/**********************************************************************************************
    Copyright (C) 2014 Oliver Eichler <oliver.eichler@gmx.de>
    Copyright (C) 2015 Christian Eichler <code@christian-eichler.de>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

**********************************************************************************************/

#include "helpers/CDraw.h"

#include <QImage>
#include <QPointF>
#include <QtMath>

#include "canvas/CCanvas.h"

QImage CDraw::createBasicArrow(const QBrush& brush, qreal scale) {
  QImage arrow(21 * scale, 16 * scale, QImage::Format_ARGB32);
  arrow.fill(qRgba(0, 0, 0, 0));

  QPainter painter(&arrow);
  USE_ANTI_ALIASING(painter, true);

  // white background, same foreground as p
  painter.setPen(QPen(Qt::white, 2));
  painter.setBrush(brush);

  QPointF arrowPoints[4] = {
      QPointF(20.0 * scale, 7.0 * scale),  // front
      QPointF(0.0 * scale, 0.0 * scale),   // upper tail
      QPointF(5.0 * scale, 7.0 * scale),   // mid   tail
      QPointF(0.0 * scale, 15.0 * scale)   // lower tail
  };
  painter.drawPolygon(arrowPoints, 4);
  painter.end();

  return arrow;
}

/**
   @brief   Calculates the square distance between two points
   @return  (int) ( (x2 - x1)^2 + (y2 - y1)^2 )
 */

static inline int pointDistanceSquare(const QPointF& p1, const QPointF& p2) {
  return (p2.x() - p1.x()) * (p2.x() - p1.x()) + (p2.y() - p1.y()) * (p2.y() - p1.y());
}

void CDraw::arrows(const QPolygonF& line, const QRectF& viewport, QPainter& p, int minPointDist, int minArrowDist,
                   qreal scale) {
  QImage arrow = createBasicArrow(p.brush(), scale);
  qreal xoff = qCeil(arrow.width() / 2.0);
  qreal yoff = qFloor((arrow.height() - 1) / 2.0);

  const qreal minArrowDistSquare = minArrowDist * minArrowDist;
  const qreal minPointDistSquare = minPointDist * minPointDist;

  QPointF prevArrow;
  bool firstArrow = true;
  for (int i = 1; i < line.size(); i++) {
    const QPointF& pt = line[i];
    const QPointF& prevPt = line[i - 1];

    // ensure there is enough space between two line points
    if (pointDistanceSquare(pt, prevPt) >= minPointDistSquare) {
      QPointF arrowPos = prevPt + (pt - prevPt) / 2;

      if ((viewport.contains(pt) || 0 == viewport.height())  // ensure the point is visible
          && (firstArrow || pointDistanceSquare(prevArrow, arrowPos) >= minArrowDistSquare)) {
        p.save();

        // rotate and draw the arrow (between bullets)
        p.translate(arrowPos);
        qreal direction = (qAtan2((pt.y() - prevPt.y()), (pt.x() - prevPt.x())) * 180.) / M_PI;
        p.rotate(direction);
        p.drawImage(-xoff, -yoff, arrow);

        p.restore();

        prevArrow = arrowPos;
        firstArrow = false;
      }
    }
  }
}

void CDraw::text(const QString& str, QPainter& p, const QPoint& center, const QColor& color, const QFont& font) {
  QFontMetrics fm(font);
  QRect r = fm.boundingRect(str);

  r.moveCenter(center);
  p.setFont(font);

  // draw the white `shadow`
  p.setPen(Qt::white);
  p.drawText(r.topLeft() - QPoint(-1, -1), str);
  p.drawText(r.topLeft() - QPoint(0, -1), str);
  p.drawText(r.topLeft() - QPoint(+1, -1), str);

  p.drawText(r.topLeft() - QPoint(-1, 0), str);
  p.drawText(r.topLeft() - QPoint(+1, 0), str);

  p.drawText(r.topLeft() - QPoint(-1, +1), str);
  p.drawText(r.topLeft() - QPoint(0, +1), str);
  p.drawText(r.topLeft() - QPoint(+1, +1), str);

  p.setPen(color);
  p.drawText(r.topLeft(), str);
}

void CDraw::text(const QString& str, QPainter& p, const QRect& r, const QColor& color) {
  p.setPen(Qt::white);
  p.setFont(CMainWindow::self().getMapFont());

  // draw the white `shadow`
  p.drawText(r.adjusted(-1, -1, -1, -1), Qt::AlignCenter, str);
  p.drawText(r.adjusted(0, -1, 0, -1), Qt::AlignCenter, str);
  p.drawText(r.adjusted(+1, -1, +1, -1), Qt::AlignCenter, str);

  p.drawText(r.adjusted(-1, 0, -1, 0), Qt::AlignCenter, str);
  p.drawText(r.adjusted(+1, 0, +1, 0), Qt::AlignCenter, str);

  p.drawText(r.adjusted(-1, +1, -1, +1), Qt::AlignCenter, str);
  p.drawText(r.adjusted(0, +1, 0, +1), Qt::AlignCenter, str);
  p.drawText(r.adjusted(+1, +1, +1, +1), Qt::AlignCenter, str);

  p.setPen(color);
  p.drawText(r, Qt::AlignCenter, str);
}

void CDraw::drawCrossHairDot(QPainter& p, const QPointF& pt) {
  USE_ANTI_ALIASING(p, false);
  p.setBrush(Qt::NoBrush);
  QRectF dot2(0, 0, 7, 7);
  p.setPen(QPen(Qt::white, 3));
  p.drawLine(pt.x(), pt.y() + 3, pt.x(), pt.y() + 20);
  p.drawLine(pt.x(), pt.y() - 3, pt.x(), pt.y() - 20);
  p.drawLine(pt.x() - 3, pt.y(), pt.x() - +20, pt.y());
  p.drawLine(pt.x() + 3, pt.y(), pt.x() + 20, pt.y());
  p.setPen(QPen(Qt::red, 1));
  p.drawLine(pt.x(), pt.y() + 3, pt.x(), pt.y() + 20);
  p.drawLine(pt.x(), pt.y() - 3, pt.x(), pt.y() - 20);
  p.drawLine(pt.x() - 3, pt.y(), pt.x() - +20, pt.y());
  p.drawLine(pt.x() + 3, pt.y(), pt.x() + 20, pt.y());

  dot2.moveCenter(pt);
  p.setPen(QPen(Qt::white, 3));
  p.drawRect(dot2);
  p.setPen(QPen(Qt::red, 1));
  p.drawRect(dot2);
  USE_ANTI_ALIASING(p, true);
}

void CDraw::drawRectangle(QPainter& p, const QRectF& rect, const QPen& pen, const QBrush& brush) {
  p.setBrush(brush);
  p.setPen(QPen(Qt::white, pen.width() + 2));
  p.drawRect(rect);
  p.setPen(pen);
  p.drawRect(rect);
}

void CDraw::drawRectangle(QPainter& p, const QRectF& rect, const Qt::GlobalColor& pen, const Qt::GlobalColor& brush) {
  drawRectangle(p, rect, QPen(pen), QBrush(brush));
}
