#include "lts_height_plot_widget.h"

#include <QPainter>
#include <QPainterPath>
#include <QPen>
#include <QTransform>
#include <QMouseEvent>

#include <cmath>


static inline double getLength(const QPointF &p1, const QPointF &p2)
{
  const double x = p1.x() - p2.x();
  const double y = p1.y() - p2.y();
  return sqrt(x * x + y * y);
}

class LtsHeightPlotWidget::Private
{
public:
  Private()
    : m_length(0)
    , m_minElevation(0)
    , m_maxElevation(0)
    , m_nullX(0)
    , m_nullY(0)
    , m_scaleX(0)
    , m_scaleY(0)
    , m_fillBrush(Qt::gray)
    , m_axisPen(Qt::black)
    , m_mousePosPen(Qt::blue)
    , m_markerPen(Qt::magenta)
    , iPositionHint(1)
  {
    m_axisPen.setWidth(1);
    m_viewLinePen.setWidth(1);
    m_textFont.setPixelSize(10);
    m_markerPen.setWidth(2);
    m_markerPen.setCapStyle(Qt::RoundCap);
    m_mousePosPen.setStyle(Qt::DashDotDotLine);
    m_viewLinePen.setStyle(Qt::DashLine);
  }
  void clearPixmap();

  double getDataHeight(double pos) const;
  QPointF getDataPos(double pos) const;
  int findDataPointIdx(const QPointF &point) const;
  void clear();
  void recalcData();
  void setData(const QVector<QPair<QPointF, double> > &data);
  void setMarks(const QVector<QPointF> &data);
  void resize(const QSize &newSize);
  void repaint();
  void paintLines(QPainter &p) const;

  QVector< QPair< QPointF, double > > m_data;
  QVector< QPointF > m_marks;
  QVector< QPair< double, double > > m_heightList;        

  double m_length;
  double m_minElevation;
  double m_maxElevation;
  double m_nullX;
  double m_nullY;
  double m_scaleX;
  double m_scaleY;
  QPainterPath m_drawPoints;  
  QBrush m_fillBrush;
  QPen m_axisPen;
  QPen m_viewLinePen;
  QPen m_mousePosPen;
  QPen m_markerPen;
  QFont m_textFont;
  QPointF m_mousePos;
  QPointF m_mouseLeftClickPos;

  QSize m_curSize;      
  QTransform m_trans1;  
  QTransform m_trans2;  
  QTransform m_transInverted; 
  QTransform m_transCombined; 

  QPixmap m_pixmap;

  mutable int iPositionHint;
};

double LtsHeightPlotWidget::Private::getDataHeight(double pos) const
{
  if (m_heightList.count() <= 1)
    return 0;
  
  if (pos <= 0.)
    return m_heightList[0].second;
  if (pos >= m_heightList[m_heightList.count() - 1].first)
    return m_heightList[m_heightList.count() - 1].second;

  if (iPositionHint >= m_heightList.size())
    iPositionHint = 1;
  if (pos <= m_heightList[iPositionHint].first)
  {
    while (iPositionHint > 1 && pos <= m_heightList[iPositionHint - 1].first)
      --iPositionHint;
  }
  else
  {
    while (iPositionHint < m_heightList.count() - 1 && pos > m_heightList[iPositionHint].first)
      ++iPositionHint;
  }
  const int iFound = iPositionHint;
  
  const double x = m_heightList[iFound].first - m_heightList[iFound - 1].first;
  const double y = m_heightList[iFound].second - m_heightList[iFound - 1].second;
  const double m = y / x;
  const double n = m_heightList[iFound].second - m * m_heightList[iFound].first;
  return m * pos + n;
}

QPointF LtsHeightPlotWidget::Private::getDataPos(double pos) const
{
  if (m_heightList.count() <= 1)
    return QPointF();
  
  if (pos <= 0.)
    return m_data[0].first;
  if (pos >= m_heightList[m_heightList.count() - 1].first)
    return m_data[m_heightList.count() - 1].first;

  if (pos <= m_heightList[iPositionHint].first)
  {
    while (iPositionHint > 1 && pos <= m_heightList[iPositionHint - 1].first)
      --iPositionHint;
  }
  else
  {
    while (iPositionHint < m_heightList.count() - 1 && pos > m_heightList[iPositionHint].first)
      ++iPositionHint;
  }
  const int iFound = iPositionHint;
  
  const double diff = m_heightList[iFound].first - m_heightList[iFound - 1].first;
  double percentile = (pos - m_heightList[iFound - 1].first) / diff;
  const QPointF &p1 = m_data[iFound - 1].first;
  const QPointF p2 = m_data[iFound].first - m_data[iFound - 1].first;
  return QPointF(p1.x() + p2.x() * percentile, p1.y() + p2.y() * percentile);
}

int LtsHeightPlotWidget::Private::findDataPointIdx(const QPointF &point) const
{
  for (int i = 0; i < m_heightList.count() - 1; ++i)
  {
    
    const double x = m_data[i + 1].first.x() - m_data[i].first.x();
    const double y = m_data[i + 1].first.y() - m_data[i].first.y();
    const double m = y / x;
    const double n = m_data[i].first.y() - m * m_data[i].first.x();

    
    const double yRes = m * point.x() + n;
    if (fabs(yRes - point.y()) < 1.)
    {
      
      const double len = getLength(m_data[ i ].first, point);
      if (len <= m_heightList[i].first)
        return i;
    }
  }
  return -1;
}

void LtsHeightPlotWidget::Private::clear()
{
  m_data.clear();
  m_marks.clear();
  m_length = 0;
  m_minElevation = 0;
  m_maxElevation = 0;
  m_scaleX = 0;
  m_scaleY = 0;
  m_drawPoints = QPainterPath();
  m_heightList.clear();
  m_curSize = QSize();

  iPositionHint = 1;
}

void LtsHeightPlotWidget::Private::clearPixmap()
{
  m_pixmap = QPixmap();
}

inline double log5(double x)
{
  return log10(x) / log10(5.);
}

void LtsHeightPlotWidget::Private::recalcData()
{
  m_heightList.clear();
  m_drawPoints = QPainterPath();

  if (m_data.isEmpty())
  {
    clear();
    return;
  }

  double length = 0;
  double minElevation = m_data.at(0).second;
  double maxElevation = minElevation;

  for (int i = 1; i < m_data.count(); ++i)
  {
    length += getLength(m_data.at(i - 1).first, m_data.at(i).first);
    minElevation = std::min(minElevation, m_data.at(i).second);
    maxElevation = std::max(maxElevation, m_data.at(i).second);
  }
  
  if (minElevation < -10000.0) minElevation = -10000.0;
  if (maxElevation < -10000.0) maxElevation = -10000.0;

  if (minElevation > 10000.0) minElevation = 10000.0;
  if (maxElevation > 10000.0) maxElevation = 10000.0;

  if (qFuzzyCompare(minElevation, maxElevation))
  {
    minElevation -= 1.0;
    maxElevation += 1.0;
  }

  
  double n2 = pow(5, floor(log5(fabs(minElevation))) - 1);
  if (qFuzzyIsNull(n2))
    n2 = 0.1;                        

  m_minElevation = lrint(floor(minElevation / n2) * n2);
  m_maxElevation = lrint(ceil(maxElevation / n2) * n2);
  m_scaleY = pow(10, floor(log10(m_maxElevation - m_minElevation)) - 1);
  if (m_scaleY < 0.1)
    m_scaleY = 0.1;
  m_nullY = m_minElevation;
  if (m_minElevation < 0 && m_maxElevation > 0)
    m_nullY = 0;

  
  const double n = pow(10, floor(log10(length))) / 2;
  m_length = lrint(ceil(length / n) * n);
  m_scaleX = pow(10, floor(log10(length)) - 1);
  if (m_scaleX < 0.1)
    m_scaleX = 0.1;
  m_nullX = 0;

  double len = 0;
  m_drawPoints.moveTo(len, m_data.at(0).second);
  m_heightList.append(QPair<double, double>(len, m_data.at(0).second));
  for (int i = 1; i < m_data.count(); ++i)
  {
    len += getLength(m_data.at(i - 1).first, m_data.at(i).first);
    m_drawPoints.lineTo(len, m_data.at(i).second);

    m_heightList.append(QPair<double, double>(len, m_data.at(i).second));
    
  }
  m_drawPoints.lineTo(len, m_minElevation);
  m_drawPoints.lineTo(0, m_minElevation);
  m_drawPoints.setFillRule(Qt::WindingFill);
}

void LtsHeightPlotWidget::Private::setData(const QVector< QPair< QPointF, double > > &data)
{
  if (data.isEmpty())
  {
    clear();
    return;
  }
  QSize tmp = m_curSize;
  clear();

  m_data = data;

  recalcData();
  resize(tmp);
}


void LtsHeightPlotWidget::Private::setMarks(const QVector< QPointF > &data)
{
  m_marks = data;

  recalcData();
  repaint();
}

void LtsHeightPlotWidget::Private::resize(const QSize &newSize)
{
  if (newSize == m_curSize)
    return;

  m_curSize = newSize;

  const int border = 25;
  const double width = m_curSize.width();
  const double height = m_curSize.height();

  const double minY = m_minElevation - m_scaleY;
  const double maxY = m_maxElevation + m_scaleY;
  const double wertebereichY = maxY - minY;

  const double minX =        0 - m_scaleX;
  const double maxX = m_length + m_scaleX;
  const double wertebereichX = maxX - minX;

  m_trans1.reset();
  m_trans2.reset();

  
  m_trans1.translate(10, height);
  
  m_trans1.scale(1, -1);
  
  m_trans1.translate(border, border);
  
  m_trans1.scale(1, -1);

  
  m_trans2.scale((width - 2 * border) / (wertebereichX),
                 (height - 2 * border) / (wertebereichY));
  
  m_trans2.translate(0, minY);
  
  m_trans2.scale(1, -1);

  m_transInverted = m_trans1.inverted() * m_trans2.inverted();
  m_transCombined = m_trans2 * m_trans1;

  repaint();
}

void LtsHeightPlotWidget::Private::repaint()
{
  if (!m_curSize.isValid())
    return;
  if (!m_heightList.count())
    return;

  QImage img(m_curSize, QImage::Format_ARGB32);
  img.fill(Qt::transparent);
  QPainter p(&img);
  const QPainter::RenderHints hints = QPainter::HighQualityAntialiasing |
                                      QPainter::SmoothPixmapTransform |
                                      QPainter::TextAntialiasing |
                                      QPainter::Antialiasing;
  p.setRenderHints(hints);
  p.setTransform(m_trans1);

  
  p.setPen(QPen(m_fillBrush, 0.1));
  p.setBrush(m_fillBrush);
  p.drawPath(m_trans2.map(m_drawPoints));
  p.setRenderHint(QPainter::Antialiasing, false);

  
  p.setPen(m_markerPen);
  for (int i = 0; i < m_marks.count(); ++i)
  {
    int posIdx = findDataPointIdx(m_marks.at(i));
    if (posIdx < 0)
      continue;
    double len = getLength(m_data.at(posIdx).first, m_marks.at(i));
    len += m_heightList.at(posIdx).first;
    const double height = getDataHeight(len);
    const QLineF l(len, m_minElevation, len, height);
    

    p.drawLine(m_trans2.map(l));
  }

  
  p.setPen(m_axisPen);
  p.setFont(m_textFont);

  
  p.drawLine(m_trans2.map(QPointF(m_nullX, m_minElevation - m_scaleY)),
             m_trans2.map(QPointF(m_nullX, m_maxElevation + m_scaleY)));

  
  for (double i = m_minElevation; i <= m_maxElevation; i += m_scaleY)
  {
    const qreal y = m_trans2.map(QPointF(0, i)).y();
    p.drawLine(QLineF(-2, y, 2, y));
  }

  
  for (double i = m_minElevation; i <= m_maxElevation; i += m_scaleY * 5)
  {
    const qreal y = m_trans2.map(QPointF(0, i)).y();
    p.drawLine(QLineF(-4, y, 4, y));
  }

  QFontMetricsF fm(m_textFont);
  for (double i = m_minElevation; i <= m_maxElevation; i += m_scaleY * 5)
  {
    if (qFuzzyCompare(i, m_nullY))
      continue;
    const qreal y = m_trans2.map(QPointF(m_nullX, i)).y();
    const QPointF p1(-20, y);
    const QString str = QString::number(i);
    QRectF r = fm.boundingRect(str);
    r.setWidth(fm.width(str));    
    r.moveTo(p1.x() - r.width() / 2., p1.y() - r.height() / 2.);
    p.drawText(r, str, Qt::AlignHCenter | Qt::AlignVCenter);
  }

  
  p.drawLine(m_trans2.map(QPointF(-m_scaleX, m_nullY)),
             m_trans2.map(QPointF(m_scaleX + m_length, m_nullY)));

  
  for (double i = m_scaleX; i <= m_length; i += m_scaleX)
  {
    const QPointF point = m_trans2.map(QPointF(i, m_nullY));
    p.drawLine(QLineF(point.x(), point.y() - 2, point.x(), point.y() + 2));
  }

  
  for (double i = 0; i <= m_length; i += m_scaleX * 5)
  {
    const QPointF point = m_trans2.map(QPointF(i, m_nullY));
    p.drawLine(QLineF(point.x(), point.y() - 4, point.x(), point.y() + 4));
  }

  for (double i = 0; i <= m_length; i += m_scaleX * 5)
  {
    if (qFuzzyCompare(i, m_nullX))
      continue;
    const QPointF point = m_trans2.map(QPointF(i, m_nullY));
    const QPointF p1(point.x(), point.y() + 15);
    const QString str = QString::number(i);
    QRectF r = fm.boundingRect(str);
    r.setWidth(fm.width(str));    
    r.moveTo(p1.x() - r.width() / 2., p1.y() - r.height() / 2.);
    p.drawText(r, str, Qt::AlignHCenter | Qt::AlignVCenter);
  }
  p.end();
  m_pixmap = QPixmap::fromImage(img);
}

void LtsHeightPlotWidget::Private::paintLines(QPainter &p) const
{
  if (m_heightList.count() > 0)
  {
    
    QPointF pos = m_mousePos;
    if (pos.x() < 0)
      pos.setX(0);
    if (pos.x() > m_heightList.at(m_heightList.count() - 1).first)
      pos.setX(m_heightList.at(m_heightList.count() - 1).first);

    
    
    const double curHeight = getDataHeight(pos.x());
    p.setPen(m_mousePosPen);
    p.drawLine(m_transCombined.map(QLineF(m_nullX, curHeight, pos.x(), curHeight)));
    p.drawLine(m_transCombined.map(QLineF(pos.x(), m_nullY,   pos.x(), curHeight)));

    
    if (!m_mouseLeftClickPos.isNull())
    {
      const double y = curHeight > pos.y() ? curHeight : pos.y();
      p.drawLine(m_transCombined.map(QLineF(m_nullX, y, pos.x(), y)));
      p.drawLine(m_transCombined.map(QLineF(pos.x(), m_nullY, pos.x(), y)));

      p.setPen(m_viewLinePen);
      const QPointF &c = m_mouseLeftClickPos;
      p.drawLine(m_transCombined.map(QLineF(m_nullX, c.y(), c.x(), c.y())));
      p.drawLine(m_transCombined.map(QLineF(c.x(), m_nullY, c.x(), c.y())));

      
      const QLineF line(m_mouseLeftClickPos, QPointF(pos.x(), y));
      p.drawLine(m_transCombined.map(line));
    }
  }
}

LtsHeightPlotWidget::LtsHeightPlotWidget(QWidget *parent)
  : QWidget(parent)
  , d(new Private)
{
  setMinimumSize(300, 300);
  resize(size());
  setMouseTracking(true);
}

LtsHeightPlotWidget::~LtsHeightPlotWidget()
{
  delete d;
}

void LtsHeightPlotWidget::clearView()
{
  d->clearPixmap();
  update();
}

void LtsHeightPlotWidget::setData(const QVector< QPair< QPointF, double > > &data)
{
  d->setData(data);
  update();
}

void LtsHeightPlotWidget::setMarks(const QVector<QPointF> &data)
{
  d->setMarks(data);
}

void LtsHeightPlotWidget::setBackgroundBrush(const QBrush &brush)
{
  QPalette pal = palette();
  pal.setBrush(QPalette::Background, brush);
  setPalette(pal);
}

void LtsHeightPlotWidget::setTextFont(const QFont &f)
{
  d->m_textFont = f;
  d->repaint();
}

void LtsHeightPlotWidget::setAxisPen(const QPen &pen)
{
  d->m_axisPen = pen;
  d->repaint();
}

void LtsHeightPlotWidget::setPositionPen(const QPen &pen)
{
  d->m_mousePosPen = pen;
}

void LtsHeightPlotWidget::setViewLinePen(const QPen &pen)
{
  d->m_viewLinePen = pen;
}

void LtsHeightPlotWidget::setContourBrush(const QBrush &brush)
{
  d->m_fillBrush = brush;
  d->repaint();
}

void LtsHeightPlotWidget::setMarkerPen(const QPen &pen)
{
  d->m_markerPen = pen;
  d->repaint();
}

void LtsHeightPlotWidget::resizeEvent(QResizeEvent *e)
{
  d->resize(size());
  QWidget::resizeEvent(e);
}

void LtsHeightPlotWidget::paintEvent(QPaintEvent *e)
{
  Q_UNUSED(e);
  QPainter p(this);

  const QPainter::RenderHints hints = QPainter::SmoothPixmapTransform |
                                      QPainter::TextAntialiasing |
                                      QPainter::Antialiasing;
  p.setRenderHints(hints);

  
  p.drawPixmap(0, 0, d->m_pixmap);

  
  d->paintLines(p);
  p.end();
}

void LtsHeightPlotWidget::mouseMoveEvent(QMouseEvent *e)
{
  QWidget::mouseMoveEvent(e);
  if (!d->m_heightList.count())
    return;

  const QPointF pos = d->m_transInverted.map(e->localPos());
  emit mousePositionChanged(d->getDataPos(pos.x()), d->getDataHeight(pos.x()), pos.y());
  d->m_mousePos = pos;
  update();
}

void LtsHeightPlotWidget::mouseReleaseEvent(QMouseEvent *e)
{
  QWidget::mouseReleaseEvent(e);
  if (!d->m_heightList.count())
    return;
  if (e->button() == Qt::LeftButton)
  {
    const QPointF &pos = d->m_mousePos;
    if (pos.x() < 0)
      return;
    if (pos.x() > d->m_heightList.at(d->m_heightList.count() - 1).first)
      return;

    const double curHeight = d->getDataHeight(pos.x());
    d->m_mouseLeftClickPos = QPointF(pos.x(), curHeight > pos.y() ? curHeight : pos.y());
    emit startLineOfSight(d->getDataPos(pos.x()));
  }
  else if (e->button() == Qt::RightButton)
  {
    d->m_mouseLeftClickPos = QPointF();
    emit stopLineOfSight();
    update();
  }
}