// TnzTools includes
#include <tools/assistant.h>
#include <tools/assistants/guidelineline.h>
#include <tools/assistants/guidelineellipse.h>
 
// TnzCore includes
#include <tgl.h>
 
// std includes
#include <limits>
 
 
//*****************************************************************************************
//    TAssistantEllipse implementation
//*****************************************************************************************
 
class TAssistantEllipse final : public TAssistant {
  Q_DECLARE_TR_FUNCTIONS(TAssistantEllipse)
public:
  const TStringId m_idRestricktA;
  const TStringId m_idRestricktB;
  const TStringId m_idRepeat;
  const TStringId m_idGrid;
  const TStringId m_idPerspective;
 
protected:
  TAssistantPoint &m_center;
  TAssistantPoint &m_a;
  TAssistantPoint &m_b;
  TAssistantPoint &m_grid0;
  TAssistantPoint &m_grid1;
 
public:
  TAssistantEllipse(TMetaObject &object):
    TAssistant(object),
    m_idRestricktA("restrictA"),
    m_idRestricktB("restrictB"),
    m_idRepeat("repeat"),
    m_idGrid("grid"),
    m_idPerspective("perspective"),
    m_center( addPoint("center", TAssistantPoint::CircleCross) ),
    m_a( addPoint("a", TAssistantPoint::CircleFill, TPointD(100.0, 0.0)) ),
    m_b( addPoint("b", TAssistantPoint::Circle,     TPointD(0.0,  50.0)) ),
    m_grid0( addPoint("grid0",  TAssistantPoint::CircleDoubleDots, TPointD(  0.0,-50.0)) ),
    m_grid1( addPoint("grid1",  TAssistantPoint::CircleDots,       TPointD( 25.0,-75.0)) )
  {
    addProperty( new TBoolProperty(m_idRestricktA.str(), getRestrictA()) );
    addProperty( new TBoolProperty(m_idRestricktB.str(), getRestrictB()) );
    addProperty( new TBoolProperty(m_idRepeat.str(), getRepeat()) );
    addProperty( new TBoolProperty(m_idGrid.str(), getGrid()) );
    addProperty( new TBoolProperty(m_idPerspective.str(), getPerspective()) );
  }
 
  static QString getLocalName()
    { return tr("Ellipse"); }
 
  void updateTranslation() const override {
    TAssistant::updateTranslation();
    setTranslation(m_idRestricktA, tr("Restrict A"));
    setTranslation(m_idRestricktB, tr("Restrict B"));
    setTranslation(m_idRepeat, tr("Repeat"));
    setTranslation(m_idGrid, tr("Grid"));
    setTranslation(m_idPerspective, tr("Perspective"));
  }
 
  inline bool getRestrictA() const
    { return data()[m_idRestricktA].getBool(); }
  inline bool getRestrictB() const
    { return data()[m_idRestricktB].getBool(); }
  inline bool getRepeat() const
    { return data()[m_idRepeat].getBool(); }
  inline bool getGrid() const
    { return data()[m_idGrid].getBool(); }
  inline bool getPerspective() const
    { return data()[m_idPerspective].getBool(); }
 
  void onDataChanged(const TVariant &value) override {
    TAssistant::onDataChanged(value);
    m_grid0.visible = m_grid1.visible = getGrid();
  }
 
private:
  void fixBAndGgid1(const TPointD &previousCenter, const TPointD &previousA) {
    TPointD dx = previousA - previousCenter;
    double l = norm2(dx);
    if (l <= TConsts::epsilon*TConsts::epsilon) return;
    dx = dx*(1.0/sqrt(l));
    TPointD dy(-dx.y, dx.x);
 
    double r2 = dy*(m_b.position - m_center.position);
 
    TPointD g1 = m_grid1.position - m_grid0.position;
    g1 = TPointD(dx*g1, dy*g1);
 
    dx = m_a.position - m_center.position;
    l = norm2(dx);
    if (l <= TConsts::epsilon*TConsts::epsilon) return;
    dx = dx*(1.0/sqrt(l));
    dy = TPointD(-dx.y, dx.x);
 
    m_grid1.position = m_grid0.position + dx*g1.x + dy*g1.y;
    m_b.position = m_center.position + dy*r2;
  }
 
public:
  void onMovePoint(TAssistantPoint &point, const TPointD &position) override {
    TPointD previousCenter = m_center.position;
    TPointD previousA = m_a.position;
    point.position = position;
    if (&point == &m_center) {
      m_a.position += m_center.position - previousCenter;
      m_b.position += m_center.position - previousCenter;
    } else
    if (&point == &m_a || &point == &m_b)
      fixBAndGgid1(previousCenter, previousA);
  }
 
  TAffine calcEllipseMatrix() const {
    TPointD da = m_a.position - m_center.position;
    TPointD db = m_b.position - m_center.position;
    double r1 = norm(da);
    if (r1 <= TConsts::epsilon) return TAffine::zero();
    double r2 = fabs( (rotate90(da)*db)*(1.0/r1) );
    if (r2 <= TConsts::epsilon) return TAffine::zero();
    return TAffine::translation(m_center.position)
         * TAffine::rotation(atan(da))
         * TAffine::scale(r1, r2);
  }
 
  void getGuidelines(
    const TPointD &position,
    const TAffine &toTool,
    TGuidelineList &outGuidelines ) const override
  {
    bool restrictA = getRestrictA();
    bool restrictB = getRestrictB();
    bool repeat = getRepeat();
 
    TAffine matrix = calcEllipseMatrix();
    if (matrix.isZero()) return;
    if (!restrictA && restrictB) {
      std::swap(matrix.a11, matrix.a12);
      std::swap(matrix.a21, matrix.a22);
      std::swap(restrictA, restrictB);
    }
 
    matrix = toTool*matrix;
    TAffine matrixInv = matrix.inv();
 
    if (restrictA && restrictB) {
      // ellipse
      outGuidelines.push_back(TGuidelineP(
        new TGuidelineEllipse(
          getEnabled(),
          getMagnetism(),
          matrix,
          matrixInv )));
    } else
    if (!restrictA && !restrictB) {
      // scaled ellipse
      TPointD p = matrixInv*position;
      double l = norm(p);
      outGuidelines.push_back(TGuidelineP(
        new TGuidelineEllipse(
          getEnabled(),
          getMagnetism(),
          matrix * TAffine::scale(l) )));
    } else { // restrictA
      TPointD p = matrixInv*position;
      if (repeat) {
        double ox = round(0.5*p.x)*2.0;
        p.x -= ox;
        matrix *= TAffine::translation(ox, 0.0);
      }
 
      // scale by Y
      if (p.x <= TConsts::epsilon - 1.0) {
        // line x = -1
        outGuidelines.push_back(TGuidelineP(
          new TGuidelineInfiniteLine(
            getEnabled(),
            getMagnetism(),
            matrix*TPointD(-1.0, 0.0),
            matrix*TPointD(-1.0, 1.0) )));
      } else
      if (p.x >= 1.0 - TConsts::epsilon) {
        // line x = 1
        outGuidelines.push_back(TGuidelineP(
          new TGuidelineInfiniteLine(
            getEnabled(),
            getMagnetism(),
            matrix*TPointD(1.0, 0.0),
            matrix*TPointD(1.0, 1.0) )));
      } else {
        // ellipse scaled by Y
        double k = fabs(p.y/sqrt(1.0 - p.x*p.x));
        outGuidelines.push_back(TGuidelineP(
          new TGuidelineEllipse(
            getEnabled(),
            getMagnetism(),
            matrix * TAffine::scale(1.0, k) )));
      }
    }
  }
 
private:
  void drawEllipseRanges(
    const TAngleRangeSet &ranges,
    const TAffine &ellipseMatrix,
    const TAffine &screenMatrixInv,
    double pixelSize,
    double alpha ) const
  {
    assert(ranges.check());
    TAngleRangeSet actualRanges(ranges);
    const TRectD oneBox(-1.0, -1.0, 1.0, 1.0);
    if (!TGuidelineEllipse::truncateEllipse(actualRanges, ellipseMatrix.inv()*screenMatrixInv, oneBox))
      return;
    assert(actualRanges.check());
 
    int segments = TGuidelineEllipse::calcSegmentsCount(ellipseMatrix, pixelSize);
    double da = M_2PI/segments;
    double s = sin(da);
    double c = cos(da);
 
    for(TAngleRangeSet::Iterator i(actualRanges); i; ++i) {
      double a0 = i.d0();
      double a1 = i.d1greater();
      int cnt = (int)floor((a1 - a0)/da);
      TPointD r(cos(a0), sin(a0));
      TPointD p0 = ellipseMatrix*r;
      for(int j = 0; j < cnt; ++j) {
        r = TPointD(r.x*c - r.y*s, r.y*c + r.x*s);
        TPointD p1 = ellipseMatrix*r;
        drawSegment(p0, p1, pixelSize, alpha);
        p0 = p1;
      }
      drawSegment(p0, ellipseMatrix*TPointD(cos(a1), sin(a1)), pixelSize, alpha);
    }
  }
 
  void drawEllipse(
    const TAffine &ellipseMatrix,
    const TAffine &screenMatrixInv,
    double pixelSize,
    double alpha ) const
      { drawEllipseRanges(TAngleRangeSet(true), ellipseMatrix, screenMatrixInv, pixelSize, alpha); }
 
  void drawRuler(const TAffine &ellipseMatrix, double pixelSize) const {
    double minStep = 10.0*pixelSize;
    double alpha = getDrawingAlpha();
 
    TAffine em = ellipseMatrix;
    TAffine ellipseMatrixInv = ellipseMatrix.inv();
    TPointD g0 = ellipseMatrixInv*m_grid0.position;
    TPointD g1 = ellipseMatrixInv*m_grid1.position;
    if (norm2(g0) <= TConsts::epsilon*TConsts::epsilon) return;
    if (norm2(g1) <= TConsts::epsilon*TConsts::epsilon) return;
    double ga0 = atan(g0);
    double ga1 = atan(g1);
 
    // x and y radiuses
    TPointD r( norm2(TPointD(em.a11, em.a21)), norm2(TPointD(em.a12, em.a22)) );
    double avgR = 0.5*(r.x + r.y);
    if (avgR <= TConsts::epsilon*TConsts::epsilon) return;
    avgR = sqrt(avgR);
    double actualMinStep = minStep/avgR;
    r.x = sqrt(r.x);
    r.y = sqrt(r.y);
    
    // remove radiuses from ellipse matrix
    double rkx = r.x > TConsts::epsilon ? 1.0/r.x : 0.0;
    double rky = r.y > TConsts::epsilon ? 1.0/r.y : 0.0;
    em.a11 *= rkx; em.a21 *= rkx;
    em.a12 *= rky; em.a22 *= rky;
    
    if (getPerspective()) {
      // draw perspective
      if (ga0 < 0.0) { if (ga1 > 0.0) ga1 -= M_2PI; }
                else { if (ga1 < 0.0) ga1 += M_2PI; }
      double k = 0.0, begin = 0.0, end = 0.0;
      if (!calcPerspectiveStep(actualMinStep, 0.0, M_2PI, 0.0, fabs(ga0), ga1, k, begin, end)) return;
      for(double a = begin; fabs(a) < fabs(end); a *= k) {
        TPointD p( cos(a), (ga0 < 0.0 ? -1.0 : 1.0)*sin(a) );
        TPointD n( p.x*r.y, p.y*r.x ); // perp to allipse
        double nl2 = norm2(n);
        if (nl2 > TConsts::epsilon*TConsts::epsilon) {
          p.x *= r.x;
          p.y *= r.y;
          n = n*(1.0/sqrt(nl2));
          drawMark(em*p, em.transformDirection(n), pixelSize, alpha);
        }
      }
    } else {
      // draw linear
      double da = ga1 - ga0;
      if (da < 0.0)         { da = -da;        std::swap(ga0, ga1); }
      if (ga1 - ga0 > M_PI) { da = M_2PI - da; std::swap(ga0, ga1); }
      if (da < actualMinStep) return;
      for(double a = ga0 - floor(M_PI/da)*da; a < ga0 + M_PI; a += da) {
        TPointD p( cos(a), sin(a) );
        TPointD n( p.x*r.y, p.y*r.x ); // perp to allipse
        double nl2 = norm2(n);
        if (nl2 > TConsts::epsilon*TConsts::epsilon) {
          p.x *= r.x;
          p.y *= r.y;
          n = n*(1.0/sqrt(nl2));
          drawMark(em*p, em.transformDirection(n), pixelSize, alpha);
        }
      }
    }
  }
 
  void drawConcentricGrid(
    const TAffine &ellipseMatrix,
    const TAffine &screenMatrixInv,
    double pixelSize ) const
  {
    double minStep = 20.0*pixelSize;
    double alpha = getDrawingGridAlpha();
    TAffine ellipseMatrixInv = ellipseMatrix.inv();
 
    // calculate bounds
    TAffine matrixInv = ellipseMatrixInv * screenMatrixInv;
    TPointD o  = matrixInv * TPointD(-1.0, -1.0);
    TPointD dx = matrixInv.transformDirection( TPointD(2.0, 0.0) );
    TPointD dy = matrixInv.transformDirection( TPointD(0.0, 2.0) );
    double max = 0.0;
    double min = std::numeric_limits<double>::infinity();
 
    // distance to points
    TPointD corners[] = { o, o+dx, o+dx+dy, o+dy };
    for(int i = 0; i < 4; ++i) {
      double k = norm(corners[i]);
      if (k < min) min = k;
      if (k > max) max = k;
    }
 
    // distance to sides
    TPointD lines[] = { dx, dy, -1.0*dx, -1.0*dy };
    int positive = 0, negative = 0;
    for(int i = 0; i < 4; ++i) {
      double len2 = norm2(lines[i]);
      if (len2 <= TConsts::epsilon*TConsts::epsilon) continue;
      double k = (corners[i]*rotate90(lines[i]))/sqrt(len2);
      if (k > TConsts::epsilon) ++positive;
      if (k < TConsts::epsilon) ++negative;
      double l = -(corners[i]*lines[i]);
      if (l <= TConsts::epsilon || l >= len2 - TConsts::epsilon) continue;
      k = fabs(k);
      if (k < min) min = k;
      if (k > max) max = k;
    }
 
    // if center is inside bounds
    if (min < 0.0 || positive == 0 || negative == 0) min = 0.0;
    if (max <= min) return;
 
    // draw
    const TAffine &em = ellipseMatrix;
    double r = sqrt(0.5*(norm2(TPointD(em.a11, em.a21)) + norm2(TPointD(em.a12, em.a22))));
    double actualMinStep = minStep/r;
    double gs0 = norm(ellipseMatrixInv*m_grid0.position);
    double gs1 = norm(ellipseMatrixInv*m_grid1.position);
    if (gs0 <= TConsts::epsilon*TConsts::epsilon) return;
    if (gs1 <= TConsts::epsilon*TConsts::epsilon) return;
 
    if (getPerspective()) {
      // draw perspective
      double k = 0.0, begin = 0.0, end = 0.0;
      if (!calcPerspectiveStep(actualMinStep, min, max, 0.0, gs0, gs1, k, begin, end)) return;
      for(double x = begin; fabs(x) < fabs(end); x *= k)
        drawEllipse(ellipseMatrix * TAffine::scale(x), screenMatrixInv, pixelSize, alpha);
    } else {
      // draw linear
      double dx = fabs(gs1 - gs0);
      if (dx*r < minStep) return;
      for(double x = gs0 + ceil((min - gs0)/dx)*dx; x < max; x += dx)
        drawEllipse(ellipseMatrix * TAffine::scale(x), screenMatrixInv, pixelSize, alpha);
    }
  }
 
  void drawParallelGrid(
    const TAffine &ellipseMatrix,
    const TAffine &screenMatrixInv,
    double pixelSize ) const
  {
    double minStep = 10.0*pixelSize;
    double alpha = getDrawingGridAlpha();
    TAffine ellipseMatrixInv = ellipseMatrix.inv();
 
    const TAffine &em = ellipseMatrix;
    double r = sqrt(0.5*(norm2(TPointD(em.a11, em.a21)) + norm2(TPointD(em.a12, em.a22))));
    double actualMinStep = minStep/r;
    TPointD g0 = ellipseMatrixInv*m_grid0.position;
    TPointD g1 = ellipseMatrixInv*m_grid1.position;
    if (getRepeat())
      { g0.x -= round(0.5*g0.x)*2.0; g1.x -= round(0.5*g1.x)*2.0; }
    if (fabs(g0.x) >= 1.0 - TConsts::epsilon) return;
    if (fabs(g1.x) >= 1.0 - TConsts::epsilon) return;
    double gs0 = g0.y/sqrt(1.0 - g0.x*g0.x);
    double gs1 = g1.y/sqrt(1.0 - g1.x*g1.x);
    if (fabs(gs0) >= 1.0 - TConsts::epsilon) return;
    if (fabs(gs1) >= 1.0 - TConsts::epsilon) return;
 
    TAngleRangeSet ranges;
    ranges.add( TAngleRangeSet::fromDouble(0.0), TAngleRangeSet::fromDouble(M_PI) );
 
    if (getPerspective()) {
      // draw perspective (actually angular)
      double k = 0.0, begin = 0.0, end = 0.0;
      double a0 = asin(gs0);
      double a1 = asin(gs1);
      double da = fabs(a1 - a0);
      if (fabs(sin(da)) < 2.0*actualMinStep) return;
      for(double a = a0 + ceil((-M_PI_2 - a0)/da)*da; a < M_PI_2; a += da)
        drawEllipseRanges(
          ranges,
          ellipseMatrix*TAffine::scale(a < 0.0 ? -1.0 : 1.0, sin(a)),
          screenMatrixInv,
          pixelSize,
          alpha );
    } else {
      // draw linear
      double dx = fabs(gs1 - gs0);
      if (dx < actualMinStep) return;
      for(double x = gs0 + ceil((-1.0 - gs0)/dx)*dx; x < 1.0; x += dx)
        drawEllipseRanges(
          ranges,
          ellipseMatrix*TAffine::scale(x < 0.0 ? -1.0 : 1.0, x),
          screenMatrixInv,
          pixelSize,
          alpha );
    }
  }
 
  void draw(
    const TAffine &ellipseMatrix,
    const TAffine &screenMatrixInv,
    double ox,
    double pixelSize,
    bool enabled ) const
  {
    const double crossSize = 0.1;
 
    double alpha = getDrawingAlpha(enabled);
    bool grid = getGrid();
    bool ruler = getRestrictA() && getRestrictB();
    bool concentric = !getRestrictA() && !getRestrictB();
 
    drawSegment( ellipseMatrix*TPointD(-crossSize, 0.0),
                 ellipseMatrix*TPointD( crossSize, 0.0), pixelSize, alpha);
    drawSegment( ellipseMatrix*TPointD(0.0, -crossSize),
                 ellipseMatrix*TPointD(0.0,  crossSize), pixelSize, alpha);
    drawEllipse(ellipseMatrix, screenMatrixInv, pixelSize, alpha);
    if (ox > 1.0)
      drawSegment( ellipseMatrix*TPointD(-1.0, -1.0),
                   ellipseMatrix*TPointD(-1.0,  1.0), pixelSize, alpha);
    else if (ox < -1.0)
      drawSegment( ellipseMatrix*TPointD( 1.0, -1.0),
                   ellipseMatrix*TPointD( 1.0,  1.0), pixelSize, alpha);
 
    if (!grid) return;
 
    if (ruler) {
      drawRuler(ellipseMatrix, pixelSize);
    } else
    if (concentric) {
      drawConcentricGrid(ellipseMatrix, screenMatrixInv, pixelSize);
    } else {
      drawParallelGrid(ellipseMatrix, screenMatrixInv, pixelSize);
    }
  }
 
public:
  void draw(TToolViewer *viewer, bool enabled) const override {
    bool restrictA = getRestrictA();
    bool restrictB = getRestrictB();
    bool repeat = getRepeat();
    double minStep = 30.0;
 
    TAffine ellipseMatrix = calcEllipseMatrix();
    if (ellipseMatrix.isZero()) return;
    if (!restrictA && restrictB) {
      std::swap(ellipseMatrix.a11, ellipseMatrix.a12);
      std::swap(ellipseMatrix.a21, ellipseMatrix.a22);
    }
 
    // common data about viewport
    const TRectD oneBox(-1.0, -1.0, 1.0, 1.0);
    TAffine4 modelview, projection;
    glGetDoublev(GL_MODELVIEW_MATRIX, modelview.a);
    glGetDoublev(GL_PROJECTION_MATRIX, projection.a);
    TAffine matrix = (projection*modelview).get2d();
    TAffine matrixInv = matrix.inv();
    double pixelSize = sqrt(tglGetPixelSize2());
 
    if (!repeat || restrictA == restrictB || norm(TPointD(ellipseMatrix.a11, ellipseMatrix.a21)) < minStep*pixelSize) {
      draw(ellipseMatrix, matrixInv, 0.0, pixelSize, enabled);
    } else {
      // calculate bounds
      TPointD o(ellipseMatrix.a13, ellipseMatrix.a23);
      TPointD proj(ellipseMatrix.a11, ellipseMatrix.a21);
      proj = proj * (1.0/norm2(proj));
      TPointD corners[4] = {
        TPointD(oneBox.x0, oneBox.y0),
        TPointD(oneBox.x0, oneBox.y1),
        TPointD(oneBox.x1, oneBox.y0),
        TPointD(oneBox.x1, oneBox.y1) };
      double minX = 0.0, maxX = 0.0;
      for(int i = 0; i < 4; ++i) {
        double x = proj * (matrixInv*corners[i] - o);
        if (i == 0 || x < minX) minX = x;
        if (i == 0 || x > maxX) maxX = x;
      }
      if (maxX <= minX) return;
 
      // draw
      for(double ox = round(0.5*minX)*2.0; ox - 1.0 < maxX; ox += 2.0)
        draw(ellipseMatrix*TAffine::translation(ox, 0.0), matrixInv, ox, pixelSize, enabled);
    }
  }
};
 
 
//*****************************************************************************************
//    Registration
//*****************************************************************************************
 
static TAssistantTypeT<TAssistantEllipse> assistantEllipse("assistantEllipse");