MODULE halo_mng
   !!======================================================================
   !!                       ***  MODULE  halo_mng  ***
   !! Ocean numerics:  massively parallel processing library
   !!=====================================================================
   !! History :  OPA  !  1994  (M. Guyon, J. Escobar, M. Imbard)
   !Original code
   !!            4.0  !  2019  (CMCC - ASC)  initial version of halo management module
   !in_out_manager
   !!----------------------------------------------------------------------

   USE dom_oce       ! ocean space and time domain

   IMPLICIT NONE
   PRIVATE

   INTERFACE halo_mng_copy
      MODULE PROCEDURE halo_mng_copy_2D, halo_mng_copy_3d, halo_mng_copy_4d
   END INTERFACE

   PUBLIC halo_mng_copy
   PUBLIC halo_mng_init
   PUBLIC halo_mng_set

   INTEGER :: jpi_1, jpj_1
   INTEGER :: jpimax_1, jpjmax_1
   INTEGER :: nlci_1, nlcj_1
   INTEGER :: jplbi_1, jplbj_1
CONTAINS

   SUBROUTINE halo_mng_init( )

        jpi_1 = jpi
        jpj_1 = jpj

        nlci_1 = nlci
        nlcj_1 = nlcj

        jplbi_1 = 1 
        jplbj_1 = 1 
        
        jplbi = 1 
        jplbj = 1 

   		jpimax_1 = jpimax
   		jpjmax_1 = jpjmax

   END SUBROUTINE halo_mng_init

   SUBROUTINE halo_mng_set( khls )
   
        INTEGER, INTENT(in   )    ::   khls

        nn_hls = khls
        jpi = jpi_1 + khls -1
        jpj = jpj_1 + khls -1

        nlci = nlci_1 + khls -1
        nlcj = nlcj_1 + khls -1
        
        jplbi = jplbi_1 - khls +1 
        jplbj = jplbj_1 - khls +1 
        
        jpimax = jpimax_1 + khls -1
        jpjmax = jpjmax_1 + khls -1

   END SUBROUTINE halo_mng_set
   
   SUBROUTINE halo_mng_copy_2D(pta_1, pta_2)
      !!----------------------------------------------------------------------
      !!                  ***  ROUTINE halo_mng_copy  ***
      !!
      !! ** Purpose : copy pta_1 into pta_2
      !! ** Method  :
      !! History :
      !!   1.0  !  07-19  ( CMCC - ASC )  halo_mng_copy
      !!----------------------------------------------------------------------
       REAL(wp), DIMENSION(:,:), INTENT(in)  :: pta_1
       REAL(wp), DIMENSION(:,:), INTENT(out)  :: pta_2
       INTEGER :: halo, off1, off2
       INTEGER, DIMENSION(2) :: dim

       halo = (SIZE(pta_1,1) - SIZE(pta_2,1))/2
       IF (halo < 0) THEN
          off1 = 0
          off2 = -halo
          dim = SHAPE(pta_1)
       ELSE
          off1 = halo
          off2 = 0
          dim = SHAPE(pta_2)
       END IF
        
       pta_2(1+off2:SIZE(pta_2,1)-off2, 1+off2:SIZE(pta_2,2)-off2) = pta_1(1+off1:SIZE(pta_1,1)-off1, 1+off1:SIZE(pta_1,2)-off1)
       
    
   END SUBROUTINE halo_mng_copy_2D

   SUBROUTINE halo_mng_copy_3D(pta_1, pta_2)
      !!----------------------------------------------------------------------
      !!                  ***  ROUTINE halo_mng_copy  ***
      !!
      !! ** Purpose : copy pta_1 into pta_2
      !! ** Method  :
      !! History :
      !!   1.0  !  07-19  ( CMCC - ASC )  halo_mng_copy
      !!----------------------------------------------------------------------
       REAL(wp), DIMENSION(:,:,:), INTENT(in) :: pta_1
       REAL(wp), DIMENSION(:,:,:), INTENT(out) :: pta_2

       INTEGER :: halo, off1, off2
       INTEGER, DIMENSION(3) :: dim

       halo = (SIZE(pta_1,1) - SIZE(pta_2,1))/2
       IF (halo < 0) THEN
          off1 = 0
          off2 = -halo
          dim = SHAPE(pta_1)
       ELSE
          off1 = halo
          off2 = 0
          dim = SHAPE(pta_2)
       END IF
        
       pta_2(1+off2:SIZE(pta_2,1)-off2, 1+off2:SIZE(pta_2,2)-off2,:) = pta_1(1+off1:SIZE(pta_1,1)-off1, 1+off1:SIZE(pta_1,2)-off1,:) 

   END SUBROUTINE halo_mng_copy_3D

   SUBROUTINE halo_mng_copy_4D(pta_1, pta_2)
      !!----------------------------------------------------------------------
      !!                  ***  ROUTINE halo_mng_copy  ***
      !!
      !! ** Purpose : copy pta_1 into pta_2
      !! ** Method  :
      !! History :
      !!   1.0  !  07-19  ( CMCC - ASC )  halo_mng_copy
      !!----------------------------------------------------------------------
       REAL(wp), DIMENSION(:,:,:,:), INTENT(in) :: pta_1
       REAL(wp), DIMENSION(:,:,:,:), INTENT(out) :: pta_2
       INTEGER :: halo, off1, off2
       INTEGER, DIMENSION(4) :: dim

       halo = (SIZE(pta_1,1) - SIZE(pta_2,1))/2
       IF (halo < 0) THEN
          off1 = 0
          off2 = -halo
          dim = SHAPE(pta_1)
       ELSE
          off1 = halo
          off2 = 0
          dim = SHAPE(pta_2)
       END IF
        
       pta_2(1+off2:SIZE(pta_2,1)-off2, 1+off2:SIZE(pta_2,2)-off2,:,:) = pta_1(1+off1:SIZE(pta_1,1)-off1, 1+off1:SIZE(pta_1,2)-off1,:,:)

   END SUBROUTINE halo_mng_copy_4D
END MODULE