! (C) Copyright 2005- ECMWF.
!
! This software is licensed under the terms of the Apache Licence Version 2.0
! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
!
! In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
! virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
!
!
!
!  Description: How to set keys for a grib2 file with
!               a Generalized Vertical Height Coordinate
!
!
program set
   use eccodes
   implicit none
   integer    :: infile, outfile
   integer    :: igrib
   real(4)    :: nlev_real4 = 12.21
   real(8)    :: nlev_real8 = 12.21
   integer(4) :: PDTN_int = 11
   integer(8) :: PDTN_long = 11

   call codes_open_file(infile, '../../data/sample.grib2', 'r')

   call codes_open_file(outfile, 'out_gvc.grib2', 'w')

   call codes_grib_new_from_file(infile, igrib)

   ! individual ensemble forecast
   call codes_set(igrib, 'productDefinitionTemplateNumber', PDTN_int)
   call codes_set(igrib, 'productDefinitionTemplateNumber', PDTN_long)

   ! select level type as Generalized Vertical Height Coordinate
   call codes_set(igrib, 'typeOfLevel', 'generalVertical')

   ! now set keys specific to this level type
   call codes_set(igrib, 'nlev', nlev_real4)
   call codes_set(igrib, 'nlev', nlev_real8)
   call codes_set(igrib, 'numberOfVGridUsed', 13.55)

   ! check integrity of GRIB message
   call check_settings(igrib)

   ! write modified message to a file
   call codes_write(igrib, outfile)

   call codes_release(igrib)
   call codes_close_file(infile)
   call codes_close_file(outfile)

contains

!======================================
   subroutine check_settings(gribid)
      implicit none
      integer, intent(in) :: gribid

      integer(kind=4) :: NV, typeOfFirstFixedSurface

      call codes_get(gribid, 'NV', NV)
      if (NV /= 6) then
         call codes_check(-2, 'NV_should_be_6', '')
      end if

      call codes_get(gribid, 'typeOfFirstFixedSurface', typeOfFirstFixedSurface)
      if (typeOfFirstFixedSurface /= 150) then
         call codes_check(-2, 'typeOfFirstFixedSurface_should_be_150', '')
      end if

   end subroutine check_settings
end program set