package civitas.crypto.algorithms;
   
   import java.util.LinkedList;
   import java.util.List;
   
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.stereotype.Controller;
   
   @Controller
  public class CreatePermutation {
  
  	@Autowired
  	GenerateRandomInt generateRandomInt;
  
  	public int[] apply(final int size) {
  		List<Integer> l = new LinkedList<>();
  		for (int i = 0; i < size; i++) {
  			l.add(i);
  		}
  
  		// now select and remove elements at random from the list.
  		int[] perm = new int[size];
  		for (int i = 0; i < size; i++) {
  			int j = generateRandomInt.apply(l.size());
  			perm[i] = l.remove(j);
  		}
  
  		return perm;
  	}
  }