// $Id$
//-----------------------------------------------------------------------
//       The GSI Online Offline Object Oriented (Go4) Project
//         Experiment Data Processing at EE department, GSI
//-----------------------------------------------------------------------
// Copyright (C) 2000- GSI Helmholtzzentrum fuer Schwerionenforschung GmbH
//                     Planckstr. 1, 64291 Darmstadt, Germany
// Contact:            http://go4.gsi.de
//-----------------------------------------------------------------------
// This software can be used under the license agreements as stated
// in Go4License.txt file which is part of the distribution.
//-----------------------------------------------------------------------

#include "TGo4ServerTask.h"

#include "TMutex.h"
#include "TApplication.h"
#include "TSystem.h"
#include "TObjArray.h"

#include "TGo4Log.h"
#include "TGo4LockGuard.h"
#include "TGo4Socket.h"
#include "TGo4BufferQueue.h"
#include "TGo4Thread.h"
#include "TGo4ThreadHandler.h"
#include "TGo4Status.h"
#include "TGo4CommandInvoker.h"
#include "TGo4TaskManager.h"
#include "TGo4TaskHandler.h"
#include "TGo4ConnectorRunnable.h"
#include "TGo4Slave.h"
#include "TGo4TaskConnectorTimer.h"


const Int_t TGo4ServerTask::fgiOPENWAITCYCLES=100; // wait cycles (100)
const UInt_t TGo4ServerTask::fguOPENWAITCYCLETIME=100; // time in ms (20)
const Int_t TGo4ServerTask::fgiCLOSEWAITCYCLES=100; // wait cycles (100)
const UInt_t TGo4ServerTask::fguCLOSEWAITCYCLETIME=100; // time in ms (20)
const Int_t TGo4ServerTask::fgiCONNECTWAITCYCLES=20; // wait cycles (20)
const UInt_t TGo4ServerTask::fguCONNECTWAITCYCLETIME=200; // time in ms (200)
const UInt_t TGo4ServerTask::fguCONNECTTIMERPERIOD=100; // time in ms (50)


const char *TGo4ServerTask::fgcLAUNCHPREFSFILE = "etc/Go4LaunchPrefs.txt";


TGo4ServerTask::TGo4ServerTask(const char *name,
                               UInt_t negotiationport,
                               Bool_t blockingmode,
                               Bool_t standalone,
                               Bool_t autostart,
                               Bool_t autocreate,
                               Bool_t ismaster)
   : TGo4Task(name,blockingmode, autostart,autocreate,ismaster),
   fxTaskManager(nullptr),fxCurrentTaskHandler(nullptr),
   fxConnectTransport(nullptr), fxDisConnectTransport(nullptr),
   fuConnectPort(0), fbKeepServerSocket(kFALSE),
   fbConnectRequest(kFALSE), fbDisConnectRequest(kFALSE),
   fbConnectIsOpen(kFALSE),fbConnectIsDone(kFALSE), fbConnectIsClose(kFALSE),
   fxConnectorTimer(nullptr)
{
   TString nomen("TaskManager of "); nomen += name;
   fxTaskManager= new TGo4TaskManager(nomen.Data(), this, negotiationport);

   if(negotiationport!=42)
      {
         // connector runnable:
         nomen.Form("ConnectorRunnable of %s", name);
         TGo4ConnectorRunnable* conny = new TGo4ConnectorRunnable(nomen.Data(),this);
         nomen.Form("CONNECTOR-%s", name);
         fxConnectorName=nomen;
         fxWorkHandler->NewThread(GetConnectorName(), conny);
      }
      else  {} // do not start connector port in local mode <- nameservice problems without wan!

   TGo4CommandInvoker::Instance(); // make sure a command invoker exists
   TGo4CommandInvoker::Register("ServerTask", this);
   fxConnectorTimer= new TGo4TaskConnectorTimer(this,fguCONNECTTIMERPERIOD);
   fxConnectorTimer->TurnOn();
   if(standalone)
      {
         Launch(); // create threads, start application control timer
      }
   else
      {
         // subclass must call Launch at end of its ctor
      }
}


TGo4ServerTask::~TGo4ServerTask()
{
   if (GetWorkHandler()) GetWorkHandler()->CancelAll();
   delete fxConnectorTimer;
   delete fxTaskManager;
   TGo4CommandInvoker::UnRegister(this);
}

Bool_t TGo4ServerTask::RemoveClient(const char *name, Bool_t clientwait, Bool_t isterminating)
{
   Bool_t rev=kTRUE;
   TGo4TaskHandler *taskhandler = nullptr;
   if(name && strstr(name,"current"))
      taskhandler=GetCurrentTaskHandler();
   else
      taskhandler=GetTaskHandler(name);
   if(!taskhandler)
      {
         // no such taskhandler for name
         TGo4Log::Debug(" ServerTask -- RemoveClient FAILED, no client %s !!! ",
                  name);
         rev=kFALSE;
      }
   else
      {
       TGo4Log::Debug(" ServerTask -- removing client task %s ",name);
       // first stop all user threads waiting on or writing into the data queues
      StopWorkThreads();
      if(clientwait)
         {
         // normal mode: handshake with client to be removed


            // send quit command to client, client will send dummy objects back
            // to release waiting sockets
            // then client will request a disconnect action from the connector runnable
            if(IsMaster())
               SubmitEmergencyCommand(kComQuit); // master quits client when removing
            else
               SubmitEmergencyData(kComQuit, taskhandler->GetName()); // client data runnable must handle quit request of server!
            TGo4Log::Debug(" Server Task --  Waiting for client %s disconnection...",taskhandler->GetName());
            Int_t removeresult=fxTaskManager->WaitForClientRemoved();
                           // disconnection is done by connector
                           // thread using task manager methods
            switch(removeresult)
               {
               case -1:
                  // timeout
                  TGo4Log::Debug(" !!! Server Task -- client remove wait TIMEOUT !!!  ");
                  rev=fxTaskManager->DisConnectClient(taskhandler->GetName(),kFALSE); // do not wait for client ok
                  break;

               case -2:
                  // we are terminating the server
                  TGo4Log::Debug(" !!! Server Task -- client remove aborted for TERMINATION MODE !!!  ");
                  rev=kFALSE;
                  break;

               default:
                  // all right
                  TGo4Log::Debug(" Server Task -- waited %d cycles until client was removed. ",removeresult);
                  rev=kTRUE;
                  break;

                     }
         } // if(clientwait)
      else
         {
         // no communication with client, just disconnect without waiting
         TGo4Log::Debug(" !!! Server Task -- removing client %s without waiting...  ",
                                    taskhandler->GetName());
         SendStopBuffers(taskhandler->GetName());
         rev= (fxTaskManager->DisConnectClient(taskhandler->GetName(),kFALSE) == 0); // do not wait
         }
      if(!isterminating) StartWorkThreads();
   }
   return rev;
}

Int_t TGo4ServerTask::RemoveAllClients(Bool_t force)
{
   Int_t rev = 0; // return value is number of removed clients
   //// new: first figure out all existing names, then remove one by one:
   TObjArray names;
   Bool_t reset = kTRUE;
   while (auto taskhandler = fxTaskManager->NextTaskHandler(reset)) {
      reset = kFALSE;
      names.AddLast(new TNamed(taskhandler->GetName(), "title"));
   }
   TIter niter(&names);
   while (auto nomen = niter()) {
      RemoveClient(nomen->GetName(), !force, kTRUE);
      rev++;
   }
   names.Delete();
   // end iteration
   return rev;
}


Bool_t TGo4ServerTask::RemoveCurrentClient()
{
   Bool_t rev=kTRUE;
   TGo4TaskHandler *taskhandler=GetCurrentTaskHandler();
   if (taskhandler) {
      // we have a current client, remove it
      TGo4Log::Debug(" Server task -- removing current client %s ", taskhandler->GetName());
      rev = RemoveClient(taskhandler->GetName());
   } else {
      rev = kFALSE;
   }
   return rev;
}

void TGo4ServerTask::SetCurrentTask(const char *name)
{
   TGo4TaskHandler *han = nullptr;
   if (!fxTaskManager) {
      TGo4Log::Debug(" TGo4ServerTask ''%s'' ERROR- task manager not existing!!! ", GetName());
   } else {
      // first stop all user threads waiting on or writing into the data queues
      if (IsWorkStopped()) {
         // Working threads have already been stopped
         // maybe by RemoveClient method.
         // We do nothing, since the current taskhandler is not
         // reset yet and any access to current task in the derived
         // _user_ method would crash the program!
      } else // if(IsWorkStopped())
      {
         // work has not been stopped, we do that
         StopWorkThreads();
      } // else if(fbWorkIsStopped)
      {
         if (!name) {
            // zero name given, set pointer to last handler still in list
            fxCurrentTaskHandler = fxTaskManager->GetLastTaskHandler();
         } else {
            // name specified, search for it
            han = fxTaskManager->GetTaskHandler(name);
            if (han) {
               fxCurrentTaskHandler = han;
            } else {
               TGo4Log::Debug(" ServerTask: FAILED setting current task to %s-- no such client! ", name);
            }
         }
      }

      // finally, start user threads again
      StartWorkThreads();
   }
}

TGo4TaskHandler *TGo4ServerTask::GetTaskHandler(const char *name)
{
   return fxTaskManager->GetTaskHandler(name);
}

TGo4TaskHandler *TGo4ServerTask::GetTaskHandler()
{
   return GetCurrentTaskHandler();
}

TGo4TaskHandler *TGo4ServerTask::GetCurrentTaskHandler()
{
   return fxCurrentTaskHandler;
}

TGo4TaskManager* TGo4ServerTask::GetTaskManager()
{
   return fxTaskManager;
}

void TGo4ServerTask::SetConnect(TGo4Socket *trans, const char *host, UInt_t port, Bool_t keepserv)
{
   fxConnectTransport=trans;
   fxConnectHost=host;
   fuConnectPort=port;
   fbConnectRequest=kTRUE;
   fbKeepServerSocket=keepserv;
}

void TGo4ServerTask::SetDisConnect(TGo4Socket *trans)
{
   fxDisConnectTransport = trans;
   fbDisConnectRequest = kTRUE;
}

Int_t TGo4ServerTask::TimerConnect()
{
   Int_t rev = 0;
   ///////////////////////////////////////
   //// handle the disconnection first:
   if(fbDisConnectRequest)
      {
      if (fxDisConnectTransport) {
         // we have a transport instance to disconnect
         fxDisConnectTransport->Close();
         // delete fxDisConnectTransport; // new
         fbConnectIsClose = kTRUE;
         fbDisConnectRequest = kFALSE; // we served the request, reset it
         rev += 1;
      } else {
         // error, zero pointer given
         rev += 32;
      }
   } else //// if(fbDisConnectRequest)
   {
      // no open request, continue
      rev += 2;
   }

   /////////////////////////////////////
   //// then handle the connection:
   if(fbConnectRequest)
      {
         // timer shall open a transport as server
      if(fxConnectTransport)
         {

            if(!fxConnectTransport->IsOpen())
               {
                  // transport is not open, so do it
//                  std::cout << "++++++++Timer will open transport"<< std::endl;
                  fbConnectIsOpen=kTRUE; // tell connector thread that we try to open
                  Int_t result = fxConnectTransport->Open(GetConnectHost(), fuConnectPort, fbKeepServerSocket);
                  if(result == 0)
                     {
                        fbConnectIsDone=kTRUE; // tell connector thread we returned from open
                        fbConnectRequest=kFALSE; // we served the request, reset it
                        fbKeepServerSocket=kFALSE; // reset keep server socket flag
                        rev+=4;
                     }
                  else
                     {
                        rev=-4;
                        // open was not finished, we poll once again...
                     }
               }
            else
               {
                  // transport was already open
//                  std::cout <<"OOOOOOOOOOOO TimerConnect transport already open!" << std::endl;
                  fbConnectIsOpen=kTRUE;
                  fbConnectIsDone=kTRUE; // tell connector thread we returned from open
                  fbConnectRequest=kFALSE; // we served the request, reset it
                  fbKeepServerSocket=kFALSE; // reset keep server socket flag
                  rev+=8;
               }
         }
      else
         {
               rev+=64;
               // no Transport specified: create raw server for negotiation port
               //fxConnectTransport=new TGo4Socket("Server",3);
         }
      } //// if(fbConnectRequest)
   else
      {
         // no open request, continue
         rev+=16;
      }
   return rev;
}

Int_t TGo4ServerTask::WaitForOpen()
{
   Int_t count = 0;
   while(!fbConnectIsOpen)
      {
         if(count>TGo4ServerTask::fgiOPENWAITCYCLES)
            {
               count = -1; // timeout
               break;
            }
         else
            {
            TGo4Thread::Sleep(TGo4ServerTask::fguOPENWAITCYCLETIME);
            ++count;
            }
//      std::cout << "*****WaitForOpen()"<< std::endl;
      }
   fbConnectIsOpen=kFALSE; //  reset for next time
   return count;
}


Int_t TGo4ServerTask::WaitForClose()
{
   Int_t count = 0;
   while(!fbConnectIsClose)
      {
          if(count>TGo4ServerTask::fgiCLOSEWAITCYCLES)
            {
               count = -1; // timeout
               break;
            }
         else
            {
               TGo4Thread::Sleep(TGo4ServerTask::fguCLOSEWAITCYCLETIME);
               ++count;
         }
      }
   fbConnectIsClose=kFALSE; //  reset for next time
   return count;
}

Int_t TGo4ServerTask::WaitForConnection()
{
   Int_t count = 0;
   while(!fbConnectIsDone)
      {
         if(IsTerminating())
            {
               count = -2; // termination mode
               break;
            }
// timeout would affect the permanent connector port Open, we skip this
//         else if(count>TGo4ServerTask::fgiCONNECTWAITCYCLES)
//            {
//               count = -1; // timeout
//               break;
//            }
         else
            {
               TGo4Thread::Sleep(TGo4ServerTask::fguCONNECTWAITCYCLETIME);
               ++count;
            }
//         std::cout << "*****WaitForConnection()"<< std::endl;
      }
   fbConnectIsDone=kFALSE; //  reset for next time
   return count;
}

TGo4Socket *TGo4ServerTask::GetConnectTransport()
{
   return fxConnectTransport;
}

TGo4BufferQueue *TGo4ServerTask::GetCommandQueue(const char *name)
{
   TGo4BufferQueue *queue = nullptr;
   TGo4TaskHandler *currenttask = nullptr;
   if(!name || strstr(name,"current"))
      currenttask=GetCurrentTaskHandler(); // find out the current client
   else
      currenttask=GetTaskHandler(name); // find out destination client by name
   if(currenttask)
         queue=dynamic_cast<TGo4BufferQueue*> (currenttask->GetCommandQueue());
   return queue;
}

TGo4BufferQueue * TGo4ServerTask::GetStatusQueue(const char *name)
{
   TGo4BufferQueue *queue = nullptr;
   TGo4TaskHandler *currenttask = nullptr;
   if(!name)
      currenttask=GetCurrentTaskHandler(); // find out the current client
   else
      currenttask=GetTaskHandler(name); // find out destination client by name
   if(currenttask)
      queue=dynamic_cast<TGo4BufferQueue*> (currenttask->GetStatusQueue());
   return queue;
}

TGo4BufferQueue * TGo4ServerTask::GetDataQueue(const char *name)
{
   TGo4BufferQueue *queue = nullptr;
   TGo4TaskHandler *currenttask = nullptr;
   if(!name || strstr(name,"current"))
      currenttask=GetCurrentTaskHandler(); // find out the current client
   else
      currenttask=GetTaskHandler(name); // find out destination client by name
   if(currenttask)
      queue=dynamic_cast<TGo4BufferQueue*> (currenttask->GetDataQueue());
   return queue;
}

TGo4Command *TGo4ServerTask::NextCommand()
{
   if (IsMaster())
      return nullptr;
   TGo4Command *com = nullptr;
   Bool_t reset = kTRUE;
   TGo4LockGuard taskmutex(fxTaskManager->GetMutex());
   while (auto han = fxTaskManager->NextTaskHandler(reset)) {
      reset = kFALSE;
      TGo4BufferQueue *comq = dynamic_cast<TGo4BufferQueue *>(han->GetCommandQueue());
      if (!comq)
         continue;          // NEVER COME HERE!
      if (!comq->IsEmpty()) { // prevent waiting on queue
         com = dynamic_cast<TGo4Command *>(comq->WaitObjectFromBuffer());
         if (com) {
            com->SetTaskName(han->GetName());
            com->SetMode(han->GetRole());
            return com;
         }
      }
   } // while
   return com;
}

void TGo4ServerTask::SendStatus(TGo4Status *stat, const char *receiver)
{
   if(IsMaster()) return;
   if(!stat) return;
   if(receiver) {
      TGo4Task::SendStatus(stat,receiver);
      return;
   }
   // send status to all
   TGo4LockGuard taskmutex(fxTaskManager->GetMutex());
   Bool_t reset = kTRUE;
   while(auto han = fxTaskManager->NextTaskHandler(reset)) {
      reset = kFALSE;
      auto statq = dynamic_cast<TGo4BufferQueue *>(han->GetStatusQueue());
      if(!statq) continue; //NEVER COME HERE!
      TGo4Log::Debug(" Task - sending status %s to task %s", stat->ClassName(), han->GetName());
      statq->AddBufferFromObject(stat);
   }
}

void TGo4ServerTask::SendStatusBuffer()
{
   if(IsMaster()) return;
   TGo4LockGuard statguard(fxStatusMutex); // do not send during buffer update
   TGo4LockGuard taskmutex(fxTaskManager->GetMutex()); // protect task list
   Bool_t reset=kTRUE;
   while(auto han = fxTaskManager->NextTaskHandler(reset)) {
      reset=kFALSE;
      TGo4BufferQueue * statq=dynamic_cast<TGo4BufferQueue*> (han->GetStatusQueue());
      if(!statq) continue; //NEVER COME HERE!
      TGo4Log::Debug(" Task - sending status buffer to task %s", han->GetName());
      statq->AddBuffer(fxStatusBuffer,kTRUE);
   }
}

Bool_t TGo4ServerTask::StartConnectorThread()
{
   return GetWorkHandler()->Start( GetConnectorName() );
}

Bool_t TGo4ServerTask::StopConnectorThread()
{
   Bool_t rev = GetWorkHandler()->Stop( GetConnectorName() ); // unset running flag
   // now establish a dummy connection to our own server to release the listen socket:
   const char *host = gSystem->HostName();
   Int_t negotiationport = fxTaskManager->GetNegotiationPort();
   TGo4Socket *connector = new TGo4Socket(kTRUE); // raw socket transport
   connector->Open(host,negotiationport); // open connection to server's connector runnable
   connector->Send(TGo4TaskHandler::Get_fgcERROR()); // force server to stop
   connector->Close();
   delete connector;
   return rev;
}


Bool_t TGo4ServerTask::ConnectorThreadIsStopped()
{
   TGo4Thread *conny = GetWorkHandler()->GetThread(GetConnectorName());
   return conny->IsWaiting();
}

void TGo4ServerTask::Quit()
{
   TGo4Log::Debug(" ServerTask Quit -- removing all connected clients ");
   SendStatusMessage(2,kTRUE,"ServerTask %s is shutting down now! All clients are removed...",GetName());
   auto slave = GetSlave();
   if(slave) {
      TGo4Log::Debug(" ServerTask Quit is stopping slave...");
      slave->Stop(); // to execute analysis postloop if still running
    }
   if(!IsMaster()) {
      fxTaskManager->GetMutex()->UnLock(); // JAM avoid deadlocking of analysis server main thread with connector thread that actually performs the remove
   }
   RemoveAllClients();
   //StopWorkThreads(); // are re-started after last client is removed...
   WakeCommandQueue(TGo4Task::Get_fgiTERMID()); // will stop local command thread, and remote
   Terminate(!IsMaster()); // terminate only slave server here!
//   if(!IsMaster())
//      fxTaskManager->GetMutex()->Lock(); // avoid conflicts with lockguard outside
}


void TGo4ServerTask::Shutdown()
{
   TGo4Log::Debug(" ServerTask Shutdown without disconnect waiting");
   SendStatusMessage(2,kTRUE,"ServerTask %s is shutting down now! All clients are removed...",GetName());
   fxTaskManager->GetMutex()->UnLock(); // avoid possible deadlock between main thread and connector thread
   TGo4Thread::Sleep(10*fguCONNECTTIMERPERIOD); // wait 1 s to broadcast shutdown message before terminating...
   StopWorkThreads();
   WakeCommandQueue(TGo4Task::Get_fgiTERMID()); // will stop local command thread, and remote

   RemoveAllClients(true);

   auto slave = GetSlave();
   if (slave) {
      TGo4Log::Debug(" ServerTask Shutdown stopping slave...");
      slave->Stop();             // to execute analysis postloop.
                                 // We are within main thread here, i.e. it never stops before termination!
      slave->SetTask(nullptr, kFALSE); // otherwise owner dtor will delete us...
      delete slave;              // call dtors of analysis framework
      // SetOwner(0);
   }
   fxTaskManager->GetMutex()->Lock();
   gApplication->Terminate(); // do not wait until appctrl timer terminates us
}

const char *TGo4ServerTask::Get_fgcLAUNCHPREFSFILE()
{
   return fgcLAUNCHPREFSFILE;
}