package net.sourceforge.fenixedu.domain.accessControl;

import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

import net.sourceforge.fenixedu.commons.CollectionUtils;
import net.sourceforge.fenixedu.domain.Person;
import net.sourceforge.fenixedu.injectionCode.IGroup;

public final class GroupDifference extends NodeGroup {

    private static final long serialVersionUID = 1L;

    private final IGroup includeGroup;
    private final IGroup excludeGroup;

    public GroupDifference(IGroup includeGroup, IGroup excludeGroup) {
	super(includeGroup, excludeGroup);

	this.includeGroup = includeGroup;
	this.excludeGroup = excludeGroup;
    }

    public GroupDifference(Collection<IGroup> includeGroups, Collection<IGroup> excludeGroups) {
	super(new GroupUnion(includeGroups), new GroupUnion(excludeGroups));

	this.includeGroup = new GroupUnion(includeGroups);
	this.excludeGroup = new GroupUnion(excludeGroups);
    }

    protected IGroup getExcludeGroup() {
	return this.excludeGroup;
    }

    protected IGroup getIncludeGroup() {
	return this.includeGroup;
    }

    @Override
    public Set<Person> getElements() {
	Set<Person> elements = new HashSet<Person>();
	elements.addAll(CollectionUtils.subtract(this.includeGroup.getElements(), this.excludeGroup.getElements()));

	return super.freezeSet(elements);
    }

    @Override
    public boolean isMember(Person person) {
	return getIncludeGroup().isMember(person) && !getExcludeGroup().isMember(person);
    }

    @Override
    protected String getExpressionOperator() {
	return "-";
    }

}