/*
 * Copyright 2010 JBoss Inc
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.optaplanner.examples.nurserostering.solver.move.factory;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

import org.optaplanner.core.impl.heuristic.selector.move.factory.MoveListFactory;
import org.optaplanner.core.impl.heuristic.move.Move;
import org.optaplanner.examples.nurserostering.domain.NurseRoster;
import org.optaplanner.examples.nurserostering.domain.ShiftAssignment;
import org.optaplanner.examples.nurserostering.domain.solver.MovableShiftAssignmentSelectionFilter;
import org.optaplanner.examples.nurserostering.solver.move.ShiftAssignmentSwapMove;

public class ShiftAssignmentSwapMoveFactory implements MoveListFactory<NurseRoster> {

    private MovableShiftAssignmentSelectionFilter filter = new MovableShiftAssignmentSelectionFilter();

    public List<Move> createMoveList(NurseRoster nurseRoster) {
        // Filter out every immovable ShiftAssignment
        List<ShiftAssignment> shiftAssignmentList = new ArrayList<ShiftAssignment>(
                nurseRoster.getShiftAssignmentList());
        for (Iterator<ShiftAssignment> it = shiftAssignmentList.iterator(); it.hasNext(); ) {
            ShiftAssignment shiftAssignment = it.next();
            if (!filter.accept(nurseRoster, shiftAssignment)) {
                it.remove();
            }
        }
        List<Move> moveList = new ArrayList<Move>();
        for (ListIterator<ShiftAssignment> leftIt = shiftAssignmentList.listIterator(); leftIt.hasNext();) {
            ShiftAssignment leftShiftAssignment = leftIt.next();
            for (ListIterator<ShiftAssignment> rightIt = shiftAssignmentList.listIterator(leftIt.nextIndex()); rightIt.hasNext();) {
                ShiftAssignment rightShiftAssignment = rightIt.next();
                moveList.add(new ShiftAssignmentSwapMove(leftShiftAssignment, rightShiftAssignment));
            }
        }
        return moveList;
    }

}
