#include "TROOT.h"
#include "TStyle.h"
#include "TCanvas.h"
#include "TView.h"
#include "TPolyLine3D.h"
#include "TLatex.h"
void DrawFrame3D(){
  Int_t k2[3][3] = {
    {1,0,0},
    {0,1,0},
    {0,0,1}};
  Double_t xyzsize[3][3] = {
    {1.1,0,0},
    {0,1.3,0},
    {0,0,1.1}};

  TPolyLine3D *l2[3];
  for (Int_t j=0;j<3;j++){
    l2[j] = new TPolyLine3D();
    l2[j]->SetNextPoint(0,0,0);
    l2[j]->SetNextPoint(xyzsize[j][0],xyzsize[j][1],xyzsize[j][2]);
    l2[j]->Draw();
  }
  Double_t arrowsize = 0.1;
  TPolyLine3D *arrow[3];
  for (Int_t j=0;j<3;j++){
    arrow[j] = new TPolyLine3D();
    arrow[j]->SetNextPoint(xyzsize[j][0]+arrowsize*k2[j][0],
			   xyzsize[j][1]+arrowsize*k2[j][1],
			   xyzsize[j][2]+arrowsize*k2[j][2]);
    arrow[j]->SetNextPoint(xyzsize[j][0]+0.3*k2[j][2]*arrowsize,
			   xyzsize[j][1]+0.3*k2[j][0]*arrowsize,
			   xyzsize[j][2]+0.3*k2[j][1]*arrowsize);
    arrow[j]->SetNextPoint(xyzsize[j][0]-0.3*k2[j][2]*arrowsize,
			   xyzsize[j][1]-0.3*k2[j][0]*arrowsize,
			   xyzsize[j][2]-0.3*k2[j][1]*arrowsize);
    arrow[j]->SetNextPoint(xyzsize[j][0]+arrowsize*k2[j][0],
			   xyzsize[j][1]+arrowsize*k2[j][1],
			   xyzsize[j][2]+arrowsize*k2[j][2]);
    arrow[j]->Draw();
  }
}

void rec_solid_angle_dxdy(){
  gROOT->SetStyle("Plain");
  gStyle->SetTextFont(132);
  TCanvas *c1 = new TCanvas("c1","c1",400,400);
  c1->SetTheta(20.);
  c1->SetPhi(-141.);
  DrawFrame3D();
  TView *view = TView::CreateView(1);
  Double_t view_size = 0.55;
  view->SetRange(-view_size*1.0,-view_size*1.0,-view_size*0.3,
		  view_size*1.0, view_size*1.0, view_size*1.7);

  const Int_t nPolyLine3D = 20;
  TPolyLine3D *guide[nPolyLine3D];
  for (Int_t i = 0; i<nPolyLine3D; i++){
    guide[i]=new TPolyLine3D();
  }

  Double_t pi = acos(-1.);
  Int_t    n = 30;
  Double_t theta0 = pi/4.0;
  Double_t phi0   = pi/4.2;
  Double_t x0 =  1.*tan(theta0);
  Double_t y0 =  1.*tan(phi0);

  Double_t theta1 = pi/11.;
  Double_t phi1   = pi/6.;
  Double_t x1 =  1.*tan(theta1);
  Double_t y1 =  1.*tan(phi1);
  Double_t r1 =  sqrt(1+x1*x1+y1*y1);

  for (Int_t i=0;i<=n;i++) {
    Double_t r = 0.5;
    Double_t theta = -i*acos(1/r1)/n+pi;
    guide[0]->SetNextPoint(r*cos(theta)+1,
			   r*sin(theta)*x1/sqrt(x1*x1+y1*y1),
			   r*sin(theta)*y1/sqrt(x1*x1+y1*y1));
  }
  std::cout << r1 << std::endl;
  std::cout << 1./r1 << std::endl;
  std::cout << acos(1./r1) << std::endl;
  std::cout << cos(acos(1./r1)) << std::endl;

  guide[1]->SetNextPoint(0,0,y0);
  guide[1]->SetNextPoint(0,x0,y0);
  guide[1]->SetNextPoint(0,x0,0);

  guide[2]->SetNextPoint(1,0,0);
  guide[2]->SetNextPoint(0,x1,y1);
  guide[2]->SetNextPoint(0,0,0);
  guide[2]->SetLineStyle(2);

  guide[3]->SetNextPoint(0,x1-0.07,y1-0.07);
  guide[3]->SetNextPoint(0,x1-0.07,y1+0.07);
  guide[3]->SetNextPoint(0,x1+0.07,y1+0.07);
  guide[3]->SetNextPoint(0,x1+0.07,y1-0.07);
  guide[3]->SetNextPoint(0,x1-0.07,y1-0.07);

  for (Int_t i=0;i<=n;i++) {
    Double_t r = 0.3;
    Double_t theta = -i*theta0/n+pi;
    Double_t phi   = -i*phi0/n+pi;
    guide[4]->SetNextPoint(1.0+r*cos(theta),r*sin(theta),0);
    guide[5]->SetNextPoint(1.0+r*cos(phi),0,r*sin(phi));
  }

  guide[6]->SetNextPoint(0,0,y0);
  guide[6]->SetNextPoint(1,0,0);
  guide[6]->SetNextPoint(0,x0,0);
  guide[6]->SetLineStyle(2);

  for (Int_t i = 0; i<nPolyLine3D; i++){
    guide[i]->Draw();
  }

  Double_t xx[3],xxt[3];
  TLatex Tl;
  Tl.SetTextSize(0.07);
  xx[0]=0.5; xx[1]=x1/2; xx[2]=y1/2+0.05; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{r}");
  xx[0]=0.00; xx[1]=1.3; xx[2]=0.07; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{x}");
  xx[0]=0.12; xx[1]=0.00; xx[2]=1.15; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{y}");
  xx[0]=1.04; xx[1]=0.0; xx[2]=-0.08; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{c}");
  xx[0]=1.18; xx[1]=0.0; xx[2]=0.10; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{z}");
//  xx[0]=1.04; xx[1]=0.0; xx[2]=0.07; view->WCtoNDC(xx,xxt);
//  Tl.DrawLatex(xxt[0],xxt[1],"P");
  xx[0]=0.62; xx[1]=0.21; xx[2]=0.17; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#gamma}");
  xx[0]=0.00; xx[1]=x1+0.1; xx[2]=y1-0.05; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#Delta}#it{y}");
  xx[0]=0.00; xx[1]=x1-0.05; xx[2]=y1+0.1; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#Delta}#it{x}");
  xx[0]=0.00; xx[1]=x0-0.05; xx[2]=-0.1; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{a}");
  xx[0]=0.00; xx[1]=-0.1; xx[2]=y0-0.05; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{b}");
  xx[0]=0.73; xx[1]=0.17; xx[2]=0.0; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#alpha}");
  xx[0]=0.70; xx[1]=0.0; xx[2]=0.12; view->WCtoNDC(xx,xxt);
  Tl.DrawLatex(xxt[0],xxt[1],"#it{#beta}");
}