/*
 * Copyright 2014 Takao Nakaguchi
 *
 * 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.trie4j.tail.index;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.Arrays;

import org.trie4j.util.FastBitSet;

public class DenseArrayTailIndexBuilder
implements Externalizable, TailIndexBuilder{
	public DenseArrayTailIndexBuilder(int initialCapacity) {
		tail = new int[initialCapacity];
	}

	public DenseArrayTailIndexBuilder() {
	}

	@Override
	public void add(int nodeId, int start, int end) {
		if(nodeId != current){
			throw new IllegalArgumentException("nodeId must be a monoinc.");
		}
		ensureCapacity();
		tail[currentIndex++] = start;
		bs.set(current++);
	}

	@Override
	public void addEmpty(int nodeId) {
		if(nodeId != current){
			throw new IllegalArgumentException("nodeId must be a monoinc.");
		}
		bs.unsetIfLE(current++);
	}

	@Override
	public void trimToSize() {
		tail = Arrays.copyOf(tail, currentIndex);
		bs.trimToSize();
	}

	@Override
	public TailIndex build() {
		trimToSize();
		return new DenseArrayTailIndex(tail, bs.getBytes(), bs.size());
	}

	private void ensureCapacity(){
		if(currentIndex == tail.length){
			tail = Arrays.copyOf(tail, (int)((current + 1) * 1.2));
		}
	}

	@Override
	public void readExternal(ObjectInput in)
	throws ClassNotFoundException, IOException{
		current = in.readInt();
		currentIndex = in.readInt();
		tail = (int[])in.readObject();
		bs = (FastBitSet)in.readObject();
	}

	@Override
	public void writeExternal(ObjectOutput out) throws IOException {
		trimToSize();
		out.writeInt(current);
		out.writeInt(currentIndex);
		out.writeObject(tail);
		out.writeObject(bs);
	}

	private FastBitSet bs = new FastBitSet();
	private int[] tail = {};
	private int current;
	private int currentIndex;
}