//
// NOTE: this code is incomplete and contains intermediate solutions that are
//       not necessarily fully correct. But we will continue form this state
//

#include "YourDetectorConstruction.hh"

// geonetry definition
#include "G4Box.hh"


// for matrial
#include "G4Material.hh"
#include "G4NistManager.hh"


// for units
#include "G4SystemOfUnits.hh"


YourDetectorConstruction::YourDetectorConstruction()
  : G4VUserDetectorConctruction(),
    fTargetMaterial(nullptr),
    fTargetShape(nullptr),
    fWorldShape(nullptr),
    fTargetLogical(nullptr){

    const G4String matName = "G4_Si";
    SetTargetMaterial(matName);

    fTargetThickness = 1.0*CLHEP::cm;
    ComputeParameters();
}


YourDetectorConstruction::~YourDetectorConstruction() { }


void YourDetectorConstruction::SetTargetMaterial(const G4String& name) {
    fTargetMaterial = G4NistManager::Instance()->FindOrBuildMaterial(name);
    if (fTargetMaterial == nullptr) {
      G4cerr << " *** ERROR YourDetectorConstruction: unknown material = "
             << name
             << G4endl;
      exit(-1);
    }
    if (fTargetLogical != nullptr) {
      fTargetLogical->SetMaterial(fTargetMaterial);
      G4RunManager::GetRunManager()->PhysicsHasBeenModified();
    }
}


void YourDetectorConstruction::SetTargetThickness(G4double val) {
   fTargetThickness = val;
   ComputeParameters();
}


void YourDetectorConstruction::ComputeParameters() {
    fTargetYZSize = 5.0*fTargetThickness;
    fWorldXSize   = 1.5*fTargetThickness;
    fWorldYZSize  = 1.5*fTargetYZSize;
    // compute gun x position
    fGunPosition  = -0.25*(fWorldXSize + fTargetThickness);
    //
    if (fWorldShape != nullptr) {
      fWorldShape->SetXHalfLength(0.5*fWorldXSize);
      fWorldShape->SetYHalfLength(0.5*fWorldYZSize);
      fWorldShape->SetZHalfLength(0.5*fWorldYZSize);

      fTargetShape->SetXHalfLength(0.5*fTargetThickness);
      fTargetShape->SetYHalfLength(0.5*fTargetYZSize);
      fTargetShape->SetZHalfLength(0.5*fTargetYZSize);
    }
}


G4VPhysicalVolume* YourDetectorConstruction::Construct() {
   // create material for the world
   const G4Material* wMat = G4NistManager::Instance()->FindOrBuildMaterial("G4_Galactic");

   // world
   fWorldShape = new G4Box("solid-world",
                             0.5*fWorldXSize,
                             0.5*fWorldYZSize,
                             0.5*fWorldYZSize);
   G4LogicalVolume*   wLogical = new G4LogicalVolume(fWorldShape, wMat, "logic-world");
   G4VPhysicalVolume* wPhys    = new G4PVPlacement(nullptr, G4ThreeVector(0,0,0), wLogical, "World", nullptr, false, 0);

   //
   // target
   fTargetShape = new G4Box("solid-target",
                             0.5*fTargetThickness,
                             0.5*fTargetYZSize,
                             0.5*fTargetYZSize);
   fTargetLogical = new G4LogicalVolume(fTargetShape, fTargetMaterial, "logic-target");
   G4VPhysicalVolume* tPhys    = new G4PVPlacement(nullptr, G4ThreeVector(0,0,0), tLogical, "Target", wLogical, false, 0);


  return wPhys;
}