreen ones, to support the case
 				// where the snap entity for the starting point has moved offscreen, or has been deleted/destroyed, or was a
 				// foundation and has been replaced with a completed entity since the user first chose it. Fetching all towers on
 				// the entire map instead of only the current screen might get expensive fast since walls all have a ton of towers
 				// in them. Might be useful to query only for entities within a certain range around the starting point and ending
 				// points.
 
 				placementSupport.wallSnapEntitiesIncludeOffscreen = true;
 				var result = updateBuildingPlacementPreview(); // includes an update of the snap entity candidates
 
 				if (result && result.cost)
 				{
 					var neededResources = Engine.GuiInterfaceCall("GetNeededResources", { "cost": result.cost });
 					placementSupport.tooltipMessage = [
 						getEntityCostTooltip(result),
 						getNeededResourcesTooltip(neededResources)
 					].filter(tip => tip).join("\n");
 				}
 
 				break;
 
 			case "mousebuttondown":
 				if (ev.button == SDL_BUTTON_LEFT)
 				{
 					var queued = Engine.HotkeyIsPressed("session.queue");
 					if (tryPlaceWall(queued))
 					{
 						if (queued)
 						{
 							// continue building, just set a new starting position where we left off
 							placementSupport.position = placementSupport.wallEndPosition;
 							placementSupport.wallEndPosition = undefined;
 
 							inputState = INPUT_BUILDING_WALL_CLICK;
 						}
 						else
 						{
 							placementSupport.Reset();
 							inputState = INPUT_NORMAL;
 						}
 					}
 					else
 						placementSupport.tooltipMessage = translate("Cannot build wall here!");
 
 					updateBuildingPlacementPreview();
 					return true;
 				}
 				else if (ev.button == SDL_BUTTON_RIGHT)
 				{
 					// reset to normal input mode
 					placementSupport.Reset();
 					updateBuildingPlacementPreview();
 
 					inputState = INPUT_NORMAL;
 					return true;
 				}
 				break;
 		}
 		break;
 
 	case INPUT_BUILDING_DRAG:
 		switch (ev.type)
 		{
 		case "mousemotion":
 			let maxDragDelta = 16;
 			if (g_DragStart.distanceTo(ev) >= maxDragDelta)
 			{
 				// Rotate in the direction of the mouse
 				placementSupport.angle = placementSupport.position.horizAngleTo(Engine.GetTerrainAtScreenPoint(ev.x, ev.y));
 			}
 			else
 			{
 				// If the mouse is near the center, snap back to the default orientation
 				placementSupport.SetDefaultAngle();
 			}
 
 			let snapData = Engine.GuiInterfaceCall("GetFoundationSnapData", {
  				"template": placementSupport.template,
  				"x": placementSupport.position.x,
 				"z": placementSupport.position.z,
 				"angle": placementSupport.angle,
 				"snapToEdges": isSnapToEdgesEnabled() && Engine.GetEdgesOfStaticObstructionsOnScreenNearTo(
 					placementSupport.position.x, placementSupport.position.z)
  			});
 			if (snapData)
 			{
 				placementSupport.angle = snapData.angle;
 				placementSupport.position.x = snapData.x;
 				placementSupport.position.z = snapData.z;
 			}
 
 			updateBuildingPlacementPreview();
 			break;
 
 		case "mousebuttonup":
 			if (ev.button == SDL_BUTTON_LEFT)
 			{
 				// If shift is down, let the player continue placing another of the same structure.
 				var queued = Engine.HotkeyIsPressed("session.queue");
 				if (tryPlaceBuilding(queued))
 				{
-					if (queued)
+					if (queued && g_Selection.toList().length)
 						inputState = INPUT_BUILDING_PLACEMENT;
 					else
 						inputState = INPUT_NORMAL;
 				}
 				else
 				{
 					inputState = INPUT_BUILDING_PLACEMENT;
 				}
 				return true;
 			}
 			break;
 
 		case "mousebuttondown":
 			if (ev.button == SDL_BUTTON_RIGHT)
 			{
 				// Cancel building
 				placementSupport.Reset();
 				inputState = INPUT_NORMAL;
 				return true;
 			}
 			break;
 		}
 		break;
 
 	case INPUT_BATCHTRAINING:
 		if (ev.type == "hotkeyup" && ev.hotkey == "session.batchtrain")
 		{
 			flushTrainingBatch();
 			inputState = INPUT_NORMAL;
 		}
 		break;
 	}
 
 	return false;
 }
 
 function handleInputAfterGui(ev)
 {
 	if (GetSimState().cinemaPlaying)
 		return false;
 
 	if (ev.hotkey === undefined)
 		ev.hotkey = null;
 
 	if (ev.hotkey == "session.highlightguarding")
 	{
 		g_ShowGuarding = (ev.type == "hotkeydown");
 		updateAdditionalHighlight();
 	}
 	else if (ev.hotkey == "session.highlightguarded")
 	{
 		g_ShowGuarded = (ev.type == "hotkeydown");
 		updateAdditionalHighlight();
 	}
 
 	if (inputState != INPUT_NORMAL && inputState != INPUT_SELECTING)
 		clickedEntity = INVALID_ENTITY;
 
 	// State-machine processing:
 
 	switch (inputState)
 	{
 	case INPUT_NORMAL:
 		switch (ev.type)
 		{
 		case "mousemotion":
 			// Highlight the first hovered entity (if any)
 			var ent = Engine.PickEntityAtPoint(ev.x, ev.y);
 			if (ent != INVALID_ENTITY)
 				g_Selection.setHighlightList([ent]);
 			else
 				g_Selection.setHighlightList([]);
 
 			return false;
 
 		case "mousebuttondown":
 			if (ev.button == SDL_BUTTON_LEFT)
 			{
 				g_DragStart = new Vector2D(ev.x, ev.y);
 				inputState = INPUT_SELECTING;
 				// If a single click occured, reset the clickedEntity.
 				// Also set it if we're double/triple clicking and missed the unit earlier.
 				if (ev.clicks == 1 || clickedEntity == INVALID_ENTITY)
 					clickedEntity = Engine.PickEntityAtPoint(ev.x, ev.y);
 				return true;
 			}
 			else if (ev.button == SDL_BUTTON_RIGHT)
 			{
 				if (!controlsPlayer(g_ViewedPlayer))
 					break;
 				g_DragStart = new Vector2D(ev.x, ev.y);
 				inputState = INPUT_UNIT_POSITION_START;
 			}
 			break;
 
 		case "hotkeydown":
 				if (ev.hotkey.indexOf("selection.group.") == 0)
 				{
 					let now = Date.now();
 					if (now - doublePressTimer < doublePressTime && ev.hotkey == prevHotkey)
 					{
 						if (ev.hotkey.indexOf("selection.group.select.") == 0)
 						{
 							var sptr = ev.hotkey.split(".");
 							performGroup("snap", sptr[3]);
 						}
 					}
 					else
 					{
 						var sptr = ev.hotkey.split(".");
 						performGroup(sptr[2], sptr[3]);
 
 						doublePressTimer = now;
 						prevHotkey = ev.hotkey;
 					}
 				}
 				break;
 		}
 		break;
 
 	case INPUT_PRESELECTEDACTION:
 		switch (ev.type)
 		{
 		case "mousemotion":
 			// Highlight the first hovered entity (if any)
 			var ent = Engine.PickEntityAtPoint(ev.x, ev.y);
 			if (ent != INVALID_ENTITY)
 				g_Selection.setHighlightList([ent]);
 			else
 				g_Selection.setHighlightList([]);
 
 			return false;
 
 		case "mousebuttondown":
 			if (ev.button == SDL_BUTTON_LEFT && preSelectedAction != ACTION_NONE)
 			{
 				var action = determineAction(ev.x, ev.y);
 				if (!action)
 					break;
 				if (!Engine.HotkeyIsPressed("session.queue") && !Engine.HotkeyIsPressed("session.orderone"))
 				{
 					preSelectedAction = ACTION_NONE;
 					inputState = INPUT_NORMAL;
 				}
 				return doAction(action, ev);
 			}
 			else if (ev.button == SDL_BUTTON_RIGHT && preSelectedAction != ACTION_NONE)
 			{
 				preSelectedAction = ACTION_NONE;
 				inputState = INPUT_NORMAL;
 				break;
 			}
 			// else
 		default:
 			// Slight hack: If selection is empty, reset the input state
 			if (g_Selection.toList().length == 0)
 			{
 				preSelectedAction = ACTION_NONE;
 				inputState = INPUT_NORMAL;
 				break;
 			}
 		}
 		break;
 
 	case INPUT_SELECTING:
 		switch (ev.type)
 		{
 		case "mousemotion":
 			// If the mouse moved further than a limit, switch to bandbox mode
 			if (g_DragStart.distanceTo(ev) >= g_MaxDragDelta)
 			{
 				inputState = INPUT_BANDBOXING;
 				return false;
 			}
 
 			var ent = Engine.PickEntityAtPoint(ev.x, ev.y);
 			if (ent != INVALID_ENTITY)
 				g_Selection.setHighlightList([ent]);
 			else
 				g_Selection.setHighlightList([]);
 			return false;
 
 		case "mousebuttonup":
 			if (ev.button == SDL_BUTTON_LEFT)
 			{
 				if (clickedEntity == INVALID_ENTITY)
 					clickedEntity = Engine.PickEntityAtPoint(ev.x, ev.y);
 				// Abort if we didn't click on an entity or if the entity was removed before the mousebuttonup event.
 				if (clickedEntity == INVALID_ENTITY || !GetEntityState(clickedEntity))
 				{
 					clickedEntity = INVALID_ENTITY;
 					if (!Engine.HotkeyIsPressed("selection.add") && !Engine.HotkeyIsPressed("selection.remove"))
 					{
 						g_Selection.reset();
 						resetIdleUnit();
 					}
 					inputState = INPUT_NORMAL;
 					return true;
 				}
 
 				// If camera following and we select different unit, stop
 				if (Engine.GetFollowedEntity() != clickedEntity)
 					Engine.CameraFollow(0);
 
 				var ents = [];
 				if (ev.clicks == 1)
 					ents = [clickedEntity];
 				else
 				{
 					// Double click or triple click has occurred
 					var showOffscreen = Engine.HotkeyIsPressed("selection.offscreen");
 					var matchRank = true;
 					var templateToMatch;
 
 					// Check for double click or triple click
 					if (ev.clicks == 2)
 					{
 						// Select similar units regardless of rank
 						templateToMatch = GetEntityState(clickedEntity).identity.selectionGroupName;
 						if (templateToMatch)
 							matchRank = false;
 						else
 							// No selection group name defined, so fall back to exact match
 							templateToMatch = GetEntityState(clickedEntity).template;
 
 					}
 					else
 						// Triple click
 						// Select units matching exact template name (same rank)
 						templateToMatch = GetEntityState(clickedEntity).template;
 
 					// TODO: Should we handle "control all units" here as well?
 					ents = Engine.PickSimilarPlayerEntities(templateToMatch, showOffscreen, matchRank, false);
 				}
 
 				// Update the list of selected units
 				if (Engine.HotkeyIsPressed("selection.add"))
 					g_Selection.addList(ents);
 				else if (Engine.HotkeyIsPressed("selection.remove"))
 					g_Selection.removeList(ents);
 				else
 				{
 					g_Selection.reset();
 					g_Selection.addList(ents);
 				}
 
 				inputState = INPUT_NORMAL;
 				return true;
 			}
 			break;
 		}
 		break;
 
 	case INPUT_UNIT_POSITION_START:
 		switch (ev.type)
 		{
 		case "mousemotion":
 			// If the mouse moved further than a limit, switch to unit position mode
 			if (g_DragStart.distanceToSquared(ev) >= Math.square(g_MaxDragDelta))
 			{
 				inputState = INPUT_UNIT_POSITION;
 				return false;
 			}
 			break;
 		case "mousebuttonup":
 			inputState = INPUT_NORMAL;
 			if (ev.button == SDL_BUTTON_RIGHT)
 			{
 				let action = determineAction(ev.x, ev.y);
 				if (action)
 					return doAction(action, ev);
 			}
 			break;
 		}
 		break;
 
 	case INPUT_BUILDING_PLACEMENT:
 		switch (ev.type)
 		{
 		case "mousemotion":
 
 			placementSupport.position = Engine.GetTerrainAtScreenPoint(ev.x, ev.y);
 
 			if (placementSupport.mode === "wall")
 			{
 				// Including only the on-screen towers in the next snap candidate list is sufficient here, since the user is
 				// still selecting a starting point (which must necessarily be on-screen). (The update of the snap entities
 				// itself happens in the call to updateBuildingPlacementPreview below).
 				placementSupport.wallSnapEntitiesIncludeOffscreen = false;
 			}
 			else
 			{
 				// cancel if not enough resources
 				if (placementSupport.template && Engine.GuiInterfaceCall("GetNeededResources", { "cost": GetTemplateData(placementSupport.template).cost }))
 				{
 					placementSupport.Reset();
 					inputState = INPUT_NORMAL;
 					return true;
 				}
 
 				let snapData = Engine.GuiInterfaceCall("GetFoundationSnapData", {
  					"template": placementSupport.template,
  					"x": placementSupport.position.x,
  					"z": placementSupport.position.z,
 					"snapToEdges": isSnapToEdgesEnabled() && Engine.GetEdgesOfStaticObstructionsOnScreenNearTo(
 						placementSupport.position.x, placementSupport.position.z)
  				});
 				if (snapData)
 				{
 					placementSupport.angle = snapData.angle;
 					placementSupport.position.x = snapData.x;
 					placementSupport.position.z = snapData.z;
 				}
 			}
 
 			updateBuildingPlacementPreview(); // includes an update of the snap entity candidates
 			return false; // continue processing mouse motion
 
 		case "mousebuttondown":
 			if (ev.button == SDL_BUTTON_LEFT)
 			{
 				if (placementSupport.mode === "wall")
 				{
 					var validPlacement = updateBuildingPlacementPreview();
 					if (validPlacement !== false)
 						inputState = INPUT_BUILDING_WALL_CLICK;
 				}
 				else
 				{
 					placementSupport.position = Engine.GetTerrainAtScreenPoint(ev.x, ev.y);
 
 					if (isSnapToEdgesEnabled())
 					{
 						let snapData = Engine.GuiInterfaceCall("GetFoundationSnapData", {
 							"template": placementSupport.template,
 							"x": placementSupport.position.x,
 							"z": placementSupport.position.z,
 							"snapToEdges": Engine.GetEdgesOfStaticObstructionsOnScreenNearTo(
 								placementSupport.position.x, placementSupport.position.z)
 						});
 						if (snapData)
 						{
 							placementSupport.angle = snapData.angle;
 							placementSupport.position.x = snapData.x;
 							placementSupport.position.z = snapData.z;
 						}
 					}
 
 					g_DragStart = new Vector2D(ev.x, ev.y);
 					inputState = INPUT_BUILDING_CLICK;
 				}
 				return true;
 			}
 			else if (ev.button == SDL_BUTTON_RIGHT)
 			{
 				// Cancel building
 				placementSupport.Reset();
 				inputState = INPUT_NORMAL;
 				return true;
 			}
 			break;
 
 		case "hotkeydown":
 
 			var rotation_step = Math.PI / 12; // 24 clicks make a full rotation
 
 			switch (ev.hotkey)
 			{
 			case "session.rotate.cw":
 				placementSupport.angle += rotation_step;
 				updateBuildingPlacementPreview();
 				break;
 			case "session.rotate.ccw":
 				placementSupport.angle -= rotation_step;
 				updateBuildingPlacementPreview();
 				break;
 			}
 			break;
 
 		}
 		break;
 	}
 	return false;
 }
 
 function doAction(action, ev)
 {
 	if (!controlsPlayer(g_ViewedPlayer))
 		return false;
 
 	return handleUnitAction(Engine.GetTerrainAtScreenPoint(ev.x, ev.y), action);
 }
 
+function popOneFromSelection(action)
+{
+	// Pick the first unit that can do this order.
+	let unit = g_Selection.find(entity =>
+		["preSelectedActionCheck", "hotkeyActionCheck", "actionCheck"].some(method =>
+			g_UnitActions[action.type][method] &&
+			g_UnitActions[action.type][method](action.target || undefined, [entity])
+		));
+	if (unit)
+	{
+		g_Selection.removeList([unit]);
+		return [unit];
+	}
+	return null;
+}
 
 function positionUnitsFreehandSelectionMouseMove(ev)
 {
 	// Converting the input line into a List of points.
 	// For better performance the points must have a minimum distance to each other.
 	let target = Vector2D.from3D(Engine.GetTerrainAtScreenPoint(ev.x, ev.y));
 	if (!g_FreehandSelection_InputLine.length ||
 	    target.distanceToSquared(g_FreehandSelection_InputLine[g_FreehandSelection_InputLine.length - 1]) >=
 	    g_FreehandSelection_ResolutionInputLineSquared)
 		g_FreehandSelection_InputLine.push(target);
 	return false;
 }
 
 function positionUnitsFreehandSelectionMouseUp(ev)
 {
 	inputState = INPUT_NORMAL;
 	let inputLine = g_FreehandSelection_InputLine;
 	g_FreehandSelection_InputLine = [];
 	if (ev.button != SDL_BUTTON_RIGHT)
 		return true;
 
 	let lengthOfLine = 0;
 	for (let i = 1; i < inputLine.length; ++i)
 		lengthOfLine += inputLine[i].distanceTo(inputLine[i - 1]);
 
 	let selection = g_Selection.toList().filter(ent => !!GetEntityState(ent).unitAI).sort((a, b) => a - b);
 
 	// Checking the line for a minimum length to save performance.
 	if (lengthOfLine < g_FreehandSelection_MinLengthOfLine || selection.length < g_FreehandSelection_MinNumberOfUnits)
 	{
 		let action = determineAction(ev.x, ev.y);
 		return !!action && doAction(action, ev);
 	}
 
 	// Even distribution of the units on the line.
 	let p0 = inputLine[0];
 	let entityDistribution = [p0];
 	let distanceBetweenEnts = lengthOfLine / (selection.length - 1);
 	let freeDist = -distanceBetweenEnts;
 
 	for (let i = 1; i < inputLine.length; ++i)
 	{
 		let p1 = inputLine[i];
 		freeDist += inputLine[i - 1].distanceTo(p1);
 
 		while (freeDist >= 0)
 		{
 			p0 = Vector2D.sub(p0, p1).normalize().mult(freeDist).add(p1);
 			entityDistribution.push(p0);
 			freeDist -= distanceBetweenEnts;
 		}
 	}
 
 	// Rounding errors can lead to missing or too many points.
 	entityDistribution = entityDistribution.slice(0, selection.length);
 	entityDistribution = entityDistribution.concat(new Array(selection.length - entityDistribution.length).fill(inputLine[inputLine.length - 1]));
 
 	if (Vector2D.from3D(GetEntityState(selection[0]).position).distanceTo(entityDistribution[0]) +
 	    Vector2D.from3D(GetEntityState(selection[selection.length - 1]).position).distanceTo(entityDistribution[selection.length - 1]) >
 	    Vector2D.from3D(GetEntityState(selection[0]).position).distanceTo(entityDistribution[selection.length - 1]) +
 	    Vector2D.from3D(GetEntityState(selection[selection.length - 1]).position).distanceTo(entityDistribution[0]))
 		entityDistribution.reverse();
 
 	Engine.PostNetworkCommand({
 		"type": Engine.HotkeyIsPressed("session.attackmove") ? "attack-walk-custom" : "walk-custom",
 		"entities": selection,
 		"targetPositions": entityDistribution.map(pos => pos.toFixed(2)),
 		"targetClasses": Engine.HotkeyIsPressed("session.attackmoveUnit") ? { "attack": ["Unit"] } : { "attack": ["Unit", "Structure"] },
 		"queued": Engine.HotkeyIsPressed("session.queue")
 	});
 
 	// Add target markers with a minimum distance of 5 to each other.
 	let entitiesBetweenMarker = Math.ceil(5 / distanceBetweenEnts);
 	for (let i = 0; i < entityDistribution.length; i += entitiesBetweenMarker)
 		DrawTargetMarker({ "x": entityDistribution[i].x, "z": entityDistribution[i].y });
 
 	Engine.GuiInterfaceCall("PlaySound", {
 		"name": "order_walk",
 		"entity": selection[0]
 	});
 
 	return true;
 }
 
 function handleUnitAction(target, action)
 {
 	if (!g_UnitActions[action.type] || !g_UnitActions[action.type].execute)
 	{
 		error("Invalid action.type " + action.type);
 		return false;
 	}
 
-	let selection = g_Selection.toList();
-	if (Engine.HotkeyIsPressed("session.orderone"))
-	{
-		// Pick the first unit that can do this order.
-		let unit = selection.find(entity =>
-			["preSelectedActionCheck", "hotkeyActionCheck", "actionCheck"].some(method =>
-				g_UnitActions[action.type][method] &&
-				g_UnitActions[action.type][method](action.target || undefined, [entity])
-			));
-		if (unit)
-		{
-			selection = [unit];
-			g_Selection.removeList(selection);
-		}
-	}
-
+	let selection = Engine.HotkeyIsPressed("session.orderone") &&
+		popOneFromSelection(action) || g_Selection.toList();
 	// If the session.queue hotkey is down, add the order to the unit's order queue instead
 	// of running it immediately
 	return g_UnitActions[action.type].execute(target, action, selection, Engine.HotkeyIsPressed("session.queue"));
 }
 
 function getEntityLimitAndCount(playerState, entType)
 {
 	let ret = {
 		"entLimit": undefined,
 		"entCount": undefined,
 		"entLimitChangers": undefined,
 		"canBeAddedCount": undefined
 	};
 	if (!playerState.entityLimits)
 		return ret;
 	let template = GetTemplateData(entType);
 	let entCategory = template.trainingRestrictions && template.trainingRestrictions.category ||
 	                  template.buildRestrictions && template.buildRestrictions.category;
 
 	if (entCategory && playerState.entityLimits[entCategory] !== undefined)
 	{
 		ret.entLimit = playerState.entityLimits[entCategory] || 0;
 		ret.entCount = playerState.entityCounts[entCategory] || 0;
 		ret.entLimitChangers = playerState.entityLimitChangers[entCategory];
 		ret.canBeAddedCount = Math.max(ret.entLimit - ret.entCount, 0);
 	}
 	return ret;
 }
 
 // Called by GUI when user clicks construction button
 // @param buildTemplate Template name of the entity the user wants to build
 function startBuildingPlacement(buildTemplate, playerState)
 {
 	if(getEntityLimitAndCount(playerState, buildTemplate).canBeAddedCount == 0)
 		return;
 
 	// TODO: we should clear any highlight selection rings here. If the mouse was over an entity before going onto the GUI
 	// to start building a structure, then the highlight selection rings are kept during the construction of the structure.
 	// Gives the impression that somehow the hovered-over entity has something to do with the structure you're building.
 
 	placementSupport.Reset();
 
 	// find out if we're building a wall, and change the entity appropriately if so
 	var templateData = GetTemplateData(buildTemplate);
 	if (templateData.wallSet)
 	{
 		placementSupport.mode = "wall";
 		placementSupport.wallSet = templateData.wallSet;
 		inputState = INPUT_BUILDING_PLACEMENT;
 	}
 	else
 	{
 		placementSupport.mode = "building";
 		placementSupport.template = buildTemplate;
 		inputState = INPUT_BUILDING_PLACEMENT;
 	}
 
 	if (templateData.attack &&
 		templateData.attack.Ranged &&
 		templateData.attack.Ranged.maxRange)
 	{
 		// add attack information to display a good tooltip
 		placementSupport.attack = templateData.attack;
 	}
 }
 
 // Batch training:
 // When the user shift-clicks, we set these variables and switch to INPUT_BATCHTRAINING
 // When the user releases shift, or clicks on a different training button, we create the batched units
 var g_BatchTrainingEntities;
 var g_BatchTrainingType;
 var g_NumberOfBatches;
 var g_BatchTrainingEntityAllowedCount;
 var g_BatchSize = getDefaultBatchTrainingSize();
 
 function OnTrainMouseWheel(dir)
 {
 	if (!Engine.HotkeyIsPressed("session.batchtrain"))
 		return;
 
 	g_BatchSize += dir / Engine.ConfigDB_GetValue("user", "gui.session.scrollbatchratio");
 	if (g_BatchSize < 1 || !Number.isFinite(g_BatchSize))
 		g_BatchSize = 1;
 
 	updateSelectionDetails();
 }
 
 function getBuildingsWhichCanTrainEntity(entitiesToCheck, trainEntType)
 {
 	return entitiesToCheck.filter(entity => {
 		let state = GetEntityState(entity);
 		return state && state.production && state.production.entities.length &&
 			state.production.entities.indexOf(trainEntType) != -1;
 	});
 }
 
 function initBatchTrain()
 {
 	registerConfigChangeHandler(changes => {
 		if (changes.has("gui.session.batchtrainingsize"))
 			updateDefaultBatchSize();
 	});
 }
 
 function getDefaultBatchTrainingSize()
 {
 	let num = +Engine.ConfigDB_GetValue("user", "gui.session.batchtrainingsize");
 	return Number.isInteger(num) && num > 0 ? num : 5;
 }
 
 function getBatchTrainingSize()
 {
 	return Math.max(Math.round(g_BatchSize), 1);
 }
 
 function updateDefaultBatchSize()
 {
 	g_BatchSize = getDefaultBatchTrainingSize();
 }
 
 // Add the unit shown at position to the training queue for all entities in the selection
 function addTrainingByPosition(position)
 {
 	let playerState = GetSimState().players[Engine.GetPlayerID()];
 	let selection = g_Selection.toList();
 
 	if (!playerState || !selection.length)
 		return;
 
 	let trainableEnts = getAllTrainableEntitiesFromSelection();
 
 	let entToTrain = trainableEnts[position];
 	// When we have no structure to train units or the position is invalid
 	if (!entToTrain)
 		return;
 
 	addTrainingToQueue(selection, entToTrain, playerState);
 	return;
 }
 
 // Called by GUI when user clicks training button
 function addTrainingToQueue(selection, trainEntType, playerState)
 {
 	let appropriateBuildings = getBuildingsWhichCanTrainEntity(selection, trainEntType);
 
 	let canBeAddedCount = getEntityLimitAndCount(playerState, trainEntType).canBeAddedCount;
 
 	let decrement = Engine.HotkeyIsPressed("selection.remove");
 	let template;
 	if (!decrement)
 		template = GetTemplateData(trainEntType);
 
 	// Batch training only possible if we can train at least 2 units
 	if (Engine.HotkeyIsPressed("session.batchtrain") && (canBeAddedCount == undefined || canBeAddedCount > 1))
 	{
 		if (inputState == INPUT_BATCHTRAINING)
 		{
 			// Check if we are training in the same structure(s) as the last batch
 			// NOTE: We just check if the arrays are the same and if the order is the same
 			// If the order changed, we have a new selection and we should create a new batch.
 			// If we're already creating a batch of this unit (in the same structure(s)), then just extend it
 			// (if training limits allow)
 			if (g_BatchTrainingEntities.length == selection.length &&
 			    g_BatchTrainingEntities.every((ent, i) => ent == selection[i]) &&
 			    g_BatchTrainingType == trainEntType)
 			{
 				if (decrement)
 				{
 					--g_NumberOfBatches;
 					if (g_NumberOfBatches <= 0)
 						inputState = INPUT_NORMAL;
 				}
 				else if (canBeAddedCount == undefined ||
 				         canBeAddedCount > g_NumberOfBatches * getBatchTrainingSize() * appropriateBuildings.length)
 				{
 					if (Engine.GuiInterfaceCall("GetNeededResources", {
 						"cost": multiplyEntityCosts(template, (g_NumberOfBatches + 1) * getBatchTrainingSize())
 					}))
 						return;
 
 					++g_NumberOfBatches;
 				}
 				g_BatchTrainingEntityAllowedCount = canBeAddedCount;
 				return;
 			}
 			// Otherwise start a new one
 			else if (!decrement)
 				flushTrainingBatch();
 				// fall through to create the new batch
 		}
 
 		// Don't start a new batch if decrementing or unable to afford it.
 		if (decrement || Engine.GuiInterfaceCall("GetNeededResources", { "cost":
 			multiplyEntityCosts(template, getBatchTrainingSize()) }))
 			return;
 
 		inputState = INPUT_BATCHTRAINING;
 		g_BatchTrainingEntities = selection;
 		g_BatchTrainingType = trainEntType;
 		g_BatchTrainingEntityAllowedCount = canBeAddedCount;
 		g_NumberOfBatches = 1;
 	}
 	else
 	{
 		// Non-batched - just create a single entity in each structure
 		// (but no more than entity limit allows)
 		let buildingsForTraining = appropriateBuildings;
 		if (canBeAddedCount !== undefined)
 			buildingsForTraining = buildingsForTraining.slice(0, canBeAddedCount);
 		Engine.PostNetworkCommand({
 			"type": "train",
 			"template": trainEntType,
 			"count": 1,
 			"entities": buildingsForTraining
 		});
 	}
 }
 
 /**
  * Returns the number of units that will be present in a batch if the user clicks
  * the training button depending on the batch training modifier hotkey
  */
 function getTrainingStatus(selection, trainEntType, playerState)
 {
 	let appropriateBuildings = getBuildingsWhichCanTrainEntity(selection, trainEntType);
 	let nextBatchTrainingCount = 0;
 
 	let canBeAddedCount;
 	if (inputState == INPUT_BATCHTRAINING && g_BatchTrainingType == trainEntType)
 	{
 		nextBatchTrainingCount = g_NumberOfBatches * getBatchTrainingSize();
 		canBeAddedCount = g_BatchTrainingEntityAllowedCount;
 	}
 	else
 		canBeAddedCount = getEntityLimitAndCount(playerState, trainEntType).canBeAddedCount;
 
 	// We need to calculate count after the next increment if possible.
 	if ((canBeAddedCount == undefined || canBeAddedCount > nextBatchTrainingCount * appropriateBuildings.length) &&
 	    Engine.HotkeyIsPressed("session.batchtrain"))
 		nextBatchTrainingCount += getBatchTrainingSize();
 
 	nextBatchTrainingCount = Math.max(nextBatchTrainingCount, 1);
 
 	// If training limits don't allow us to train batchedSize in each appropriate structure,
 	// train as many full batches as we can and the remainder in one more structure.
 	let buildingsCountToTrainFullBatch = appropriateBuildings.length;
 	let remainderToTrain = 0;
 	if (canBeAddedCount !== undefined &&
 	    canBeAddedCount < nextBatchTrainingCount * appropriateBuildings.length)
 	{
 		buildingsCountToTrainFullBatch = Math.floor(canBeAddedCount / nextBatchTrainingCount);
 		remainderToTrain = canBeAddedCount % nextBatchTrainingCount;
 	}
 
 	return [buildingsCountToTrainFullBatch, nextBatchTrainingCount, remainderToTrain];
 }
 
 function flushTrainingBatch()
 {
 	let batchedSize = g_NumberOfBatches * getBatchTrainingSize();
 	let appropriateBuildings = getBuildingsWhichCanTrainEntity(g_BatchTrainingEntities, g_BatchTrainingType);
 	// If training limits don't allow us to train batchedSize in each appropriate structure.
 	if (g_BatchTrainingEntityAllowedCount !== undefined &&
 		g_BatchTrainingEntityAllowedCount < batchedSize * appropriateBuildings.length)
 	{
 		// Train as many full batches as we can.
 		let buildingsCountToTrainFullBatch = Math.floor(g_BatchTrainingEntityAllowedCount / batchedSize);
 		Engine.PostNetworkCommand({
 			"type": "train",
 			"entities": appropriateBuildings.slice(0, buildingsCountToTrainFullBatch),
 			"template": g_BatchTrainingType,
 			"count": batchedSize
 		});
 
 		// Train remainer in one more structure.
 		let remainer = g_BatchTrainingEntityAllowedCount % batchedSize;
 		if (remainer)
 			Engine.PostNetworkCommand({
 				"type": "train",
 				"entities": [appropriateBuildings[buildingsCountToTrainFullBatch]],
 				"template": g_BatchTrainingType,
 				"count": remainer
 			});
 	}
 	else
 		Engine.PostNetworkCommand({
 			"type": "train",
 			"entities": appropriateBuildings,
 			"template": g_BatchTrainingType,
 			"count": batchedSize
 		});
 }
 
 function performGroup(action, groupId)
 {
 	switch (action)
 	{
 	case "snap":
 	case "select":
 	case "add":
 		var toSelect = [];
 		g_Groups.update();
 		for (var ent in g_Groups.groups[groupId].ents)
 			toSelect.push(+ent);
 
 		if (action != "add")
 			g_Selection.reset();
 
 		g_Selection.addList(toSelect);
 
 		if (action == "snap" && toSelect.length)
 		{
 			let entState = GetEntityState(toSelect[0]);
 			let position = entState.position;
 			if (position && entState.visibility != "hidden")
 				Engine.CameraMoveTo(position.x, position.z);
 		}
 		break;
 	case "save":
 	case "breakUp":
 		g_Groups.groups[groupId].reset();
 
 		if (action == "save")
 			g_Groups.addEntities(groupId, g_Selection.toList());
 
 		updateGroups();
 		break;
 	}
 }
 
 var lastIdleUnit = 0;
 var currIdleClassIndex = 0;
 var lastIdleClasses = [];
 
 function resetIdleUnit()
 {
 	lastIdleUnit = 0;
 	currIdleClassIndex = 0;
 	lastIdleClasses = [];
 }
 
 function findIdleUnit(classes)
 {
 	var append = Engine.HotkeyIsPressed("selection.add");
 	var selectall = Engine.HotkeyIsPressed("selection.offscreen");
 
 	// Reset the last idle unit, etc., if the selection type has changed.
 	if (selectall || classes.length != lastIdleClasses.length || !classes.every((v,i) => v === lastIdleClasses[i]))
 		resetIdleUnit();
 	lastIdleClasses = classes;
 
 	var data = {
 		"viewedPlayer": g_ViewedPlayer,
 		"excludeUnits": append ? g_Selection.toList() : [],
 		// If the current idle class index is not 0, put the class at that index first.
 		"idleClasses": classes.slice(currIdleClassIndex, classes.length).concat(classes.slice(0, currIdleClassIndex))
 	};
 	if (!selectall)
 	{
 		data.limit = 1;
 		data.prevUnit = lastIdleUnit;
 	}
 
 	var idleUnits = Engine.GuiInterfaceCall("FindIdleUnits", data);
 	if (!idleUnits.length)
 	{
 		// TODO: display a message or play a sound to indicate no more idle units, or something
 		// Reset for next cycle
 		resetIdleUnit();
 		return;
 	}
 
 	if (!append)
 		g_Selection.reset();
 	g_Selection.addList(idleUnits);
 
 	if (selectall)
 		return;
 
 	lastIdleUnit = idleUnits[0];
 	var entityState = GetEntityState(lastIdleUnit);
 	var position = entityState.position;
 	if (position)
 		Engine.CameraMoveTo(position.x, position.z);
 	// Move the idle class index to the first class an idle unit was found for.
 	var indexChange = data.idleClasses.findIndex(elem => MatchesClassList(entityState.identity.classes, elem));
 	currIdleClassIndex = (currIdleClassIndex + indexChange) % classes.length;
 }
 
 function clearSelection()
 {
 	if(inputState==INPUT_BUILDING_PLACEMENT || inputState==INPUT_BUILDING_WALL_PATHING)
 	{
 		inputState = INPUT_NORMAL;
 		placementSupport.Reset();
 	}
 	else
 		g_Selection.reset();
 	preSelectedAction = ACTION_NONE;
 }
 
Index: ps/trunk/binaries/data/mods/public/gui/session/selection.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/selection.js	(revision 23829)
+++ ps/trunk/binaries/data/mods/public/gui/session/selection.js	(revision 23830)
@@ -1,530 +1,538 @@
 // Limits selection size
 var g_MaxSelectionSize = 200;
 
 // Alpha value of hovered/mouseover/highlighted selection overlays
 // (should probably be greater than always visible alpha value,
 //	see CCmpSelectable)
 var g_HighlightedAlpha = 0.75;
 
 function _setHighlight(ents, alpha, selected)
 {
 	if (ents.length)
 		Engine.GuiInterfaceCall("SetSelectionHighlight", { "entities": ents, "alpha": alpha, "selected": selected });
 }
 
 function _setStatusBars(ents, enabled)
 {
 	if (!ents.length)
 		return;
 	Engine.GuiInterfaceCall("SetStatusBars", {
 		"entities": ents,
 		"enabled": enabled,
 		"showRank": Engine.ConfigDB_GetValue("user", "gui.session.rankabovestatusbar") == "true",
 		"showExperience": Engine.ConfigDB_GetValue("user", "gui.session.experiencestatusbar") == "true"
 	});
 }
 
 function _setMotionOverlay(ents, enabled)
 {
 	if (ents.length)
 		Engine.GuiInterfaceCall("SetMotionDebugOverlay", { "entities": ents, "enabled": enabled });
 }
 
 function _playSound(ent)
 {
 	Engine.GuiInterfaceCall("PlaySound", { "name": "select", "entity": ent });
 }
 
 /**
  * EntityGroups class for managing grouped entities
  */
 function EntityGroups()
 {
 	this.groups = {};
 	this.ents = {};
 }
 
 EntityGroups.prototype.reset = function()
 {
 	this.groups = {};
 	this.ents = {};
 };
 
 EntityGroups.prototype.add = function(ents)
 {
 	for (let ent of ents)
 	{
 		if (this.ents[ent])
 			continue;
 		var entState = GetEntityState(ent);
 
 		// When this function is called during group rebuild, deleted
 		// entities will not yet have been removed, so entities might
 		// still be present in the group despite not existing.
 		if (!entState)
 			continue;
 
 		var templateName = entState.template;
 		var key = GetTemplateData(templateName).selectionGroupName || templateName;
 
 		// Group the ents by player and template
 		if (entState.player !== undefined)
 			key = "p" + entState.player + "&" + key;
 
 		if (this.groups[key])
 			this.groups[key] += 1;
 		else
 			this.groups[key] = 1;
 
 		this.ents[ent] = key;
 	}
 };
 
 EntityGroups.prototype.removeEnt = function(ent)
 {
 	var key = this.ents[ent];
 
 	// Remove the entity
 	delete this.ents[ent];
 	--this.groups[key];
 
 	// Remove the entire group
 	if (this.groups[key] == 0)
 		delete this.groups[key];
 };
 
 EntityGroups.prototype.rebuildGroup = function(renamed)
 {
 	var oldGroup = this.ents;
 	this.reset();
 
 	var toAdd = [];
 	for (var ent in oldGroup)
 		toAdd.push(renamed[ent] ? renamed[ent] : +ent);
 
 	this.add(toAdd);
 };
 
 EntityGroups.prototype.getCount = function(key)
 {
 	return this.groups[key];
 };
 
 EntityGroups.prototype.getTotalCount = function()
 {
 	let totalCount = 0;
 	for (let key in this.groups)
 		totalCount += this.groups[key];
 	return totalCount;
 };
 
 EntityGroups.prototype.getKeys = function()
 {
 	// Preserve order even when shuffling units around
 	// Can be optimized by moving the sorting elsewhere
 	return Object.keys(this.groups).sort();
 };
 
 EntityGroups.prototype.getEntsByKey = function(key)
 {
 	var ents = [];
 	for (var ent in this.ents)
 		if (this.ents[ent] == key)
 			ents.push(+ent);
 
 	return ents;
 };
 
 /**
  * get a list of entities grouped by a key
  */
 EntityGroups.prototype.getEntsGrouped = function()
 {
 	return this.getKeys().map(key => ({
 		"ents": this.getEntsByKey(key),
 		"key": key
 	}));
 };
 
 /**
  * Gets all ents in every group except ones of the specified group
  */
 EntityGroups.prototype.getEntsByKeyInverse = function(key)
 {
 	var ents = [];
 	for (var ent in this.ents)
 		if (this.ents[ent] != key)
 			ents.push(+ent);
 
 	return ents;
 };
 
 /**
  * EntitySelection class for managing the entity selection list and the primary selection
  */
 function EntitySelection()
 {
 	// Private properties:
 	this.selected = {}; // { id:id, id:id, ... } for each selected entity ID 'id'
 
 	// { id:id, ... } for mouseover-highlighted entity IDs in these, the key is a string and the value is an int;
 	//	we want to use the int form wherever possible since it's more efficient to send to the simulation code)
 	this.highlighted = {};
 
 	this.motionDebugOverlay = false;
 
 	// Public properties:
 	this.dirty = false; // set whenever the selection has changed
 	this.groups = new EntityGroups();
 }
 
 /**
  * Deselect everything but entities of the chosen type if inverse is true otherwise deselect just the chosen entity
  */
 EntitySelection.prototype.makePrimarySelection = function(key, inverse)
 {
 	let ents = inverse ?
 		this.groups.getEntsByKeyInverse(key) :
 		this.groups.getEntsByKey(key);
 
 	this.reset();
 	this.addList(ents);
 };
 
 /**
  * Get a list of the template names
  */
 EntitySelection.prototype.getTemplateNames = function()
 {
 	var templateNames = [];
 
 	for (let ent in this.selected)
 	{
 		let entState = GetEntityState(+ent);
 		if (entState)
 			templateNames.push(entState.template);
 	}
 	return templateNames;
 };
 
 /**
  * Update the selection to take care of changes (like units that have been killed)
  */
 EntitySelection.prototype.update = function()
 {
 	this.checkRenamedEntities();
 
 	let controlsAll = g_SimState.players[g_ViewedPlayer] && g_SimState.players[g_ViewedPlayer].controlsAll;
 	let removeOwnerChanges = !g_IsObserver && !controlsAll && this.toList().length > 1;
 
 	let changed = false;
 
 	for (let ent in this.selected)
 	{
 		let entState = GetEntityState(+ent);
 
 		// Remove deleted units
 		if (!entState)
 		{
 			delete this.selected[ent];
 			this.groups.removeEnt(+ent);
 			changed = true;
 			continue;
 		}
 
 		// Remove non-visible units (e.g. moved back into fog-of-war)
 		// At the next update, mirages will be renamed to the real
 		// entity they replace, so just ignore them now
 		// Futhermore, when multiple selection, remove units which have changed ownership
 		if (entState.visibility == "hidden" && !entState.mirage ||
 			removeOwnerChanges && entState.player != g_ViewedPlayer)
 		{
 			// Disable any highlighting of the disappeared unit
 			_setHighlight([+ent], 0, false);
 			_setStatusBars([+ent], false);
 			_setMotionOverlay([+ent], false);
 
 			delete this.selected[ent];
 			this.groups.removeEnt(+ent);
 			changed = true;
 			continue;
 		}
 	}
 	if (changed)
 		this.onChange();
 };
 
 /**
  * Update selection if some selected entities were renamed
  * (in case of unit promotion or finishing building structure)
  */
 EntitySelection.prototype.checkRenamedEntities = function()
 {
 	var renamedEntities = Engine.GuiInterfaceCall("GetRenamedEntities");
 	if (renamedEntities.length > 0)
 	{
 		var renamedLookup = {};
 		for (let renamedEntity of renamedEntities)
 			renamedLookup[renamedEntity.entity] = renamedEntity.newentity;
 
 		// Reconstruct the selection if at least one entity has been renamed.
 		for (let renamedEntity of renamedEntities)
 			if (this.selected[renamedEntity.entity])
 			{
 				this.rebuildSelection(renamedLookup);
 				return;
 			}
 	}
 };
 
 /**
  * Add entities to selection. Play selection sound unless quiet is true
  */
 EntitySelection.prototype.addList = function(ents, quiet, force = false)
 {
 	let selection = this.toList();
 
 	// If someone else's player is the sole selected unit, don't allow adding to the selection
 	let firstEntState = selection.length == 1 && GetEntityState(selection[0]);
 	if (firstEntState && firstEntState.player != g_ViewedPlayer && !force)
 		return;
 
 	let i = 1;
 	let added = [];
 
 	for (let ent of ents)
 	{
 		if (selection.length + i > g_MaxSelectionSize)
 			break;
 
 		if (this.selected[ent])
 			continue;
 
 		var entState = GetEntityState(ent);
 		if (!entState)
 			continue;
 
 		let isUnowned = g_ViewedPlayer != -1 && entState.player != g_ViewedPlayer ||
 		                g_ViewedPlayer == -1 && entState.player == 0;
 
 		// Don't add unowned entities to the list, unless a single entity was selected
 		if (isUnowned && (ents.length > 1 || selection.length) && !force)
 			continue;
 
 		added.push(ent);
 		this.selected[ent] = ent;
 		++i;
 	}
 
 	_setHighlight(added, 1, true);
 	_setStatusBars(added, true);
 	_setMotionOverlay(added, this.motionDebugOverlay);
 	if (added.length)
 	{
 		// Play the sound if the entity is controllable by us or Gaia-owned.
 		var owner = GetEntityState(added[0]).player;
 		if (!quiet && (controlsPlayer(owner) || g_IsObserver || owner == 0))
 			_playSound(added[0]);
 	}
 
 	this.groups.add(this.toList()); // Create Selection Groups
 	this.onChange();
 };
 
 EntitySelection.prototype.removeList = function(ents)
 {
 	var removed = [];
 
 	for (let ent of ents)
 		if (this.selected[ent])
 		{
 			this.groups.removeEnt(ent);
 			removed.push(ent);
 			delete this.selected[ent];
 		}
 
 	_setHighlight(removed, 0, false);
 	_setStatusBars(removed, false);
 	_setMotionOverlay(removed, false);
 
 	this.onChange();
 };
 
 EntitySelection.prototype.reset = function()
 {
 	_setHighlight(this.toList(), 0, false);
 	_setStatusBars(this.toList(), false);
 	_setMotionOverlay(this.toList(), false);
 	this.selected = {};
 	this.groups.reset();
 	this.onChange();
 };
 
 EntitySelection.prototype.rebuildSelection = function(renamed)
 {
 	var oldSelection = this.selected;
 	this.reset();
 
 	var toAdd = [];
 	for (let ent in oldSelection)
 		toAdd.push(renamed[ent] || +ent);
 
 	this.addList(toAdd, true); // don't play selection sounds
 };
 
 EntitySelection.prototype.getFirstSelected = function()
 {
 	for (let ent in this.selected)
 		return +ent;
 	return undefined;
 };
 
 /**
  * TODO: This array should not be recreated every call
  */
 EntitySelection.prototype.toList = function()
 {
 	let ents = [];
 	for (let ent in this.selected)
 		ents.push(+ent);
 	return ents;
 };
 
+EntitySelection.prototype.find = function(condition)
+{
+	for (let ent in this.selected)
+		if (condition(ent))
+			return +ent;
+	return null;
+};
+
 EntitySelection.prototype.setHighlightList = function(ents)
 {
 	var highlighted = {};
 	for (let ent of ents)
 		highlighted[ent] = ent;
 
 	var removed = [];
 	var added = [];
 
 	// Remove highlighting for the old units that are no longer highlighted
 	// (excluding ones that are actively selected too)
 	for (let ent in this.highlighted)
 		if (!highlighted[ent] && !this.selected[ent])
 			removed.push(+ent);
 
 	// Add new highlighting for units that aren't already highlighted
 	for (let ent of ents)
 		if (!this.highlighted[ent] && !this.selected[ent])
 			added.push(+ent);
 
 	_setHighlight(removed, 0, false);
 	_setStatusBars(removed, false);
 
 	_setHighlight(added, g_HighlightedAlpha, true);
 	_setStatusBars(added, true);
 
 	// Store the new highlight list
 	this.highlighted = highlighted;
 };
 
 EntitySelection.prototype.SetMotionDebugOverlay = function(enabled)
 {
 	this.motionDebugOverlay = enabled;
 	_setMotionOverlay(this.toList(), enabled);
 };
 
 EntitySelection.prototype.onChange = function()
 {
 	this.dirty = true;
 	if (this.isSelection)
 		onSelectionChange();
 };
 
 EntitySelection.prototype.selectAndMoveTo = function(entityID)
 {
 	let entState = GetEntityState(entityID);
 	if (!entState || !entState.position)
 		return;
 
 	this.reset();
 	this.addList([entityID]);
 
 	Engine.CameraMoveTo(entState.position.x, entState.position.z);
 }
 
 /**
  * Cache some quantities which depends only on selection
  */
 
 var g_Selection = new EntitySelection();
 g_Selection.isSelection = true;
 
 var g_canMoveIntoFormation = {};
 var g_allBuildableEntities;
 var g_allTrainableEntities;
 
 // Reset cached quantities
 function onSelectionChange()
 {
 	g_canMoveIntoFormation = {};
 	g_allBuildableEntities = undefined;
 	g_allTrainableEntities = undefined;
 }
 
 /**
  * EntityGroupsContainer class for managing grouped entities
  */
 function EntityGroupsContainer()
 {
 	this.groups = [];
 	for (var i = 0; i < 10; ++i)
 		this.groups[i] = new EntityGroups();
 }
 
 /**
  * Add entities to a group.
  * @param {string} groupName - The number of the group to add the entities to.
  * @param {number[]} ents - The entities to add to the group.
  */
 EntityGroupsContainer.prototype.addEntities = function(groupName, ents)
 {
 	if (Engine.ConfigDB_GetValue("user", "gui.session.disjointcontrolgroups") == "true")
 		for (let ent of ents)
 			for (let group of this.groups)
 				if (ent in group.ents)
 					group.removeEnt(ent);
 
 	this.groups[groupName].add(ents);
 };
 
 EntityGroupsContainer.prototype.update = function()
 {
 	this.checkRenamedEntities();
 	for (let group of this.groups)
 		for (var ent in group.ents)
 		{
 			var entState = GetEntityState(+ent);
 			// Remove deleted units
 			if (!entState)
 				group.removeEnt(ent);
 		}
 };
 
 /**
  * Update control group if some entities in the group were renamed
  * (in case of unit promotion or finishing building structure)
  */
 EntityGroupsContainer.prototype.checkRenamedEntities = function()
 {
 	var renamedEntities = Engine.GuiInterfaceCall("GetRenamedEntities");
 	if (renamedEntities.length > 0)
 	{
 		var renamedLookup = {};
 		for (let renamedEntity of renamedEntities)
 			renamedLookup[renamedEntity.entity] = renamedEntity.newentity;
 
 		for (let group of this.groups)
 			for (let renamedEntity of renamedEntities)
 				// Reconstruct the group if at least one entity has been renamed.
 				if (renamedEntity.entity in group.ents)
 				{
 					group.rebuildGroup(renamedLookup);
 					break;
 				}
 	}
 };
 
 var g_Groups = new EntityGroupsContainer();
Index: ps/trunk/binaries/data/mods/public/gui/session/unit_actions.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/unit_actions.js	(revision 23829)
+++ ps/trunk/binaries/data/mods/public/gui/session/unit_actions.js	(revision 23830)
@@ -1,1648 +1,1662 @@
 /**
  * Specifies which template should indicate the target location of a player command,
  * given a command type.
  */
 var g_TargetMarker = {
 	"move": "special/target_marker"
 };
 
 /**
  * Which enemy entity types will be attacked on sight when patroling.
  */
 var g_PatrolTargets = ["Unit"];
 
 const g_DisabledTags = { "color": "255 140 0" };
 
 /**
  * List of different actions units can execute,
  * this is mostly used to determine which actions can be executed
  *
  * "execute" is meant to send the command to the engine
  *
  * The next functions will always return false
  * in case you have to continue to seek
  * (i.e. look at the next entity for getActionInfo, the next
  * possible action for the actionCheck ...)
  * They will return an object when the searching is finished
  *
  * "getActionInfo" is used to determine if the action is possible,
  * and also give visual feedback to the user (tooltips, cursors, ...)
  *
  * "preSelectedActionCheck" is used to select actions when the gui buttons
  * were used to set them, but still require a target (like the guard button)
  *
  * "hotkeyActionCheck" is used to check the possibility of actions when
  * a hotkey is pressed
  *
  * "actionCheck" is used to check the possibilty of actions without specific
  * command. For that, the specificness variable is used
  *
  * "specificness" is used to determine how specific an action is,
  * The lower the number, the more specific an action is, and the bigger
  * the chance of selecting that action when multiple actions are possible
  */
 var g_UnitActions =
 {
 	"move":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "walk",
 				"entities": selection,
 				"x": target.x,
 				"z": target.z,
 				"queued": queued
 			});
 
 			DrawTargetMarker(target);
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_walk",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			return { "possible": true };
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			if (!someUnitAI(selection) ||
 			    !Engine.HotkeyIsPressed("session.move") ||
 			    !getActionInfo("move", target, selection).possible)
 				return false;
 
 			return { "type": "move" };
 		},
 		"actionCheck": function(target, selection)
 		{
 			if (!someUnitAI(selection) || !getActionInfo("move", target, selection).possible)
 				return false;
 
 			return { "type": "move" };
 		},
 		"specificness": 12,
 	},
 
 	"attack-move":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			let targetClasses;
 			if (Engine.HotkeyIsPressed("session.attackmoveUnit"))
 				targetClasses = { "attack": ["Unit"] };
 			else
 				targetClasses = { "attack": ["Unit", "Structure"] };
 
 			Engine.PostNetworkCommand({
 				"type": "attack-walk",
 				"entities": selection,
 				"x": target.x,
 				"z": target.z,
 				"targetClasses": targetClasses,
 				"queued": queued
 			});
 
 			DrawTargetMarker(target);
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_walk",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			return { "possible": true };
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			if (!someUnitAI(selection) ||
 			    !Engine.HotkeyIsPressed("session.attackmove") ||
 			    !getActionInfo("attack-move", target, selection).possible)
 				return false;
 
 			return {
 				"type": "attack-move",
 				"cursor": "action-attack-move"
 			};
 		},
 		"specificness": 30,
 	},
 
 	"capture":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "attack",
 				"entities": selection,
 				"target": action.target,
 				"allowCapture": true,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_attack",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!entState.attack || !targetState.hitpoints)
 				return false;
 
 			return {
 				"possible": Engine.GuiInterfaceCall("CanAttack", {
 					"entity": entState.id,
 					"target": targetState.id,
 					"types": ["Capture"]
 				})
 			};
 		},
 		"actionCheck": function(target, selection)
 		{
 			if (!getActionInfo("capture", target, selection).possible)
 				return false;
 
 			return {
 				"type": "capture",
 				"cursor": "action-capture",
 				"target": target
 			};
 		},
 		"specificness": 9,
 	},
 
 	"attack":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "attack",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued,
 				"allowCapture": false
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_attack",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!entState.attack || !targetState.hitpoints)
 				return false;
 
 			return {
 				"possible": Engine.GuiInterfaceCall("CanAttack", {
 					"entity": entState.id,
 					"target": targetState.id,
 					"types": ["!Capture"]
 				})
 			};
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			if (!Engine.HotkeyIsPressed("session.attack") ||
 			    !getActionInfo("attack", target, selection).possible)
 				return false;
 
 			return {
 				"type": "attack",
 				"cursor": "action-attack",
 				"target": target
 			};
 		},
 		"actionCheck": function(target, selection)
 		{
 			if (!getActionInfo("attack", target, selection).possible)
 				return false;
 
 			return {
 				"type": "attack",
 				"cursor": "action-attack",
 				"target": target
 			};
 		},
 		"specificness": 10,
 	},
 
 	"patrol":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "patrol",
 				"entities": selection,
 				"x": target.x,
 				"z": target.z,
 				"target": action.target,
 				"targetClasses": { "attack": g_PatrolTargets },
 				"queued": queued,
 				"allowCapture": false
 			});
 
 			DrawTargetMarker(target);
 
 			Engine.GuiInterfaceCall("PlaySound", { "name": "order_patrol", "entity": selection[0] });
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!entState.unitAI || !entState.unitAI.canPatrol)
 				return false;
 
 			return { "possible": true };
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			if (!someCanPatrol(selection) ||
 			    !Engine.HotkeyIsPressed("session.patrol") ||
 			    !getActionInfo("patrol", target, selection).possible)
 				return false;
 			return {
 				"type": "patrol",
 				"cursor": "action-patrol",
 				"target": target
 			};
 		},
 		"preSelectedActionCheck": function(target, selection)
 		{
 			if (preSelectedAction != ACTION_PATROL || !getActionInfo("patrol", target, selection).possible)
 				return false;
 			return {
 				"type": "patrol",
 				"cursor": "action-patrol",
 				"target": target
 			};
 		},
 		"specificness": 37,
 	},
 
 	"heal":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "heal",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_heal",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!entState.heal ||
 			    !hasClass(targetState, "Unit") || !targetState.needsHeal ||
 			    !playerCheck(entState, targetState, ["Player", "Ally"]) ||
 			    entState.id == targetState.id) // Healers can't heal themselves.
 				return false;
 
 			let unhealableClasses = entState.heal.unhealableClasses;
 			if (MatchesClassList(targetState.identity.classes, unhealableClasses))
 				return false;
 
 			let healableClasses = entState.heal.healableClasses;
 			if (!MatchesClassList(targetState.identity.classes, healableClasses))
 				return false;
 
 			return { "possible": true };
 		},
 		"actionCheck": function(target, selection)
 		{
 			if (!getActionInfo("heal", target, selection).possible)
 				return false;
 
 			return {
 				"type": "heal",
 				"cursor": "action-heal",
 				"target": target
 			};
 		},
 		"specificness": 7,
 	},
 
+	// "Fake" action to check if an entity can be ordered to "construct"
+	// which is handled differently from repair as the target does not exist.
+	"construct":
+	{
+		"preSelectedActionCheck": function(target, selection)
+		{
+			let state = GetEntityState(selection[0]);
+			if (state && state.builder && target.constructor.name == "PlacementSupport")
+				return { "type": "construct" };
+			return false;
+		},
+		"specificness": 0,
+	},
+
 	"repair":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "repair",
 				"entities": selection,
 				"target": action.target,
 				"autocontinue": true,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": action.foundation ? "order_build" : "order_repair",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!entState.builder ||
 			    !targetState.needsRepair && !targetState.foundation ||
 			    !playerCheck(entState, targetState, ["Player", "Ally"]))
 				return false;
 
 			return {
 				"possible": true,
 				"foundation": targetState.foundation
 			};
 		},
 		"preSelectedActionCheck": function(target, selection)
 		{
 			if (preSelectedAction != ACTION_REPAIR)
 				return false;
 
 			let actionInfo = getActionInfo("repair", target, selection);
 			if (actionInfo.possible)
 				return {
 					"type": "repair",
 					"cursor": "action-repair",
 					"target": target,
 					"foundation": actionInfo.foundation
 				};
 
 			return {
 				"type": "none",
 				"cursor": "action-repair-disabled",
 				"target": null
 			};
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			let actionInfo = getActionInfo("repair", target, selection);
 			if (!Engine.HotkeyIsPressed("session.repair") ||
 			    !actionInfo.possible)
 				return false;
 
 			return {
 				"type": "repair",
 				"cursor": "action-repair",
 				"target": target,
 				"foundation": actionInfo.foundation
 			};
 		},
 		"actionCheck": function(target, selection)
 		{
 			let actionInfo = getActionInfo("repair", target, selection);
 			if (!actionInfo.possible)
 				return false;
 
 			return {
 				"type": "repair",
 				"cursor": "action-repair",
 				"target": target,
 				"foundation": actionInfo.foundation
 			};
 		},
 		"specificness": 11,
 	},
 
 	"gather":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "gather",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_gather",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!targetState.resourceSupply)
 				return false;
 
 			let resource = findGatherType(entState, targetState.resourceSupply);
 			if (!resource)
 				return false;
 
 			return {
 				"possible": true,
 				"cursor": "action-gather-" + resource
 			};
 		},
 		"actionCheck": function(target, selection)
 		{
 			let actionInfo = getActionInfo("gather", target, selection);
 
 			if (!actionInfo.possible)
 				return false;
 
 			return {
 				"type": "gather",
 				"cursor": actionInfo.cursor,
 				"target": target
 			};
 		},
 		"specificness": 1,
 	},
 
 	"returnresource":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "returnresource",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_gather",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!targetState.resourceDropsite)
 				return false;
 
 			let playerState = GetSimState().players[entState.player];
 			if (playerState.hasSharedDropsites && targetState.resourceDropsite.shared)
 			{
 				if (!playerCheck(entState, targetState, ["Player", "MutualAlly"]))
 					return false;
 			}
 			else if (!playerCheck(entState, targetState, ["Player"]))
 				return false;
 
 			if (!entState.resourceCarrying || !entState.resourceCarrying.length)
 				return false;
 
 			let carriedType = entState.resourceCarrying[0].type;
 			if (targetState.resourceDropsite.types.indexOf(carriedType) == -1)
 				return false;
 
 			return {
 				"possible": true,
 				"cursor": "action-return-" + carriedType
 			};
 		},
 		"actionCheck": function(target, selection)
 		{
 			let actionInfo = getActionInfo("returnresource", target, selection);
 			if (!actionInfo.possible)
 				return false;
 
 			return {
 				"type": "returnresource",
 				"cursor": actionInfo.cursor,
 				"target": target
 			};
 		},
 		"specificness": 2,
 	},
 
 	"cancel-setup-trade-route":
 	{
 		"execute":function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "cancel-setup-trade-route",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (targetState.foundation || !entState.trader || !targetState.market ||
 			    playerCheck(entState, targetState, ["Enemy"]) ||
 			    !(targetState.market.land && hasClass(entState, "Organic") ||
 			      targetState.market.naval && hasClass(entState, "Ship")))
 				return false;
 
 			let tradingDetails = Engine.GuiInterfaceCall("GetTradingDetails", {
 				"trader": entState.id,
 				"target": targetState.id
 			});
 
 			if (!tradingDetails || !tradingDetails.type)
 				return false;
 
 			if (tradingDetails.type == "is first" && !tradingDetails.hasBothMarkets)
 				return {
 					"possible": true,
 					"tooltip": translate("This is the origin trade market.\nRight-click to cancel trade route.")
 				};
 			return false;
 		},
 		"actionCheck": function(target, selection)
 		{
 			let actionInfo = getActionInfo("cancel-setup-trade-route", target, selection);
 
 			if (!actionInfo.possible)
 				return false;
 			return {
 				"type": "cancel-setup-trade-route",
 				"cursor": "action-cancel-setup-trade-route",
 				"tooltip": actionInfo.tooltip,
 				"target": target
 			}
 		},
 		"specificness": 2,
 	},
 
 	"setup-trade-route":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "setup-trade-route",
 				"entities": selection,
 				"target": action.target,
 				"source": null,
 				"route": null,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_trade",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (targetState.foundation || !entState.trader || !targetState.market ||
 			    playerCheck(entState, targetState, ["Enemy"]) ||
 			    !(targetState.market.land && hasClass(entState, "Organic") ||
 			      targetState.market.naval && hasClass(entState, "Ship")))
 				return false;
 
 			let tradingDetails = Engine.GuiInterfaceCall("GetTradingDetails", {
 				"trader": entState.id,
 				"target": targetState.id
 			});
 
 			if (!tradingDetails)
 				return false;
 
 			let tooltip;
 			switch (tradingDetails.type)
 			{
 			case "is first":
 				tooltip = translate("Origin trade market.") + "\n";
 				if (tradingDetails.hasBothMarkets)
 					tooltip += sprintf(translate("Gain: %(gain)s"), {
 						"gain": getTradingTooltip(tradingDetails.gain)
 					});
 				else
 					return false;
 				break;
 
 			case "is second":
 				tooltip = translate("Destination trade market.") + "\n" +
 					sprintf(translate("Gain: %(gain)s"), {
 						"gain": getTradingTooltip(tradingDetails.gain)
 					});
 				break;
 
 			case "set first":
 				tooltip = translate("Right-click to set as origin trade market");
 				break;
 
 			case "set second":
 				if (tradingDetails.gain.traderGain == 0)
 					return {
 						"possible": true,
 						"tooltip": setStringTags(translate("This market is too close to the origin market."), g_DisabledTags),
 						"disabled": true
 					};
 
 				tooltip = translate("Right-click to set as destination trade market.") + "\n" +
 					sprintf(translate("Gain: %(gain)s"), {
 						"gain": getTradingTooltip(tradingDetails.gain)
 					});
 				break;
 			}
 
 			return {
 				"possible": true,
 				"tooltip": tooltip
 			};
 		},
 		"actionCheck": function(target, selection)
 		{
 			let actionInfo = getActionInfo("setup-trade-route", target, selection);
 
 			if (actionInfo.disabled)
 				return {
 					"type": "none",
 					"cursor": "action-setup-trade-route-disabled",
 					"target": null,
 					"tooltip": actionInfo.tooltip
 				};
 
 			if (!actionInfo.possible)
 				return false;
 
 			return {
 				"type": "setup-trade-route",
 				"cursor": "action-setup-trade-route",
 				"tooltip": actionInfo.tooltip,
 				"target": target
 			};
 		},
 		"specificness": 0,
 	},
 
 	"garrison":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "garrison",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_garrison",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!entState.canGarrison || !targetState.garrisonHolder ||
 			    !playerCheck(entState, targetState, ["Player", "MutualAlly"]))
 				return false;
 
 			let tooltip = sprintf(translate("Current garrison: %(garrisoned)s/%(capacity)s"), {
 				"garrisoned": targetState.garrisonHolder.garrisonedEntitiesCount,
 				"capacity": targetState.garrisonHolder.capacity
 			});
 
 			let extraCount = 0;
 			if (entState.garrisonHolder)
 				extraCount += entState.garrisonHolder.garrisonedEntitiesCount;
 
 			if (targetState.garrisonHolder.garrisonedEntitiesCount + extraCount >= targetState.garrisonHolder.capacity)
 				tooltip = coloredText(tooltip, "orange");
 
 			if (!MatchesClassList(entState.identity.classes, targetState.garrisonHolder.allowedClasses))
 				return false;
 
 			return {
 				"possible": true,
 				"tooltip": tooltip
 			};
 		},
 		"preSelectedActionCheck": function(target, selection)
 		{
 			if (preSelectedAction != ACTION_GARRISON)
 				return false;
 
 			let actionInfo = getActionInfo("garrison", target, selection);
 			if (!actionInfo.possible)
 				return {
 					"type": "none",
 					"cursor": "action-garrison-disabled",
 					"target": null
 				};
 
 			return {
 				"type": "garrison",
 				"cursor": "action-garrison",
 				"tooltip": actionInfo.tooltip,
 				"target": target
 			};
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			let actionInfo = getActionInfo("garrison", target, selection);
 
 			if (!Engine.HotkeyIsPressed("session.garrison") || !actionInfo.possible)
 				return false;
 
 			return {
 				"type": "garrison",
 				"cursor": "action-garrison",
 				"tooltip": actionInfo.tooltip,
 				"target": target
 			};
 		},
 		"specificness": 20,
 	},
 
 	"guard":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "guard",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_guard",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!targetState.guard ||
 			    !playerCheck(entState, targetState, ["Player", "Ally"]) ||
 			    !entState.unitAI || !entState.unitAI.canGuard ||
 			    targetState.unitAI && targetState.unitAI.isGuarding)
 				return false;
 
 			return { "possible": true };
 		},
 		"preSelectedActionCheck": function(target, selection)
 		{
 			if (preSelectedAction != ACTION_GUARD)
 				return false;
 
 			if (getActionInfo("guard", target, selection).possible)
 				return {
 					"type": "guard",
 					"cursor": "action-guard",
 					"target": target
 				};
 
 			return {
 				"type": "none",
 				"cursor": "action-guard-disabled",
 				"target": null
 			};
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			if (!Engine.HotkeyIsPressed("session.guard") ||
 			    !getActionInfo("guard", target, selection).possible)
 				return false;
 
 			return {
 				"type": "guard",
 				"cursor": "action-guard",
 				"target": target
 			};
 		},
 		"specificness": 40,
 	},
 
 	"remove-guard":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "remove-guard",
 				"entities": selection,
 				"target": action.target,
 				"queued": queued
 			});
 
 			Engine.GuiInterfaceCall("PlaySound", {
 				"name": "order_guard",
 				"entity": selection[0]
 			});
 
 			return true;
 		},
 		"hotkeyActionCheck": function(target, selection)
 		{
 			if (!Engine.HotkeyIsPressed("session.guard") ||
 			    !getActionInfo("remove-guard", target, selection).possible ||
 			    !someGuarding(selection))
 				return false;
 
 			return {
 				"type": "remove-guard",
 				"cursor": "action-remove-guard"
 			};
 		},
 
 		"specificness": 41,
 	},
 
 	"set-rallypoint":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			// if there is a position set in the action then use this so that when setting a
 			// rally point on an entity it is centered on that entity
 			if (action.position)
 				target = action.position;
 
 			Engine.PostNetworkCommand({
 				"type": "set-rallypoint",
 				"entities": selection,
 				"x": target.x,
 				"z": target.z,
 				"data": action.data,
 				"queued": queued
 			});
 
 			// Display rally point at the new coordinates, to avoid display lag
 			Engine.GuiInterfaceCall("DisplayRallyPoint", {
 				"entities": selection,
 				"x": target.x,
 				"z": target.z,
 				"queued": queued
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			let tooltip;
 			let disabled = false;
 			// default to walking there (or attack-walking if hotkey pressed)
 			let data = { "command": "walk" };
 			let cursor = "";
 
 			if (Engine.HotkeyIsPressed("session.attackmove"))
 			{
 				let targetClasses;
 				if (Engine.HotkeyIsPressed("session.attackmoveUnit"))
 					targetClasses = { "attack": ["Unit"] };
 				else
 					targetClasses = { "attack": ["Unit", "Structure"] };
 
 				data.command = "attack-walk";
 				data.targetClasses = targetClasses;
 				cursor = "action-attack-move";
 			}
 
 			if (Engine.HotkeyIsPressed("session.repair") &&
 			    (targetState.needsRepair || targetState.foundation) &&
 			    playerCheck(entState, targetState, ["Player", "Ally"]))
 			{
 				data.command = "repair";
 				data.target = targetState.id;
 				cursor = "action-repair";
 			}
 			else if (targetState.garrisonHolder &&
 			    playerCheck(entState, targetState, ["Player", "MutualAlly"]))
 			{
 				data.command = "garrison";
 				data.target = targetState.id;
 				cursor = "action-garrison";
 
 				tooltip = sprintf(translate("Current garrison: %(garrisoned)s/%(capacity)s"), {
 					"garrisoned": targetState.garrisonHolder.garrisonedEntitiesCount,
 					"capacity": targetState.garrisonHolder.capacity
 				});
 
 				if (targetState.garrisonHolder.garrisonedEntitiesCount >=
 				    targetState.garrisonHolder.capacity)
 					tooltip = coloredText(tooltip, "orange");
 			}
 			else if (targetState.resourceSupply)
 			{
 				let resourceType = targetState.resourceSupply.type;
 				if (resourceType.generic == "treasure")
 					cursor = "action-gather-" + resourceType.generic;
 				else
 					cursor = "action-gather-" + resourceType.specific;
 
 				data.command = "gather-near-position";
 				data.resourceType = resourceType;
 				data.resourceTemplate = targetState.template;
 				if (!targetState.speed)
 				{
 					data.command = "gather";
 					data.target = targetState.id;
 				}
 			}
 			else if (entState.market && targetState.market &&
 			         entState.id != targetState.id &&
 			         (!entState.market.naval || targetState.market.naval) &&
 			         !playerCheck(entState, targetState, ["Enemy"]))
 			{
 				// Find a trader (if any) that this structure can train.
 				let trader;
 				if (entState.production && entState.production.entities.length)
 					for (let i = 0; i < entState.production.entities.length; ++i)
 						if ((trader = GetTemplateData(entState.production.entities[i]).trader))
 							break;
 
 				let traderData = {
 					"firstMarket": entState.id,
 					"secondMarket": targetState.id,
 					"template": trader
 				};
 
 				let gain = Engine.GuiInterfaceCall("GetTradingRouteGain", traderData);
 				if (gain)
 				{
 					data.command = "trade";
 					data.target = traderData.secondMarket;
 					data.source = traderData.firstMarket;
 					cursor = "action-setup-trade-route";
 
 					if (gain.traderGain)
 						tooltip = translate("Right-click to establish a default route for new traders.") + "\n" +
 							sprintf(
 								trader ?
 									translate("Gain: %(gain)s") :
 									translate("Expected gain: %(gain)s"),
 								{ "gain": getTradingTooltip(gain) });
 					else
 					{
 						disabled = true;
 						tooltip = setStringTags(translate("This market is too close to the origin market."), g_DisabledTags);
 						cursor = "action-setup-trade-route-disabled";
 					}
 				}
 			}
 			else if ((targetState.needsRepair || targetState.foundation) && playerCheck(entState, targetState, ["Ally"]))
 			{
 				data.command = "repair";
 				data.target = targetState.id;
 				cursor = "action-repair";
 			}
 			else if (playerCheck(entState, targetState, ["Enemy"]))
 			{
 				data.target = targetState.id;
 				data.command = "attack";
 				cursor = "action-attack";
 			}
 
 			// Don't allow the rally point to be set on any of the currently selected entities (used for unset)
 			// except if the autorallypoint hotkey is pressed and the target can produce entities
 			if (!Engine.HotkeyIsPressed("session.autorallypoint") ||
 			    !targetState.production ||
 			    !targetState.production.entities.length)
 				for (let ent in g_Selection.selected)
 					if (targetState.id == +ent)
 						return false;
 
 			return {
 				"possible": true,
 				"data": data,
 				"position": targetState.position,
 				"cursor": cursor,
 				"disabled": disabled,
 				"tooltip": tooltip
 			};
 
 		},
 		"actionCheck": function(target, selection)
 		{
 			if (someUnitAI(selection) || !someRallyPoints(selection))
 				return false;
 
 			let actionInfo = getActionInfo("set-rallypoint", target, selection);
 
 			if (actionInfo.disabled)
 				return {
 					"type": "none",
 					"cursor": actionInfo.cursor,
 					"target": null,
 					"tooltip": actionInfo.tooltip
 				};
 
 			if (!actionInfo.possible)
 				return false;
 
 			return {
 				"type": "set-rallypoint",
 				"cursor": actionInfo.cursor,
 				"data": actionInfo.data,
 				"tooltip": actionInfo.tooltip,
 				"position": actionInfo.position
 			};
 		},
 		"specificness": 6,
 	},
 
 	"unset-rallypoint":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			Engine.PostNetworkCommand({
 				"type": "unset-rallypoint",
 				"entities": selection
 			});
 
 			// Remove displayed rally point
 			Engine.GuiInterfaceCall("DisplayRallyPoint", {
 				"entities": []
 			});
 
 			return true;
 		},
 		"getActionInfo": function(entState, targetState)
 		{
 			if (entState.id != targetState.id ||
 			    !entState.rallyPoint || !entState.rallyPoint.position)
 				return false;
 
 			return { "possible": true };
 		},
 		"actionCheck": function(target, selection)
 		{
 			if (someUnitAI(selection) || !someRallyPoints(selection) ||
 			    !getActionInfo("unset-rallypoint", target, selection).possible)
 				return false;
 
 			return {
 				"type": "unset-rallypoint",
 				"cursor": "action-unset-rally"
 			};
 		},
 		"specificness": 11,
 	},
 
 	"none":
 	{
 		"execute": function(target, action, selection, queued)
 		{
 			return true;
 		},
 		"specificness": 100,
 	},
 };
 
 var g_UnitActionsSortedKeys = Object.keys(g_UnitActions).sort((a, b) => g_UnitActions[a].specificness - g_UnitActions[b].specificness);
 
 /**
  * Info and actions for the entity commands
  * Currently displayed in the bottom of the central panel
  */
 var g_EntityCommands =
 {
 	"unload-all": {
 		"getInfo": function(entStates)
 		{
 			let count = 0;
 			for (let entState of entStates)
 				if (entState.garrisonHolder)
 					count += entState.garrisonHolder.entities.length;
 
 			if (!count)
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.unload") +
 				           translate("Unload All."),
 				"icon": "garrison-out.png",
 				"count": count,
 			};
 		},
 		"execute": function()
 		{
 			unloadAll();
 		},
 	},
 
 	"delete": {
 		"getInfo": function(entStates)
 		{
 			return entStates.some(entState => !isUndeletable(entState)) ?
 				{
 					"tooltip":
 						colorizeHotkey("%(hotkey)s" + " ", "session.kill") +
 						translate("Destroy the selected units or structures.") + "\n" +
 						colorizeHotkey(
 							translate("Use %(hotkey)s to avoid the confirmation dialog."),
 							"session.noconfirmation"
 						),
 					"icon": "kill_small.png"
 				} :
 				{
 					// Get all delete reasons and remove duplications
 					"tooltip": entStates.map(entState => isUndeletable(entState))
 						.filter((reason, pos, self) =>
 							self.indexOf(reason) == pos && reason
 						).join("\n"),
 					"icon": "kill_small_disabled.png"
 				};
 		},
 		"execute": function(entStates)
 		{
 			let entityIDs = entStates.reduce(
 				(ids, entState) => {
 					if (!isUndeletable(entState))
 						ids.push(entState.id);
 					return ids;
 				},
 				[]);
 
 			if (!entityIDs.length)
 				return;
 
 			let deleteSelection = () => Engine.PostNetworkCommand({
 				"type": "delete-entities",
 				"entities": entityIDs
 			});
 
 			if (Engine.HotkeyIsPressed("session.noconfirmation"))
 				deleteSelection();
 			else
 				(new DeleteSelectionConfirmation(deleteSelection)).display();
 		},
 	},
 
 	"stop": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => !entState.unitAI))
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.stop") +
 				           translate("Abort the current order."),
 				"icon": "stop.png"
 			};
 		},
 		"execute": function(entStates)
 		{
 			if (entStates.length)
 				stopUnits(entStates.map(entState => entState.id));
 		},
 	},
 
 	"garrison": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => !entState.unitAI || entState.turretParent || false))
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.garrison") +
 				           translate("Order the selected units to garrison in a structure or unit."),
 				"icon": "garrison.png"
 			};
 		},
 		"execute": function()
 		{
 			inputState = INPUT_PRESELECTEDACTION;
 			preSelectedAction = ACTION_GARRISON;
 		},
 	},
 
 	"unload": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => {
 				if (!entState.unitAI || !entState.turretParent)
 					return true;
 				let parent = GetEntityState(entState.turretParent);
 				return !parent || !parent.garrisonHolder || parent.garrisonHolder.entities.indexOf(entState.id) == -1;
 			}))
 				return false;
 
 			return {
 				"tooltip": translate("Unload"),
 				"icon": "garrison-out.png"
 			};
 		},
 		"execute": function()
 		{
 			unloadSelection();
 		},
 	},
 
 	"repair": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => !entState.builder))
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.repair") +
 				           translate("Order the selected units to repair a structure, ship, or siege engine."),
 				"icon": "repair.png"
 			};
 		},
 		"execute": function()
 		{
 			inputState = INPUT_PRESELECTEDACTION;
 			preSelectedAction = ACTION_REPAIR;
 		},
 	},
 
 	"focus-rally": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => !entState.rallyPoint))
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "camera.rallypointfocus") +
 				           translate("Focus on Rally Point."),
 				"icon": "focus-rally.png"
 			};
 		},
 		"execute": function(entStates)
 		{
 			// TODO: Would be nicer to cycle between the rallypoints of multiple entities instead of just using the first
 			let focusTarget;
 			for (let entState of entStates)
 				if (entState.rallyPoint && entState.rallyPoint.position)
 				{
 					focusTarget = entState.rallyPoint.position;
 					break;
 				}
 			if (!focusTarget)
 				for (let entState of entStates)
 					if (entState.position)
 					{
 						focusTarget = entState.position;
 						break;
 					}
 
 			if (focusTarget)
 				Engine.CameraMoveTo(focusTarget.x, focusTarget.z);
 		},
 	},
 
 	"back-to-work": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => !entState.unitAI || !entState.unitAI.hasWorkOrders))
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.backtowork") +
 				           translate("Back to Work"),
 				"icon": "back-to-work.png"
 			};
 		},
 		"execute": function()
 		{
 			backToWork();
 		},
 	},
 
 	"add-guard": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState =>
 				!entState.unitAI || !entState.unitAI.canGuard || entState.unitAI.isGuarding))
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.guard") +
 				           translate("Order the selected units to guard a structure or unit."),
 				"icon": "add-guard.png"
 			};
 		},
 		"execute": function()
 		{
 			inputState = INPUT_PRESELECTEDACTION;
 			preSelectedAction = ACTION_GUARD;
 		},
 	},
 
 	"remove-guard": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => !entState.unitAI || !entState.unitAI.isGuarding))
 				return false;
 
 			return {
 				"tooltip": translate("Remove guard"),
 				"icon": "remove-guard.png"
 			};
 		},
 		"execute": function()
 		{
 			removeGuard();
 		},
 	},
 
 	"select-trading-goods": {
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => !entState.market))
 				return false;
 
 			return {
 				"tooltip": translate("Barter & Trade"),
 				"icon": "economics.png"
 			};
 		},
 		"execute": function()
 		{
 			g_TradeDialog.toggle();
 		},
 	},
 
 	"patrol": {
 		"getInfo": function(entStates)
 		{
 			if (!entStates.some(entState => entState.unitAI && entState.unitAI.canPatrol))
 				return false;
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.patrol") +
 				           translate("Patrol") + "\n" +
 				           translate("Attack all encountered enemy units while avoiding structures."),
 				"icon": "patrol.png"
 			};
 		},
 		"execute": function()
 		{
 			inputState = INPUT_PRESELECTEDACTION;
 			preSelectedAction = ACTION_PATROL;
 		},
 	},
 
 	"share-dropsite": {
 		"getInfo": function(entStates)
 		{
 			let sharableEntities = entStates.filter(
 				entState => entState.resourceDropsite && entState.resourceDropsite.sharable);
 			if (!sharableEntities.length)
 				return false;
 
 			// Returns if none of the entities belong to a player with a mutual ally
 			if (entStates.every(entState => !GetSimState().players[entState.player].isMutualAlly.some(
 				(isAlly, playerId) => isAlly && playerId != entState.player)))
 				return false;
 
 			return sharableEntities.some(entState => !entState.resourceDropsite.shared) ?
 				{
 					"tooltip": translate("Press to allow allies to use this dropsite"),
 					"icon": "locked_small.png"
 				} :
 				{
 					"tooltip": translate("Press to prevent allies from using this dropsite"),
 					"icon": "unlocked_small.png"
 				};
 		},
 		"execute": function(entStates)
 		{
 			let sharableEntities = entStates.filter(
 				entState => entState.resourceDropsite && entState.resourceDropsite.sharable);
 			Engine.PostNetworkCommand({
 				"type": "set-dropsite-sharing",
 				"entities": sharableEntities.map(entState => entState.id),
 				"shared": sharableEntities.some(entState => !entState.resourceDropsite.shared)
 			});
 		},
 	}
 };
 
 var g_AllyEntityCommands =
 {
 	"unload-all": {
 		"getInfo": function(entState)
 		{
 			if (!entState.garrisonHolder)
 				return false;
 
 			let player = Engine.GetPlayerID();
 
 			let count = 0;
 			for (let ent in g_Selection.selected)
 			{
 				let selectedEntState = GetEntityState(+ent);
 				if (!selectedEntState.garrisonHolder)
 					continue;
 
 				for (let entity of selectedEntState.garrisonHolder.entities)
 				{
 					let state = GetEntityState(entity);
 					if (state.player == player)
 						++count;
 				}
 			}
 
 			return {
 				"tooltip": colorizeHotkey("%(hotkey)s" + " ", "session.unload") +
 				           translate("Unload All."),
 				"icon": "garrison-out.png",
 				"count": count,
 			};
 		},
 		"execute": function(entState)
 		{
 			unloadAll();
 		},
 	},
 
 	"share-dropsite": {
 		"getInfo": function(entState)
 		{
 			if (Engine.GetPlayerID() == -1 ||
 			    !GetSimState().players[Engine.GetPlayerID()].hasSharedDropsites ||
 			    !entState.resourceDropsite || !entState.resourceDropsite.sharable)
 				return false;
 
 			if (entState.resourceDropsite.shared)
 				return {
 					"tooltip": translate("You are allowed to use this dropsite"),
 					"icon": "unlocked_small.png"
 				};
 
 			return {
 				"tooltip": translate("The use of this dropsite is prohibited"),
 				"icon": "locked_small.png"
 			};
 		},
 		"execute": function(entState)
 		{
 			// This command button is always disabled
 		},
 	}
 };
 
 function playerCheck(entState, targetState, validPlayers)
 {
 	let playerState = GetSimState().players[entState.player];
 	for (let player of validPlayers)
 		if (player == "Gaia" && targetState.player == 0 ||
 		    player == "Player" && targetState.player == entState.player ||
 		    playerState["is" + player] && playerState["is" + player][targetState.player])
 			return true;
 
 	return false;
 }
 
 function hasClass(entState, className)
 {
 	// note: use the functions in globalscripts/Templates.js for more versatile matching
 	return entState.identity && entState.identity.classes.indexOf(className) != -1;
 }
 
 /**
  * Work out whether at least part of the selected entities have UnitAI.
  */
 function someUnitAI(entities)
 {
 	return entities.some(ent => {
 		let entState = GetEntityState(ent);
 		return entState && entState.unitAI || false;
 	});
 }
 
 function someRallyPoints(entities)
 {
 	return entities.some(ent => {
 		let entState = GetEntityState(ent);
 		return entState && entState.rallyPoint || false;
 	});
 }
 
 function someGuarding(entities)
 {
 	return entities.some(ent => {
 		let entState = GetEntityState(ent);
 		return entState && entState.unitAI && entState.unitAI.isGuarding;
 	});
 }
 
 function someCanPatrol(entities)
 {
 	return entities.some(ent => {
 		let entState = GetEntityState(ent);
 		return entState && entState.unitAI && entState.unitAI.canPatrol;
 	});
 }
 
 /**
  * Keep in sync with Commands.js.
  */
 function isUndeletable(entState)
 {
 	let playerState = g_SimState.players[entState.player];
 	if (playerState && playerState.controlsAll)
 		return false;
 
 	if (entState.resourceSupply && entState.resourceSupply.killBeforeGather)
 		return translate("The entity has to be killed before it can be gathered from");
 
 	if (entState.capturePoints && entState.capturePoints[entState.player] < entState.maxCapturePoints / 2)
 		return translate("You cannot destroy this entity as you own less than half the capture points");
 
 	if (!entState.identity.canDelete)
 		return translate("This entity is undeletable");
 
 	return false;
 }
 
 function DrawTargetMarker(target)
 {
 	Engine.GuiInterfaceCall("AddTargetMarker", {
 		"template": g_TargetMarker.move,
 		"x": target.x,
 		"z": target.z
 	});
 }
 
 function findGatherType(gatherer, supply)
 {
 	if (!gatherer.resourceGatherRates || !supply)
 		return undefined;
 
 	if (gatherer.resourceGatherRates[supply.type.generic + "." + supply.type.specific])
 		return supply.type.specific;
 
 	if (gatherer.resourceGatherRates[supply.type.generic])
 		return supply.type.generic;
 
 	return undefined;
 }
 
 function getActionInfo(action, target, selection)
 {
 	let simState = GetSimState();
 
 	// If the selection doesn't exist, no action
 	if (!GetEntityState(selection[0]))
 		return { "possible": false };
 
 	if (!target) // TODO move these non-target actions to an object like unit_actions.js
 	{
 		if (action == "set-rallypoint")
 		{
 			let cursor = "";
 			let data = { "command": "walk" };
 			if (Engine.HotkeyIsPressed("session.attackmove"))
 			{
 				data.command = "attack-walk";
 				data.targetClasses = Engine.HotkeyIsPressed("session.attackmoveUnit") ?
 					{ "attack": ["Unit"] } : { "attack": ["Unit", "Structure"] };
 				cursor = "action-attack-move";
 			}
 			else if (Engine.HotkeyIsPressed("session.patrol"))
 			{
 				data.command = "patrol";
 				data.targetClasses = { "attack": g_PatrolTargets };
 				cursor = "action-patrol";
 			}
 			return {
 				"possible": true,
 				"data": data,
 				"cursor": cursor
 			};
 		}
 
 		return {
 			"possible": ["move", "attack-move", "remove-guard", "patrol"].indexOf(action) != -1
 		};
 	}
 
 	// Look at the first targeted entity
 	// (TODO: maybe we eventually want to look at more, and be more context-sensitive?
 	// e.g. prefer to attack an enemy unit, even if some friendly units are closer to the mouse)
 	let targetState = GetEntityState(target);
 	if (!targetState)
 		return { "possible": false };
 
 	// Check if any entities in the selection can do some of the available actions with target
 	for (let entityID of selection)
 	{
 		let entState = GetEntityState(entityID);
 		if (!entState)
 			continue;
 
 		if (g_UnitActions[action] && g_UnitActions[action].getActionInfo)
 		{
 			let r = g_UnitActions[action].getActionInfo(entState, targetState, simState);
 			if (r && r.possible) // return true if it's possible for one of the entities
 				return r;
 		}
 	}
 	return { "possible": false };
 }