#include "GaudiKernel/StateMachine.h"

namespace Gaudi { namespace StateMachine {
/**
 * Function to get the new state according to the required transition, checking
 * if the transition is allowed.
 */  
State ChangeState(const Transition transition, const State state) {
  switch (transition) {
  case CONFIGURE:
    if ( OFFLINE == state ) {
      return CONFIGURED;
    }
    break;
  case INITIALIZE:
    if ( CONFIGURED == state ) {
      return INITIALIZED;
    }
    break;
  case START:
    if ( INITIALIZED == state ) {
      return RUNNING;
    }
    break;
  case STOP:
    if ( RUNNING == state ) {
      return INITIALIZED;
    }
    break;
  case FINALIZE:
    if ( INITIALIZED == state ) {
      return CONFIGURED;
    }
    break;
  case TERMINATE:
    if ( CONFIGURED == state ) {
      return OFFLINE;
    }
    break;
  }
  std::stringstream msg;
  msg << "Invalid transition '" << transition << "' from state '" << state << "'";
  throw GaudiException(msg.str(), "Gaudi::StateMachine::ChangeState",
      StatusCode(StatusCode::FAILURE,true));
  return OFFLINE; // never reached, but maked the compiler happy
}

} } // namespace Gaudi::StateMachine