/*

 * Copyright (c) 2007 Sun Microsystems, Inc.  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.

 *

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

import java.text.BreakIterator;

import java.text.CharacterIterator;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;

import java.util.NoSuchElementException;

public class MirroredBreakIterator extends BreakIterator {

    private final List<Integer> boundaries;

    private int charIndex;

    private int boundaryIndex;

    MirroredBreakIterator(BreakIterator bi) {

        List<Integer> b = new ArrayList<Integer>();

        int i = bi.first();

        charIndex = i;

        for (; i != DONE; i = bi.next()) {

            b.add(i);

        }

        boundaries = Collections.unmodifiableList(b);

    }

    @Override

    public Object clone() {

        try {

            return super.clone();

        } catch (Exception e) {

            throw new RuntimeException("clone failed", e);

        }

    }

    @Override

    public int first() {

        return changeIndices(0);

    }

    @Override

    public int last() {

        return changeIndices(boundaries.size() - 1);

    }

    @Override

    public int next(int n) {

        if (n == 0) {

            return current();

        }

        int newBoundary = boundaryIndex + n;

        if (newBoundary < 0) {

            first();

            return DONE;

        }

        if (newBoundary > lastBoundary()) {

            last();

            return DONE;

        }

        return changeIndices(newBoundary);

    }

    @Override

    public int next() {

        if (boundaryIndex == lastBoundary()) {

            return DONE;

        }

        return changeIndices(boundaryIndex + 1);

    }

    @Override

    public int previous() {

        if (boundaryIndex == 0) {

            return DONE;

        }

        return changeIndices(boundaryIndex - 1);

    }

    @Override

    public int following(int offset) {

        validateOffset(offset);

        for (int b = 0; b <= lastBoundary(); b++) {

            int i = boundaries.get(b);

            if (i > offset) {

                return changeIndices(i, b);

            }

        }

        return DONE;

    }

    @Override

    public int preceding(int offset) {

        validateOffset(offset);

        for (int b = lastBoundary(); b >= 0; b--) {

            int i = boundaries.get(b);

            if (i < offset) {

                return changeIndices(i, b);

            }

        }

        return DONE;

    }

    @Override

    public boolean isBoundary(int offset) {

        // Call the default impelementation in BreakIterator

        return super.isBoundary(offset);

    }

    @Override

    public int current() {

        return charIndex;

    }

    @Override

    public CharacterIterator getText() {

        throw new UnsupportedOperationException();

    }

    @Override

    public void setText(CharacterIterator newText) {

        throw new UnsupportedOperationException();

    }

    private int lastBoundary() {

        return boundaries.size() - 1;

    }

    private int changeIndices(int newCharIndex, int newBoundary) {

        boundaryIndex = newBoundary;

        return charIndex = newCharIndex;

    }

    private int changeIndices(int newBoundary) {

        try {

            return changeIndices(boundaries.get(newBoundary), newBoundary);

        } catch (IndexOutOfBoundsException e) {

            throw new IllegalArgumentException(e);

        }

    }

    private void validateOffset(int offset) {

        if (offset < boundaries.get(0) || offset > boundaries.get(lastBoundary())) {

            throw new IllegalArgumentException();

        }

    }

}