package listFW.visitor;

import listFW.*;

/**
 * <p>Title: </p>
 * <p>Description: Remove the minimum element from a list of Integer</p>
 * <p>Copyright: Copyright (c) 2002 by DXN - All rights reserved</p>
 * @author DXN
 * @version 1.0
 */
public class RemMin implements IListAlgo {

    private static class AccMin {
        public Integer _accMin;
        public IList _accList;
        public AccMin(Integer m, IList acc) {
            _accMin = m;
            _accList = acc;
        }
    }

    private IListFactory _fact;


    public RemMin(IListFactory f) {
        _fact = f;
    }

    public Object emptyCase(IEmptyList host, Object inp) {
        return host;
    }

    public Object nonEmptyCase(INEList host, Object inp) {
        AccMin am = (AccMin)host.execute(new IListAlgo() {

            public Object emptyCase(IEmptyList host, Object min) {
                return new AccMin((Integer)min, _fact.makeEmptyList());
            }

            public Object nonEmptyCase(INEList host, Object min) {
                int m = ((Integer)min).intValue();
                int f = ((Integer)host.getFirst()).intValue();
                if (f < m) {
                    min = host.getFirst();
                }

                AccMin temp = (AccMin)host.getRest().execute(this, min);

                if (host.getFirst().equals(temp._accMin)) {
                    return temp;
                }
                else {
                    return new AccMin(temp._accMin,
                                      _fact.makeNEList(host.getFirst(), temp._accList));

                }
            }
        }, host.getFirst());
        return am._accList;
    }
}