/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2013 Google 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 "core/dom/StyleSheetCollection.h"

#include "core/css/CSSStyleSheet.h"
#include "core/css/StyleInvalidationAnalysis.h"
#include "core/css/StyleSheetContents.h"
#include "core/css/resolver/StyleResolver.h"
#include "core/dom/Document.h"
#include "core/dom/Element.h"
#include "core/dom/StyleEngine.h"
#include "core/html/HTMLStyleElement.h"
#include "core/page/Settings.h"

namespace WebCore {

StyleSheetCollection::StyleSheetCollection(TreeScope& treeScope)
    : m_treeScope(treeScope)
    , m_hadActiveLoadingStylesheet(false)
{
}

void StyleSheetCollection::addStyleSheetCandidateNode(Node* node, bool createdByParser)
{
    if (!node->inDocument())
        return;

    // Until the <body> exists, we have no choice but to compare document positions,
    // since styles outside of the body and head continue to be shunted into the head
    // (and thus can shift to end up before dynamically added DOM content that is also
    // outside the body).
    if (createdByParser && document()->body())
        m_styleSheetCandidateNodes.parserAdd(node);
    else
        m_styleSheetCandidateNodes.add(node);

    if (!isHTMLStyleElement(node))
        return;

    ContainerNode* scopingNode = toHTMLStyleElement(node)->scopingNode();
    if (!isTreeScopeRoot(scopingNode))
        m_scopingNodesForStyleScoped.add(scopingNode);
}

void StyleSheetCollection::removeStyleSheetCandidateNode(Node* node, ContainerNode* scopingNode)
{
    m_styleSheetCandidateNodes.remove(node);

    if (!isTreeScopeRoot(scopingNode))
        m_scopingNodesForStyleScoped.remove(scopingNode);
}

StyleSheetCollection::StyleResolverUpdateType StyleSheetCollection::compareStyleSheets(const Vector<RefPtr<CSSStyleSheet> >& oldStyleSheets, const Vector<RefPtr<CSSStyleSheet> >& newStylesheets, Vector<StyleSheetContents*>& addedSheets)
{
    // Find out which stylesheets are new.
    unsigned newStylesheetCount = newStylesheets.size();
    unsigned oldStylesheetCount = oldStyleSheets.size();
    if (newStylesheetCount < oldStylesheetCount)
        return Reconstruct;

    unsigned newIndex = 0;
    for (unsigned oldIndex = 0; oldIndex < oldStylesheetCount; ++oldIndex) {
        if (newIndex >= newStylesheetCount)
            return Reconstruct;
        while (oldStyleSheets[oldIndex] != newStylesheets[newIndex]) {
            addedSheets.append(newStylesheets[newIndex]->contents());
            ++newIndex;
            if (newIndex == newStylesheetCount)
                return Reconstruct;
        }
        ++newIndex;
    }
    bool hasInsertions = !addedSheets.isEmpty();
    while (newIndex < newStylesheetCount) {
        addedSheets.append(newStylesheets[newIndex]->contents());
        ++newIndex;
    }
    // If all new sheets were added at the end of the list we can just add them to existing StyleResolver.
    // If there were insertions we need to re-add all the stylesheets so rules are ordered correctly.
    return hasInsertions ? Reset : Additive;
}

bool StyleSheetCollection::activeLoadingStyleSheetLoaded(const Vector<RefPtr<CSSStyleSheet> >& newStyleSheets)
{
    // StyleSheets of <style> elements that @import stylesheets are active but loading. We need to trigger a full recalc when such loads are done.
    bool hasActiveLoadingStylesheet = false;
    unsigned newStylesheetCount = newStyleSheets.size();
    for (unsigned i = 0; i < newStylesheetCount; ++i) {
        if (newStyleSheets[i]->isLoading())
            hasActiveLoadingStylesheet = true;
    }
    if (m_hadActiveLoadingStylesheet && !hasActiveLoadingStylesheet) {
        m_hadActiveLoadingStylesheet = false;
        return true;
    }
    m_hadActiveLoadingStylesheet = hasActiveLoadingStylesheet;
    return false;
}

void StyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updateMode, const Vector<RefPtr<CSSStyleSheet> >& oldStyleSheets, const Vector<RefPtr<CSSStyleSheet> >& newStyleSheets, StyleResolverUpdateType& styleResolverUpdateType, bool& requiresFullStyleRecalc)
{
    styleResolverUpdateType = Reconstruct;
    requiresFullStyleRecalc = true;

    if (activeLoadingStyleSheetLoaded(newStyleSheets))
        return;

    if (updateMode != AnalyzedStyleUpdate)
        return;
    if (!document()->styleResolverIfExists())
        return;

    // Find out which stylesheets are new.
    Vector<StyleSheetContents*> addedSheets;
    styleResolverUpdateType = compareStyleSheets(oldStyleSheets, newStyleSheets, addedSheets);

    // If we are already parsing the body and so may have significant amount of elements, put some effort into trying to avoid style recalcs.
    if (!document()->body() || document()->hasNodesWithPlaceholderStyle())
        return;
    StyleInvalidationAnalysis invalidationAnalysis(addedSheets);
    if (invalidationAnalysis.dirtiesAllStyle())
        return;
    invalidationAnalysis.invalidateStyle(document());
    requiresFullStyleRecalc = false;
}

void StyleSheetCollection::resetAllRuleSetsInTreeScope(StyleResolver* styleResolver)
{
    // FIXME: If many web developers use style scoped, implement reset RuleSets in per-scoping node manner.
    if (DocumentOrderedList* styleScopedScopingNodes = scopingNodesForStyleScoped()) {
        for (DocumentOrderedList::iterator it = styleScopedScopingNodes->begin(); it != styleScopedScopingNodes->end(); ++it)
            styleResolver->resetAuthorStyle(toContainerNode(*it));
    }
    if (ListHashSet<Node*, 4>* removedNodes = scopingNodesRemoved()) {
        for (ListHashSet<Node*, 4>::iterator it = removedNodes->begin(); it != removedNodes->end(); ++it)
            styleResolver->resetAuthorStyle(toContainerNode(*it));
    }
    styleResolver->resetAuthorStyle(toContainerNode(m_treeScope.rootNode()));
}

static bool styleSheetsUseRemUnits(const Vector<RefPtr<CSSStyleSheet> >& sheets)
{
    for (unsigned i = 0; i < sheets.size(); ++i) {
        if (sheets[i]->contents()->usesRemUnits())
            return true;
    }
    return false;
}

void StyleSheetCollection::updateUsesRemUnits()
{
    m_usesRemUnits = styleSheetsUseRemUnits(m_activeAuthorStyleSheets);
}

}