Refactoring, Bug Prediction, Shortest Paths prediction

Chase bug and FarChase bug simulators implemented. Codes faster reachable by
opponent get lowered values.

farbot/src/farbot/FarbotIO.java

@@ -5,7 +5,6 @@ import java.util.regex.Pattern;
 
 import farbot.ai.AI;
 import farbot.game.GameState;
-import farbot.game.Settings;
 
 public class FarbotIO {
 	private static Scanner in;

farbot/src/farbot/Settings.java

@@ -1,4 +1,4 @@
-package farbot.game;
+package farbot;
 
 public class Settings {
 	private Integer timebank;

farbot/src/farbot/ai/AI.java

@@ -1,11 +1,12 @@
 package farbot.ai;
 
 import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
 import java.util.Set;
 
 import farbot.game.GameState;
-import farbot.game.MoveResult;
-import farbot.game.map.Move;
+import farbot.game.Move;
 
 import static farbot.FarbotIO.logln;
 
@@ -21,28 +22,46 @@ public class AI {
 	
 	public String calcMove(Integer time) {
 		logln("Calculating move in "+time+"ms");
+		
+		Set<Move> validMoves = getValidMoves();
+		List<MoveValue> valuedMoves = getValuedMoves(validMoves);
+		MoveValue maxMove = getMaxMove(valuedMoves);
+		
+		this.lastMove = maxMove;
+		
+		logln("Max.move '"+maxMove.move+"': "+maxMove.value);
+		return maxMove.move.name().toLowerCase();
+	}
+	
+	private Set<Move> getValidMoves(){
 		Set<Move> validMoves = currentState.selfMoves();
 		logln("Valid moves: "+validMoves.toString());
+		return validMoves;
+	}
 	
+	private List<MoveValue> getValuedMoves(Set<Move> validMoves){
 		ArrayList<MoveValue> valuedMoves = new ArrayList<>();
 		
 		for(Move m: validMoves) {
 			logln("Checking move: "+m.name());
-			GameState fork = currentState.fork();
-			MoveResult mr = fork.moveSelf(m);
-			GameTree gt = new GameTree(fork);
+			
+			GameTree gt = new GameTree(currentState.fork(), m);
 			gt.build(treeDepth);
 			Double value = gt.getValue();
-			value += mr.getCollectedCodes()*Math.pow((treeDepth+1), 1.6);
-			value -= mr.getKilledBugs()*8*Math.pow((treeDepth+1), 1.6);
 
 			logln("Move '"+m.name()+"': "+value);
 			valuedMoves.add(new MoveValue(m, value));
 		}
 		
-		valuedMoves.sort((mv1, mv2) -> -mv1.value.compareTo(mv2.value));
+		return valuedMoves;
+	}
+	
+	private MoveValue getMaxMove(List<MoveValue> valuedMoves) {
+		valuedMoves.sort(Comparator.comparingDouble(m -> -m.value));
 		MoveValue maxMove = valuedMoves.get(0);
-		if(this.lastMove != null && this.lastMove.value <= maxMove.value) {
+		
+		// Prevent fallback loop
+		if(this.lastMove != null && this.lastMove.value >= maxMove.value) {
 			switch(this.lastMove.move) {
 			case LEFT:
 				if(maxMove.move == Move.RIGHT) maxMove = valuedMoves.get(1);
@@ -61,10 +80,7 @@ public class AI {
 			}
 		}
 		
-		this.lastMove = maxMove;
-		
-		logln("Max.move '"+maxMove.move+"': "+maxMove.value);
-		return maxMove.move.name().toLowerCase();
+		return maxMove;
 	}
 	
 	public void parseUpdate(String[] update) {

farbot/src/farbot/ai/GameTree.java

@@ -2,33 +2,42 @@ package farbot.ai;
 
 import static farbot.FarbotIO.logln;
 
-import farbot.game.map.Point;
 import java.util.HashSet;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.Queue;
 import java.util.Set;
+import java.util.function.BinaryOperator;
 
 import farbot.game.GameState;
-import farbot.game.MoveResult;
+import farbot.game.Move;
+import farbot.game.Point;
+import farbot.game.map.util.ShortestPaths;
+import farbot.game.token.Code;
 
 public class GameTree {
 	private GameState node;
 	private Double value;
 	private HashSet<Point> visited;
 	private Integer totalLevel;
+	private Move initMove;
 	
-	public GameTree(GameState root) {
+	public GameTree(GameState root, Move initMove) {
 		this.node = root;
 		this.value = 0.0;
 		this.totalLevel = 1;
 		this.visited = new HashSet<>();
+		this.initMove = initMove;
 	}
 	
 	public void build(int level) {
 		this.totalLevel = level;
 		
-		Queue<GameState> children = makeChildren(node, this, level);
+		MoveResult mr = Simulator.move(initMove, node);
+		value += valueCodes(mr, level, node, this);
+		value += valueBugs(mr, level, node);
 		
+		Queue<GameState> children = makeChildren(node, this, --level);
 		while(level > 0) {
 			level--;
 			
@@ -62,16 +71,10 @@ public class GameTree {
 
 		for(Point selfMove: selfMoves) {			
 			GameState child = state.fork();
-			MoveResult mr = child.moveSelf(selfMove);
+			MoveResult mr = Simulator.move(selfMove, child);
 			
-			if(mr.getCollectedCodes() != 0){
-				logln("Got "+mr.getCollectedCodes()+" codes at "+selfMove.toString()+" in level "+level);
-				gtRoot.value += Math.pow(level*mr.getCollectedCodes(), 1.3);
-			}
-			if(mr.getKilledBugs() != 0) {
-				logln("Killed "+mr.getKilledBugs()+" bugs at "+selfMove.toString()+" in level "+level);
-				gtRoot.value -= Math.pow(level*4*mr.getKilledBugs(), level/totalLevel);
-			}
+			gtRoot.value += valueCodes(mr, level, child, gtRoot);
+			gtRoot.value += valueBugs(mr, level, child);
 			
 			gtRoot.visited.add(selfMove);
 			
@@ -80,4 +83,50 @@ public class GameTree {
 		
 		return children;
 	}
+	
+	private double valueBugs(MoveResult moveResult, int level, GameState state) {
+		double value = 0.0;
+		if(moveResult.lenKilledBugs() != 0) {
+			value =  -1 * Math.pow(level*4*moveResult.lenKilledBugs(), (double) level/totalLevel);
+			if (level >= totalLevel-1) value *= 2;
+			if (level >= 5) value /= 2; 
+			
+			logln("Killed "+moveResult.lenKilledBugs()+" bugs at "+state.getSelfPosition()+" in level "+level+" @ "+value);
+			
+		}
+		return value;
+	}
+	
+	private double valueCodes(MoveResult moveResult, int level, GameState state, GameTree gtRoot) {
+		double value = 0.0;
+		if(moveResult.lenCollectedCodes() != 0){
+			
+			double codeValSum = moveResult.getCollectedCodes().stream()
+					.map(c -> codeVal(c, gtRoot))
+					.reduce(Double::sum).get();
+			
+			value = Math.pow(level*codeValSum, 1.7);
+			logln("Got "+moveResult.lenCollectedCodes()+" codes at "+state.getSelfPosition()+" in level "+level+ " @ "+value);
+		}
+		return value;
+	}
+	
+	private Double codeVal(Code code, GameTree gtRoot) {
+		List<Point> opponentShortestPath = ShortestPaths.shortestPath(
+				gtRoot.node.getOpponentPosition(), code.getPosition());
+		
+		List<Point> selfShortestPath = ShortestPaths.shortestPath(
+				gtRoot.node.getSelfPosition(), code.getPosition());
+		
+		logln("Shortest path for Code at "+code.getPosition()+
+				": Opponent="+opponentShortestPath.size()+
+				", Self="+selfShortestPath.size());
+		
+		
+		if(opponentShortestPath.size() < selfShortestPath.size()) {
+			if(opponentShortestPath.size() <= 3) return 0.0;
+			return 1.0/(selfShortestPath.size() - opponentShortestPath.size()+0.5);
+		}
+		return 1.0;
+	}
 }

farbot/src/farbot/ai/MoveResult.java

@@ -0,0 +1,40 @@
+package farbot.ai;
+
+import java.util.List;
+
+import farbot.game.Player;
+import farbot.game.token.Bug;
+import farbot.game.token.Code;
+
+public class MoveResult {
+	private Player player;
+	private List<Bug> killedBugs;
+	private List<Code> collectedCodes;
+	
+	public MoveResult(Player player, List<Code> collectedCodes, List<Bug> killedBugs) {
+		this.player = player;
+		this.killedBugs = killedBugs;
+		this.collectedCodes = collectedCodes;
+	}
+
+	public Player getPlayer() {
+		return player;
+	}
+
+	public List<Bug> getKilledBugs() {
+		return killedBugs;
+	}
+	
+	public int lenKilledBugs() {
+		return killedBugs.size();
+	}
+
+	public List<Code> getCollectedCodes() {
+		return collectedCodes;
+	}
+	
+	public int lenCollectedCodes() {
+		return collectedCodes.size();
+	}
+	
+}

farbot/src/farbot/ai/Parser.java

@@ -1,19 +1,24 @@
 package farbot.ai;
 
-import farbot.game.map.Point;
-
+import farbot.Settings;
 import farbot.game.GameState;
-import farbot.game.Settings;
+import farbot.game.Point;
 import farbot.game.token.Bug;
 import farbot.game.token.Bug.BugAI;
 import farbot.game.token.Code;
 import farbot.game.token.Mine;
 
+import static farbot.FarbotIO.logln;
+import static farbot.FarbotIO.log;
+
 public class Parser {
 	public static void parse(String[] update, GameState state) {
 		switch(update[2]) {
 		case "round":
 			state.setRound(Integer.parseInt(update[3]));
+			log("\n");
+			logln("******* Round "+state.getRound()+" *******");
+			log("\n");
 			break;
 		case "field":
 			parseMap(update[3].split(","), state);

farbot/src/farbot/ai/Simulator.java

@@ -0,0 +1,103 @@
+package farbot.ai;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Set;
+
+import farbot.game.GameState;
+import farbot.game.Move;
+import farbot.game.Player;
+import farbot.game.Point;
+import farbot.game.token.Bug;
+import farbot.game.token.Code;
+
+public class Simulator {
+	public static MoveResult move(Move move, GameState state) {
+		Point movePoint = state.calcMovePoint(state.getSelfPosition(), move);
+		return move(movePoint, state);
+	}
+	
+	public static MoveResult move(Point position, GameState state) {
+		state.moveSelf(position);
+		List<Bug> bugs = state.removeBugsAt(state.getSelfPosition());
+		List<Code> codes = state.removeCodesAt(state.getSelfPosition());
+		
+		predictBugs(state);
+
+		bugs.addAll(state.removeBugsAt(state.getSelfPosition()));
+
+		state.addSelfSnippets(codes.size());
+		state.removeSelfSnippets(bugs.size()*4);
+		
+		return new MoveResult(state.getSelfClone(), codes, bugs);
+	
+	}
+	
+	private static void predictBugs(GameState state) {
+		List<Bug> bugs = state.getBugs();
+		state.clearBugs();
+		
+		for(Bug bug: bugs) {
+			Point movePoint = bug.getPosition();
+			switch(bug.getAiType()) {
+			case CHASE:
+				movePoint = chaseAI(bug, state);
+				break;
+			case FAR_CHASE:
+				movePoint = farChaseAI(bug, state);
+				break;
+			default:
+				break;
+			}
+			state.putToken(new Bug(movePoint.x, movePoint.y, bug.getAiType()));
+		}
+	}
+	
+	private static Point chaseAI(Bug chaseBug, GameState state) {
+		Player nearestPlayer = state.getPlayerClones().stream()
+				.min(Comparator.comparingDouble(p -> p.distance(chaseBug.getPosition())))
+				.get();
+		
+		return euclideanBugMove(chaseBug.getPosition(), 
+				nearestPlayer.getPosition(), 
+				state);
+	}
+	
+	private static Point farChaseAI(Bug farChaseBug, GameState state) {
+		// only difference to chaseAI: uses .max
+		Player farthestPlayer = state.getPlayerClones().stream()
+				.max(Comparator.comparingDouble(p -> p.distance(farChaseBug.getPosition())))
+				.get();
+		
+		return euclideanBugMove(farChaseBug.getPosition(), 
+				farthestPlayer.getPosition(), 
+				state);
+	}
+	
+	private static Point euclideanBugMove(Point from, Point to, GameState state) {
+		ArrayList<Point> movePoints = new ArrayList<Point>();
+		movePoints.addAll(bugMovePoints(from, state));
+		Collections.shuffle(movePoints);
+		Point nearestPoint = movePoints.stream()
+				.min(Comparator.comparingDouble(to::distance))
+				.get(); // .min returns an Optional<Point>
+		
+		return nearestPoint;
+	}
+	
+	private static Set<Point> bugMovePoints(Point from, GameState state){
+		Set<Point> movePoints = state.movePoints(from);
+		
+		// Bugs can't use Gates 
+		// TODO: Move this to GameMap
+		if(from.equals(new Point(0,7))) {
+			movePoints.remove(new Point(18,7));
+		}else if(from.equals(new Point(18,7))) {
+			movePoints.remove(new Point(0,7));
+		}
+		
+		return movePoints;
+	}
+}

farbot/src/farbot/game/GameState.java

@@ -1,20 +1,32 @@
 package farbot.game;
 
-import farbot.game.map.Point;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 
+import farbot.Settings;
+import farbot.ai.MoveResult;
 import farbot.game.map.GameMap;
-import farbot.game.map.Move;
+import farbot.game.map.util.Movement;
 import farbot.game.token.Bug;
 import farbot.game.token.Code;
 import farbot.game.token.Mine;
 
 /**
- * Manager for the GameState.
+ * The public interface for managing the game state
  * 
- * Any data retrieved from GameState belongs to the caller.
+ * Users may not alter player, map or token
+ * states directly, but only through the API provided by
+ * this class.  
+ * 
+ * Any data retrieved from GameState belongs to the caller
+ * and is safe to use. You cannot change the GameState by
+ * altering data returned from GameState methods. Use
+ * the appropriate mutating methods instead.
+ * 
+ * GameState can create a fast, lazy clone of itself
+ * by calling fork(). Forking itself is as cheap as possible. 
+ * Deep field copies are created lazily, i.e. only if needed.
  */
 public class GameState {
 	private Integer round;
@@ -44,33 +56,17 @@ public class GameState {
 		this.forked = forked;
 	}
 
-	public List<GameState> fork(Integer times) {
-		ArrayList<GameState> forks = new ArrayList<>();
-		for (int i=0; i<times; i++) forks.add(fork());
-		return forks;
+	
+	public Integer getRound() {
+		return round;
+	}
+	public void setRound(Integer round) {
+		this.round = round;
 	}
 	
-	public GameState fork() {
-		GameState fork = new GameState(self.clone(), opponent.clone(), map.fork(), round, true);
-		fork.map.setForked(true);
-		return fork;
-	}
-
-	public void putToken(Bug bug) {
-		map.putToken(bug);
-	}
-
-	public void putToken(Code code) {
-		map.putToken(code);
-	}
-
-	public void putToken(Mine mine) {
-		map.putToken(mine);
-	}
-
-	public void clearTokens() {
-		map.clearTokens();
-	}
+	/*
+	 * Player Management
+	 */
 	
 	public void setSnippets(String playerName, Integer snippets) {
 		Settings s = Settings.getInstance();
@@ -82,8 +78,12 @@ public class GameState {
 		return self.getSnippets();
 	}
 	
-	public Integer getOpponentSnippets() {
-		return opponent.getSnippets();
+	public void addSelfSnippets(Integer snippets) {
+		self.addSnippets(snippets);
+	}
+	
+	public void removeSelfSnippets(Integer snippets) {
+		self.removeSnippets(snippets);
 	}
 
 	public void setBombs(String playerName, Integer bombs) {
@@ -102,64 +102,107 @@ public class GameState {
 		return self.getPosition();
 	}
 	
-	public MoveResult moveSelf(Point position) {
-		return makeMove(self, position);
+	public Point getOpponentPosition() {
+		return opponent.getPosition();
 	}
 
-	public MoveResult moveSelf(Move move) {
-		return makeMove(self, calcMovePoint(self.getPosition(), move));
+	public void moveSelf(Point position) {
+		self.setPosition(position);
 	}
 	
-	public MoveResult moveOpponent(Point position) {
-		return makeMove(opponent, position);
+	public void moveSelf(Move move) {
+		self.setPosition(calcMovePoint(self.getPosition(), move));
 	}
 	
-	public MoveResult moveOpponent(Move move) {
-		return makeMove(self, calcMovePoint(opponent.getPosition(), move));
+	public Player getSelfClone() {
+		return self.clone();
 	}
 	
-	private MoveResult makeMove(Player player, Point position) {
-		player.setPosition(position);
-		
-		List<Code> codes = map.removeCodesAt(position);
-		List<Bug> bugs = map.removeBugsAt(position);
-
-		player.addSnippets(codes.size());
-		player.removeSnippets(bugs.size()*4);
-		
-		return new MoveResult(player.clone(), codes.size(), bugs.size());
+	public List<Player> getPlayerClones() {
+		ArrayList<Player> players = new ArrayList<>();
+		players.add(self.clone());
+		players.add(opponent.clone());
+		return players;
 	}
 	
-	public Integer getRound() {
-		return round;
+	/*
+	 * Token Management
+	 */
+	
+	public void putToken(Bug bug) {
+		map.putToken(bug);
 	}
-	public void setRound(Integer round) {
-		this.round = round;
+
+	public void putToken(Code code) {
+		map.putToken(code);
 	}
 
+	public void putToken(Mine mine) {
+		map.putToken(mine);
+	}
+	
+	public List<Code> removeCodesAt(Point position){
+		return map.removeCodesAt(position);
+	}
+	
+	public List<Bug> removeBugsAt(Point position){
+		return map.removeBugsAt(position);
+	}
+	
+	public List<Bug> getBugs(){
+		return map.getBugs();
+	}
+	
+	public void clearBugs() {
+		map.clearBugs();
+	}
+
+	public void clearTokens() {
+		map.clearTokens();
+	}
+	
+	/*
+	 * Movements Management
+	 */
+	
+	public Set<Point> selfMovePoints(){
+		return movePoints(self.getPosition());
+	}
+	
+	public Set<Move> selfMoves(){
+		return Movement.validMoves(self.getPosition());
+	}
+	
+	public Point calcMovePoint(Point from, Move move) {
+		return Movement.calcMovePoint(from, move);
+	}
+	
+	public Set<Point> movePoints(Point from){
+		return Movement.validMovePoints(from);
+	}
+	
+	/*
+	 * Fork Managment
+	 * 
+	 */
+
+	public List<GameState> fork(Integer times) {
+		ArrayList<GameState> forks = new ArrayList<>();
+		for (int i=0; i<times; i++) forks.add(fork());
+		return forks;
+	}
+	
+	public GameState fork() {
+		GameState fork = new GameState(self.clone(), opponent.clone(), map.fork(), round, true);
+		fork.map.setForked(true);
+		return fork;
+	}
+	
+
 	public boolean isForked() {
 		return forked;
 	}
 
-	public Set<Point> selfMovePoints(){
-		return map.validMovePoints(self.getPosition());
-	}
-	
-	public Set<Move> selfMoves(){
-		return map.validMoves(self.getPosition());
-	}
-	
-	public Set<Point> opponentMovePoints(){
-		return map.validMovePoints(opponent.getPosition());
-	}
-	
-	public Set<Move> opponentMoves(){
-		return map.validMoves(opponent.getPosition());
-	}
-	
-	public Point calcMovePoint(Point from, Move move) {
-		return map.calcMovePoint(from, move);
-	}
 
 	@Override
 	public String toString() {

farbot/src/farbot/game/Move.java

@@ -0,0 +1,14 @@
+package farbot.game;
+
+public enum Move {
+	UP (0,-1), 
+	DOWN (0,1), 
+	LEFT (-1,0), 
+	RIGHT (1,0);
+	
+	private final int x;
+	private final int y;
+	Move(int x, int y) { this.x = x; this.y = y; }
+	public int getX() { return x; }
+	public int getY() { return y; }
+}

farbot/src/farbot/game/MoveResult.java

@@ -1,27 +0,0 @@
-package farbot.game;
-
-public class MoveResult {
-	private Player player;
-	private int killedBugs;
-	private int collectedCodes;
-	
-	public MoveResult(Player player, int collectedCodes, int killedBugs) {
-		this.player = player;
-		this.killedBugs = killedBugs;
-		this.collectedCodes = collectedCodes;
-	}
-
-	public Player getPlayer() {
-		return player;
-	}
-
-	public int getKilledBugs() {
-		return killedBugs;
-	}
-
-	public int getCollectedCodes() {
-		return collectedCodes;
-	}
-	
-	
-}

farbot/src/farbot/game/Player.java

@@ -1,7 +1,5 @@
 package farbot.game;
 
-import farbot.game.map.Point;
-
 public class Player implements Cloneable {
 	private Integer bombs;
 	private Integer snippets;
@@ -53,6 +51,10 @@ public class Player implements Cloneable {
 		this.id = id;
 	}
 	
+	public double distance(Point point) {
+		return this.position.distance(point);
+	}
+	
 	@Override
 	public Player clone() {
 		return new Player(this.bombs, this.snippets, new Point(this.position), this.id);

farbot/src/farbot/game/Point.java

@@ -1,4 +1,4 @@
-package farbot.game.map;
+package farbot.game;
 
 public class Point extends java.awt.Point{
 
@@ -10,6 +10,11 @@ public class Point extends java.awt.Point{
 
     public Point(int x, int y) { super(x,y); }
     
+	
+	public Integer taxiDistance(Point to) {
+		return Math.abs(this.x - to.x) + Math.abs(this.y - to.y);
+	}
+   	
 	@Override
 	public String toString() {
 		return "(x=" + x + ",y=" + y + ")";

farbot/src/farbot/game/map/GameMap.java

@@ -1,6 +1,5 @@
 package farbot.game.map;
 
-import farbot.game.map.Point;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.EnumSet;
@@ -10,7 +9,9 @@ import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import farbot.game.Settings;
+import farbot.game.Move;
+import farbot.game.Point;
+import farbot.Settings;
 import farbot.game.token.Bug;
 import farbot.game.token.Code;
 import farbot.game.token.Mine;
@@ -85,37 +86,6 @@ public final class GameMap {
 		return new GameMap(this);
 	}
 
-	public Set<Move> validMoves(Point from) {
-		EnumSet<Move> moves;
-
-		switch(base[from.x][from.y]) {
-		case GATE_L:
-		case GATE_R:
-			moves = EnumSet.of(Move.LEFT, Move.RIGHT);
-			break;
-		default:
-			moves = EnumSet.allOf(Move.class);
-			moves.removeIf( move -> from.x+move.x < 0 
-					|| from.y+move.y < 0 
-					|| from.x+move.x >= s.getFieldWidth() 
-					|| from.y+move.y >= s.getFieldHeight()
-					|| base[from.x+move.x][from.y+move.y] == Field.WALL );
-			break;
-		}
-
-		return moves;
-	}
-
-	public Set<Point> validMovePoints(Point from){
-		return validMoves(from).stream()
-				.map(move -> calcMovePoint(from, move))
-				.collect(Collectors.toSet());
-	}
-	
-	public Point calcMovePoint(Point from, Move move) {
-		return new Point(Math.floorMod(from.x+move.x, s.getFieldWidth()),
-		 		   		 Math.floorMod(from.y+move.y, s.getFieldHeight()));
-	}
 
 	public void putToken(Bug bug) {
 		if(dirtyBugs) {
@@ -148,6 +118,12 @@ public final class GameMap {
 		mineMap.computeIfAbsent(mine.getPosition(), k -> new ArrayList<>()).add(mine);
 	}
 	
+	public void clearBugs() {
+		this.bugs = new ArrayList<>();
+		this.bugMap = new HashMap<>();
+		this.dirtyBugs = false;
+	}
+
 	public void clearTokens() {
 		this.bugs = new ArrayList<>();
 		this.codes = new ArrayList<>();
@@ -300,4 +276,8 @@ public final class GameMap {
 		
 		return Collections.unmodifiableList(tokens);
 	}
+
+	public static Field[][] getBase() {
+		return base;
+	}
 }

farbot/src/farbot/game/map/Move.java

@@ -1,12 +0,0 @@
-package farbot.game.map;
-
-public enum Move {
-	UP (0,-1), 
-	DOWN (0,1), 
-	LEFT (-1,0), 
-	RIGHT (1,0);
-	
-	protected final int x;
-	protected final int y;
-	Move(int x, int y) { this.x = x; this.y = y; }
-}

farbot/src/farbot/game/map/util/Movement.java

@@ -0,0 +1,53 @@
+package farbot.game.map.util;
+
+import java.util.EnumSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import farbot.Settings;
+import farbot.game.Move;
+import farbot.game.Point;
+import farbot.game.map.Field;
+import farbot.game.map.GameMap;
+
+/**
+ * Utility functions working on the invariant base map (GameMap.base).
+ * 
+ * Obey functional contract. Functions must not have side-effects.
+ */
+public class Movement {
+	private static Field[][] base = GameMap.getBase();
+
+	public static Set<Move> validMoves(Point from) {
+		EnumSet<Move> moves;
+
+		switch(base[from.x][from.y]) {
+		case GATE_L:
+		case GATE_R:
+			moves = EnumSet.of(Move.LEFT, Move.RIGHT);
+			break;
+		default:
+			moves = EnumSet.allOf(Move.class);
+			moves.removeIf( move -> 
+					from.getX()+move.getX() < 0 
+					|| from.y+move.getY() < 0 
+					|| from.x+move.getX() >= Settings.getInstance().getFieldWidth() 
+					|| from.y+move.getY() >= Settings.getInstance().getFieldHeight()
+					|| base[from.x+move.getX()][from.y+move.getY()] == Field.WALL );
+			break;
+		}
+
+		return moves;
+	}
+
+	public static Set<Point> validMovePoints(Point from){
+		return validMoves(from).stream()
+				.map(move -> calcMovePoint(from, move))
+				.collect(Collectors.toSet());
+	}
+	
+	public static Point calcMovePoint(Point from, Move move) {
+		return new Point(Math.floorMod(from.x+move.getX(), Settings.getInstance().getFieldWidth()),
+		 		   		 Math.floorMod(from.y+move.getY(), Settings.getInstance().getFieldHeight()));
+	}
+}

farbot/src/farbot/game/map/util/ShortestPaths.java

@@ -0,0 +1,119 @@
+package farbot.game.map.util;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.PriorityQueue;
+
+import farbot.game.Point;
+
+import static farbot.FarbotIO.logln;
+
+/**
+ * Utility functions working on the invariant base map (GameMap.base).
+ * 
+ * Obey functional contract. Functions must not have side-effects.
+ * 
+ * Memoized shortest paths calculation.
+ */
+public class ShortestPaths {
+	private static HashMap<Points, List<Point>> memo = new HashMap<>();
+	
+	public static List<Point> shortestPath(Point a, Point b){
+		assert(a != null); assert(b != null);
+		Points points = new Points(a,b);
+		
+		if(memo.containsKey(points)) return memo.get(points);
+		
+		List<Point> path = aStarSearch(a,b);
+		memo.put(new Points(a,b), path);
+		
+		return path; 
+	}
+	
+	private static List<Point> aStarSearch(Point start, Point goal){
+		logln("Calculating aStar from "+start+" to "+goal);
+		
+		PriorityQueue<ANode> frontier = new PriorityQueue<>(Comparator.comparingInt(a -> a.priority));
+		HashMap<Point, Point> cameFrom = new HashMap<>();
+		HashMap<Point, Integer> cost = new HashMap<>();
+		
+		frontier.add(new ANode(start,0));
+		cost.put(start, 0);
+		
+		while(!frontier.isEmpty()) {
+			ANode current = frontier.poll();
+			Point currentP = current.point;
+			
+			if(currentP.equals(goal)) break;
+			
+			for(Point nextP: Movement.validMovePoints(currentP)) {
+				int newCost = cost.get(currentP) + 1;
+				
+				if(!cost.containsKey(nextP) || newCost < cost.get(nextP)) {
+					cost.put(nextP, newCost);
+					int priority = newCost + goal.taxiDistance(nextP);
+					frontier.add(new ANode(nextP, priority));
+					cameFrom.put(nextP, currentP);
+					
+					//logln("Added "+nextP+" with cost "+newCost+" and priority "+priority);
+				}
+			}
+		}
+		
+		LinkedList<Point> path = new LinkedList<>();
+		Point last = goal;
+		path.add(last);
+		Point newLast;
+		while( (newLast = cameFrom.get(last)) != null) {
+			cameFrom.remove(last);
+			path.add(newLast);
+			last = newLast;
+		}
+		Collections.reverse(path);
+		
+		logln("Shortest path: "+path.toString());
+		
+		return path;
+	}
+	
+	private static class ANode {
+		private Point point;
+		private Integer priority;
+		
+		private ANode(Point point, Integer priority) {
+			this.point = point;
+			this.priority = priority;
+		}
+	}
+	
+	private static class Points {
+		private Point a;
+		private Point b;
+		
+		private Points(Point a, Point b) {
+			this.a = a;
+			this.b = b;
+		}
+
+		@Override
+		public int hashCode() {
+			return 31 * (31 + a.hashCode()) + b.hashCode();
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) return true;
+			if (obj == null) return false;
+			if (getClass() != obj.getClass()) return false;
+			
+			Points other = (Points) obj;
+
+			if(!a.equals(other.a) || !b.equals(other.b)) return false;
+			
+			return true;
+		}
+	}
+}

farbot/src/farbot/game/token/Token.java

@@ -1,6 +1,6 @@
 package farbot.game.token;
 
-import farbot.game.map.Point;
+import farbot.game.Point;
 
 public abstract class Token {
 	Point position;