/*
 * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 *******************************************************************************
 * (C) Copyright IBM Corp. 1996-2005 - All Rights Reserved                     *
 *                                                                             *
 * The original version of this source code and documentation is copyrighted   *
 * and owned by IBM, These materials are provided under terms of a License     *
 * Agreement between IBM and Sun. This technology is protected by multiple     *
 * US and International patents. This notice and attribution to IBM may not    *
 * to removed.                                                                 *
 *******************************************************************************
 */

package jdk_internal.icu.impl;

import jdk_internal.icu.text.Replaceable;
import jdk_internal.icu.text.ReplaceableString;
import jdk_internal.icu.text.UCharacterIterator;

/**
 * DLF docs must define behavior when Replaceable is mutated underneath the
 * iterator.
 *
 * This and ICUCharacterIterator share some code, maybe they should share an
 * implementation, or the common state and implementation should be moved up
 * into UCharacterIterator.
 *
 * What are first, last, and getBeginIndex doing here?!?!?!
 */
public class ReplaceableUCharacterIterator extends UCharacterIterator {

	// public constructor ------------------------------------------------------

	/**
	 * Replaceable object
	 */
	private Replaceable replaceable;

	/**
	 * Current currentIndex
	 */
	private int currentIndex;

	// public methods ----------------------------------------------------------

	/**
	 * Public constructor
	 *
	 * @param str text which the iterator will be based on
	 */
	public ReplaceableUCharacterIterator(String str) {
		if (str == null) {
			throw new IllegalArgumentException();
		}
		this.replaceable = new ReplaceableString(str);
		this.currentIndex = 0;
	}

	/**
	 * Public constructor
	 *
	 * @param buf buffer of text on which the iterator will be based
	 */
	public ReplaceableUCharacterIterator(StringBuffer buf) {
		if (buf == null) {
			throw new IllegalArgumentException();
		}
		this.replaceable = new ReplaceableString(buf);
		this.currentIndex = 0;
	}

	/**
	 * Creates a copy of this iterator, does not clone the underlying
	 * <code>Replaceable</code>object
	 *
	 * @return copy of this iterator
	 */
	@Override
	public Object clone() {
		try {
			return super.clone();
		} catch (CloneNotSupportedException e) {
			return null; // never invoked
		}
	}

	/**
	 * Returns the current UTF16 character.
	 *
	 * @return current UTF16 character
	 */
	public int current() {
		if (currentIndex < replaceable.length()) {
			return replaceable.charAt(currentIndex);
		}
		return DONE;
	}

	/**
	 * Gets the current currentIndex in text.
	 *
	 * @return current currentIndex in text.
	 */
	@Override
	public int getIndex() {
		return currentIndex;
	}

	/**
	 * Returns the length of the text
	 *
	 * @return length of the text
	 */
	@Override
	public int getLength() {
		return replaceable.length();
	}

	@Override
	public int getText(char[] fillIn, int offset) {
		int length = replaceable.length();
		if (offset < 0 || offset + length > fillIn.length) {
			throw new IndexOutOfBoundsException(Integer.toString(length));
		}
		replaceable.getChars(0, length, fillIn, offset);
		return length;
	}

	/**
	 * Returns next UTF16 character and increments the iterator's currentIndex by 1.
	 * If the resulting currentIndex is greater or equal to the text length, the
	 * currentIndex is reset to the text length and a value of DONECODEPOINT is
	 * returned.
	 *
	 * @return next UTF16 character in text or DONE if the new currentIndex is off
	 *         the end of the text range.
	 */
	@Override
	public int next() {
		if (currentIndex < replaceable.length()) {
			return replaceable.charAt(currentIndex++);
		}
		return DONE;
	}

	// private data members ----------------------------------------------------

	/**
	 * Returns previous UTF16 character and decrements the iterator's currentIndex
	 * by 1. If the resulting currentIndex is less than 0, the currentIndex is reset
	 * to 0 and a value of DONECODEPOINT is returned.
	 *
	 * @return next UTF16 character in text or DONE if the new currentIndex is off
	 *         the start of the text range.
	 */
	@Override
	public int previous() {
		if (currentIndex > 0) {
			return replaceable.charAt(--currentIndex);
		}
		return DONE;
	}

	/**
	 * Sets the currentIndex to the specified currentIndex in the text and returns
	 * that single UTF16 character at currentIndex. This assumes the text is stored
	 * as 16-bit code units.
	 *
	 * @param currentIndex the currentIndex within the text.
	 * @exception IllegalArgumentException is thrown if an invalid currentIndex is
	 *                                     supplied. i.e. currentIndex is out of
	 *                                     bounds.
	 */
	@Override
	public void setIndex(int currentIndex) {
		if (currentIndex < 0 || currentIndex > replaceable.length()) {
			throw new IllegalArgumentException();
		}
		this.currentIndex = currentIndex;
	}

}
