import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.List; // import java for lists

/**
 * Write a description of class SnakeHead here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class SnakeHead extends Actor
{

  public int offsetX = 0; //global variable storing the random X direction (1, 0 or -1)
  public int offsetY = -1; //global variable storing the random Y direction (1, 0 or -1)
  public int lastx; //variable for storing the last x co-ordinate
  public int lasty; //variable for storing the last x co-ordinate
  public SnakeBody nextSnakeBody=null;
 
  public SnakeHead() // constructor
   {
       setDirection(); //set a direction for the lizard.
   }  
 
   public void act()
   {
        lastx = getX(); //get current x co-ordinate
        lasty = getY(); // get current y co-ordinate
        processKeys();
        move();
        setDirection();
        findEatFood(); 
    }
    
   private void processKeys()
   {
     if(Greenfoot.isKeyDown("left")) //move left
     {
         offsetX=-1;
         offsetY=0;
        }
     if(Greenfoot.isKeyDown("right")) //move right
     {
         offsetX=1;
         offsetY=0;
        }
     if(Greenfoot.isKeyDown("up")) //move up
     {
         offsetX=0;
         offsetY=-1;
        }
     if(Greenfoot.isKeyDown("down")) //move down
     {
         offsetX=-0;
         offsetY=1;
        }
    }
    
   private void move() //
    {
     int currX = getX(); //get current x co-ordinate
     int currY = getY(); // get current y co-ordinate
     if(canMove(currX + offsetX, currY + offsetY))
     setLocation(currX + offsetX, currY + offsetY); //if the snake can move it will move in a direction
    }
    
     private void setDirection() //method to set the current direction
    {
        do{ }while(offsetX==0 && offsetY==0);
    
        if(offsetX == -1 && offsetY == 0) //if the snake will go west
            setRotation(180); //set rotation to south
        else if(offsetX == 0 && offsetY == -1) //if the snake will go north
            setRotation(270); //set rotation to west
        else if(offsetX == 0 && offsetY == 1) //if the snake will go south
            setRotation(90); //set rotation to east
        else if(offsetX == 1 && offsetY == 0) //if the snake will go east
            setRotation(0); //set rotation to north
    }
    
    private void findEatFood()// funcion to eat an actor. Specifically Food
       {
      Actor thisFood=getOneObjectAtOffset(0,0,Food.class); // is there Food in the current square?
      if(thisFood!=null) //there is no Food
      {
          Greenfoot.playSound("Belch.wav"); //play sound file
          getWorld().removeObject(thisFood); //removes an actor from the world once it has been eaten.
          List getScore=getWorld().getObjects(Score.class); //get the score
      if(!getScore.isEmpty())
      {
         Score currScore=(Score)getScore.get(0); // check that there is a score
         currScore.updateScore(1); //add 1 to the current score
        }    
        
      int x = Greenfoot.getRandomNumber(27)+1; //random x co-ordinate
      int y = Greenfoot.getRandomNumber(27)+1; //random y co-ordinate
      getWorld().addObject(new Food(), x, y); //add new object at a random co-ordinate
      
      addSnakeBody(); //addSnakeBody actor
      }
    }
    
    private void addSnakeBody() //
    {
        if(nextSnakeBody==null){ //if there is no SnakeBody
            int currX = getX(); //get current x co-ordinate
            int currY = getY(); // get current y co-ordinate 
            nextSnakeBody=new SnakeBody((Actor)this, true); //newSnakeBody is a SnakeBody actor
            getWorld().addObject(nextSnakeBody, lastx, lasty); //add SnakeBody at the last location of SnakeHead
        }
         else nextSnakeBody.addSnakeBody(); // if there is a SnakeBody add another 
         }
    
     boolean canMove(int x,int y)     
        {
        List foundWall = getWorld().getObjectsAt(x,y, Wall.class); //canMove is false if a Wall is found
        if(!foundWall.isEmpty  ())return false;   //if Wall found return false and stop otherwise continue
        
        List foundSnakeHead = getWorld().getObjectsAt(x,y, SnakeHead.class); //canMove is false if a SnakeHead is found
        if(!foundSnakeHead.isEmpty  ())return false;   //if SnakeHead found return false and stop otherwise continue
        
        List foundSnakeBody = getWorld().getObjectsAt(x,y, SnakeBody.class); //canMove is false if a SnakeBody is found
        if(!foundSnakeBody.isEmpty  ())return false;   //if SnakeBody found return false and stop otherwise continue
       
        return true;    //this must be at the end – if canMove got this far it didn't find any of the listed objects.
        
        
    }
}

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.util.List; // import java for lists

/**
 * Write a description of class SnakeBody here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class SnakeBody  extends Actor
{
    public int offsetX = 0; //global variable storing the random X direction (0)
    public int offsetY = 0; //global variable storing the random Y direction (0)
    public SnakeBody lastSnakeBody=null; //there is no last SnakeBody
    public SnakeHead lastSnakeHead=null; //there is no last SnakeHead
    public int lastx; //variable for storing the last x co-ordinate
    public int lasty; //variable for storing the last x co-ordinate
    boolean joinedtoHead;
    
    public SnakeBody (Actor thisBody, boolean isSnakeHead)
    {
      if(isSnakeHead)  
      {
          lastSnakeHead=(SnakeHead)thisBody;
          joinedtoHead=isSnakeHead;
          setLocation(lastSnakeHead.lastx, lastSnakeHead.lasty);
        }
      else
      {
      lastSnakeBody=(SnakeBody)thisBody;
      setLocation(lastSnakeBody.lastx, lastSnakeBody.lasty);
        }

    }
  
    public void act() 
    {
        lastx=getX();
        lasty=getY();
         move();
         growSnake();
    }    
    
    
    private void growSnake() //the SnakeBody will follow behind the head by using the current x and y of the head 
    {
         int offsetX=0;
         int offsetY=0;
         
         int currX = getX(); //get current x co-ordinate
         int currY = getY(); // get current y co-ordinate 
         
         List getSnakeHead=getWorld().getObjects(SnakeHead.class); //get the SnakeHead actor from the world.
         if(!getSnakeHead.isEmpty  ()) //if there is no SnakeHead
         {
            SnakeHead thisSnakeHead=(SnakeHead)getSnakeHead.get(0); //is there a SnakeHead in the current location?
            offsetX=thisSnakeHead.offsetX; //the x co-ordinate of SnakeHead
            offsetY=thisSnakeHead.offsetY; //the y co-ordinate of SnakeHead
        }
        setLocation(currX+offsetX, currY+offsetY); //
    }
    
     private void move() //
    {
         if(joinedtoHead)
         {
             setLocation(lastSnakeHead.lastx, lastSnakeHead.lasty);
            }
            else
            {
                setLocation(lastSnakeBody.lastx, lastSnakeBody.lasty);
            }
         }
    
    public void addSnakeBody()
    {
        if(lastSnakeBody==null){ //if there is no SnakeBody
            int currX = getX(); //get current x co-ordinate
            int currY = getY(); // get current y co-ordinate 
            lastSnakeBody=new SnakeBody((Actor)this, false); //newSnakeBody is a SnakeBody actor
            getWorld().addObject(lastSnakeBody, currX-offsetX, currY-offsetY); //add SnakeBody at location of SnakeHead - 1
        }
         else lastSnakeBody.addSnakeBody(); // if there is a SnakeBody add another   
         }
    
      boolean canMove(int x,int y)     
        {
        List foundWall = getWorld().getObjectsAt(x,y, Wall.class); //canMove is false if a Wall is found
        if(!foundWall.isEmpty  ())return false;   //if Wall found return false and stop otherwise continue
       
        List foundSnakeHead = getWorld().getObjectsAt(x,y, SnakeHead.class); //canMove is false if a SnakeHead is found
        if(!foundSnakeHead.isEmpty  ())return false;   //if SnakeHead found return false and stop otherwise continue
        
        List foundSnakeBody = getWorld().getObjectsAt(x,y, SnakeBody.class); //canMove is false if a SnakeBody is found
        if(!foundSnakeBody.isEmpty  ())return false;   //if SnakeBody found return false and stop otherwise continue
        
        return true;    //this must be at the end – if canMove got this far it didn't find any of the listed objects.
        
        
    }
}