MODULE lmdz_filtre_fft_loc
  IMPLICIT NONE; PRIVATE
  PUBLIC use_filtre_fft, filtre_u, filtre_v, filtre_inv, init_filtre_fft, filtre_u_fft, &
          filtre_v_fft, filtre_inv_fft

  LOGICAL, SAVE :: use_filtre_fft
  REAL, SAVE, ALLOCATABLE :: Filtre_u(:, :)
  REAL, SAVE, ALLOCATABLE :: Filtre_v(:, :)
  REAL, SAVE, ALLOCATABLE :: Filtre_inv(:, :)

CONTAINS

  SUBROUTINE Init_filtre_fft(coeffu, modfrstu, jfiltnu, jfiltsu, coeffv, modfrstv, jfiltnv, jfiltsv)
    USE lmdz_fft
    IMPLICIT NONE
    INCLUDE 'dimensions.h'
    REAL, INTENT(IN) :: coeffu(iim, jjm)
    INTEGER, INTENT(IN) :: modfrstu(jjm)
    INTEGER, INTENT(IN) :: jfiltnu
    INTEGER, INTENT(IN) :: jfiltsu
    REAL, INTENT(IN) :: coeffv(iim, jjm)
    INTEGER, INTENT(IN) :: modfrstv(jjm)
    INTEGER, INTENT(IN) :: jfiltnv
    INTEGER, INTENT(IN) :: jfiltsv

    INTEGER :: index_vp(iim)
    INTEGER :: i, j

    index_vp(1) = 1
    DO i = 1, iim / 2
      index_vp(i + 1) = i * 2
    ENDDO

    DO i = 1, iim / 2 - 1
      index_vp(iim / 2 + i + 1) = iim - 2 * i + 1
    ENDDO

    ALLOCATE(Filtre_u(iim, jjm))
    ALLOCATE(Filtre_v(iim, jjm))
    ALLOCATE(Filtre_inv(iim, jjm))

    DO j = 2, jfiltnu
      DO i = 1, iim
        IF (index_vp(i) < modfrstu(j)) THEN
          Filtre_u(i, j) = 0
        ELSE
          Filtre_u(i, j) = coeffu(index_vp(i), j)
        ENDIF
      ENDDO
    ENDDO

    DO j = jfiltsu, jjm
      DO i = 1, iim
        IF (index_vp(i) < modfrstu(j)) THEN
          Filtre_u(i, j) = 0
        ELSE
          Filtre_u(i, j) = coeffu(index_vp(i), j)
        ENDIF
      ENDDO
    ENDDO

    DO j = 1, jfiltnv
      DO i = 1, iim
        IF (index_vp(i) < modfrstv(j)) THEN
          Filtre_v(i, j) = 0
        ELSE
          Filtre_v(i, j) = coeffv(index_vp(i), j)
        ENDIF
      ENDDO
    ENDDO

    DO j = jfiltsv, jjm
      DO i = 1, iim
        IF (index_vp(i) < modfrstv(j)) THEN
          Filtre_v(i, j) = 0
        ELSE
          Filtre_v(i, j) = coeffv(index_vp(i), j)
        ENDIF
      ENDDO
    ENDDO

    DO j = 2, jfiltnu
      DO i = 1, iim
        IF (index_vp(i) < modfrstu(j)) THEN
          Filtre_inv(i, j) = 0
        ELSE
          Filtre_inv(i, j) = coeffu(index_vp(i), j) / (1. + coeffu(index_vp(i), j))
        ENDIF
      ENDDO
    ENDDO

    DO j = jfiltsu, jjm
      DO i = 1, iim
        IF (index_vp(i) < modfrstu(j)) THEN
          Filtre_inv(i, j) = 0
        ELSE
          Filtre_inv(i, j) = coeffu(index_vp(i), j) / (1. + coeffu(index_vp(i), j))
        ENDIF
      ENDDO
    ENDDO


    !    CALL Init_FFT(iim,(jjm+1)*(llm+1))

  END SUBROUTINE Init_filtre_fft

  SUBROUTINE Filtre_u_fft(vect_inout, jjb, jje, jj_begin, jj_end, nbniv)
    USE lmdz_fft
#ifdef CPP_PARA
    USE parallel_lmdz,ONLY: OMP_CHUNK
#endif
    IMPLICIT NONE
    INCLUDE 'dimensions.h'
    INTEGER, INTENT(IN) :: jjb
    INTEGER, INTENT(IN) :: jje
    INTEGER, INTENT(IN) :: jj_begin
    INTEGER, INTENT(IN) :: jj_end
    INTEGER, INTENT(IN) :: nbniv
    REAL, INTENT(INOUT) :: vect_inout(iim + 1, jjb:jje, nbniv)

    REAL :: vect(iim + inc, jj_end - jj_begin + 1, nbniv)
    COMPLEX :: TF_vect(iim / 2 + 1, jj_end - jj_begin + 1, nbniv)
    INTEGER :: nb_vect
    INTEGER :: i, j, l
    INTEGER :: ll_nb
    !    REAL               :: vect_tmp(iim+inc,jj_end-jj_begin+1,nbniv)

    ll_nb = 0
    !$OMP DO SCHEDULE(STATIC,OMP_CHUNK)
    DO l = 1, nbniv
      ll_nb = ll_nb + 1
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim + 1
          vect(i, j, ll_nb) = vect_inout(i, j + jj_begin - 1, l)
        ENDDO
      ENDDO
    ENDDO
    !$OMP END DO NOWAIT

    nb_vect = (jj_end - jj_begin + 1) * ll_nb

    !    vect_tmp=vect

    CALL FFT_forward(vect, TF_vect, nb_vect)

    !    CALL FFT_forward(vect,TF_vect_test,nb_vect)
    !      PRINT *,"XXXXXXXXXXXXX Filtre_u_FFT xxxxxxxxxxxx"
    !      DO j=1,jj_end-jj_begin+1
    !      DO i=1,iim/2+1
    !         PRINT *,"====",i,j,"----->",TF_vect_test(i,j,1)
    !       ENDDO
    !      ENDDO

    DO l = 1, ll_nb
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim / 2 + 1
          TF_vect(i, j, l) = TF_vect(i, j, l) * Filtre_u(i, jj_begin + j - 1)
        ENDDO
      ENDDO
    ENDDO

    CALL FFT_backward(TF_vect, vect, nb_vect)
    !    CALL FFT_backward(TF_vect_test,vect_test,nb_vect)

    !      PRINT *,"XXXXXXXXXXXXX Filtre_u_FFT xxxxxxxxxxxx"
    !      DO j=1,jj_end-jj_begin+1
    !         DO i=1,iim
    !           PRINT *,"====",i,j,"----->",vect_test(i,j,1)
    !         ENDDO
    !      ENDDO

    ll_nb = 0
    !$OMP DO SCHEDULE(STATIC,OMP_CHUNK)
    DO l = 1, nbniv
      ll_nb = ll_nb + 1
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim + 1
          vect_inout(i, j + jj_begin - 1, l) = vect(i, j, ll_nb)
        ENDDO
      ENDDO
    ENDDO
    !$OMP END DO NOWAIT

  END SUBROUTINE Filtre_u_fft


  SUBROUTINE Filtre_v_fft(vect_inout, jjb, jje, jj_begin, jj_end, nbniv)
    USE lmdz_fft
#ifdef CPP_PARA
    USE parallel_lmdz,ONLY: OMP_CHUNK
#endif
    IMPLICIT NONE
    INCLUDE 'dimensions.h'
    INTEGER, INTENT(IN) :: jjb
    INTEGER, INTENT(IN) :: jje
    INTEGER, INTENT(IN) :: jj_begin
    INTEGER, INTENT(IN) :: jj_end
    INTEGER, INTENT(IN) :: nbniv
    REAL, INTENT(INOUT) :: vect_inout(iim + 1, jjb:jje, nbniv)

    REAL :: vect(iim + inc, jj_end - jj_begin + 1, nbniv)
    COMPLEX :: TF_vect(iim / 2 + 1, jj_end - jj_begin + 1, nbniv)
    INTEGER :: nb_vect
    INTEGER :: i, j, l
    INTEGER :: ll_nb

    ll_nb = 0
    !$OMP DO SCHEDULE(STATIC,OMP_CHUNK)
    DO l = 1, nbniv
      ll_nb = ll_nb + 1
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim + 1
          vect(i, j, ll_nb) = vect_inout(i, j + jj_begin - 1, l)
        ENDDO
      ENDDO
    ENDDO
    !$OMP END DO NOWAIT

    nb_vect = (jj_end - jj_begin + 1) * ll_nb

    CALL FFT_forward(vect, TF_vect, nb_vect)

    DO l = 1, ll_nb
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim / 2 + 1
          TF_vect(i, j, l) = TF_vect(i, j, l) * Filtre_v(i, jj_begin + j - 1)
        ENDDO
      ENDDO
    ENDDO

    CALL FFT_backward(TF_vect, vect, nb_vect)

    ll_nb = 0
    !$OMP DO SCHEDULE(STATIC,OMP_CHUNK)
    DO l = 1, nbniv
      ll_nb = ll_nb + 1
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim + 1
          vect_inout(i, j + jj_begin - 1, l) = vect(i, j, ll_nb)
        ENDDO
      ENDDO
    ENDDO
    !$OMP END DO NOWAIT

  END SUBROUTINE Filtre_v_fft


  SUBROUTINE Filtre_inv_fft(vect_inout, jjb, jje, jj_begin, jj_end, nbniv)
    USE lmdz_fft
#ifdef CPP_PARA
    USE parallel_lmdz,ONLY: OMP_CHUNK
#endif
    IMPLICIT NONE
    INCLUDE 'dimensions.h'
    INTEGER, INTENT(IN) :: jjb
    INTEGER, INTENT(IN) :: jje
    INTEGER, INTENT(IN) :: jj_begin
    INTEGER, INTENT(IN) :: jj_end
    INTEGER, INTENT(IN) :: nbniv
    REAL, INTENT(INOUT) :: vect_inout(iim + 1, jjb:jje, nbniv)

    REAL :: vect(iim + inc, jj_end - jj_begin + 1, nbniv)
    COMPLEX :: TF_vect(iim / 2 + 1, jj_end - jj_begin + 1, nbniv)
    INTEGER :: nb_vect
    INTEGER :: i, j, l
    INTEGER :: ll_nb

    ll_nb = 0
    !$OMP DO SCHEDULE(STATIC,OMP_CHUNK)
    DO l = 1, nbniv
      ll_nb = ll_nb + 1
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim + 1
          vect(i, j, ll_nb) = vect_inout(i, j + jj_begin - 1, l)
        ENDDO
      ENDDO
    ENDDO
    !$OMP END DO NOWAIT

    nb_vect = (jj_end - jj_begin + 1) * ll_nb

    CALL FFT_forward(vect, TF_vect, nb_vect)

    DO l = 1, ll_nb
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim / 2 + 1
          TF_vect(i, j, l) = TF_vect(i, j, l) * Filtre_inv(i, jj_begin + j - 1)
        ENDDO
      ENDDO
    ENDDO

    CALL FFT_backward(TF_vect, vect, nb_vect)

    ll_nb = 0
    !$OMP DO SCHEDULE(STATIC,OMP_CHUNK)
    DO l = 1, nbniv
      ll_nb = ll_nb + 1
      DO j = 1, jj_end - jj_begin + 1
        DO i = 1, iim + 1
          vect_inout(i, j + jj_begin - 1, l) = vect(i, j, ll_nb)
        ENDDO
      ENDDO
    ENDDO
    !$OMP END DO NOWAIT

  END SUBROUTINE Filtre_inv_fft


  !  SUBROUTINE get_ll_index(nbniv,ll_index,ll_nb)
  !  IMPLICIT NONE
  !    INTEGER,INTENT(IN)  :: nbniv
  !    INTEGER,INTENT(OUT) :: ll_index(nbniv)
  !    INTEGER,INTENT(OUT) :: ll_nb

  !    INTEGER :: l,ll_begin, ll_end
  !   INTEGER :: omp_rank,omp_size
  !   INTEGER :: OMP_GET_NUM_THREADS
  !   INTEGER :: omp_chunk
  !   EXTERNAL OMP_GET_NUM_THREADS
  !   INTEGER :: OMP_GET_THREAD_NUM
  !   EXTERNAL OMP_GET_THREAD_NUM


  !   omp_size=OMP_GET_NUM_THREADS()
  !   omp_rank=OMP_GET_THREAD_NUM()
  !   omp_chunk=nbniv/omp_size+min(1,MOD(nbniv,omp_size))

  !   ll_begin=omp_rank*OMP_CHUNK+1
  !   ll_nb=0
  !   DO WHILE (ll_begin<=nbniv)
  !     ll_end=min(ll_begin+OMP_CHUNK-1,nbniv)
  !     DO l=ll_begin,ll_end
  !       ll_nb=ll_nb+1
  !       ll_index(ll_nb)=l
  !     ENDDO
  !     ll_begin=ll_begin+omp_size*OMP_CHUNK
  !   ENDDO

  !  END SUBROUTINE get_ll_index

END MODULE lmdz_filtre_fft_loc