REveManager.cxx

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// @(#)root/eve7:$Id$
// Authors: Matevz Tadel & Alja Mrak-Tadel: 2006, 2007

/*************************************************************************
 * Copyright (C) 1995-2019, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#include <ROOT/REveManager.hxx>

#include <ROOT/REveUtil.hxx>
#include <ROOT/REveSelection.hxx>
#include <ROOT/REveViewer.hxx>
#include <ROOT/REveScene.hxx>
#include <ROOT/REveClient.hxx>
#include <ROOT/REveGeomViewer.hxx>
#include <ROOT/RWebWindow.hxx>

#include "TGeoManager.h"
#include "TObjString.h"
#include "TROOT.h"
#include "TFile.h"
#include "TMap.h"
#include "TExMap.h"
#include "TMacro.h"
#include "TFolder.h"
#include "TSystem.h"
#include "TRint.h"
#include "TEnv.h"
#include "TColor.h"
#include "TPluginManager.h"
#include "TPRegexp.h"
#include "TClass.h"
#include "THttpServer.h"

#include "Riostream.h"

#include "json.hpp"
#include <sstream>
#include <iostream>

using namespace ROOT::Experimental;
namespace REX = ROOT::Experimental;

REveManager* REX::gEve = 0;




/** \class REveManager
\ingroup REve
Central application manager for Eve.
Manages elements, GUI, GL scenes and GL viewers.
*/

////////////////////////////////////////////////////////////////////////////////

REveManager::REveManager() : // (Bool_t map_window, Option_t* opt) :
   fExcHandler  (nullptr),
   fVizDB       (nullptr),
   fVizDBReplace(kTRUE),
   fVizDBUpdate(kTRUE),
   fGeometries  (nullptr),
   fGeometryAliases (nullptr),

   fMacroFolder (nullptr),

   fRedrawDisabled (0),
   fResetCameras   (kFALSE),
   fDropLogicals   (kFALSE),
   fKeepEmptyCont  (kFALSE),
   fTimerActive    (kFALSE),
   fRedrawTimer    ()
{
   // Constructor.

   static const REveException eh("REveManager::REveManager ");

   if (REX::gEve)
      throw eh + "There can be only one REve!";

   REX::gEve = this;

   fExcHandler = new RExceptionHandler;

   fGeometries      = new TMap; fGeometries->SetOwnerKeyValue();
   fGeometryAliases = new TMap; fGeometryAliases->SetOwnerKeyValue();
   fVizDB           = new TMap; fVizDB->SetOwnerKeyValue();

   fElementIdMap[0] = nullptr; // do not increase count for null element.

   fRedrawTimer.Connect("Timeout()", "ROOT::Experimental::REveManager", this, "DoRedraw3D()");
   fMacroFolder = new TFolder("EVE", "Visualization macros");
   gROOT->GetListOfBrowsables()->Add(fMacroFolder);

   fWorld = new REveScene("EveWorld", "Top-level Eve Scene");
   fWorld->IncDenyDestroy();
   AssignElementId(fWorld);

   fSelectionList = new REveElement("Selection List");
   fSelectionList->SetChildClass(TClass::GetClass<REveSelection>());
   fSelectionList->IncDenyDestroy();
   fWorld->AddElement(fSelectionList);
   fSelection = new REveSelection("Global Selection", "", kRed, kViolet);
   fSelection->IncDenyDestroy();
   fSelectionList->AddElement(fSelection);
   fHighlight = new REveSelection("Global Highlight", "", kGreen, kCyan);
   fHighlight->SetHighlightMode();
   fHighlight->IncDenyDestroy();
   fSelectionList->AddElement(fHighlight);

   fViewers = new REveViewerList("Viewers");
   fViewers->IncDenyDestroy();
   fWorld->AddElement(fViewers);

   fScenes  = new REveSceneList ("Scenes");
   fScenes->IncDenyDestroy();
   fWorld->AddElement(fScenes);

   fGlobalScene = new REveScene("Geometry scene");
   fGlobalScene->IncDenyDestroy();
   fScenes->AddElement(fGlobalScene);

   fEventScene = new REveScene("Event scene");
   fEventScene->IncDenyDestroy();
   fScenes->AddElement(fEventScene);

   {
      REveViewer *v = SpawnNewViewer("Default Viewer");
      v->AddScene(fGlobalScene);
      v->AddScene(fEventScene);
   }

   // !!! AMT increase threshold to enable color pick on client
   TColor::SetColorThreshold(0.1);

   fWebWindow = RWebWindow::Create();
   fWebWindow->SetDefaultPage("file:rootui5sys/eve7/index.html");

   // this is call-back, invoked when message received via websocket
   fWebWindow->SetCallBacks([this](unsigned connid) { WindowConnect(connid); },
                            [this](unsigned connid, const std::string &arg) { WindowData(connid, arg); },
                            [this](unsigned connid) { WindowDisconnect(connid); });
   fWebWindow->SetGeometry(900, 700); // configure predefined window geometry
   fWebWindow->SetConnLimit(100); // maximal number of connections
   fWebWindow->SetMaxQueueLength(30); // number of allowed entries in the window queue
}

////////////////////////////////////////////////////////////////////////////////
/// Destructor.

REveManager::~REveManager()
{
   // Stop timer and deny further redraw requests.
   fRedrawTimer.Stop();
   fTimerActive = kTRUE;

   fGlobalScene->DecDenyDestroy();
   fEventScene->DecDenyDestroy();
   fScenes->DestroyScenes();
   fScenes->DecDenyDestroy();
   // Not needed - no more top-items: fScenes->Destroy();
   fScenes = nullptr;

   fViewers->DestroyElements();
   fViewers->DecDenyDestroy();
   // Not needed - no more top-items: fViewers->Destroy();
   fViewers = nullptr;

   // fWindowManager->DestroyWindows();
   // fWindowManager->DecDenyDestroy();
   // fWindowManager->Destroy();
   // fWindowManager = 0;

   fHighlight->DecDenyDestroy();
   fSelection->DecDenyDestroy();

   gROOT->GetListOfBrowsables()->Remove(fMacroFolder);
   delete fMacroFolder;

   delete fGeometryAliases;
   delete fGeometries;
   delete fVizDB;
   delete fExcHandler;
}

////////////////////////////////////////////////////////////////////////////////
/// Create a new GL viewer.

REveViewer* REveManager::SpawnNewViewer(const char* name, const char* title)
{
   REveViewer* v = new REveViewer(name, title);
   fViewers->AddElement(v);
   return v;
}

////////////////////////////////////////////////////////////////////////////////
/// Create a new scene.

REveScene* REveManager::SpawnNewScene(const char* name, const char* title)
{
   REveScene* s = new REveScene(name, title);
   AddElement(s, fScenes);
   return s;
}

////////////////////////////////////////////////////////////////////////////////
/// Find macro in fMacroFolder by name.

TMacro* REveManager::GetMacro(const char* name) const
{
   return dynamic_cast<TMacro*>(fMacroFolder->FindObject(name));
}

////////////////////////////////////////////////////////////////////////////////
/// Register a request for 3D redraw.

void REveManager::RegisterRedraw3D()
{
   fRedrawTimer.Start(0, kTRUE);
   fTimerActive = kTRUE;
}

////////////////////////////////////////////////////////////////////////////////
/// Perform 3D redraw of scenes and viewers whose contents has
/// changed.

void REveManager::DoRedraw3D()
{
   static const REveException eh("REveManager::DoRedraw3D ");
   nlohmann::json jobj = {};
   
   jobj["content"] = "BeginChanges";
   fWebWindow->Send(0, jobj.dump());

   // Process changes in scenes.
   fWorld ->ProcessChanges();
   fScenes->ProcessSceneChanges();

   jobj["content"] = "EndChanges";
   fWebWindow->Send(0, jobj.dump());

   fResetCameras = kFALSE;
   fDropLogicals = kFALSE;

   fTimerActive = kFALSE;
}

////////////////////////////////////////////////////////////////////////////////
/// Perform 3D redraw of all scenes and viewers.

void REveManager::FullRedraw3D(Bool_t /*resetCameras*/, Bool_t /*dropLogicals*/)
{
   // XXXX fScenes ->RepaintAllScenes (dropLogicals);
   // XXXX fViewers->RepaintAllViewers(resetCameras, dropLogicals);
}

////////////////////////////////////////////////////////////////////////////////
/// Clear all selection objects. Can make things easier for EVE when going to
/// the next event. Still, destruction os selected object should still work
/// correctly as long as it is executed within a change cycle.

void REveManager::ClearAllSelections()
{
   for (auto el : fSelectionList->fChildren)
   {
      dynamic_cast<REveSelection*>(el)->ClearSelection();
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Add an element. If parent is not specified it is added into
/// current event (which is created if does not exist).

void REveManager::AddElement(REveElement *element, REveElement *parent)
{
   if (parent == nullptr) {
      // XXXX
   }

   parent->AddElement(element);
}

////////////////////////////////////////////////////////////////////////////////
/// Add a global element, i.e. one that does not change on each
/// event, like geometry or projection manager.
/// If parent is not specified it is added to a global scene.

void REveManager::AddGlobalElement(REveElement* element, REveElement* parent)
{
   if (!parent)
      parent = fGlobalScene;

   parent->AddElement(element);
}

////////////////////////////////////////////////////////////////////////////////
/// Remove element from parent.

void REveManager::RemoveElement(REveElement* element,
                                REveElement* parent)
{
   parent->RemoveElement(element);
}

////////////////////////////////////////////////////////////////////////////////
/// Lookup ElementId in element map and return corresponding REveElement*.
/// Returns nullptr if the id is not found

REveElement* REveManager::FindElementById(ElementId_t id) const
{
   static const REveException eh("REveManager::FindElementById ");

   auto it = fElementIdMap.find(id);
   return (it != fElementIdMap.end()) ? it->second : nullptr;
}

////////////////////////////////////////////////////////////////////////////////
/// Assign a unique ElementId to given element.

void REveManager::AssignElementId(REveElement* element)
{
   static const REveException eh("REveManager::AssignElementId ");

   if (fNumElementIds == fMaxElementIds)
      throw eh + "ElementId map is full.";

next_free_id:
   while (fElementIdMap.find(++fLastElementId) != fElementIdMap.end());
   if (fLastElementId == 0) goto next_free_id;
   // MT - alternatively, we could spawn a thread to find next thousand or so ids and
   // put them in a vector of ranges. Or collect them when they are freed.
   // Don't think this won't happen ... online event display can run for months
   // and easily produce 100000 objects per minute -- about a month to use up all id space!

   element->fElementId = fLastElementId;
   fElementIdMap.insert(std::make_pair(fLastElementId, element));
   ++fNumElementIds;
}

////////////////////////////////////////////////////////////////////////////////
/// Called from REveElement prior to its destruction so the
/// framework components (like object editor) can unreference it.

void REveManager::PreDeleteElement(REveElement* el)
{
   if (el->fImpliedSelected > 0)
   {
      for (auto slc : fSelectionList->fChildren)
      {
         REveSelection *sel = dynamic_cast<REveSelection*>(slc);
         sel->RemoveImpliedSelectedReferencesTo(el);
      }

      if (el->fImpliedSelected != 0)
         Error("REveManager::PreDeleteElement", "ImpliedSelected not zero (%d) after cleanup of selections.", el->fImpliedSelected);
   }
   // Primary selection deregistration is handled through Niece removal from Aunts.

   if (el->fElementId != 0)
   {
      auto it = fElementIdMap.find(el->fElementId);
      if (it != fElementIdMap.end())
      {
         if (it->second == el)
         {
            fElementIdMap.erase(it);
            --fNumElementIds;
         }
         else Error("PreDeleteElement", "element ptr in ElementIdMap does not match the argument element.");
      }
      else Error("PreDeleteElement", "element id %u was not registered in ElementIdMap.", el->fElementId);
   }
   else Error("PreDeleteElement", "element with 0 ElementId passed in.");
}

////////////////////////////////////////////////////////////////////////////////
/// Insert a new visualization-parameter database entry. Returns
/// true if the element is inserted successfully.
/// If entry with the same key already exists the behaviour depends on the
/// 'replace' flag:
///  - true  - The old model is deleted and new one is inserted (default).
///            Clients of the old model are transferred to the new one and
///            if 'update' flag is true (default), the new model's parameters
///            are assigned to all clients.
///  - false - The old model is kept, false is returned.
///
/// If insert is successful, the ownership of the model-element is
/// transferred to the manager.

Bool_t REveManager::InsertVizDBEntry(const TString& tag, REveElement* model,
                                     Bool_t replace, Bool_t update)
{
   TPair* pair = (TPair*) fVizDB->FindObject(tag);
   if (pair)
   {
      if (replace)
      {
         model->IncDenyDestroy();
         model->SetRnrChildren(kFALSE);

         REveElement* old_model = dynamic_cast<REveElement*>(pair->Value());
         if (old_model)
         {
            while (old_model->HasChildren())
            {
               REveElement *el = old_model->FirstChild();
               el->SetVizModel(model);
               if (update)
               {
                  el->CopyVizParams(model);
                  el->PropagateVizParamsToProjecteds();
               }
            }
            old_model->DecDenyDestroy();
         }
         pair->SetValue(dynamic_cast<TObject*>(model));
         return kTRUE;
      }
      else
      {
         return kFALSE;
      }
   }
   else
   {
      model->IncDenyDestroy();
      model->SetRnrChildren(kFALSE);
      fVizDB->Add(new TObjString(tag), dynamic_cast<TObject*>(model));
      return kTRUE;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Insert a new visualization-parameter database entry with the default
/// parameters for replace and update, as specified by members
/// fVizDBReplace(default=kTRUE) and fVizDBUpdate(default=kTRUE).
/// See docs of the above function.

Bool_t REveManager::InsertVizDBEntry(const TString& tag, REveElement* model)
{
   return InsertVizDBEntry(tag, model, fVizDBReplace, fVizDBUpdate);
}

////////////////////////////////////////////////////////////////////////////////
/// Find a visualization-parameter database entry corresponding to tag.
/// If the entry is not found 0 is returned.

REveElement* REveManager::FindVizDBEntry(const TString& tag)
{
   return dynamic_cast<REveElement*>(fVizDB->GetValue(tag));
}

////////////////////////////////////////////////////////////////////////////////
/// Load visualization-parameter database from file filename. The
/// replace, update arguments replace the values of fVizDBReplace
/// and fVizDBUpdate members for the duration of the macro
/// execution.

void REveManager::LoadVizDB(const TString& filename, Bool_t replace, Bool_t update)
{
   Bool_t ex_replace = fVizDBReplace;
   Bool_t ex_update  = fVizDBUpdate;
   fVizDBReplace = replace;
   fVizDBUpdate  = update;

   LoadVizDB(filename);

   fVizDBReplace = ex_replace;
   fVizDBUpdate  = ex_update;
}

////////////////////////////////////////////////////////////////////////////////
/// Load visualization-parameter database from file filename.
/// State of data-members fVizDBReplace and fVizDBUpdate determine
/// how the registered entries are handled.

void REveManager::LoadVizDB(const TString& filename)
{
   REveUtil::Macro(filename);
   Redraw3D();
}

////////////////////////////////////////////////////////////////////////////////
/// Save visualization-parameter database to file filename.

void REveManager::SaveVizDB(const TString& filename)
{
   TPMERegexp re("(.+)\\.\\w+");
   if (re.Match(filename) != 2) {
      Error("SaveVizDB", "filename does not match required format '(.+)\\.\\w+'.");
      return;
   }

   TString exp_filename(filename);
   gSystem->ExpandPathName(exp_filename);

   std::ofstream out(exp_filename, std::ios::out | std::ios::trunc);
   out << "void " << re[1] << "()\n";
   out << "{\n";
   out << "   REveManager::Create();\n";

   ClearROOTClassSaved();

   Int_t       var_id = 0;
   TString     var_name;
   TIter       next(fVizDB);
   TObjString *key;
   while ((key = (TObjString*)next()))
   {
      REveElement* mdl = dynamic_cast<REveElement*>(fVizDB->GetValue(key));
      if (mdl)
      {
         var_name.Form("x%03d", var_id++);
         mdl->SaveVizParams(out, key->String(), var_name);
      }
      else
      {
         Warning("SaveVizDB", "Saving failed for key '%s'.", key->String().Data());
      }
   }

   out << "}\n";
   out.close();
}

////////////////////////////////////////////////////////////////////////////////
/// Get geometry with given filename.
/// This is cached internally so the second time this function is
/// called with the same argument the same geo-manager is returned.
/// gGeoManager is set to the return value.

TGeoManager* REveManager::GetGeometry(const TString& filename)
{
   static const REveException eh("REveManager::GetGeometry ");

   TString exp_filename = filename;
   gSystem->ExpandPathName(exp_filename);
   printf("REveManager::GetGeometry loading: '%s' -> '%s'.\n",
          filename.Data(), exp_filename.Data());

   gGeoManager = (TGeoManager*) fGeometries->GetValue(filename);
   if (gGeoManager)
   {
      gGeoIdentity = (TGeoIdentity*) gGeoManager->GetListOfMatrices()->At(0);
   }
   else
   {
      Bool_t locked = TGeoManager::IsLocked();
      if (locked) {
         Warning("REveManager::GetGeometry", "TGeoManager is locked ... unlocking it.");
         TGeoManager::UnlockGeometry();
      }
      if (TGeoManager::Import(filename) == 0) {
         throw eh + "TGeoManager::Import() failed for '" + exp_filename + "'.";
      }
      if (locked) {
         TGeoManager::LockGeometry();
      }

      gGeoManager->GetTopVolume()->VisibleDaughters(1);

      // Import colors exported by Gled, if they exist.
      {
         TFile f(exp_filename, "READ");
         TObjArray* collist = (TObjArray*) f.Get("ColorList");
         f.Close();
         if (collist) {
            TIter next(gGeoManager->GetListOfVolumes());
            TGeoVolume* vol;
            while ((vol = (TGeoVolume*) next()) != nullptr)
            {
               Int_t oldID = vol->GetLineColor();
               TColor* col = (TColor*)collist->At(oldID);
               Float_t r, g, b;
               col->GetRGB(r, g, b);
               Int_t  newID = TColor::GetColor(r,g,b);
               vol->SetLineColor(newID);
            }
         }
      }

      fGeometries->Add(new TObjString(filename), gGeoManager);
   }
   return gGeoManager;
}

////////////////////////////////////////////////////////////////////////////////
/// Get geometry with given alias.
/// The alias must be registered via RegisterGeometryAlias().

TGeoManager* REveManager::GetGeometryByAlias(const TString& alias)
{
   static const REveException eh("REveManager::GetGeometry ");

   TObjString* full_name = (TObjString*) fGeometryAliases->GetValue(alias);
   if (!full_name)
      throw eh + "geometry alias '" + alias + "' not registered.";
   return GetGeometry(full_name->String());
}

////////////////////////////////////////////////////////////////////////////////
/// Get the default geometry.
/// It should be registered via RegisterGeometryName("Default", <URL>).

TGeoManager* REveManager::GetDefaultGeometry()
{
   return GetGeometryByAlias("Default");
}

////////////////////////////////////////////////////////////////////////////////
/// Register 'name' as an alias for geometry file 'filename'.
/// The old aliases are silently overwritten.
/// After that the geometry can be retrieved also by calling:
///   REX::gEve->GetGeometryByName(name);

void REveManager::RegisterGeometryAlias(const TString& alias, const TString& filename)
{
   fGeometryAliases->Add(new TObjString(alias), new TObjString(filename));
}

////////////////////////////////////////////////////////////////////////////////
/// Work-around uber ugly hack used in SavePrimitive and co.

void REveManager::ClearROOTClassSaved()
{
   TIter   nextcl(gROOT->GetListOfClasses());
   TClass *cls;
   while((cls = (TClass *)nextcl()))
   {
      cls->ResetBit(TClass::kClassSaved);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Register new directory to THttpServer
//  For example: AddLocation("mydir/", "/test/EveWebApp/ui5");
//
void REveManager::AddLocation(const std::string& locationName, const std::string& path)
{
   fWebWindow->GetServer()->AddLocation(locationName.c_str(), path.c_str());
}

////////////////////////////////////////////////////////////////////////////////
/// Set content of default window HTML page
//  Got example: SetDefaultHtmlPage("file:currentdir/test.html")
//
void REveManager::SetDefaultHtmlPage(const std::string& path)
{
   fWebWindow->SetDefaultPage(path.c_str());
}


////////////////////////////////////////////////////////////////////////////////
/// Set client version, used as prefix in scripts URL
/// When changed, web browser will reload all related JS files while full URL will be different
/// Default is empty value - no extra string in URL
/// Version should be string like "1.2" or "ver1.subv2" and not contain any special symbols
void REveManager::SetClientVersion(const std::string& version)
{
   fWebWindow->SetClientVersion(version);
}

////////////////////////////////////////////////////////////////////////////////
/// If global REveManager* REX::gEve is not set initialize it.
/// Returns REX::gEve.

REveManager* REveManager::Create()
{
   static const REveException eh("REveManager::Create ");

   if (!REX::gEve)
   {
      // XXXX Initialize some server stuff ???

      REX::gEve = new REveManager();
   }
   return REX::gEve;
}

////////////////////////////////////////////////////////////////////////////////
/// Properly terminate global REveManager.

void REveManager::Terminate()
{
   if (!REX::gEve) return;

   delete REX::gEve;
   REX::gEve = nullptr;
}

/** \class REveManager::RExceptionHandler
\ingroup REve
Exception handler for Eve exceptions.
*/


////////////////////////////////////////////////////////////////////////////////
/// Handle exceptions deriving from REveException.

TStdExceptionHandler::EStatus
REveManager::RExceptionHandler::Handle(std::exception &exc)
{
   REveException *ex = dynamic_cast<REveException *>(&exc);
   if (ex) {
      Info("Handle", "Exception %s", ex->what());
      // REX::gEve->SetStatusLine(ex->Data());
      gSystem->Beep();
      return kSEHandled;
   }
   return kSEProceed;
}

////////////////////////////////////////////////////////////////////////////////
/// Process new connection from web window

void REveManager::WindowConnect(unsigned connid)
{
   fConnList.emplace_back(connid);
   printf("connection established %u\n", connid);

   // This prepares core and render data buffers.
   printf("\nEVEMNG ............. streaming the world scene.\n");

   fWorld->AddSubscriber(std::make_unique<REveClient>(connid, fWebWindow));
   fWorld->StreamElements();

   printf("   sending json, len = %d\n", (int) fWorld->fOutputJson.size());
   Send(connid, fWorld->fOutputJson);
   printf("   for now assume world-scene has no render data, binary-size=%d\n", fWorld->fTotalBinarySize);
   assert(fWorld->fTotalBinarySize == 0);

   for (auto &c: fScenes->RefChildren())
   {
      REveScene* scene = dynamic_cast<REveScene *>(c);

      scene->AddSubscriber(std::make_unique<REveClient>(connid, fWebWindow));
      printf("\nEVEMNG ............. streaming scene %s [%s]\n",
             scene->GetCTitle(), scene->GetCName());

      // This prepares core and render data buffers.
      scene->StreamElements();

      printf("   sending json, len = %d\n", (int) scene->fOutputJson.size());
      Send(connid, scene->fOutputJson);

      if (scene->fTotalBinarySize > 0)
      {
         printf("   sending binary, len = %d\n", scene->fTotalBinarySize);
         SendBinary(connid, &scene->fOutputBinary[0], scene->fTotalBinarySize);
      }
      else
      {
         printf("   NOT sending binary, len = %d\n", scene->fTotalBinarySize);
      }
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Process disconnect of web window

void REveManager::WindowDisconnect(unsigned connid)
{
   auto conn = fConnList.end();
   for (auto i = fConnList.begin(); i != fConnList.end(); ++i)
   {
      if (i->fId == connid)
      {
         conn = i;
         break;
      }
   }
   // this should not happen, just check
   if (conn == fConnList.end()) {
      printf("error, connection not found!");
   } else {
      printf("connection closed %u\n", connid);
      fConnList.erase(conn);
      for (auto &c: fScenes->RefChildren())
      {
         REveScene* scene = dynamic_cast<REveScene *>(c);
         scene->RemoveSubscriber(connid);
      }
      fWorld->RemoveSubscriber(connid);

   }

}

////////////////////////////////////////////////////////////////////////////////
/// Process data from web window

void REveManager::WindowData(unsigned connid, const std::string &arg)
{
   static const REveException eh("REveManager::WindowData ");

   // find connection object
   auto conn = fConnList.end();
   for (auto i = fConnList.begin(); i != fConnList.end(); ++i)
   {
      if (i->fId == connid)
      {
         conn = i;
         break;
      }
   }
   // this should not happen, just check
   if (conn == fConnList.end()) {
      printf("error, connection not found!");
      return;
   }

   fWorld->BeginAcceptingChanges();
   fScenes->AcceptChanges(true);

   // MIR
   nlohmann::json cj = nlohmann::json::parse(arg);
   if (gDebug > 0)
      ::Info("REveManager::WindowData", "MIR test %s", cj.dump().c_str());
   std::string mir = cj["mir"];
   std::string ctype = cj["class"];
   int id = cj["fElementId"];

   auto el = FindElementById(id);
   std::stringstream cmd;
   cmd << "((" << ctype << "*)" << std::hex << std::showbase << (size_t)el << ")->" << mir << ";";
   if (gDebug > 0)
      ::Info("REveManager::WindowData", "MIR cmd %s", cmd.str().c_str());
   gROOT->ProcessLine(cmd.str().c_str());

   fScenes->AcceptChanges(false);
   fWorld->EndAcceptingChanges();

   Redraw3D();

   /*
   nlohmann::json resp;
   resp["function"] = "replaceElement";
   //el->SetCoreJson(resp);
   for (auto &conn : fConnList)
      fWebWindow->Send(conn.fId, resp.dump());
   */
}

void REveManager::Send(unsigned connid, const std::string &data)
{
   fWebWindow->Send(connid, data);
}


void REveManager::SendBinary(unsigned connid, const void *data, std::size_t len)
{
   fWebWindow->SendBinary(connid, data, len);
}

//------------------------------------------------------------------------------

void REveManager::DestroyElementsOf(REveElement::List_t& els)
{
   // XXXXX - not called, what's with end accepting changes?

   fWorld->EndAcceptingChanges();
   fScenes->AcceptChanges(false);

   nlohmann::json jarr = nlohmann::json::array();

   nlohmann::json jhdr = {};
   jhdr["content"]  = "REveManager::DestroyElementsOf";

   nlohmann::json jels = nlohmann::json::array();

   for (auto &ep : els) {
      jels.push_back(ep->GetElementId());

      ep->DestroyElements();
   }

   jhdr["element_ids"] = jels;

   jarr.push_back(jhdr);

   std::string msg = jarr.dump();

   // XXXX Do we have broadcast?

   for (auto &conn : fConnList) {
      fWebWindow->Send(conn.fId, msg);
   }
}

void REveManager::BroadcastElementsOf(REveElement::List_t &els)
{
   // XXXXX - not called, what's with begin accepting changes?

   for (auto &ep : els)
   {
      REveScene* scene = dynamic_cast<REveScene*>(ep);
      assert (scene != nullptr);

      printf("\nEVEMNG ............. streaming scene %s [%s]\n",
             scene->GetCTitle(), scene->GetCName());

      // This prepares core and render data buffers.
      scene->StreamElements();

      for (auto &conn : fConnList) {
         printf("   sending json, len = %d --> to conn_id = %d\n", (int)scene->fOutputJson.size(), conn.fId);
         fWebWindow->Send(conn.fId, scene->fOutputJson);
         printf("   sending binary, len = %d --> to conn_id = %d\n", scene->fTotalBinarySize, conn.fId);
         fWebWindow->SendBinary(conn.fId, &scene->fOutputBinary[0], scene->fTotalBinarySize);
      }
   }

   // AMT: These calls may not be necessary
   fScenes->AcceptChanges(true);
   fWorld->BeginAcceptingChanges();
}

//////////////////////////////////////////////////////////////////
/// Show eve manager in specified browser.

/// If rootrc variable WebEve.DisableShow is set, HTTP server will be
/// started and access URL printed on stdout.

void REveManager::Show(const RWebDisplayArgs &args)
{
   if (gEnv->GetValue("WebEve.DisableShow", 0) != 0) {
      std::string url = fWebWindow->GetUrl(true);
      printf("EVE URL %s\n", url.c_str());
   } else {
      fWebWindow->Show(args);
   }
}

//////////////////////////////////////////////////////////////////
/// Show current geometry in web browser

std::shared_ptr<REveGeomViewer> REveManager::ShowGeometry(const RWebDisplayArgs &args)
{
   if (!gGeoManager) {
      Error("ShowGeometry", "No geometry is loaded");
      return nullptr;
   }

   auto viewer = std::make_shared<REveGeomViewer>(gGeoManager);

   viewer->Show(args);

   return viewer;
}