// Demonstrates usage of TEveJetCone class.
// Author: Jochen Thaeder

void cone_test() {

  using namespace TMath;

  TRandom r(0);

  // -- Set Constants
  Int_t nCones  = 10;
  Int_t nTracks = 200;

  Float_t coneRadius = 0.4;
  Float_t length = 300.;

  // -- Define palette
  gStyle->SetPalette(1, 0);
  TEveRGBAPalette* pal = new TEveRGBAPalette(0, 500);

  // -----------------------------------------------------------------------------------
  // -- Line sets
  // -----------------------------------------------------------------------------------

  // -- Define cone center
  TEveStraightLineSet* axis = new TEveStraightLineSet("Cone Axis");
  axis->SetLineColor(kGreen);
  axis->SetLineWidth(2);
  
  TEveStraightLineSet* tracksXYZ = new TEveStraightLineSet("StraightLinesXYZ");
  tracksXYZ->SetLineColor(kRed);
  tracksXYZ->SetLineWidth(2);

  TEveStraightLineSet* tracksEtaPhi = new TEveStraightLineSet("StraightLinesEtaPhi");
  tracksEtaPhi->SetLineColor(kYellow);
  tracksEtaPhi->SetLineWidth(2);

  TEveStraightLineSet* tracksSeedEtaPhi = new TEveStraightLineSet("StraightLinesEtaPhiSeed");
  tracksSeedEtaPhi->SetLineColor(kBlue);
  tracksSeedEtaPhi->SetLineWidth(2);

  // -----------------------------------------------------------------------------------
  // -- Draw track distribution in XYZ ( in TPC Volume ) ( +/-250, +/-250, +/-250 )
  // -----------------------------------------------------------------------------------
  
  for ( Int_t track=0; track < nTracks ; track++ ) {
    
    Float_t trackX = r.Uniform(-250.0, 250.0);
    Float_t trackY = r.Uniform(-250.0, 250.0);
    Float_t trackZ = r.Uniform(-250.0, 250.0);
    Float_t trackR = (Float_t) Sqrt ( trackX*trackX + trackY*trackY + trackZ*trackZ );
    
    /*
      Float_t trackEta =  0.5 * (Float_t) Log( (Double_t)(( trackR+trackZ )/( trackR-trackZ )) ); 
      Float_t trackPhi = (Float_t) ATan2( (Double_t) trackY, (Double_t) trackX );  
      if ( trackPhi < 0. ) trackPhi += (Float_t) TwoPi();
    */

    TEveVector trackDir(trackX/trackR, trackY/trackR ,trackZ/trackR);
    TEveVector trackEnd = trackDir * length; 
    tracksXYZ->AddLine(0., 0., 0., trackEnd.fX, trackEnd.fY, trackEnd.fZ );
  }
  
  // -----------------------------------------------------------------------------------
  // -- Draw track distribution in eta phi ( in TPC Volume ) ( +/-0.9, {0, 2Pi} )
  // -----------------------------------------------------------------------------------

  for ( Int_t track=0; track < nTracks ; track++ ) {

    Float_t trackEta = r.Uniform(-0.9, 0.9);
    Float_t trackPhi = r.Uniform(0.0, TwoPi());

    TEveVector trackDir( GetTEveVector(trackEta, trackPhi) );
    TEveVector trackEnd = trackDir * length; 
    
    if ( trackEta > coneRadius || trackEta < -coneRadius )
      tracksEtaPhi->AddLine(0., 0., 0., trackEnd.fX, trackEnd.fY, trackEnd.fZ );
    else
      tracksSeedEtaPhi->AddLine(0., 0., 0., trackEnd.fX, trackEnd.fY, trackEnd.fZ );
  }
  
  // -----------------------------------------------------------------------------------
  // -- Draw cones
  // -----------------------------------------------------------------------------------

  for ( Int_t iter = 0; iter < nCones; ++iter ) {
  
    // -- Get Random ( eta ,phi )
    Float_t coneEta = r.Uniform(-0.9, 0.9);
    Float_t conePhi = r.Uniform(0.0, TwoPi() );

    // -- Primary vertx as origin
    TEveVector coneOrigin(0.0,0.0,0.0);
    
    // -- Get Cone Axis - axis line 10% longer than cone height
    TEveVector coneAxis ( GetTEveVector( coneEta, conePhi) );
    coneAxis *= length * 1.1;
    
    axis->AddLine( 0., 0., 0., coneAxis.fX, coneAxis.fY, coneAxis.fZ );	
    
    // -- Draw jet cone
    TEveJetCone* jetCone = new TEveJetCone("JetCone");
    jetCone->SetCylinder( 250., 250. );
    if ( (jetCone->AddCone( coneEta, conePhi, coneRadius   ) ) != -1)
      gEve->AddElement( jetCone );
  }

  // -----------------------------------------------------------------------------------
 
  // -- Add cone axis
  gEve->AddElement(axis);
  
  // -- Add lines
  //  gEve->AddElement(tracksXYZ);
  gEve->AddElement(tracksSeedEtaPhi);
  gEve->AddElement(tracksEtaPhi);
  
  // -- Load TPC geometry
  geomGentleTPC();

  gEve->Redraw3D(kTRUE);

  return;
}

// ################################################################################
// ################################################################################

// ################################################################################
TEveVector GetTEveVector( Float_t& eta, Float_t& phi ) {
  
  TEveVector vec( (Float_t) Cos ( (Double_t) phi)/ CosH( (Double_t) eta ),
		  (Float_t) Sin ( (Double_t) phi)/ CosH( (Double_t) eta ),
		  (Float_t) TanH( (Double_t) eta ) );
  return vec;
}

// ################################################################################
void geomGentleTPC() {  
  
  TFile f("$ALICE_ROOT/EVE/alice-data/gentle_geo.root");
  TEveGeoShapeExtract* gse = (TEveGeoShapeExtract*) f.Get("Gentle");
  TEveGeoShape* gsre = TEveGeoShape::ImportShapeExtract(gse, 0);
  gEve->AddGlobalElement(gsre);
  f.Close();

  TEveElement* elTRD = gsre->FindChild("TRD+TOF");
  elTRD->SetRnrState(kFALSE);

  TEveElement* elPHOS = gsre->FindChild("PHOS");
  elPHOS->SetRnrState(kFALSE);

  TEveElement* elHMPID = gsre->FindChild("HMPID");
  elHMPID->SetRnrState(kFALSE);
}