/*
 * 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.commons.lang3.text.translate;

import java.io.IOException;
import java.io.Writer;

/**
 * Translates codepoints to their XML numeric entity escaped value.
 *
 * @since 3.0
 * @version $Id: NumericEntityEscaper.java 1436768 2013-01-22 07:07:42Z ggregory
 *          $
 */
public class NumericEntityEscaper extends CodePointTranslator {

	/**
	 * <p>
	 * Constructs a <code>NumericEntityEscaper</code> above the specified value
	 * (exclusive).
	 * </p>
	 *
	 * @param codepoint above which to escape
	 * @return the newly created {@code NumericEntityEscaper} instance
	 */
	public static NumericEntityEscaper above(final int codepoint) {
		return outsideOf(0, codepoint);
	}

	/**
	 * <p>
	 * Constructs a <code>NumericEntityEscaper</code> below the specified value
	 * (exclusive).
	 * </p>
	 *
	 * @param codepoint below which to escape
	 * @return the newly created {@code NumericEntityEscaper} instance
	 */
	public static NumericEntityEscaper below(final int codepoint) {
		return outsideOf(codepoint, Integer.MAX_VALUE);
	}

	/**
	 * <p>
	 * Constructs a <code>NumericEntityEscaper</code> between the specified values
	 * (inclusive).
	 * </p>
	 *
	 * @param codepointLow  above which to escape
	 * @param codepointHigh below which to escape
	 * @return the newly created {@code NumericEntityEscaper} instance
	 */
	public static NumericEntityEscaper between(final int codepointLow, final int codepointHigh) {
		return new NumericEntityEscaper(codepointLow, codepointHigh, true);
	}

	/**
	 * <p>
	 * Constructs a <code>NumericEntityEscaper</code> outside of the specified
	 * values (exclusive).
	 * </p>
	 *
	 * @param codepointLow  below which to escape
	 * @param codepointHigh above which to escape
	 * @return the newly created {@code NumericEntityEscaper} instance
	 */
	public static NumericEntityEscaper outsideOf(final int codepointLow, final int codepointHigh) {
		return new NumericEntityEscaper(codepointLow, codepointHigh, false);
	}

	private final int below;

	private final int above;

	private final boolean between;

	/**
	 * <p>
	 * Constructs a <code>NumericEntityEscaper</code> for all characters.
	 * </p>
	 */
	public NumericEntityEscaper() {
		this(0, Integer.MAX_VALUE, true);
	}

	/**
	 * <p>
	 * Constructs a <code>NumericEntityEscaper</code> for the specified range. This
	 * is the underlying method for the other constructors/builders. The
	 * <code>below</code> and <code>above</code> boundaries are inclusive when
	 * <code>between</code> is <code>true</code> and exclusive when it is
	 * <code>false</code>.
	 * </p>
	 *
	 * @param below   int value representing the lowest codepoint boundary
	 * @param above   int value representing the highest codepoint boundary
	 * @param between whether to escape between the boundaries or outside them
	 */
	private NumericEntityEscaper(final int below, final int above, final boolean between) {
		this.below = below;
		this.above = above;
		this.between = between;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public boolean translate(final int codepoint, final Writer out) throws IOException {
		if (between) {
			if (codepoint < below || codepoint > above) {
				return false;
			}
		} else {
			if (codepoint >= below && codepoint <= above) {
				return false;
			}
		}

		out.write("&#");
		out.write(Integer.toString(codepoint, 10));
		out.write(';');
		return true;
	}
}
