!> @file outflow_turbulence.f90
!--------------------------------------------------------------------------------------------------!
! This file is part of the PALM model system.
!
! PALM is free software: you can redistribute it and/or modify it under the terms of the GNU General
! Public License as published by the Free Software Foundation, either version 3 of the License, or
! (at your option) any later version.
!
! PALM is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
! implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
! Public License for more details.
!
! You should have received a copy of the GNU General Public License along with PALM. If not, see
! <http://www.gnu.org/licenses/>.
!
! Copyright 1997-2021 Leibniz Universitaet Hannover
!--------------------------------------------------------------------------------------------------!
!
! Description:
! ------------
!> Routine based on inflow_turbulence.f90. Copies values of 3d data from a 2d vertical source plane
!> (defined by outflow_source_plane) to the outflow boundary.
!--------------------------------------------------------------------------------------------------!
 SUBROUTINE outflow_turbulence

#if defined( __parallel )
    USE MPI
#endif

    USE arrays_3d,                                                                                 &
        ONLY:  e, pt, q, s, u, v, w

    USE control_parameters,                                                                        &
        ONLY:  humidity, passive_scalar, outflow_source_plane

    USE cpulog,                                                                                    &
        ONLY:  cpu_log, log_point

    USE grid_variables,                                                                            &
        ONLY:  ddx

    USE indices,                                                                                   &
        ONLY:  nbgp, nx, nxr, nyn, nys, nyng, nysg, nzb, nzt

    USE kinds

    USE pegrid!,                                                                                    &
        !ONLY:  comm1dx, id_outflow, id_outflow_source, ierr, myidx, status

    IMPLICIT NONE

    INTEGER(iwp) ::  i        !< loop index
    INTEGER(iwp) ::  j        !< loop index
    INTEGER(iwp) ::  k        !< loop index
    INTEGER(iwp) ::  l        !< loop index
    INTEGER(iwp) ::  ngp_ofv  !< number of grid points stored in outflow_val

    REAL(wp), DIMENSION(nzb:nzt+1,nysg:nyng,7,nbgp) ::  outflow_val  !< values to be copied to the outflow boundary


    CALL cpu_log( log_point(56), 'outflow_turbulence', 'start' )
!
!-- Get number of grid points stored in outflow_val
    ngp_ofv = ( nzt - nzb + 2 ) * ( nyn - nys + 1 + 2 * nbgp ) * 7 * nbgp
!
!-- Get position of the source plane inside the palm grid
    i = outflow_source_plane * ddx
!
!-- Use instantaneous values instead of averaged profiles
#if defined( __parallel )
    IF ( myidx == id_outflow_source )  THEN
       DO  l = 1, nbgp
          DO  j = nysg, nyng
             DO  k = nzb, nzt + 1

                outflow_val(k,j,1,l) = u(k,j,i)
                outflow_val(k,j,2,l) = v(k,j,i)
                outflow_val(k,j,3,l) = w(k,j,i)
                outflow_val(k,j,4,l) = pt(k,j,i)
                outflow_val(k,j,5,l) = e(k,j,i)
                IF ( humidity  )                                                                   &
                   outflow_val(k,j,6,l) = q(k,j,i)
                IF ( passive_scalar )                                                              &
                   outflow_val(k,j,7,l) = s(k,j,i)

            ENDDO
          ENDDO
          i = i + 1
       ENDDO

    ENDIF
#else
    DO  l = 1, nbgp
       DO  j = nysg, nyng
          DO  k = nzb, nzt+1

             outflow_val(k,j,1,l) = u(k,j,i)
             outflow_val(k,j,2,l) = v(k,j,i)
             outflow_val(k,j,3,l) = w(k,j,i)
             outflow_val(k,j,4,l) = pt(k,j,i)
             outflow_val(k,j,5,l) = e(k,j,i)
             IF ( humidity  )                                                                      &
                outflow_val(k,j,6,l) = q(k,j,i)
             IF ( passive_scalar )                                                                 &
                outflow_val(k,j,7,l) = s(k,j,i)

          ENDDO
       ENDDO
       i = i + 1
    ENDDO
#endif

!
!-- For parallel runs, send the values to the respective outflow PE
#if defined( __parallel )
    IF ( myidx == id_outflow_source  .AND.  myidx /= id_outflow )  THEN

       CALL MPI_SEND( outflow_val(nzb,nysg,1,1), ngp_ofv, MPI_REAL, id_outflow, 1, comm1dx, ierr )

    ELSEIF ( myidx /= id_outflow_source  .AND.  myidx == id_outflow )  THEN

       outflow_val = 0.0_wp
       CALL MPI_RECV( outflow_val(nzb,nysg,1,1), ngp_ofv, MPI_REAL, id_outflow_source, 1, comm1dx, &
                      status, ierr )

    ENDIF
#endif

!
!-- Copy values to the outflow
    IF ( nxr == nx )  THEN

       DO  j = nysg, nyng
          DO  k = nzb, nzt + 1

             u(k,j,nx+1:nx+nbgp)  = outflow_val(k,j,1,1:nbgp)
             v(k,j,nx+1:nx+nbgp)  = outflow_val(k,j,2,1:nbgp)
             w(k,j,nx+1:nx+nbgp)  = outflow_val(k,j,3,1:nbgp)
             pt(k,j,nx+1:nx+nbgp) = outflow_val(k,j,4,1:nbgp)
             e(k,j,nx+1:nx+nbgp)  = outflow_val(k,j,5,1:nbgp)
             e(k,j,nx+1:nx+nbgp)  = MAX( e(k,j,nx+1:nx+nbgp), 0.0_wp )

             IF ( humidity )                                                                       &
                q(k,j,nx+1:nx+nbgp)  = outflow_val(k,j,6,1:nbgp)
             IF ( passive_scalar )                                                                 &
                s(k,j,nx+1:nx+nbgp)  = outflow_val(k,j,7,1:nbgp)

          ENDDO
       ENDDO


    ENDIF

    CALL cpu_log( log_point(56), 'outflow_turbulence', 'stop' )

 END SUBROUTINE outflow_turbulence