/*
 * 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;

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

import org.trie4j.tail.builder.TailBuilder;
import org.trie4j.tail.index.TailIndexBuilder;

public abstract class AbstractTailArrayBuilder
implements Externalizable, TailArrayBuilder{
	protected abstract TailBuilder newTailBuilder(StringBuilder tails);
	protected abstract TailIndexBuilder newTailIndexBuilder(int initialCapacity);

	public AbstractTailArrayBuilder(){
		this(1024);
	}

	public AbstractTailArrayBuilder(int initialCapacity){
		builder = newTailBuilder(tails);
		indexBuilder = newTailIndexBuilder(initialCapacity);
	}

	@Override
	public void append(int nodeId, CharSequence letters, int offset, int len) {
		int ret = builder.insert(letters, offset, len);
		indexBuilder.add(nodeId, ret, tails.length());
	}

	@Override
	public void append(int nodeId, char[] letters, int offset, int len) {
		int ret = builder.insert(letters, offset, len);
		indexBuilder.add(nodeId, ret, tails.length());
	}

	@Override
	public void appendEmpty(int nodeId) {
		indexBuilder.addEmpty(nodeId);
	}

	@Override
	public void trimToSize() {
		tails.trimToSize();
		indexBuilder.trimToSize();
	}

	@Override
	public TailArray build() {
		tails.trimToSize();
		return new DefaultTailArray(tails, indexBuilder.build());
	}

	@Override
	public void readExternal(ObjectInput in)
	throws IOException, ClassNotFoundException {
		int n = in.readInt();
		tails = new StringBuilder(n);
		for(int i = 0; i < n; i++){
			tails.append(in.readChar());
		}
		builder = newTailBuilder(tails);
		indexBuilder = (TailIndexBuilder)in.readObject();
	}

	@Override
	public void writeExternal(ObjectOutput out) throws IOException {
		int n = tails.length();
		out.writeInt(n);
		for(int i = 0; i < n; i++){
			out.writeChar(tails.charAt(i));
		}
		out.writeObject(indexBuilder);
	}

	private StringBuilder tails = new StringBuilder();
	private TailBuilder builder;
	private TailIndexBuilder indexBuilder;
}