import java.util.ArrayList;
import java.util.Arrays;

public class KnightShell {
    private int[][] board;
    private int[][] heuristic={
            {2,3,4,4,4,4,3,2},
            {3,4,6,6,6,6,4,3},
            {4,6,8,8,8,8,6,4},
            {4,6,8,8,8,8,6,4},
            {4,6,8,8,8,8,6,4},
            {4,6,8,8,8,8,6,4},
            {3,4,6,6,6,6,4,3},
            {2,3,4,4,4,4,3,2},
    };
    final int NUM_ROWS=8, NUM_COLS=8;

    private int moveCounter=1;
    private int locRow, locCol;

    private final int[] H_SHIFT={2,1,-1,-2,-2,-1,1,2};
    private final int[] V_SHIFT={-1,-2,-2,-1,1,2,2,1};

    public KnightShell(int startRow, int startCol){
        locCol=startCol;
        locRow=startRow;
        board=new int[NUM_ROWS][NUM_COLS];
    }

    public boolean runBasicTour(int startRow, int startCol){
        boolean canMakeMove=false;
        resetBoard();
        moveCounter=1;
        locRow=startRow;
        locCol=startCol;
        board[locRow][locCol]=moveCounter;
        moveCounter++;
        canMakeMove=makeMove();
        while(canMakeMove){
            canMakeMove=makeMove();
        }
        return moveCounter==65;

    }

    public boolean makeMove(){
        boolean moveMade=false;
        ArrayList<Integer>moves=getValidMoves();
        if(moves.size()>0){
            moveMade=true;
            //pick random move
            //pick best move
            int move=(int)(Math.random()*moves.size());//pick a move
            //update Location
            locRow=locRow+V_SHIFT[moves.get(move)];
            locCol=locCol+H_SHIFT[moves.get(move)];
            //update board
            board[locRow][locCol]=moveCounter;
            //update heuristic
            moveCounter++;
        }

        return moveMade;
    }

    public int pickBestMove(ArrayList<Integer> moves){
        int row = locRow+V_SHIFT[moves.get(0)];
        int col = ;
        int accesVal=heuristic[row][col];
    }

    public ArrayList<Integer> getValidMoves(){
        ArrayList<Integer> moves=new ArrayList<>();

        for(int i=0; i<H_SHIFT.length; i++){
            int vMove=locRow+V_SHIFT[i];
            int hMove=locCol+H_SHIFT[i];
            if(validMove(vMove, hMove)){
                moves.add(i);
            }
        }

        return moves;
    }

    public boolean validMove(int row, int col){
        //2,3
        boolean validTop=row>=0;
        boolean validBottom=row<board.length;
        boolean validLeft=col>=0;

        return validTop&&validBottom&&validLeft&&col<board[row].length&&board[row][col]<1;
    }

    public int getMoveCounter(){
        return moveCounter;
    }

    public void printBoard(){
        for(int[] row: board){
            System.out.println(Arrays.toString(row));
        }
    }

    public void resetBoard(){
        for(int i=0; i<board.length; i++){
            Arrays.fill(board[i], 0);
        }
    }


}