/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package samples.websocket.snake;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Deque;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
public class Snake {
private static final int DEFAULT_LENGTH = 5;
private final int id;
private final WebSocketSession session;
private Direction direction;
private int length = DEFAULT_LENGTH;
private Location head;
private final Deque<Location> tail = new ArrayDeque<Location>();
private final String hexColor;
public Snake(int id, WebSocketSession session) {
this.id = id;
this.session = session;
this.hexColor = SnakeUtils.getRandomHexColor();
resetState();
}
private void resetState() {
this.direction = Direction.NONE;
this.head = SnakeUtils.getRandomLocation();
this.tail.clear();
this.length = DEFAULT_LENGTH;
}
private synchronized void kill() throws Exception {
resetState();
sendMessage("{'type': 'dead'}");
}
private synchronized void reward() throws Exception {
this.length++;
sendMessage("{'type': 'kill'}");
}
protected void sendMessage(String msg) throws Exception {
this.session.sendMessage(new TextMessage(msg));
}
public synchronized void update(Collection<Snake> snakes) throws Exception {
Location nextLocation = this.head.getAdjacentLocation(this.direction);
if (nextLocation.x >= SnakeUtils.PLAYFIELD_WIDTH) {
nextLocation.x = 0;
}
if (nextLocation.y >= SnakeUtils.PLAYFIELD_HEIGHT) {
nextLocation.y = 0;
}
if (nextLocation.x < 0) {
nextLocation.x = SnakeUtils.PLAYFIELD_WIDTH;
}
if (nextLocation.y < 0) {
nextLocation.y = SnakeUtils.PLAYFIELD_HEIGHT;
}
if (this.direction != Direction.NONE) {
this.tail.addFirst(this.head);
if (this.tail.size() > this.length) {
this.tail.removeLast();
}
this.head = nextLocation;
}
handleCollisions(snakes);
}
private void handleCollisions(Collection<Snake> snakes) throws Exception {
for (Snake snake : snakes) {
boolean headCollision = this.id != snake.id
&& snake.getHead().equals(this.head);
boolean tailCollision = snake.getTail().contains(this.head);
if (headCollision || tailCollision) {
kill();
if (this.id != snake.id) {
snake.reward();
}
}
}
}
public synchronized Location getHead() {
return this.head;
}
public synchronized Collection<Location> getTail() {
return this.tail;
}
public synchronized void setDirection(Direction direction) {
this.direction = direction;
}
public synchronized String getLocationsJson() {
StringBuilder sb = new StringBuilder();
sb.append(String.format("{x: %d, y: %d}", Integer.valueOf(this.head.x),
Integer.valueOf(this.head.y)));
for (Location location : this.tail) {
sb.append(',');
sb.append(String.format("{x: %d, y: %d}", Integer.valueOf(location.x),
Integer.valueOf(location.y)));
}
return String.format("{'id':%d,'body':[%s]}", Integer.valueOf(this.id),
sb.toString());
}
public int getId() {
return this.id;
}
public String getHexColor() {
return this.hexColor;
}
}