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/*
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 * Licensed to the Apache Software Foundation (ASF) under one or more
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 * contributor license agreements.  See the NOTICE file distributed with
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 * this work for additional information regarding copyright ownership.
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 * The ASF licenses this file to You under the Apache License, Version 2.0
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 * (the "License"); you may not use this file except in compliance with
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 * the License.  You may obtain a copy of the License at
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 *
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 *      http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package websocket.snake;
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import java.io.IOException;
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import java.util.ArrayDeque;
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import java.util.Collection;
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import java.util.Deque;
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import javax.websocket.CloseReason;
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import javax.websocket.CloseReason.CloseCodes;
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import javax.websocket.Session;
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public class Snake {
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    private static final int DEFAULT_LENGTH = 5;
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    private final int id;
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    private final Session session;
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    private Direction direction;
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    private int length = DEFAULT_LENGTH;
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    private Location head;
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    private final Deque<Location> tail = new ArrayDeque<>();
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    private final String hexColor;
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    public Snake(int id, Session session) {
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        this.id = id;
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        this.session = session;
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        this.hexColor = SnakeAnnotation.getRandomHexColor();
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        resetState();
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    }
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    private void resetState() {
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        this.direction = Direction.NONE;
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        this.head = SnakeAnnotation.getRandomLocation();
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        this.tail.clear();
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        this.length = DEFAULT_LENGTH;
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    }
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    private synchronized void kill() {
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        resetState();
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        sendMessage("{\"type\": \"dead\"}");
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    }
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    private synchronized void reward() {
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        length++;
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        sendMessage("{\"type\": \"kill\"}");
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    }
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    protected void sendMessage(String msg) {
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        try {
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            session.getBasicRemote().sendText(msg);
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        } catch (IOException ioe) {
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            CloseReason cr = new CloseReason(CloseCodes.CLOSED_ABNORMALLY, ioe.getMessage());
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            try {
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                session.close(cr);
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            } catch (IOException ioe2) {
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                // Ignore
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            }
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        }
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    }
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    public synchronized void update(Collection<Snake> snakes) {
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        Location nextLocation = head.getAdjacentLocation(direction);
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        if (nextLocation.x >= SnakeAnnotation.PLAYFIELD_WIDTH) {
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            nextLocation.x = 0;
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        }
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        if (nextLocation.y >= SnakeAnnotation.PLAYFIELD_HEIGHT) {
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            nextLocation.y = 0;
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        }
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        if (nextLocation.x < 0) {
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            nextLocation.x = SnakeAnnotation.PLAYFIELD_WIDTH;
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        }
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        if (nextLocation.y < 0) {
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            nextLocation.y = SnakeAnnotation.PLAYFIELD_HEIGHT;
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        }
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        if (direction != Direction.NONE) {
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            tail.addFirst(head);
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            if (tail.size() > length) {
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                tail.removeLast();
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            }
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            head = nextLocation;
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        }
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        handleCollisions(snakes);
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    }
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    private void handleCollisions(Collection<Snake> snakes) {
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        for (Snake snake : snakes) {
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            boolean headCollision = id != snake.id && snake.getHead().equals(head);
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            boolean tailCollision = snake.getTail().contains(head);
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            if (headCollision || tailCollision) {
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                kill();
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                if (id != snake.id) {
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                    snake.reward();
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                }
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            }
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        }
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    }
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    public synchronized Location getHead() {
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        return head;
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    }
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    public synchronized Collection<Location> getTail() {
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        return tail;
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    }
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    public synchronized void setDirection(Direction direction) {
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        this.direction = direction;
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    }
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    public synchronized String getLocationsJson() {
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        StringBuilder sb = new StringBuilder();
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        sb.append(String.format("{\"x\": %d, \"y\": %d}",
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                Integer.valueOf(head.x), Integer.valueOf(head.y)));
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        for (Location location : tail) {
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            sb.append(',');
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            sb.append(String.format("{\"x\": %d, \"y\": %d}",
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                    Integer.valueOf(location.x), Integer.valueOf(location.y)));
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        }
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        return String.format("{\"id\":%d,\"body\":[%s]}",
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                Integer.valueOf(id), sb.toString());
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    }
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    public int getId() {
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        return id;
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    }
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    public String getHexColor() {
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        return hexColor;
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    }
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}