package Sudoku;
import java.util.LinkedList;
public class Solver {

	private int[][] matrix = new int[9][9]; //[row][column]
	private LinkedList<Sudoku> help=new LinkedList<Sudoku>();
	private boolean[][] isEditable=new boolean[9][9];
	private int[] pointer={0,0};
	private boolean finished=false;
	private int durchl=0;


	public Solver(int[][] matrix){
		help.add(new Sudoku(matrix, pointer));
		this.matrix=matrix;
		generateEditable(matrix);
	}

	private void generateEditable(int[][] matrix){
		for(int i=0;i<9;i++){
			for(int j=0;j<9;j++){
				if(matrix[i][j]==0)isEditable[i][j]=true;
				else isEditable[i][j]=false;
			}
		}

	}

	private boolean isEditable(){
		return isEditable[pointer[0]][pointer[1]];
	}

	public void solveField(int row, int column){
		/*System.out.println("Durchlauf: "+durchl++);
		System.out.println("Pointer: "+pointer[0]+" "+pointer[1]);
		output();*/
		int k=matrix[row][column];
		boolean b=Checker.check(matrix, row, column, k);
		while(!b&&k<9){
			k++;
			b=Checker.check(matrix, row, column, k);
		}
		if(b){
			matrix[row][column]=k;
			output();
			help.addLast(new Sudoku(matrix.clone(),pointer.clone()));
			next();
		}
		else {
			/*System.out.println("Groesse LinkedList: "+help.size());
			System.out.println("Pointer: "+pointer[0]+" "+pointer[1]);
			output();*/
			help.removeLast();
			pointer=help.getLast().getPointer().clone();
			matrix=help.getLast().getMatrix().clone();
			/*System.out.println("Groesse LinkedList: "+help.size());
			System.out.println("Pointer: "+pointer[0]+" "+pointer[1]);
			output();*/
		}
	}

	public void solveSudoku(){

		//pointer=help.getLast().getPointer().clone();
		//matrix=help.getLast().getMatrix().clone();
		/*if(help.size()==666){
			if(help.getFirst().getMatrix()==help.getLast().getMatrix()){
				System.out.println("FUCK OFF");
			}
			matrix=help.getFirst().getMatrix().clone();
			pointer=help.getFirst().getPointer().clone();
			output();
			System.out.println("Pointer: "+pointer[0]+" "+pointer[1]);
		}*/
		//pointer=help.getLast().getPointer().clone();
		if(isEditable()){
			solveField(pointer[0],pointer[1]);
			if(!finished)solveSudoku();
		}
		else{
			next();
			//help.add(new Sudoku(matrix.clone(),pointer.clone()));
			if(!finished)solveSudoku();
		}

	}

	private void next(){
		if(pointer[1]<8)pointer[1]++;
		else{
			pointer[1]=0;
			if(pointer[0]<8)pointer[0]++;
			else finished=true;
		}
	}

	public int[][] getSolved() {
		return matrix;
	}

	public void output(){
		for(int i=0;i<9;i++){
			for(int j=0;j<9;j++){
				System.out.print(matrix[i][j]+" ");
			}
			System.out.println();
		}
		System.out.println();
	}
}