/* ====================================================================
   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.poi.hwpf.model;

import java.util.Arrays;
import java.util.Comparator;
import java.util.Objects;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.poi.common.Duplicatable;
import org.apache.poi.util.Internal;

import static org.apache.logging.log4j.util.Unbox.box;

/**
 * Represents a lightweight node in the Trees used to store content
 * properties.
 * This only ever works in characters. For the few odd cases when
 * the start and end aren't in characters (eg PAPX and CHPX), use
 * {@link BytePropertyNode} between you and this.
 */
@Internal
public abstract class PropertyNode<T extends PropertyNode<T>> implements Comparable<T>, Duplicatable {

    public static final Comparator<PropertyNode<?>> EndComparator = Comparator.comparingInt(PropertyNode::getEnd);

    public static final Comparator<PropertyNode<?>> StartComparator = Comparator.comparingInt(PropertyNode::getStart);

    private static final Logger LOG = LogManager.getLogger(PropertyNode.class);


    protected Object _buf;
    /**
     * The start, in characters
     */
    private int _cpStart;
    /**
     * The end, in characters
     */
    private int _cpEnd;

    protected PropertyNode(PropertyNode<T> other) {
        // TODO: clone _buf?
        _buf = other._buf;
        _cpStart = other._cpStart;
        _cpEnd = other._cpEnd;
    }


    /**
     * @param fcStart The start of the text for this property, in characters.
     * @param fcEnd   The end of the text for this property, in characters.
     * @param buf     FIXME: Old documentation is: "grpprl The property description in compressed form."
     */
    protected PropertyNode(int fcStart, int fcEnd, Object buf) {
        _cpStart = fcStart;
        _cpEnd = fcEnd;
        _buf = buf;

        if (_cpStart < 0) {
            LOG.atWarn().log("A property claimed to start before zero, at {}! Resetting it to zero, and hoping for the best", box(_cpStart));
            _cpStart = 0;
        }

        if (_cpEnd < _cpStart) {
            LOG.atWarn().log("A property claimed to end ({}) before start! Resetting end to start, and hoping for the best", box(_cpEnd));
            _cpEnd = _cpStart;
        }
    }

    /**
     * @return The start offset of this property's text.
     */
    public int getStart() {
        return _cpStart;
    }

    public void setStart(int start) {
        _cpStart = start;
    }

    /**
     * @return The offset of the end of this property's text.
     */
    public int getEnd() {
        return _cpEnd;
    }

    public void setEnd(int end) {
        _cpEnd = end;
    }

    /**
     * Adjust for a deletion that can span multiple PropertyNodes.
     */
    public void adjustForDelete(int start, int length) {
        int end = start + length;

        if (_cpEnd > start) {
            // The start of the change is before we end

            if (_cpStart < end) {
                // The delete was somewhere in the middle of us
                _cpEnd = end >= _cpEnd ? start : _cpEnd - length;
                _cpStart = Math.min(start, _cpStart);
            } else {
                // The delete was before us
                _cpEnd -= length;
                _cpStart -= length;
            }
        }
    }

    protected boolean limitsAreEqual(Object o) {
        return ((PropertyNode<?>) o).getStart() == _cpStart &&
                ((PropertyNode<?>) o).getEnd() == _cpEnd;

    }

    @Override
    public int hashCode() {
        return Objects.hash(_cpStart,_buf);
    }

    public boolean equals(Object o) {
        if (!(o instanceof PropertyNode)) return false;

        if (limitsAreEqual(o)) {
            Object testBuf = ((PropertyNode<?>) o)._buf;
            if (testBuf instanceof byte[] && _buf instanceof byte[]) {
                return Arrays.equals((byte[]) testBuf, (byte[]) _buf);
            }
            return _buf.equals(testBuf);
        }
        return false;
    }

    @Override
    public abstract PropertyNode<?> copy();

    /**
     * Used for sorting in collections.
     */
    public int compareTo(T o) {
        return Integer.compare(_cpEnd, o.getEnd());
    }
}