/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.apache.jena.permissions.model.impl;

import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.function.Function;
import java.util.function.Predicate;

import org.apache.jena.graph.Node;
import org.apache.jena.permissions.SecurityEvaluator;
import org.apache.jena.permissions.SecurityEvaluator.Action;
import org.apache.jena.permissions.model.SecuredModel;
import org.apache.jena.rdf.model.RSIterator ;
import org.apache.jena.rdf.model.ReifiedStatement ;
import org.apache.jena.util.iterator.ExtendedIterator ;

/**
 * A secured RSIterator implementation
 */
public class SecuredRSIterator implements RSIterator
{
	private class PermReifiedStatementFilter implements Predicate<ReifiedStatement>
	{
		private final SecurityEvaluator evaluator;
		private final Node modelNode;
		private final Set<Action> actions;

		public PermReifiedStatementFilter( final Action[] actions,
				final SecuredModel securedModel )
		{
			this.modelNode = securedModel.getModelNode();
			this.actions = SecurityEvaluator.Util.asSet(actions);
			this.evaluator = securedModel.getSecurityEvaluator();
		}

		@Override
		public boolean test( final ReifiedStatement t )
		{
			return evaluator.evaluateAny(evaluator.getPrincipal(), actions, modelNode,
					t.getStatement().asTriple());
		}

	}

	private class PermReifiedStatementMap implements Function<ReifiedStatement, ReifiedStatement>
	{
		private final SecuredModel securedModel;

		public PermReifiedStatementMap( final SecuredModel securedModel )
		{
			this.securedModel = securedModel;
		}

		@Override
		public ReifiedStatement apply( final ReifiedStatement o )
		{
			return SecuredReifiedStatementImpl.getInstance(securedModel, o);
		}
	}

	private final ExtendedIterator<ReifiedStatement> iter;

	/**
	 * Constructor
	 * 
	 * @param securedModel
	 *            The secured model that provides the security context
	 * @param wrapped
	 *            The wrapped iterator.
	 */
	public SecuredRSIterator( final SecuredModel securedModel,
			final ExtendedIterator<ReifiedStatement> wrapped )
	{
		final PermReifiedStatementFilter filter = new PermReifiedStatementFilter(
				new Action[] { Action.Read }, securedModel);
		final PermReifiedStatementMap map1 = new PermReifiedStatementMap(
				securedModel);
		iter = wrapped.filterKeep(filter).mapWith(map1);
	}

	@Override
	public <X extends ReifiedStatement> ExtendedIterator<ReifiedStatement> andThen(
			final Iterator<X> other )
	{
		return iter.andThen(other);
	}

	@Override
	public void close()
	{
		iter.close();
	}

	@Override
	public ExtendedIterator<ReifiedStatement> filterDrop(
			final Predicate<ReifiedStatement> f )
	{
		return iter.filterDrop(f);
	}

	@Override
	public ExtendedIterator<ReifiedStatement> filterKeep(
			final Predicate<ReifiedStatement> f )
	{
		return iter.filterKeep(f);
	}

	@Override
	public boolean hasNext()
	{
		return iter.hasNext();
	}

	@Override
	public <U> ExtendedIterator<U> mapWith( final Function<ReifiedStatement, U> map1 )
	{
		return iter.mapWith(map1);
	}

	@Override
	public ReifiedStatement next()
	{
		return iter.next();
	}

	@Override
	public ReifiedStatement nextRS()
	{
		return next();
	}

	@Override
	public void remove()
	{
		iter.remove();
	}

	@Override
	public ReifiedStatement removeNext()
	{
		return iter.removeNext();
	}

	@Override
	public List<ReifiedStatement> toList()
	{
		return iter.toList();
	}

	@Override
	public Set<ReifiedStatement> toSet()
	{
		return iter.toSet();
	}
}
