! (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: Count messages before processing
!
!
program grib_count_messages
   use eccodes
   implicit none

   integer                            ::  ifile
   integer                            ::  iret
   integer                            ::  n
   integer                            ::  i
   integer, dimension(:), allocatable ::  igrib
   real                               ::  latitudeOfFirstPointInDegrees
   real                               ::  longitudeOfFirstPointInDegrees
   real                               ::  latitudeOfLastPointInDegrees
   real                               ::  longitudeOfLastPointInDegrees
   integer                            ::  numberOfPointsAlongAParallel
   integer                            ::  numberOfPointsAlongAMeridian
   real, dimension(:), allocatable    ::  values
   integer(8)                         ::  numberOfValues
   real                               ::  average, min_val, max_val

   call codes_open_file(ifile, '../../data/tigge_pf_ecmwf.grib2', 'r')

   ! count the messages in the file
   call codes_count_in_file(ifile, n)
   allocate (igrib(n))
   igrib = -1

   ! load the messages from the file.
   DO i = 1, n
      call codes_grib_new_from_file(ifile, igrib(i), iret)
   END DO

   ! we can close the file
   call codes_close_file(ifile)

   ! loop on all the messages in memory
   DO i = 1, n
      write (*, *) 'processing message number ', i
      ! get as a integer
      call codes_get(igrib(i), 'Ni', numberOfPointsAlongAParallel)
      write (*, *) 'numberOfPointsAlongAParallel=', &
         numberOfPointsAlongAParallel

      ! get as a integer
      call codes_get(igrib(i), 'Nj', numberOfPointsAlongAMeridian)
      write (*, *) 'numberOfPointsAlongAMeridian=', &
         numberOfPointsAlongAMeridian

      ! get as a real
      call codes_get(igrib(i), 'latitudeOfFirstGridPointInDegrees', &
                     latitudeOfFirstPointInDegrees)
      write (*, *) 'latitudeOfFirstGridPointInDegrees=', &
         latitudeOfFirstPointInDegrees

      ! get as a real
      call codes_get(igrib(i), 'longitudeOfFirstGridPointInDegrees', &
                     longitudeOfFirstPointInDegrees)
      write (*, *) 'longitudeOfFirstGridPointInDegrees=', &
         longitudeOfFirstPointInDegrees

      ! get as a real
      call codes_get(igrib(i), 'latitudeOfLastGridPointInDegrees', &
                     latitudeOfLastPointInDegrees)
      write (*, *) 'latitudeOfLastGridPointInDegrees=', &
         latitudeOfLastPointInDegrees

      ! get as a real
      call codes_get(igrib(i), 'longitudeOfLastGridPointInDegrees', &
                     longitudeOfLastPointInDegrees)
      write (*, *) 'longitudeOfLastGridPointInDegrees=', &
         longitudeOfLastPointInDegrees

      ! get the size of the values array
      call codes_get_size(igrib(i), 'values', numberOfValues)
      write (*, *) 'numberOfValues=', numberOfValues

      allocate (values(numberOfValues), stat=iret)
      ! get data values
      call codes_get(igrib(i), 'values', values)
      call codes_get(igrib(i), 'min', min_val) ! can also be obtained through minval(values)
      call codes_get(igrib(i), 'max', max_val) ! can also be obtained through maxval(values)
      call codes_get(igrib(i), 'average', average) ! can also be obtained through maxval(values)

      write (*, *) 'There are ', numberOfValues, &
         ' average is ', average, &
         ' min is ', min_val, &
         ' max is ', max_val
      write (*, *) '---------------------'
      deallocate (values)
   END DO

   DO i = 1, n
      call codes_release(igrib(i))
   END DO

   deallocate (igrib)

end program