ClassBoard

import java.util.InputMismatchException;
import java.util.Iterator;
//import java.util.List;
import java.util.Stack;

import static java.lang.Math.abs;
/**
 * This class represents a generic TicTacToe game board.
 */
public class Board {
    private int n;
    //TODO

    Position[][] positions;
    int [][] tokens;
    int free_fields;
    /**
     *  Creates Board object, am game board of size n * n with 1<=n<=10.
     */
    public Board(int n)
    {
        // TODO
        if (n < 1  || n > 10) throw new InputMismatchException();

        this.n = n;
        this.positions = new Position[n][n];
        this.tokens = new int[n][n];
        this.free_fields = n*n;


        for (int i = 0; i < n; i++){
            for (int j = 0; j < n; j++){
                this.positions[i][j] = new Position(i, j);
                this.tokens[i][j] = 0;
            }
        }

    }

    /**
     *  @return     length/width of the Board object
     */
    public int getN() { return n; }

    /**
     *  @return     number of currently free fields
     */

    public int nFreeFields() {
        // TODO
      return this.free_fields;

    }

    /**
     *  @return     token at position pos
     */
    public void is_valid(Position pos){

        assert(pos != null); // pos existiert?

        int x = pos.x;
        int y = pos.y;
        assert (x >= 0 && x < n && y >= 0 && y < n); //valid pos?
    }

    public int getField(Position pos) throws InputMismatchException
    {
        // TODO
        is_valid(pos); //meine funktion, ueberprueft ob die position existiert und valid ist

        int token = this.tokens[pos.x][pos.y];
        if (token != 0 && token != -1 && token != 1) //wenn ungueltiger value
            throw new InputMismatchException();

        return token;
    }

    /**
     *  Sets the specified token at Position pos.
     */
    public void setField(Position pos, int token) throws InputMismatchException
    {
        // TODO
        if (token != 0 && token != -1 && token != 1) //wenn ungueltiger value
            throw new InputMismatchException();

        is_valid(pos);

        if (this.tokens[pos.x][pos.y] == 0) //wenn kaestchen unbesetzt
            this.free_fields--; // dann neuer zug gemacht
        this.tokens[pos.x][pos.y] = token; // ob da schon was stand oder nicht ist egal, koennen tauschen
    }

    /**
     *  Places the token of a player at Position pos.
     */

    public void doMove(Position pos, int player)
    {
        // TODO
        // wenn es keinen moeglichen zug gibt assert(this.free_fields > 0); aber man kann ja tauschen

        assert(player == 1 || player == -1); //spieler*in ist alzeptabel

        setField(pos, player); // x (1) oder o (1) gestellt
    }

    /**
     *  Clears board at Position pos.
     */
    public void undoMove(Position pos)
    {
        // TODO
        is_valid(pos);
        setField(pos, 0); //nun frei
        this.free_fields++; //nun ein freies feld erzeugt
    }

    /**
     *  @return     true if game is won, false if not
     */
    public boolean isGameWon() {
        // TODO
        //row 1
        //for (Position pos ???)

        return false;
    }

    /**
     *  @return     set of all free fields as some Iterable object
     */
    public Iterable<Position> validMoves() {
        // TODO
        Stack<Position> validMoves = new Stack<>();
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                if (tokens[i][j] == 0) { // Unbesetzt
                    validMoves.push(positions[i][j]);
                }
            }
        }
        return validMoves;
    }

    /**
     *  Outputs current state representation of the Board object.
     *  Practical for debugging.
     */
    public void print()
    {
        // TODO
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {

                //fuer (x,y,value)
                //System.out.print("(" + positions[i][j].x +
                        //"," + positions[i][j].y + "," + tokens[i][j] + ") ");

                if(tokens[i][j] == -1) System.out.print("(o)");
                if(tokens[i][j] == 0) System.out.print("( )");
                if(tokens[i][j] == 1) System.out.print("(x)");
            }
            System.out.println();
        }
    }

    public static void main(String[] args)
    {
        Board myBoard = new Board(3);
        //myBoard.print();
        System.out.println("free fields = " + myBoard.free_fields);

        Position pos1 = new Position(0,0);

        myBoard.setField(pos1, 1);
        myBoard.print();

        System.out.println("(0,0) has the value = " + myBoard.getField((pos1)));
        System.out.println("free fields = " + myBoard.free_fields);

        myBoard.undoMove(pos1);
        myBoard.print();
        System.out.println("free fields = " + myBoard.free_fields);

    }

}