import java.util.ArrayList;
import java.util.List;
/**
 * The Sudoku field, containing 9x9 squares.
 *
 * @author Lucas Taubert
 * @version 2009-10-26
 */
public class Field{
    Square[][] squares;
    int size;
   // private ArrayList<Square> squares;

    /**
     * Initiates a field with the sides 'size'.
     * @param size The number of squares on each side.
     */
    public Field(int size){
        this.size = size;
        squares = new Square[size][size];
        for(int i=0;i<size;i++){
            for(int j=0;j<size;j++){
                squares[i][j] = new Square(i+1, j+1);
            }
        }
    }

    /**
     * Removes choices in the row, column and 3x3 square of
     * selected square.
     * @param square The square of which to receive data.
     * @return False if the square didn't have any value, else true.
     */
    private boolean removeChoices(Square square){
        boolean removed = false;
        int x = square.getX()-1;
        int y = square.getY()-1;
        if(square.getValue() == null){
            return false;
        }
        int value = square.getValue();
        for(int i=0; i<size;i++){              //Purges a column with X-value x.
            if(squares[x-1][i].purgeChoice(value)){
                removed = true;
            }
        }
        for(int i=0;i<size;i++){               //Purges a row with Y-value y.
            if(squares[i][y-1].purgeChoice(value)){
                removed = true;
            }
        }
        for(int xx = x - x%3; xx< (x - x%3) + 3; xx++){ //Purges the 3x3 of the x and y coordinates.
            for(int yy = y - y%3; yy<(y - y%3) + 3; yy++){
                if(squares[xx][yy].purgeChoice(value)){
                    removed = true;
                }
            }
        }
        return removed;
    }

    /**
     * Removes choices through a square on specified position.
     * @param x The X-coordinate.
     * @param y The Y-coordinate.
     */
    public boolean removeChoices(int x, int y){
        return removeChoices(squares[x][y]);
    }

    /**
     * Prints the field.
     * @return The string which to print
     */
    public String toString(){
        String myString = "";
        for(int xx = 0; xx<size; xx++){
            for(int yy= 0; yy<size; yy++){
                myString = myString + " " + squares[xx][yy];
            }
            myString = myString + "\n";
        }
        return myString;
    }

    /**
     * Prints the field.
     */
    public void printField(){
        System.out.print("\n" + this);
    }

    /**
     * Adds a value in the square of specified coordinates.
     * @param x The X-coordinate.
     * @param y The Y-coordinate.
     * @param value The value which the square shall have.
     */
    public void addValue(int x, int y, int value){
        squares[x-1][y-1].setValue(value);
    }

    public void addValues(int[] x, int[] y, int[] value){
        int counter = 0;
        for(int i=0; i<x.length; i++){
            for(int j=0; j<y.length; j++){
                addValue(x[i], y[j], value[counter]);
                counter++;
            }
        }
    }

    /**
     * Removes choices by checking data on all squares
     * on the field.
     */
    public boolean removeField(){
        boolean removed = false;
        for(int xx=0; xx<size; xx++){
            for(int yy=0; yy<size; yy++){
                if(removeChoices(squares[xx][yy])){
                    removed = true;
                }
            }
        }
        return removed;
    }

    /**
     * Checks if any fields only have one choice left. Updates value
     * if it does.
     */
    public boolean checkField(){
        boolean changed = false;
        for(int xx=0; xx<size; xx++){
            for(int yy=0; yy<size; yy++){
               if(squares[xx][yy].check()){
                   changed = true;
                }
            }
        }
        return changed;
    }

    /**
     * Attempts to solve the puzzle.
     * @param number of tries.
     */
    public void solve(int tries){
        boolean solved=false;
        int counter=0;
        while(!solved && counter++<tries){
            solved = true;
            if(checkField() | removeField()){
                solved = false;
            }
        }
    }

    /**
     * Initiate a test puzzle.
     */
    public void initiatePuzzle(){
        addValues({1},{1,4,6,7},{5,1,6,4);
        addValues({2},{2,3,4},{2,4,5});
        addValues({3},{2,6,9},{1,7,8});
        addValues({4},{5,7,9},{2,7,1});
        addValues({5},{1,7,9},{6,5,9});
        addValues({6},{4,5},{7,1});
        addValues({7},{3},{5});
        addValues({8},{2,5,6},{7,8});
        addValues({9},{7,8},{1,4});
    }
}