/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   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 .
 */

#include "MasterPageObserver.hxx"

#include <algorithm>
#include "drawdoc.hxx"
#include "sdpage.hxx"
#include <boost/unordered_map.hpp>
#include <set>
#include <vector>
#include <svl/lstner.hxx>
#include <osl/doublecheckedlocking.h>
#include <osl/getglobalmutex.hxx>

namespace sd {

class MasterPageObserver::Implementation
    : public SfxListener
{
public:
    /** The single instance of this class.  It is created on demand when
        Instance() is called for the first time.
    */
    static MasterPageObserver* mpInstance;

    /** The master page observer will listen to events of this document and
        detect changes of the use of master pages.
    */
    void RegisterDocument (SdDrawDocument& rDocument);

    /** The master page observer will stop to listen to events of this
        document.
    */
    void UnregisterDocument (SdDrawDocument& rDocument);

    /** Add a listener that is informed of master pages that are newly
        assigned to slides or become unassigned.
        @param rEventListener
            The event listener to call for future events.  Call
            RemoveEventListener() before the listener is destroyed.
    */
    void AddEventListener (const Link& rEventListener);

    /** Remove the given listener from the list of listeners.
        @param rEventListener
            After this method returns the given listener is not called back
            from this object.  Passing a listener that has not
            been registered before is safe and is silently ignored.
    */
    void RemoveEventListener (const Link& rEventListener);

private:
    ::std::vector<Link> maListeners;

    struct DrawDocHash {
        size_t operator()(SdDrawDocument* argument) const
        { return reinterpret_cast<unsigned long>(argument); }
    };
    typedef ::boost::unordered_map<SdDrawDocument*,
                            MasterPageObserver::MasterPageNameSet,
                            DrawDocHash>
        MasterPageContainer;
    MasterPageContainer maUsedMasterPages;

    virtual void Notify(
        SfxBroadcaster& rBroadcaster,
        const SfxHint& rHint) SAL_OVERRIDE;

    void AnalyzeUsedMasterPages (SdDrawDocument& rDocument);

    void SendEvent (MasterPageObserverEvent& rEvent);
};

MasterPageObserver* MasterPageObserver::Implementation::mpInstance = NULL;

//===== MasterPageObserver ====================================================

MasterPageObserver&  MasterPageObserver::Instance (void)
{
    if (Implementation::mpInstance == NULL)
    {
        ::osl::GetGlobalMutex aMutexFunctor;
        ::osl::MutexGuard aGuard (aMutexFunctor());
        if (Implementation::mpInstance == NULL)
        {
            MasterPageObserver* pInstance = new MasterPageObserver ();
            SdGlobalResourceContainer::Instance().AddResource (
                ::std::unique_ptr<SdGlobalResource>(pInstance));
            OSL_DOUBLE_CHECKED_LOCKING_MEMORY_BARRIER();
            Implementation::mpInstance = pInstance;
        }
    }
    else
    {
        OSL_DOUBLE_CHECKED_LOCKING_MEMORY_BARRIER();
    }

    DBG_ASSERT(Implementation::mpInstance!=NULL,
        "MasterPageObserver::Instance(): instance is NULL");
    return *Implementation::mpInstance;
}

void MasterPageObserver::RegisterDocument (SdDrawDocument& rDocument)
{
    mpImpl->RegisterDocument (rDocument);
}

void MasterPageObserver::UnregisterDocument (SdDrawDocument& rDocument)
{
    mpImpl->UnregisterDocument (rDocument);
}

void MasterPageObserver::AddEventListener (const Link& rEventListener)
{

    mpImpl->AddEventListener (rEventListener);
}

void MasterPageObserver::RemoveEventListener (const Link& rEventListener)
{
    mpImpl->RemoveEventListener (rEventListener);
}

MasterPageObserver::MasterPageObserver (void)
    : mpImpl (new Implementation())
{}

MasterPageObserver::~MasterPageObserver (void)
{}

//===== MasterPageObserver::Implementation ====================================

void MasterPageObserver::Implementation::RegisterDocument (
    SdDrawDocument& rDocument)
{
    // Gather the names of all the master pages in the given document.
    MasterPageContainer::mapped_type aMasterPageSet;
    sal_uInt16 nMasterPageCount = rDocument.GetMasterSdPageCount(PK_STANDARD);
    for (sal_uInt16 nIndex=0; nIndex<nMasterPageCount; nIndex++)
    {
        SdPage* pMasterPage = rDocument.GetMasterSdPage (nIndex, PK_STANDARD);
        if (pMasterPage != NULL)
            aMasterPageSet.insert (pMasterPage->GetName());
    }

    maUsedMasterPages[&rDocument] = aMasterPageSet;

    StartListening (rDocument);
}

void MasterPageObserver::Implementation::UnregisterDocument (
    SdDrawDocument& rDocument)
{
    EndListening (rDocument);

    MasterPageContainer::iterator aMasterPageDescriptor(maUsedMasterPages.find(&rDocument));
    if(aMasterPageDescriptor != maUsedMasterPages.end())
        maUsedMasterPages.erase(aMasterPageDescriptor);
}

void MasterPageObserver::Implementation::AddEventListener (
    const Link& rEventListener)
{
    if (::std::find (
        maListeners.begin(),
        maListeners.end(),
        rEventListener) == maListeners.end())
    {
        maListeners.push_back (rEventListener);

        // Tell the new listener about all the master pages that are
        // currently in use.
        MasterPageContainer::iterator aDocumentIterator;
        for (aDocumentIterator=maUsedMasterPages.begin();
             aDocumentIterator!=maUsedMasterPages.end();
             ++aDocumentIterator)
        {
            ::std::set<OUString>::reverse_iterator aNameIterator;
            for (aNameIterator=aDocumentIterator->second.rbegin();
                 aNameIterator!=aDocumentIterator->second.rend();
                 ++aNameIterator)
            {
              MasterPageObserverEvent aEvent (
                  MasterPageObserverEvent::ET_MASTER_PAGE_EXISTS,
                  *aDocumentIterator->first,
                  *aNameIterator);
              SendEvent (aEvent);
            }
        }
    }
}

void MasterPageObserver::Implementation::RemoveEventListener (
    const Link& rEventListener)
{
    maListeners.erase (
        ::std::find (
            maListeners.begin(),
            maListeners.end(),
            rEventListener));
}

void MasterPageObserver::Implementation::Notify(
    SfxBroadcaster& rBroadcaster,
    const SfxHint& rHint)
{
    const SdrHint* pSdrHint = dynamic_cast<const SdrHint*>(&rHint);
    if (pSdrHint)
    {
        switch (pSdrHint->GetKind())
        {
            case HINT_PAGEORDERCHG:
                // Process the modified set of pages only when the number of
                // standard and notes master pages are equal.  This test
                // filters out events that are sent in between the insertion
                // of a new standard master page and a new notes master
                // page.
                if (rBroadcaster.ISA(SdDrawDocument))
                {
                    SdDrawDocument& rDocument (
                        static_cast<SdDrawDocument&>(rBroadcaster));
                    if (rDocument.GetMasterSdPageCount(PK_STANDARD)
                        == rDocument.GetMasterSdPageCount(PK_NOTES))
                    {
                        AnalyzeUsedMasterPages (rDocument);
                    }
                }
                break;

            default:
                break;
        }
    }
}

void MasterPageObserver::Implementation::AnalyzeUsedMasterPages (
    SdDrawDocument& rDocument)
{
    // Create a set of names of the master pages used by the given document.
    sal_uInt16 nMasterPageCount = rDocument.GetMasterSdPageCount(PK_STANDARD);
    ::std::set<OUString> aCurrentMasterPages;
    for (sal_uInt16 nIndex=0; nIndex<nMasterPageCount; nIndex++)
    {
        SdPage* pMasterPage = rDocument.GetMasterSdPage (nIndex, PK_STANDARD);
        if (pMasterPage != NULL)
            aCurrentMasterPages.insert (pMasterPage->GetName());
        OSL_TRACE("currently used master page %d is %s",
            nIndex,
            ::rtl::OUStringToOString(pMasterPage->GetName(),
                RTL_TEXTENCODING_UTF8).getStr());
    }

    typedef ::std::vector<OUString> StringList;
    StringList aNewMasterPages;
    StringList aRemovedMasterPages;
    MasterPageContainer::iterator aOldMasterPagesDescriptor (
        maUsedMasterPages.find(&rDocument));
    if (aOldMasterPagesDescriptor != maUsedMasterPages.end())
    {
        StringList::iterator I;

        ::std::set<OUString>::iterator J;
        int i=0;
        for (J=aOldMasterPagesDescriptor->second.begin();
             J!=aOldMasterPagesDescriptor->second.end();
             ++J)
            OSL_TRACE("old used master page %d is %s",
            i++,
            ::rtl::OUStringToOString(*J,
                RTL_TEXTENCODING_UTF8).getStr());

        // Send events about the newly used master pages.
        ::std::set_difference (
            aCurrentMasterPages.begin(),
            aCurrentMasterPages.end(),
            aOldMasterPagesDescriptor->second.begin(),
            aOldMasterPagesDescriptor->second.end(),
            ::std::back_insert_iterator<StringList>(aNewMasterPages));
        for (I=aNewMasterPages.begin(); I!=aNewMasterPages.end(); ++I)
        {
            OSL_TRACE("    added master page %s",
                ::rtl::OUStringToOString(*I,
                    RTL_TEXTENCODING_UTF8).getStr());

            MasterPageObserverEvent aEvent (
                MasterPageObserverEvent::ET_MASTER_PAGE_ADDED,
                rDocument,
                *I);
            SendEvent (aEvent);
        }

        // Send events about master pages that are not used any longer.
        ::std::set_difference (
            aOldMasterPagesDescriptor->second.begin(),
            aOldMasterPagesDescriptor->second.end(),
            aCurrentMasterPages.begin(),
            aCurrentMasterPages.end(),
            ::std::back_insert_iterator<StringList>(aRemovedMasterPages));
        for (I=aRemovedMasterPages.begin(); I!=aRemovedMasterPages.end(); ++I)
        {
            OSL_TRACE("    removed master page %s",
                ::rtl::OUStringToOString(*I,
                    RTL_TEXTENCODING_UTF8).getStr());

            MasterPageObserverEvent aEvent (
                MasterPageObserverEvent::ET_MASTER_PAGE_REMOVED,
                rDocument,
                *I);
            SendEvent (aEvent);
        }

        // Store the new list of master pages.
        aOldMasterPagesDescriptor->second = aCurrentMasterPages;
    }
}

void MasterPageObserver::Implementation::SendEvent (
    MasterPageObserverEvent& rEvent)
{
    ::std::vector<Link>::iterator aLink (maListeners.begin());
    ::std::vector<Link>::iterator aEnd (maListeners.end());
    while (aLink!=aEnd)
    {
        aLink->Call (&rEvent);
        ++aLink;
    }
}

} // end of namespace sd

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