package lrs.visitor;
import lrs.*;

public class InsertInOrderLRS implements IAlgo {
    
    public static final InsertInOrderLRS Singleton 
        = new InsertInOrderLRS();
    
    private InsertInOrderLRS() {
    }
    
    /**
     * Simply inserts the given parameter n at the front.
     * @param host an empty LRStruct.
     * @param n n[0] isan Integer to be inserted in order into host.
     * @return LRStruct
     */
    public Object emptyCase(LRStruct host, Object... n) {
        return host.insertFront(n[0]);
    }
    
    /**
     * Based on the comparison between first and n,
     * inserts at the front or recurs!
     * @param host a non-empty LRStruct.
     * @param n n[0] is  an Integer to be inserted in order into host.
     * @return LRStruct
     */
    public Object nonEmptyCase(LRStruct host, Object... n) {
        if ((Integer)n[0] < (Integer)host.getFirst()) {
            return host.insertFront(n[0]);
        }
        else {
            return host.getRest().execute(this, n[0]);
        }
    }
}