/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2004, 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "DynamicNodeList.h"

#include "Document.h"
#include "Element.h"

namespace WebCore {

DynamicSubtreeNodeList::DynamicSubtreeNodeList(PassRefPtr<Node> node)
    : DynamicNodeList(node)
{
    rootNode()->registerDynamicSubtreeNodeList(this);
}

DynamicSubtreeNodeList::~DynamicSubtreeNodeList()
{
    rootNode()->unregisterDynamicSubtreeNodeList(this);
}

unsigned DynamicSubtreeNodeList::length() const
{
    if (m_caches.isLengthCacheValid)
        return m_caches.cachedLength;

    unsigned length = 0;

    for (Node* n = node()->firstChild(); n; n = n->traverseNextNode(rootNode()))
        length += n->isElementNode() && nodeMatches(static_cast<Element*>(n));

    m_caches.cachedLength = length;
    m_caches.isLengthCacheValid = true;

    return length;
}

Node* DynamicSubtreeNodeList::itemForwardsFromCurrent(Node* start, unsigned offset, int remainingOffset) const
{
    ASSERT(remainingOffset >= 0);
    for (Node* n = start; n; n = n->traverseNextNode(rootNode())) {
        if (n->isElementNode() && nodeMatches(static_cast<Element*>(n))) {
            if (!remainingOffset) {
                m_caches.lastItem = n;
                m_caches.lastItemOffset = offset;
                m_caches.isItemCacheValid = true;
                return n;
            }
            --remainingOffset;
        }
    }

    return 0; // no matching node in this subtree
}

Node* DynamicSubtreeNodeList::itemBackwardsFromCurrent(Node* start, unsigned offset, int remainingOffset) const
{
    ASSERT(remainingOffset < 0);
    for (Node* n = start; n; n = n->traversePreviousNode(rootNode())) {
        if (n->isElementNode() && nodeMatches(static_cast<Element*>(n))) {
            if (!remainingOffset) {
                m_caches.lastItem = n;
                m_caches.lastItemOffset = offset;
                m_caches.isItemCacheValid = true;
                return n;
            }
            ++remainingOffset;
        }
    }

    return 0; // no matching node in this subtree
}

Node* DynamicSubtreeNodeList::item(unsigned offset) const
{
    int remainingOffset = offset;
    Node* start = node()->firstChild();
    if (m_caches.isItemCacheValid) {
        if (offset == m_caches.lastItemOffset)
            return m_caches.lastItem;
        if (offset > m_caches.lastItemOffset || m_caches.lastItemOffset - offset < offset) {
            start = m_caches.lastItem;
            remainingOffset -= m_caches.lastItemOffset;
        }
    }

    if (remainingOffset < 0)
        return itemBackwardsFromCurrent(start, offset, remainingOffset);
    return itemForwardsFromCurrent(start, offset, remainingOffset);
}

Node* DynamicNodeList::itemWithName(const AtomicString& elementId) const
{
    if (node()->isDocumentNode() || node()->inDocument()) {
        Element* node = this->node()->treeScope()->getElementById(elementId);
        if (node && nodeMatches(node) && node->isDescendantOf(this->node()))
            return node;
        if (!node)
            return 0;
        // In the case of multiple nodes with the same name, just fall through.
    }

    unsigned length = this->length();
    for (unsigned i = 0; i < length; i++) {
        Node* node = item(i);
        // FIXME: This should probably be using getIdAttribute instead of idForStyleResolution.
        if (node->hasID() && static_cast<Element*>(node)->idForStyleResolution() == elementId)
            return node;
    }

    return 0;
}

} // namespace WebCore