/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
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#pragma once

#include <drawinglayer/drawinglayerdllapi.h>
#include <drawinglayer/primitive2d/groupprimitive2d.hxx>
#include <chrono>

namespace drawinglayer::primitive2d
{
class BufferedDecompositionFlusher;

/** BufferedDecompositionGroupPrimitive2D class

    Baseclass for all C++ implementations which are derived from GroupPrimitive2D
    which want to buffer the decomposition result

    For discussion please refer to BufferedDecompositionPrimitive2D, this is the same
    but for GroupPrimitive2D which want to buffer their decomposition
 */
class UNLESS_MERGELIBS(DRAWINGLAYERCORE_DLLPUBLIC) BufferedDecompositionGroupPrimitive2D
    : public GroupPrimitive2D
{
private:
    // exclusive helper for Primitive2DFlusher
    friend class BufferedDecompositionFlusher;

    /// a sequence used for buffering the last create2DDecomposition() result
    mutable Primitive2DContainer maBuffered2DDecomposition;

    /// offer callback mechanism to flush buffered content timer-based
    mutable std::mutex maCallbackLock;
    /// atomic because this is touched from the main thread and the background thread running
    /// the BufferedDecompositionFlusher.
    mutable std::atomic<std::chrono::time_point<std::chrono::steady_clock>> maLastAccess;
    bool mbFlushOnTimer;

protected:
    /// identical to BufferedDecompositionPrimitive2D, see there please
    bool hasBuffered2DDecomposition() const;
    void setBuffered2DDecomposition(Primitive2DContainer&& rNew);

    /// method which is to be used to implement the local decomposition of a 2D group primitive.
    virtual void
    create2DDecomposition(Primitive2DContainer& rContainer,
                          const geometry::ViewInformation2D& rViewInformation) const = 0;

    // when changing from null (which is inactive) to a count of seconds, the
    // callback mechanism to flush buffered content timer-based will be activated.
    // it is protected since the idea is that this gets called in the constructor
    // of derived classes.
    void activateFlushOnTimer();

public:
    /// constructor/destructor. For GroupPrimitive2D we need the child parameter, too.
    BufferedDecompositionGroupPrimitive2D(Primitive2DContainer&& aChildren);
    virtual ~BufferedDecompositionGroupPrimitive2D();

    /// identical to BufferedDecompositionPrimitive2D, see there please
    virtual void
    get2DDecomposition(Primitive2DDecompositionVisitor& rVisitor,
                       const geometry::ViewInformation2D& rViewInformation) const override;
};

} // end of namespace drawinglayer::primitive2d

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