MODULE Error_Handling
      USE Precision
      IMPLICIT NONE
      PUBLIC::InitializeErrorHandling,TerminateErrorHandling,&
      Warning,NonCriticalError,CriticalError
      PRIVATE
      
      INTEGER,PUBLIC,SAVE::error_status=0
      
      CHARACTER(LEN=100),PUBLIC,PARAMETER::options_file="/home/hpf/Fortran/src/NO01/F90/Plots.options",&
      null_file="ScratchFile.log"
      CHARACTER(LEN=100),PUBLIC,SAVE::log_file="Network.log"
      CHARACTER(LEN=100),PUBLIC,SAVE::print_file=""
      LOGICAL,PUBLIC,SAVE::append=.FALSE.
      
      INTEGER,PARAMETER,PUBLIC::stdin=5,stdout=6,stderr=0
      INTEGER,PARAMETER,PUBLIC::null_unit=1,log_unit=2
      INTEGER,SAVE,PUBLIC::print_unit=stdout
      INTEGER,PARAMETER,PUBLIC::program_options_unit=10
      
      INTEGER,PUBLIC,SAVE::log_level=3,print_level=4
      INTEGER,PUBLIC,SAVE::message_log_unit=log_unit,message_print_unit=null_unit,&
      warning_log_unit=log_unit,warning_print_unit=stdout,&
      error_log_unit=log_unit,error_print_unit=stdout
      CHARACTER(LEN=1),PUBLIC,SAVE::warning_action="C",non_critical_action="P"
      
      CONTAINS
      
      
      SUBROUTINE InitializeErrorHandling()
      IMPLICIT NONE
      CHARACTER(LEN=15)::file_positioning
      
      IF(append)THEN
      file_positioning="APPEND"
      ELSE
      file_positioning="REWIND"
      END IF
      IF(print_file/="")THEN
      print_unit=3
      OPEN(UNIT=print_unit,FILE=TRIM(print_file),STATUS="UNKNOWN",&
      ACCESS="SEQUENTIAL",ACTION="WRITE",POSITION=file_positioning)
      ELSE
      print_unit=stdout
      END IF
      
      OPEN(UNIT=log_unit,FILE=TRIM(log_file),STATUS="UNKNOWN",&
      ACCESS="SEQUENTIAL",ACTION="WRITE",POSITION=file_positioning)
      OPEN(UNIT=null_unit,FILE=TRIM(null_file),STATUS="UNKNOWN",&
      ACCESS="SEQUENTIAL",ACTION="WRITE",POSITION=file_positioning)
      
      
      IF(log_level>=4)THEN
      message_log_unit=log_unit
      ELSE
      message_log_unit=null_unit
      END IF
      
      IF(print_level>=4)THEN
      message_print_unit=print_unit
      ELSE
      message_print_unit=null_unit
      END IF
      
      IF(log_level>=3)THEN
      warning_log_unit=log_unit
      ELSE
      warning_log_unit=null_unit
      END IF
      
      IF(print_level>=3)THEN
      warning_print_unit=print_unit
      ELSE
      warning_print_unit=null_unit
      END IF
      
      IF(log_level>=2)THEN
      error_log_unit=log_unit
      ELSE
      error_log_unit=null_unit
      END IF
      
      IF(print_level>=2)THEN
      error_print_unit=print_unit
      ELSE
      error_print_unit=null_unit
      END IF
      
      END SUBROUTINE InitializeErrorHandling
      
      
      
      SUBROUTINE TerminateErrorHandling(keep_null)
      IMPLICIT NONE
      LOGICAL,INTENT(IN),OPTIONAL::keep_null
      
      CLOSE(unit=log_unit)
      IF(print_unit/=stdout)CLOSE(UNIT=print_unit)
      IF(PRESENT(keep_null))THEN
      IF(keep_null)THEN
      CLOSE(UNIT=null_unit,STATUS="KEEP")
      ELSE
      CLOSE(UNIT=null_unit,STATUS="DELETE")
      END IF
      ELSE
      CLOSE(UNIT=null_unit,STATUS="DELETE")
      END IF
      
      END SUBROUTINE TerminateErrorHandling
      
      
      
      SUBROUTINE Warning(message,caller,action)
      IMPLICIT NONE
      CHARACTER(LEN=*),INTENT(IN)::message
      CHARACTER(LEN=*),INTENT(IN),OPTIONAL::caller
      CHARACTER(LEN=*),INTENT(IN),OPTIONAL::action
      
      CHARACTER(LEN=1)::local_action
      
      
      WRITE(UNIT=warning_log_unit,FMT="(A,A,A)",ADVANCE="NO")"Warning"," (!!!): ",message
      IF(PRESENT(caller))WRITE(UNIT=warning_log_unit,FMT="(A,A)")" occured in: ",caller
      
      WRITE(UNIT=warning_print_unit,FMT="(A,A,A)",ADVANCE="NO")"Warning"," (!!!): ",message
      IF(PRESENT(caller))WRITE(UNIT=warning_print_unit,FMT="(A,A)")" occured in: ",caller
      IF(PRESENT(action))THEN
      local_action=action(1:1)
      ELSE
      local_action=warning_action
      END IF
      
      SELECT CASE(local_action)
      CASE('P','p')
      PAUSE
      CASE DEFAULT
      RETURN
      ENDSELECT
      
      END SUBROUTINE Warning
      
      SUBROUTINE NonCriticalError(message,caller,action)
      IMPLICIT NONE
      CHARACTER(LEN=*),INTENT(IN)::message
      CHARACTER(LEN=*),INTENT(IN),OPTIONAL::caller
      CHARACTER(LEN=*),INTENT(IN),OPTIONAL::action
      
      CHARACTER(LEN=1)::local_action
      
      IF(PRESENT(action))THEN
      local_action=action(1:1)
      ELSE
      local_action=non_critical_action
      END IF
      
      
      WRITE(UNIT=error_log_unit,FMT="(A,A,A)",ADVANCE="NO")"Non-Critical error"," (!!!): ",message
      IF(PRESENT(caller))WRITE(UNIT=error_log_unit,FMT="(A,A)")" occured in: ",caller
      
      WRITE(UNIT=error_print_unit,FMT="(A,A,A)",ADVANCE="NO")"Non-Critical error"," (!!!): ",message
      IF(PRESENT(caller))WRITE(UNIT=error_print_unit,FMT="(A,A)")" occured in: ",caller
      SELECT CASE(local_action)
      CASE('C','c')
      RETURN
      CASE('S','s')
      
      WRITE(UNIT=error_log_unit,FMT="(A)")"Stopping program with hard breakdown..."
      WRITE(UNIT=error_print_unit,FMT="(A)")"Stopping program with hard breakdown..."
      STOP
      CASE DEFAULT
      PAUSE
      ENDSELECT
      
      END SUBROUTINE NonCriticalError
      
      SUBROUTINE CriticalError(message,caller)
      IMPLICIT NONE
      CHARACTER(LEN=*),INTENT(IN)::message
      CHARACTER(LEN=*),INTENT(IN),OPTIONAL::caller
      
      
      WRITE(UNIT=error_log_unit,FMT="(A,A,A)",ADVANCE="NO")"Critical error"," (!!!): ",message
      IF(PRESENT(caller))WRITE(UNIT=error_log_unit,FMT="(A,A)")" occured in: ",caller
      
      WRITE(UNIT=error_print_unit,FMT="(A,A,A)",ADVANCE="NO")"Critical error"," (!!!): ",message
      IF(PRESENT(caller))WRITE(UNIT=error_print_unit,FMT="(A,A)")" occured in: ",caller
      
      WRITE(UNIT=error_log_unit,FMT="(A)")"Stopping program with hard breakdown..."
      WRITE(UNIT=error_print_unit,FMT="(A)")"Stopping program with hard breakdown..."
      STOP
      
      END SUBROUTINE CriticalError
      
      
      
      END MODULE Error_Handling