#ifndef FRACTALZOOMWIDGET_H
#define FRACTALZOOMWIDGET_H

#include "EscapeTimeVisualWidget.h"
#include "FractalWidgetUtils.h"
#include "Bitmap.h"

#include <QThreadPool>
#include <QMutex>

class FractalZoomWidget;



///
/// \brief represents a grid of images at a certain depth
///        in the fractal.
///
class SliceGrid
{
public:
    FractalZoomWidget& owner;
    int level;
    mnd::Real dpp;
    std::unordered_map<std::pair<GridIndex, GridIndex>, std::unique_ptr<GridElement>, IndexPairHash> cells;
public:
    SliceGrid(FractalZoomWidget& owner, int level);

    std::pair<GridIndex, GridIndex> getCellIndices(mnd::Real x, mnd::Real y);
    std::pair<mnd::Real, mnd::Real> getPositions(GridIndex i, GridIndex j);
    GridElement* getCell(GridIndex i, GridIndex j);
    void setCell(GridIndex i, GridIndex j, std::unique_ptr<GridElement> tex);

    inline size_t countAllocatedCells(void) const { return cells.size(); }
    void clearCells(void);
    void clearUncleanCells(void);
};


class Calcer : public QObject
{
    Q_OBJECT

    /// tuple contains level, i, j of the job
    std::unordered_map<std::tuple<int, GridIndex, GridIndex>, CalcJob*, IndexTripleHash> jobs;
    QMutex jobsMutex;
    QThreadPool* threadPool;
    FractalZoomWidget& owner;
    int currentLevel;

    volatile unsigned int calcState = 0;
public:
    Calcer(FractalZoomWidget& owner);
    void clearAll(void);

    inline void changeState(void) { calcState++; }

public slots:
    void calc(SliceGrid& grid, int level, GridIndex i, GridIndex j, int priority);
    void setCurrentLevel(int level);
    void notFinished(int level, GridIndex i, GridIndex j);
    void jobFailed(void);
    void redirect(Bitmap<float>* bmp);
signals:
    void done(int level, GridIndex i, GridIndex j, Bitmap<float>* bmp);
};


class FractalZoomWidget :
    public EscapeTimeVisualWidget
{
    Q_OBJECT

    // a grid should not be deleted once constructed.
    // to free up memory one can call SliceGrid::clearCells()
    std::unordered_map<int, SliceGrid> levels;
    mnd::MandelGenerator* generator;
    Calcer calcer;

    mnd::MandelInfo mandelInfo;

public:
    static const int chunkSize = 256;

    FractalZoomWidget(QWidget* parent = nullptr);

    mnd::Real getDpp(int level);
    const mnd::MandelInfo& getMandelInfo(void) const;

    void setGenerator(mnd::MandelGenerator*);
    mnd::MandelGenerator* getGenerator(void) const;

    void paintGL(void) override;
};

#endif // FRACTALZOOMWIDGET_H