// -*- Mode: C++ -*-
///////////////////////////////////////////////////////////////////////////
// Some code in this file and accompanying files is based on work by
// Moe Wheatley, AE4Y, released under the "Simplified BSD License".
// For more details see the accompanying file LICENSE_WHEATLEY.TXT
///////////////////////////////////////////////////////////////////////////

#ifndef PLOTTER_H
#define PLOTTER_H

#include <algorithm>
#include <array>
#include <cmath>
#include <limits>
#include <variant>
#include <QColor>
#include <QPixmap>
#include <QPolygonF>
#include <QSize>
#include <QString>
#include <QTimer>
#include <QVector>
#include <QWidget>
#include <boost/circular_buffer.hpp>
#include "Flatten.hpp"
#include "RDP.hpp"
#include "WF.hpp"

class CPlotter final : public QWidget
{
  Q_OBJECT

  // Scaler for the waterfall portion of the display; given a
  // y value, returns an index [0, 255) into the colors array.

  class Scaler1D
  {
    int const & m_avg;
    int const & m_bpp;
    int         m_gain = 0;
    int         m_zero = 0;
    float       m_scale;

  public:

    Scaler1D(int const & avg,
             int const & bpp)
    : m_avg(avg)
    , m_bpp(bpp)
    {
      rescale();
    }

    void
    rescale()
    {
      m_scale = 10.0f
              * std::sqrt(m_bpp * m_avg / 15.0f)
              * std::pow(10.0f, 0.015f * m_gain);
    }

    int gain() const { return m_gain; }
    int zero() const { return m_zero; }

    void setGain(int const gain) { m_gain = gain; rescale(); }
    void setZero(int const zero) { m_zero = zero;            } 

    inline auto
    operator()(float const value) const
    {
      return std::clamp(m_zero + static_cast<int>(m_scale * value), 0, 254);
    }
  };

  // Scaler for the spectrum portion of the display; given a
  // y value, returns a pixel offset into the spectrum view.

  class Scaler2D
  {
    int const & m_h2;
    int         m_gain = 0;
    int         m_zero = 0;
    float       m_scaledGain;
    float       m_scaledZero;

  public:

    Scaler2D(int const & h2)
    : m_h2(h2)
    {
      rescale();
    }

    void
    rescale()
    {
      m_scaledGain = m_h2               / 70.0f * std::pow(10.0f, 0.02f * m_gain);
      m_scaledZero = m_h2 * 0.9f - m_h2 / 70.0f *                         m_zero;
    }

    int gain() const { return m_gain; }
    int zero() const { return m_zero; }

    void setGain(int const gain) { m_gain = gain; rescale(); }
    void setZero(int const zero) { m_zero = zero; rescale(); }

    inline auto
    operator()(float const value) const
    {
      return m_scaledZero - m_scaledGain * value;
    }
  };

public:

  using Colors   = QVector<QColor>;
  using Spectrum = WF::Spectrum;

  explicit CPlotter(QWidget *parent = nullptr);

  ~CPlotter();

  // Sizing

  QSize minimumSizeHint() const override;
  QSize sizeHint()        const override;

  // Inline accessors

  int      binsPerPixel() const { return m_binsPerPixel;    }
  int      flatten()      const { return m_flatten.live();  }
  int      freq()         const { return m_freq;            }
  int      percent2D()    const { return m_percent2D;       }
  int      plot2dGain()   const { return m_scaler2D.gain(); }
  int      plot2dZero()   const { return m_scaler2D.zero(); }
  int      plotGain()     const { return m_scaler1D.gain(); }
  int      plotZero()     const { return m_scaler1D.zero(); }
  Spectrum spectrum()     const { return m_spectrum;        }
  int      startFreq()    const { return m_startFreq;       }

  int
  frequencyAt(int const x) const
  {
    return static_cast<int>(freqFromX(x));
  }

  // Inline manipulators

  void setFlatten   (bool     const flatten   ) { m_flatten(flatten);             } 
  void setPlot2dGain(int      const plot2dGain) { m_scaler2D.setGain(plot2dGain); }
  void setPlot2dZero(int      const plot2dZero) { m_scaler2D.setZero(plot2dZero); }
  void setSpectrum  (Spectrum const spectrum  ) { m_spectrum = spectrum;          }

  // Manipulators

  void drawLine(QString const &);
  void drawData(WF::SWide, WF::State);
  void drawDecodeLine    (const QColor &, int, int);
  void drawHorizontalLine(const QColor &, int, int);
  void setBinsPerPixel(int);
  void setColors(Colors const &);
  void setDialFreq(float);
  void setFilter(int, int);
  void setFilterEnabled(bool);
  void setFilterOpacity(int);
  void setFreq(int);
  void setPercent2D(int);
  void setPlotGain(int);
  void setPlotZero(int);
  void setStartFreq(int);
  void setSubMode(int);
  void setWaterfallAvg(int);

signals:

  void changeFreq(int);

protected:

  // Event Handlers

  void paintEvent       (QPaintEvent  *) override;
  void resizeEvent      (QResizeEvent *) override;
  void leaveEvent       (QEvent       *) override;
  void wheelEvent       (QWheelEvent  *) override;
  void mouseMoveEvent   (QMouseEvent  *) override;
  void mouseReleaseEvent(QMouseEvent  *) override;

private:

  // Replot data storage; alternatives of nothing at all, a
  // string denoting the label of a transmit period interval
  // start, and waterfall display data, flattened. Important
  // that the monostate alternative is first in the list.

  using Replot = boost::circular_buffer<std::variant<
    std::monostate,
    QString,
    WF::SWide
  >>;

  // Accessors

  bool  shouldDrawSpectrum(WF::State) const;
  bool  in30MBand()                   const;
  int   xFromFreq(float f)            const;
  float freqFromX(int   x)            const;

  // Manipulators

  void drawMetrics();
  void drawFilter();
  void drawDials();
  void replot();
  void resize();

  // Data members ** ORDER DEPENDENCY **

  float  m_dialFreq      =  0.0f;
  int    m_nSubMode      =  0;
  int    m_filterCenter  =  0;
  int    m_filterWidth   =  0;
  int    m_filterOpacity =  127;
  int    m_percent2D     =  0;
  int    m_binsPerPixel  =  2;
  int    m_waterfallAvg  =  1;
  int    m_lastMouseX    = -1;
  int    m_line          =  std::numeric_limits<int>::max();
  int    m_startFreq     =  0;
  int    m_freq          =  0;
  int    m_w             =  0;
  int    m_h1            =  0;
  int    m_h2            =  0;
  bool   m_filterEnabled = false;
  float  m_freqPerPixel;

  RDP       m_rdp;
  Scaler1D  m_scaler1D;
  Scaler2D  m_scaler2D;
  Colors    m_colors;
  Replot    m_replot;
  QPolygonF m_points;
  Flatten   m_flatten;
  Spectrum  m_spectrum = Spectrum::Current;
  QTimer  * m_replotTimer;
  QTimer  * m_resizeTimer;

  QPixmap m_ScalePixmap;
  QPixmap m_WaterfallPixmap;
  QPixmap m_OverlayPixmap;
  QPixmap m_SpectrumPixmap;
  
  std::array<QPixmap, 2> m_FilterPixmap = {};
  std::array<QPixmap, 2> m_DialPixmap   = {};

  QString m_text;
};

#endif // PLOTTER_H