// @(#) $Id$

#ifndef ALIHLTSYSTEM_H
#define ALIHLTSYSTEM_H
/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 * See cxx source for full Copyright notice                               */

/** @file   AliHLTSystem.h
    @author Matthias Richter
    @date   
    @brief  Global HLT module management and AliRoot integration.
    @note   The class is used in Offline (AliRoot) context
*/

/**
 * @defgroup alihlt_system HLT integration into AliRoot
 * This section describes the HLT integration into AliRoot.
 */

#include "AliHLTLogging.h"
#include <TList.h>

class AliHLTComponentHandler;
class AliHLTConfiguration;
class AliHLTConfigurationHandler;
class AliHLTTask;
class AliRunLoader;
class AliRawReader;
class AliESD;
class TObjArray;
class TStopwatch;

/**
 * @class AliHLTSystem
 * Main class for the HLT integration into AliRoot.
 * The class handles a list of configurations. Configurations are translated
 * into task lists which can be executed. 
 *
 * @note This class is only used for the @ref alihlt_system.
 *
 * @ingroup alihlt_system
 */
class AliHLTSystem : public AliHLTLogging {
 public:
  /** default constructor */
  AliHLTSystem();
  /** not a valid copy constructor, defined according to effective C++ style */
  AliHLTSystem(const AliHLTSystem&);
  /** not a valid assignment op, but defined according to effective C++ style */
  AliHLTSystem& operator=(const AliHLTSystem&);
  /** destructor */
  virtual ~AliHLTSystem();

  /**
   * Pointer to an instance of @ref AliHLTComponentHandler.
   */
  AliHLTComponentHandler* fpComponentHandler;                      //! transient

  /**
   * Pointer to an instance of @ref AliHLTConfigurationHandler.
   */
  AliHLTConfigurationHandler* fpConfigurationHandler;              //! transient

  /**
   * Add a configuration to the end of the list.
   * @param pConf    pointer to configuration to add
   */
  int AddConfiguration(AliHLTConfiguration* pConf);

  /**
   * Insert a configuration to the end of the list after the specified
   * configuration.
   * @param pConf    pointer to configuration to insert
   * @param pPrec    pointer to configuration to insert the new one after
   */
  int InsertConfiguration(AliHLTConfiguration* pConf, AliHLTConfiguration* pPrec);

  /**
   * Remove a configuration from the list.
   * @param pConf    pointer to configuration to delete
   */
  int DeleteConfiguration(AliHLTConfiguration* pConf);

  /**
   * Build a task list 
   * This method is used to build the tasks from the 'master' configuration
   * objects which are added to the HLT system handler. This is an iterative
   * process since the task might depend upon other configurations. For each
   * configuration object which has not yet been converted into a task, the
   * method will be called iteratively. Finally, after building all tasks which
   * the current one depends on have been created, the task is inserted to the
   * list of tasks with the InsertTask method.
   * @param pConf    configuration name/id
   */
  int BuildTaskList(const char* pConf);

  /**
   * Build task list from a configuration object.
   * This method is kept for backward compatibility. Use the version
   * with the configuration name.
   * @param pConf    pointer to configuration to build the task list from
   */
  int BuildTaskList(AliHLTConfiguration* pConf);

  /**
   * Clean the list of tasks and delete all the task objects.
   */
  int CleanTaskList();

  /**
   * Insert a task to the task list.
   * The method first checks whether all dependencies are resolved (i.e. exist 
   * already in the task list). During this iteration the cross links between
   * the tasks are set as well. If all dependencies are resolved, the task is
   * added at the end of the list.
   * @param pTask    pointer to task to add
   */
  int InsertTask(AliHLTTask* pTask);

  /**
   * Find a task with an id.
   * @param id       CONFIGURATION id (not a COMPONENT id!)
   */
  AliHLTTask* FindTask(const char* id);

  /**
   * Print the task list.
   */
  void PrintTaskList();

  /**
   * Run the task list.
   * The method checks whether the task list has already been build. If not,
   * or the configuration list has been changed, the @ref BuildTaskList
   * method is scalled
   * All tasks of the list will be subsequently processed for each event.
   * @param iNofEvents number of events
   * @return number of reconstructed events, neg error code if failed
   */
  int Run(Int_t iNofEvents=1);

  /**
   * Init all tasks from the list.
   * The @ref AliHLTTask::Init method is called for each task, the components
   * will be created.
   * @return neg error code if failed
   */
  int InitTasks();

  /**
   * Init the stopwatches for all tasks.
   * @param pStopwatches    object array of stopwatches, for types
   *                        @see AliHLTComponent::AliHLTStopwatchType
   * @return neg error code if failed
   */
  int InitBenchmarking(TObjArray* pStopwatches);

  /**
   * Start task list.
   * The @ref AliHLTTask::StartRun method is called for each task, the
   * components will be prepared for event processing.
   * @return neg error code if failed
   */
  int StartTasks();

  /**
   * Process task list.
   * The @ref AliHLTTask::ProcessTask method is called for each task.
   * @return neg error code if failed
   */
  int ProcessTasks(Int_t eventNo);

  /**
   * Stop task list.
   * The @ref AliHLTTask::EndRun method is called for each task, the components
   * will be cleaned after event processing.
   * @return neg error code if failed
   */
  int StopTasks();

  /**
   * De-init all tasks from the list.
   * The @ref AliHLTTask::Deinit method is called for each task, the components
   * will be deleted.
   * @return neg error code if failed
   */
  int DeinitTasks();

  /**
   * The memory allocation function for components.
   * This function is part of the running environment of the components.
   */
  static void* AllocMemory( void* param, unsigned long size );

  /**
   * Reconstruction inside AliRoot.
   * To be called by the AliHLTReconstructor plugin during the
   * LocalReconstruction step of the AliRoot reconstruction. The latter means
   * that all events are reconstructed at once, the event loop is internally
   * implemented. In contrast to that, the FillESD method is called event by
   * event. This requires an 'ESD' recorder at the end of the HLT chain, in
   * order to have the reconstructed events available for the FillESD loop.
   * The 'runLoader' and 'rawReader' parameters are set to all active
   * AliHLTOfflineDataSource's and the HLT chain is processed for the given
   * number of events. If the rawReader is NULL, reconstruction is done on
   * simulated data, from real data if a RawReader is specified.
   * @param nofEvents     number of events
   * @param runLoader     the AliRoot runloader
   * @param rawReader     the AliRoot RawReader
   * @return number of reconstructed events, neg. error code if failed 
   */
  int Reconstruct(int nofEvents, AliRunLoader* runLoader, 
		  AliRawReader* rawReader=NULL);

  /**
   * Fill ESD for one event.
   * To be called by the AliHLTReconstructor plugin during the event loop
   * and FillESD method of the AliRoot reconstruction.
   * This method is called on event basis, and thus must copy the previously
   * reconstructed data of the event from the 'ESD' recorder. The FillESD
   * method of all active AliHLTOfflineDataSink's is called.
   * @param eventNo       current event no (Note: this event number is just a
   *                      processing counter and is not related to the nature/
   *                      origin of the event
   * @param runLoader     the AliRoot runloader
   * @param esd           an AliESD instance
   * @return neg. error code if failed 
   */
  int FillESD(int eventNo, AliRunLoader* runLoader, AliESD* esd);

  /**
   * Load component libraries.
   * @param libs          string of blank separated library names
   * @return neg. error code if failed 
   */
  int LoadComponentLibraries(const char* libs);

  /**
   * Find a symbol in a dynamically loaded library.
   * @param library      library
   * @param symbol       the symbol to find
   * @return void pointer to function
   */
  void* FindDynamicSymbol(const char* library, const char* symbol);

  /**
   * Prepare the HLT system for running.
   * - module agents are requested to register configurations
   * - task lists are built from the top configurations of the modules
   * @return neg. error code if failed <br>
   *         -EBUSY      system is in kRunning state <br>
   */
  int Configure(AliRunLoader* runloader=NULL);

  /**
   * Reset the HLT system.
   * Reset is not possible while the system is in running state.
   * @param bForce       force the reset
   * @return neg. error code if failed <br>
   *         -EBUSY      system is in kRunning state <br>
   */
  int Reset(int bForce=0);

  /**
   * Load the configurations specified by the module agents.
   * The runLoader is passed to the agent and allows configuration
   * selection.
   * @return neg. error code if failed 
   */
  int LoadConfigurations(AliRunLoader* runloader=NULL);

  /**
   * Get the top configurations of all agents and build the task lists.
   * @return neg. error code if failed 
   */
  int BuildTaskListsFromTopConfigurations(AliRunLoader* runloader=NULL);

  enum AliHLTSystemState_t {
    kUninitialized       = 0x0,
    kLibrariesLoaded     = 0x1,
    kConfigurationLoaded = 0x2,
    kTaskListCreated     = 0x4,
    kReady               = 0x7,
    kRunning             = 0x8,
    kError               = 0x1000
  };

  /**
   * Check status of the system.
   * @param flag          AliHLTSystemState_t value to check for
   * @return 1 if set, 0 if not
   */
  int CheckStatus(int flag);

  /**
   * Get the current status.
   * @return status flags of @ref AliHLTSystemState_t
   */
  int GetStatusFlags();

 protected:
 
 private:
  /**
   * Set status flags.
   */
  int SetStatusFlags(int flags);

  /**
   * clear status flags.
   */
  int ClearStatusFlags(int flags);

/*   TList fConfList; */
/*   int fbListChanged; */

  /** list of tasks */
  TList fTaskList;                                                 // see above

  /** the number of instances of AliHLTSystem */
  static int fgNofInstances;                                       // see above

  /** state of the object */
  int fState;                                                      // see above

 private:
  ClassDef(AliHLTSystem, 2);
};
#endif