package sudoku.solver;

import sudoku.Cell;
import sudoku.MultiDoku;
import sudoku.MutableCell;
import sudoku.Sudoku;
import sudoku.constraint.IConstraint;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class Solver {
    Caretaker stack;

    public Solver() {
    }

    public MultiDoku solve(MultiDoku doku, List<IConstraint> constraints) throws Exception {
        if (!doku.isValid(constraints)) {
            throw new Exception("Invalid doku");
        }
        List<MutableCell> allMutableCells = doku.getMutableCells();
        List<MutableCell> remainingCellsToCheck = new ArrayList<>(allMutableCells);
        Random rand = new Random();
        while (!remainingCellsToCheck.isEmpty()) {
            int indexCurrentCell = rand.nextInt(remainingCellsToCheck.size());
            MutableCell currentCell = remainingCellsToCheck.get(indexCurrentCell);
            if (currentCell.getHints().isEmpty()){
                MutableCell modify = stack.undo();
                modify.removeHint(modify.clear());
            }


            remainingCellsToCheck.remove(indexCurrentCell);
        }
        return doku;
    }
}