/* -*- 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 <iterator>

#include <drawdoc.hxx>

#include <sdpage.hxx>

#include <set>

#include <unordered_map>

#include <memory>

#include <vector>

#include <svl/lstner.hxx>

#include <osl/doublecheckedlocking.h>

#include <osl/getglobalmutex.hxx>

#include <tools/debug.hxx>

namespace sd {

class MasterPageObserver::Implementation

    : public SfxListener

{

public:

    /** 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<MasterPageObserverEvent&,void>& 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<MasterPageObserverEvent&,void>& rEventListener);

private:

    ::std::vector<Link<MasterPageObserverEvent&,void>> maListeners;

    struct DrawDocHash {

        size_t operator()(SdDrawDocument* argument) const

        { return reinterpret_cast<sal_uIntPtr>(argument); }

    };

    typedef std::unordered_map<SdDrawDocument*,

                            MasterPageObserver::MasterPageNameSet,

                            DrawDocHash>

        MasterPageContainer;

    MasterPageContainer maUsedMasterPages;

    virtual void Notify(

        SfxBroadcaster& rBroadcaster,

        const SfxHint& rHint) override;

    void AnalyzeUsedMasterPages (SdDrawDocument& rDocument);

    void SendEvent (MasterPageObserverEvent& rEvent);

};

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

MasterPageObserver&  MasterPageObserver::Instance()

{

    static MasterPageObserver* gInstance = []()

    {

        MasterPageObserver* pInstance = new MasterPageObserver ();

        SdGlobalResourceContainer::Instance().AddResource (

            ::std::unique_ptr<SdGlobalResource>(pInstance));

        return pInstance;

    }();

    return *gInstance;

}

void MasterPageObserver::RegisterDocument (SdDrawDocument& rDocument)

{

    mpImpl->RegisterDocument (rDocument);

}

void MasterPageObserver::UnregisterDocument (SdDrawDocument& rDocument)

{

    mpImpl->UnregisterDocument (rDocument);

}

void MasterPageObserver::AddEventListener (const Link<MasterPageObserverEvent&,void>& rEventListener)

{

    mpImpl->AddEventListener (rEventListener);

}

void MasterPageObserver::RemoveEventListener (const Link<MasterPageObserverEvent&,void>& rEventListener)

{

    mpImpl->RemoveEventListener (rEventListener);

}

MasterPageObserver::MasterPageObserver()

    : mpImpl (new Implementation)

{}

MasterPageObserver::~MasterPageObserver()

{}

//===== 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(PageKind::Standard);

    for (sal_uInt16 nIndex=0; nIndex<nMasterPageCount; nIndex++)

    {

        SdPage* pMasterPage = rDocument.GetMasterSdPage (nIndex, PageKind::Standard);

        if (pMasterPage != nullptr)

            aMasterPageSet.insert (pMasterPage->GetName());

    }

    bool bAlreadyExists = maUsedMasterPages.find(&rDocument) != maUsedMasterPages.end();

    maUsedMasterPages[&rDocument] = std::move(aMasterPageSet);

    if (!bAlreadyExists)

        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<MasterPageObserverEvent&,void>& rEventListener)

{

    if (::std::find (

        maListeners.begin(),

        maListeners.end(),

        rEventListener) != maListeners.end())

        return;

    maListeners.push_back (rEventListener);

    // Tell the new listener about all the master pages that are

    // currently in use.

    for (const auto& rDocument : maUsedMasterPages)

    {

        ::std::set<OUString>::reverse_iterator aNameIterator;

        for (aNameIterator=rDocument.second.rbegin();

             aNameIterator!=rDocument.second.rend();

             ++aNameIterator)

        {

          MasterPageObserverEvent aEvent (

              MasterPageObserverEvent::ET_MASTER_PAGE_EXISTS,

              *aNameIterator);

          SendEvent (aEvent);

        }

    }

}

void MasterPageObserver::Implementation::RemoveEventListener (

    const Link<MasterPageObserverEvent&,void>& rEventListener)

{

    maListeners.erase (

        ::std::find (

            maListeners.begin(),

            maListeners.end(),

            rEventListener));

}

void MasterPageObserver::Implementation::Notify(

    SfxBroadcaster& rBroadcaster,

    const SfxHint& rHint)

{

    if (rHint.GetId() != SfxHintId::ThisIsAnSdrHint)

        return;

    const SdrHint* pSdrHint = static_cast<const SdrHint*>(&rHint);

    switch (pSdrHint->GetKind())

    {

        case SdrHintKind::PageOrderChange:

            // 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 (auto pDrawDocument = dynamic_cast<SdDrawDocument *>( &rBroadcaster ))

            {

                if (pDrawDocument->GetMasterSdPageCount(PageKind::Standard)

                    == pDrawDocument->GetMasterSdPageCount(PageKind::Notes))

                {

                    AnalyzeUsedMasterPages (*pDrawDocument);

                }

            }

            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(PageKind::Standard);

    ::std::set<OUString> aCurrentMasterPages;

    for (sal_uInt16 nIndex=0; nIndex<nMasterPageCount; nIndex++)

    {

        SdPage* pMasterPage = rDocument.GetMasterSdPage (nIndex, PageKind::Standard);

        if (pMasterPage != nullptr)

            aCurrentMasterPages.insert (pMasterPage->GetName());

    }

    std::vector<OUString> aNewMasterPages;

    std::vector<OUString> aRemovedMasterPages;

    MasterPageContainer::iterator aOldMasterPagesDescriptor (

        maUsedMasterPages.find(&rDocument));

    if (aOldMasterPagesDescriptor == maUsedMasterPages.end())

        return;

    // Send events about the newly used master pages.

    ::std::set_difference (

        aCurrentMasterPages.begin(),

        aCurrentMasterPages.end(),

        aOldMasterPagesDescriptor->second.begin(),

        aOldMasterPagesDescriptor->second.end(),

        std::back_inserter(aNewMasterPages));

    for (const auto& aNewMasterPage : aNewMasterPages)

    {

        MasterPageObserverEvent aEvent (

            MasterPageObserverEvent::ET_MASTER_PAGE_ADDED,

            aNewMasterPage);

        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_inserter(aRemovedMasterPages));

    for (const auto& aRemovedMasterPage : aRemovedMasterPages)

    {

        MasterPageObserverEvent aEvent (

            MasterPageObserverEvent::ET_MASTER_PAGE_REMOVED,

            aRemovedMasterPage);

        SendEvent (aEvent);

    }

    // Store the new list of master pages.

    aOldMasterPagesDescriptor->second = std::move(aCurrentMasterPages);

}

void MasterPageObserver::Implementation::SendEvent (

    MasterPageObserverEvent& rEvent)

{

    for (const auto& aLink : maListeners)

    {

        aLink.Call(rEvent);

    }

}

} // end of namespace sd

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