/*//////////////////////////////////////////////////////////////////////////////
// CMT Cosmic Muon Tomography project //////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

  Copyright (c) 2014, Universita' degli Studi di Padova, INFN sez. di Padova
  All rights reserved

  Authors: Andrea Rigoni Garola < andrea.rigoni@pd.infn.it >

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

#include "Geant/Solid.h"
#include "Vtk/HEP/Geant/vtkGeantEvent.h"
#include "HEP/Geant/Scene.h"
#include "HEP/Geant/EmitterPrimary.hh"
#include "Vtk/Math/vtkContainerBox.h"
#include "Vtk/Math/vtkDense.h"
#include "Math/Units.h"
#include "Vtk/uLibVtkViewer.h"
#include "Vtk/HEP/Geant/vtkGeantEvent.h"
#include "Vtk/Math/vtkContainerBox.h"

#include <vtkSmartPointer.h>
#include <vtkCallbackCommand.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>

#include <Geant4/Randomize.hh>
#include <Geant4/G4ParticleGun.hh>
#include <Geant4/G4SystemOfUnits.hh>

#include <iostream>

using namespace uLib;

// Custom emitter to fire random muons towards the cube
class RandomEmitter : public Geant::EmitterPrimary {
public:
    virtual void GeneratePrimaries(G4Event* anEvent) override {
        // Start from a random point on the top face of the world box (z = 15m)
        double x = 0_m; 
        double y = 0_m; 
        double z = 14.9_m; // Top face
        
        fParticleGun->SetParticlePosition(G4ThreeVector(x, y, z));
        
        // Aim at a random point on the bottom face (z = -15m)
        double tx = 0_m;
        double ty = 0_m;
        double tz = -14.9_m; // Bottom face
        
        G4ThreeVector dir(tx - x, ty - y, tz - z);
        fParticleGun->SetParticleMomentumDirection(dir.unit());
        fParticleGun->SetParticleEnergy(15_GeV);
        fParticleGun->GeneratePrimaryVertex(anEvent);
    }
};

struct AppState {
    Geant::Scene* scene;
    Vtk::Viewer* viewer;
    Vector<Geant::GeantEvent> results;
};

void KeyPressCallbackFunction(vtkObject* caller, long unsigned int eventId, void* clientData, void* callData) {
    auto* interactor = static_cast<vtkRenderWindowInteractor*>(caller);
    auto* state = static_cast<AppState*>(clientData);
    
    std::string key = interactor->GetKeySym();
    if (key == "Return") {
        std::cout << "--> Firing random muon..." << std::endl;
        
        // Run one event
        state->scene->RunSimulation(1, state->results);
        
        if (!state->results.empty()) {
            // Get the last event
            Geant::GeantEvent* lastEvent = &state->results.back();
            std::cout << "    Collected event " << lastEvent->GetEventID() 
                      << " with " << lastEvent->Path().size() << " steps." << std::endl;
                      
            // Wrap it for VTK
            Vtk::GeantEvent* vtkEvent = new Vtk::GeantEvent(lastEvent);
            state->viewer->AddProp3D(*vtkEvent);
            
            // Re-render
            state->viewer->GetRenderer()->Render();
            state->viewer->GetRenderWindow()->Render();
        }
        else {
            std::cout << "    No event collected." << std::endl;
        }
    }
}

int main(int argc, char** argv) {
    // 1. Setup Geant4 Scene
    Geant::Scene scene;
    scene.ConstructWorldBox(Vector3f(30_m, 30_m, 30_m), "G4_AIR");

    ContainerBox iron_box;
    iron_box.Scale(Vector3f(10_m, 10_m, 10_m));
    iron_box.SetPosition(Vector3f(-5_m, -5_m, -5_m));
    Geant::BoxSolid* iron_cube = new Geant::BoxSolid("IronCube", &iron_box);
    iron_cube->SetNistMaterial("G4_Fe");
    iron_cube->Update();
    scene.AddSolid(iron_cube);

    RandomEmitter* emitter = new RandomEmitter();
    scene.SetEmitter(emitter);
    scene.Initialize();

    // 2. Setup VTK Viewer
    Vtk::Viewer viewer;
    viewer.GetRenderer()->SetBackground(0.05, 0.05, 0.1);
    
    // Visualize world box
    Vtk::ContainerBox* vtkWorld = new Vtk::ContainerBox(scene.GetWorldBox());
    // vtkWorld->ShowBoundingBox(true);
    vtkWorld->ShowScaleMeasures(true);
    viewer.AddProp3D(*vtkWorld);
    
    // Visualize iron cube
    Vtk::ContainerBox* vtkIron = new Vtk::ContainerBox(&iron_box);
    vtkIron->SetOpacity(0.2);
    vtkIron->SetRepresentation(Vtk::Prop3D::Surface);
    viewer.AddProp3D(*vtkIron);
    
    // 3. Event Handling
    AppState state = { &scene, &viewer, {} };
    
    vtkSmartPointer<vtkCallbackCommand> keyCallback = vtkSmartPointer<vtkCallbackCommand>::New();
    keyCallback->SetCallback(KeyPressCallbackFunction);
    keyCallback->SetClientData(&state);
    
    viewer.GetInteractor()->AddObserver(vtkCommand::KeyPressEvent, keyCallback);

    std::cout << "=================================================" << std::endl;
    std::cout << " Geant Muon Simulation Viewer" << std::endl;
    std::cout << " Press [ENTER] to fire a new random muon" << std::endl;
    std::cout << " Press [q] to exit" << std::endl;
    std::cout << "=================================================" << std::endl;

    viewer.ZoomAuto();
    viewer.Start();

    return 0;
}