// @(#) $Id$

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

/** @file   AliHLTModuleAgent.h
    @author Matthias Richter
    @date   
    @brief  Agent helper class for component libraries.
    @note   The class is used in Offline (AliRoot) context
*/

#include <TObject.h>
#include <TList.h>
#include "AliHLTLogging.h"
#include "AliHLTConfiguration.h"
#include "AliHLTConfigurationHandler.h"

class AliRunLoader;

/**
 * @class AliHLTModuleAgent
 * @brief Agent helper class for HLT sub modules, e.g. PHOS, TPC, Trigger
 *
 * This class describes 
 *
 * There must be only one agent per module/library.
 *
 * @ingroup alihlt_system
 */
class AliHLTModuleAgent : public TObject, public AliHLTLogging {
 public:
  /**
   * standard constructor. The agent is automatically registered in the
   * global agent manager
   */
  AliHLTModuleAgent();
  /** not a valid copy constructor, defined according to effective C++ style */
  AliHLTModuleAgent(const AliHLTModuleAgent&);
  /** not a valid assignment op, but defined according to effective C++ style */
  AliHLTModuleAgent& operator=(const AliHLTModuleAgent&);
  /** destructor */
  virtual ~AliHLTModuleAgent();

  /**
   * Print status info.
   * Short summary on registered agents. This function acts globally on the list
   * of agents if no specific agent is specified.
   */
  static void PrintStatus(const char* agent=NULL);

  /**
   * Get the first agent in the list
   * @return  pointer to first agent in the list, NULL if empty
   */
  static AliHLTModuleAgent* GetFirstAgent();

  /**
   * Get the next agent in the list
   * @return  pointer to next agent in the list, NULL if end of list
   */
  static AliHLTModuleAgent* GetNextAgent();

  /**
   * Register all configurations belonging to this module with the
   * AliHLTConfigurationHandler. The agent can adapt the configurations
   * to be registered to the current AliRoot setup by checking the
   * runloader.
   * @param handler   [in] the configuration handler
   * @param runloader [in] AliRoot runloader
   * @return neg. error code if failed
   */
  virtual int CreateConfigurations(AliHLTConfigurationHandler* handler,
				   AliRunLoader* runloader=NULL) const;

  /**
   * Get the top configurations belonging to this module.
   * A top configuration describes a processing chain. It can simply be
   * described by the last configuration(s) in the chain. 
   * The agent can adapt the configurations to be registered to the current
   * AliRoot setup by checking the runloader.
   * @param runloader  [in] AliRoot runloader
   * @return string containing the top configurations separated by blanks
   */
  virtual const char* GetTopConfigurations(AliRunLoader* runloader=NULL) const;

  /**
   * Component libraries which the configurations of this agent depend on.
   * @return list of component libraries as a blank-separated string.
   */
  virtual const char* GetRequiredComponentLibraries() const;

  /**
   * Register componets.
   * This method can be used to register components for the module instead
   * of the 'static object approach'. Registration is don by passing a
   * sample object to @ref AliHLTComponentHandler::RegisterComponent<br>
   * \em Note: The sample object is owned by the agent, make sure to delete
   * it.
   */
  virtual int RegisterComponents(AliRunLoader* runloader=NULL) const;

 protected:

 private:
  /**
   * Register agent in the global list.
   * @return neg. error code if failed
   */
  static int Register(AliHLTModuleAgent* pAgent);

  /**
   * Unregister agent in the global list.
   * @return neg. error code if failed
   */
  static int Unregister(AliHLTModuleAgent* pAgent);

  /** the list of active agents */
  static TList fgAgentList;

  /** the current object link (list position) */
  static TObjLink* fgCurrentLnk;

  ClassDef(AliHLTModuleAgent, 0);
};

#endif