/*******************************************************************************
 * Copyright 2015-2016 - CNRS (Centre National de Recherche Scientifique)
 *
 * 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 eu.project.ttc.models;

import java.util.Deque;
import java.util.Iterator;
import java.util.List;

import com.google.common.base.Preconditions;
import com.google.common.collect.Iterators;
import com.google.common.collect.Lists;

public class VariationPath implements Iterable<TermVariation> {
	private static final String MSG_NOT_A_PATH = "Not a path";

	private Deque<TermVariation> variations;
	
	public VariationPath(TermVariation tv1, TermVariation... variations) {
		super();
		this.variations = Lists.newLinkedList();
		this.variations.add(tv1);
		for(TermVariation tv:variations) 
			addTermVariation(tv);
	}

	public VariationPath(List<TermVariation> path) {
		super();
		Preconditions.checkArgument(!path.isEmpty());
		this.variations = Lists.newLinkedList(path);
	}

	public void addTermVariation(TermVariation tv) {
		Preconditions.checkArgument(this.variations.getLast().getVariant().equals(tv.getBase()), MSG_NOT_A_PATH);
		this.variations.add(tv);
	}

	public Term getBase() {
		return this.variations.getFirst().getBase();
	}
	
	public Term getVariant() {
		return this.variations.getLast().getVariant();
	}
	
	public int size() {
		return variations.size();
	}

	@Override
	public Iterator<TermVariation> iterator() {
		return Iterators.unmodifiableIterator(variations.iterator());
	}

	public TermVariation[] toArray() {
		return variations.toArray(new TermVariation[this.variations.size()]);
	}

	public boolean isCycle() {
		return this.getBase().equals(this.getVariant());
	}
}