BoardState.java

import java.util.ArrayList;

/**
 *
 * @author leyantong
 */
public class BoardState {
    
    
    private int[][] board;
    public int colour;
    
    
    public BoardState(){
        
        // Create board
        board= new int[8][8];
    }
    
    
    // Clone the current object
    public BoardState deepCopy(){
        
        BoardState newBoardState= new BoardState();
        for(int i= 0; i< 8; i++)
            for(int j= 0; j < 8; j++)
                newBoardState.setContents(i, j, getContents(i,j));
        newBoardState.colour= colour;
        return newBoardState;
    }
    
    
    public int getContents(int x, int y){
        
        return board[x][y]; 
    }
    
    public void setContents(int x, int y, int piece){
        
        board[x][y]= piece;
    }
    
    // Under construction Assumes coordinates are in order.
    
    
    private boolean checkOnBoard(int x, int y){
        
        return (x >=0) && (x < 8) &&  (y >=0) && (y < 8);
    }
    
    
    // Returns the list of legal moves for current player.
   public ArrayList<Move> getLegalMoves(){
       
       // Very simple method
       ArrayList<Move> ans= new ArrayList<Move>();
       for(int i= 0; i < 8; i++)
            for(int j= 0; j < 8; j++)
                if(checkLegalMove(i,j))
                    ans.add(new Move(i,j));
       return ans;       
   }
    
   
   // Tests whether the game is over
    public boolean gameOver(){
    
        boolean ans= false;
        if(getLegalMoves().isEmpty()){
            colour= -colour;              // change colour temporarily
            if(getLegalMoves().isEmpty())
                ans= true;
            colour= -colour;               // change colour back
        }
        return ans;
    }
    
    
    public boolean checkLegalMove(int x, int y){       
        return 
            checkOnBoard(x,y) && (getContents(x,y) == 0) &&    
            ((checkLeft(x, y) != -1) || (checkRight(x, y) != -1) || 
                 (checkUp(x, y) != -1) || (checkDown(x, y) != -1) ||
                     (checkUpLeft(x, y) != -1) || (checkUpRight(x, y) != -1) || 
                        (checkDownLeft(x, y) != -1) || (checkDownRight(x, y) != -1));
    }
    
   
    public void makeLegalMove(int x, int y){
        
        int a,b; // work variables (indices)
        
        // Current square
        // setContents(x, y, colour);
        
        // Squares to left
        a= checkLeft(x, y);  
        if(a != -1)
            for(int i=x; i > a; i--)
                setContents(i,y, colour);

        // Squares to right
        a= checkRight(x, y);  
        if(a != -1)
            for(int i=x; i < a; i++)
                setContents(i,y, colour);
        
        
        // Squares above
        a= checkUp(x, y);  
        if(a != -1)
            for(int j=y; j > a; j--)
                setContents(x, j, colour);

        
        // Squares below
        a= checkDown(x, y);  
        if(a != -1)
            for(int j=y; j < a; j++)
                setContents(x, j, colour);
        
        
        // Squares to above left
        a= checkUpLeft(x, y);  
        if(a != -1)
            for(int i=x, j= y; i > a; i--, j--)
                setContents(i,j, colour);

        // Squares above right
        a= checkUpRight(x, y);  
        if(a != -1)
            for(int i=x, j= y; i < a; i++,j--)
                setContents(i,j, colour);
      
            
        // Squares to below left
        a= checkDownLeft(x, y);  
        if(a != -1)
            for(int i=x, j= y; i > a; i--, j++)
                setContents(i,j, colour);

        // Squares below right
        a= checkDownRight(x, y);  
        if(a != -1)
            for(int i=x, j= y; i < a; i++,j++)
                setContents(i,j, colour); 
        colour= -colour;                         // Change player
        
        
        // Now the computer moves 
        
    }
    
    
    // Return largest value of i < x st board[j,i] is opposite to color for all
    // j (i < j < x) and board[i,y] is colour, and return -1 if none in range
    private int checkLeft(int x, int y){
        
        int i= x-1;
        while((i > 0) && (getContents(i,y) == -colour))  //check almost to start
            i--;
        if((i < x-1) && getContents(i,y) == colour)
            return i;
        else
            return -1;
    }
    
    
    // Return largest value of i > x st board[j,i] is opposite to color for all
    // j (i > j > x) and board[i,y] is colour, and return -1 if none in range
    private int checkRight(int x, int y){
        
        int i= x+1;
        while((i < 7) && (getContents(i,y) == -colour))   // Check almost to end
            i++;
        if((i > x+1) && getContents(i,y) == colour)
            return i;
        else
            return -1;
    }
    
    // Return largest value of i < y st board[x,j] is opposite to color for all
    // j (i < j < y) and board[x,i] is colour, and return -1 if none in range
    private int checkUp(int x, int y){
        
        int i= y-1;
        while((i > 0) && (getContents(x,i) == -colour)) // Check almost to start
            i--;
        if((i < y-1) && getContents(x,i) == colour)
            return i;
        else
            return -1;
    }
    
    
    // Return largest value of i > y st board[x,j] is opposite to color for all
    // j (i > j > y) and board[x,i] is colour, and return -1 if none in range
    private int checkDown(int x, int y){
        
        int i= y+1;
        while((i < 7) && (getContents(x,i) == -colour))   // Check almost to end
            i++;
        if((i > y+1) && getContents(x,i) == colour)
            return i;
        else
            return -1;
    }   
    
        
    // Return largest value of i < x st board[x-j,y-j] is opposite to color for all
    // j (i < j < endOfBoard) and board[i,y] is colour, and return -1 if none in range
    private int checkUpLeft(int x, int y){
        
        int i= x-1;
        int j= y-1;
        while((i > 0) && (j > 0) && (getContents(i,j) == -colour)){  //check almost to start
            i--;
            j--;
        }
        if((i < x-1) && getContents(i,j) == colour)
            return i;
        else
            return -1;
    }
    
    
    // Return largest value of i > x st board[j,i] is opposite to color for all
    // j (i > j > x) and board[i,y] is colour, and return -1 if none in range
    private int checkUpRight(int x, int y){
        
        int i= x+1;
        int j= y-1;
        while((i < 7) && (j > 0) && (getContents(i,j) == -colour)){  // Check almost to end
            i++;
            j--;
        }
        if((i > x+1) && getContents(i,j) == colour)
            return i;
        else
            return -1;
    }
    
    
    
    // Return largest value of i < x st board[x-j,y-j] is opposite to color for all
    // j (i < j < endOfBoard) and board[i,y] is colour, and return -1 if none in range
    private int checkDownLeft(int x, int y){
        
        int i= x-1;
        int j= y+1;
        while((i > 0) && (j <7) && (getContents(i,j) == -colour)){  //check almost to start
            i--;
            j++;
        }
        if((i < x-1) && getContents(i,j) == colour)
            return i;
        else
            return -1;
    }
    
    
    // Return largest value of i > x st board[j,i] is opposite to color for all
    // j (i > j > x) and board[i,y] is colour, and return -1 if none in range
    private int checkDownRight(int x, int y){
        
        int i= x+1;
        int j= y+1;
        while((i < 7) && (j < 7) && (getContents(i,j) == -colour)){  // Check almost to end
            i++;
            j++;
        }
        if((i > x+1) && getContents(i,j) == colour)
            return i;
        else
            return -1;
    }
    
    
    public String resultString(){
        
        String ans;
        int white= 0;
        int black= 0;
        for(int i= 0; i < 8; i++)
            for(int j=0; j < 8; j++)
                if(getContents(i,j)==1)
                    white++;
                else if(getContents(i,j)==-1)
                    black++;
        if(white > black)
            ans= "White wins";
        else if(black > white)
            ans= "Black wins";
        else
            ans= "Draw";
        ans+= "[White: " + white+"; black: "+black+"]";
        return ans;
    }
}