module shr_ndep_mod

  !========================================================================
  ! Module for handling nitrogen depostion of tracers.
  ! This module is shared by land and atmosphere models for the computations of
  ! dry deposition of tracers
  !========================================================================

  !USES:
  use shr_sys_mod,   only : shr_sys_abort
  use shr_log_mod,   only : s_loglev  => shr_log_Level
  use shr_kind_mod,  only : r8 => shr_kind_r8, CS => SHR_KIND_CS, CX => SHR_KIND_CX

  implicit none
  save

  private

  ! !PUBLIC MEMBER FUNCTIONS
  public :: shr_ndep_readnl       ! Read namelist
  !====================================================================================

CONTAINS

  !====================================================================================
  subroutine shr_ndep_readnl(NLFilename, ID, ndep_fields, add_ndep_fields)

    !========================================================================
    ! reads ndep_inparm namelist and sets up driver list of fields for
    ! atmosphere -> land and atmosphere -> ocn communications.
    !========================================================================

    use shr_file_mod , only : shr_file_getUnit, shr_file_freeUnit
    use shr_log_mod  , only : s_logunit => shr_log_Unit
    use seq_comm_mct , only : seq_comm_iamroot, seq_comm_setptrs
    use shr_mpi_mod  , only : shr_mpi_bcast
    use shr_nl_mod   , only : shr_nl_find_group_name
    implicit none

    character(len=*), intent(in)  :: NLFilename ! Namelist filename
    integer         , intent(in)  :: ID         ! seq_comm ID
    character(len=*), intent(out) :: ndep_fields
    logical         , intent(out) :: add_ndep_fields

    !----- local -----
    integer :: i                ! Indices
    integer :: unitn            ! namelist unit number
    integer :: ierr             ! error code
    logical :: exists           ! if file exists or not
    integer :: mpicom           ! MPI communicator

    integer, parameter :: maxspc = 100             ! Maximum number of species
    character(len=32)  :: ndep_list(maxspc) = ''   ! List of ndep species

    !----- formats -----
    character(*),parameter :: subName = '(shr_ndep_read) '
    character(*),parameter :: F00   = "('(shr_ndep_read) ',8a)"
    character(*),parameter :: FI1   = "('(shr_ndep_init) ',a,I2)"

    namelist /ndep_inparm/ ndep_list

    !-----------------------------------------------------------------------------
    ! Read namelist and figure out the ndep field list to pass
    ! First check if file exists and if not, n_ndep will be zero
    !-----------------------------------------------------------------------------

    !--- Open and read namelist ---
    if ( len_trim(NLFilename) == 0 ) then
       call shr_sys_abort( subName//'ERROR: nlfilename not set' )
    end if
    call seq_comm_setptrs(ID,mpicom=mpicom)
    if (seq_comm_iamroot(ID)) then
       inquire( file=trim(NLFileName), exist=exists)
       if ( exists ) then
          unitn = shr_file_getUnit()
          open( unitn, file=trim(NLFilename), status='old' )
          if ( s_loglev > 0 ) then
             write(s_logunit,F00) 'Read in ndep_inparm namelist from: ', trim(NLFilename)
          end if
          call shr_nl_find_group_name(unitn, 'ndep_inparm', ierr)
          if (ierr == 0) then
             ierr = 1
             do while ( ierr /= 0 )
                read(unitn, ndep_inparm, iostat=ierr)
                if (ierr < 0) then
                   call shr_sys_abort( subName//'ERROR: encountered end-of-file on namelist read' )
                endif
             end do
          else
             write(s_logunit,*) 'shr_ndep_readnl:  no ndep_inparm namelist found in ',NLFilename
          endif
          close( unitn )
          call shr_file_freeUnit( unitn )
       end if
    end if
    call shr_mpi_bcast( ndep_list, mpicom )

    ndep_fields = ' '
    if (len_trim(ndep_list(1)) == 0) then
       add_ndep_fields = .false.
    else
       ! Loop over species to fill list of fields to communicate for ndep
       add_ndep_fields = .true.
       do i=1,maxspc
          if ( len_trim(ndep_list(i))==0 ) exit
          if ( i == 1 ) then
             ndep_fields = 'Faxa_' // trim(ndep_list(i))
          else
             ndep_fields = trim(ndep_fields)//':'//'Faxa_' // trim(ndep_list(i))
          endif
       enddo
    end if

  end subroutine shr_ndep_readnl

end module shr_ndep_mod