!
! Copyright (C) 2008 Quantum ESPRESSO group
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
MODULE recover_mod

  IMPLICIT NONE
  !
  SAVE
  !
  PRIVATE

  INTEGER ::  iunrec=99

  PUBLIC :: write_rec, read_rec, clean_recover

CONTAINS

!-----------------------------------------------------------------------
SUBROUTINE write_rec(where, irr, dr2, iter, convt, npe, dvscfin, &
                     drhoscfh, dbecsum)
!-----------------------------------------------------------------------
!
!  This routine saves the information needed to recover the GW calculations
!
USE kinds, ONLY : DP
USE ions_base, ONLY : nat
USE uspp_param, ONLY : nhm
USE lsda_mod,  ONLY : nspin
USE units_gw, ONLY : this_pcxpsi_is_on_file
USE noncollin_module, ONLY : nspin_mag
USE nlcc_gw, ONLY : nlcc_any
USE qpoint, ONLY : nksq
USE gvect, ONLY : nrxx
USE uspp, ONLY : okvan
USE gwus, ONLY : int1, int2, int3
USE eqv,  ONLY : drhoscfs
USE control_gw, ONLY : where_rec, rec_code, reduce_io
USE gw_restart, ONLY : gw_writefile

IMPLICIT NONE
CHARACTER(LEN=10), INTENT(IN) :: where
INTEGER, INTENT(IN) :: irr, iter, npe
LOGICAL, INTENT(IN) :: convt
REAL(DP), INTENT(IN) :: dr2
COMPLEX(DP), INTENT(IN) :: dvscfin(nrxx,nspin_mag,npe)
COMPLEX(DP), INTENT(IN), OPTIONAL :: drhoscfh ( nrxx , nspin_mag, npe)
COMPLEX(DP), INTENT(IN), OPTIONAL :: dbecsum((nhm*(nhm+1))/2,nat,nspin_mag,npe)

LOGICAL :: exst
CALL start_clock ('write_rec')
where_rec=where
CALL gw_writefile('data',0)
IF (where_rec=='done_drhod') CALL gw_writefile('data_dyn',irr)
CALL seqopn (iunrec, 'recover', 'unformatted', exst)
!
! info on current iteration (iter=0 potential mixing not available)
!
IF (reduce_io.or.convt) THEN
   WRITE (iunrec) 0, dr2, convt
ELSE
   WRITE (iunrec) iter, dr2, convt
ENDIF
!HL
!WRITE (iunrec) this_pcxpsi_is_on_file
WRITE (iunrec) dvscfin
IF (PRESENT(drhoscfh).AND.convt.AND.nlcc_any) WRITE (iunrec) drhoscfh
IF (convt.AND.ALLOCATED(drhoscfs)) WRITE(iunrec) drhoscfs
IF (PRESENT(dbecsum)) WRITE(iunrec) dbecsum
IF (okvan) WRITE (iunrec) int1, int2, int3

CLOSE (UNIT = iunrec, STATUS = 'keep')

rec_code = 0
CALL stop_clock ('write_rec')

RETURN
END SUBROUTINE write_rec

SUBROUTINE read_rec(dr2, iter0, npe, dvscfin, dvscfins, drhoscfh, dbecsum)
!
!  General restart reading routine
!
USE kinds, ONLY : DP
USE ions_base, ONLY : nat
USE uspp_param, ONLY : nhm
USE gvect,  ONLY : nrxx
USE gsmooth, ONLY : nrxxs, doublegrid
USE uspp,  ONLY : okvan
USE lsda_mod, ONLY : nspin
USE noncollin_module, ONLY : noncolin, nspin_mag
USE units_gw, ONLY : this_pcxpsi_is_on_file
USE control_gw, ONLY : ext_recover, convt
USE nlcc_gw, ONLY : nlcc_any
USE eqv,   ONLY : drhoscfs
USE gwus, ONLY : int1, int2, int3

IMPLICIT NONE
INTEGER, INTENT(OUT) :: iter0
INTEGER, INTENT(IN)  :: npe
REAL(DP), INTENT(OUT) :: dr2
COMPLEX(DP), INTENT(OUT) :: dvscfin ( nrxx , nspin_mag, npe)
COMPLEX(DP), INTENT(OUT) :: dvscfins ( nrxxs , nspin_mag, npe)
COMPLEX(DP), INTENT(OUT), OPTIONAL :: drhoscfh ( nrxx , nspin_mag, npe)
COMPLEX(DP), INTENT(OUT), OPTIONAL :: dbecsum((nhm*(nhm+1))/2,nat,nspin_mag,npe)

INTEGER :: is, ipol
LOGICAL :: exst

CALL start_clock ('read_rec')
CALL seqopn (iunrec, 'recover', 'unformatted', exst)
READ (iunrec) iter0, dr2, convt
READ (iunrec) this_pcxpsi_is_on_file
READ (iunrec) dvscfin
IF (convt.AND.nlcc_any) READ(iunrec) drhoscfh
IF (convt.AND.ALLOCATED(drhoscfs)) READ(iunrec) drhoscfs
IF (PRESENT(dbecsum)) READ(iunrec) dbecsum
CLOSE (UNIT = iunrec, STATUS = 'keep')
IF (doublegrid) THEN
   DO is=1,nspin_mag
      DO ipol=1,npe
         CALL cinterpolate (dvscfin(1,is,ipol), dvscfins(1,is,ipol), -1)
      END DO
   END DO
END IF
ext_recover=.FALSE.
CALL stop_clock ('read_rec')

RETURN
END SUBROUTINE read_rec

SUBROUTINE clean_recover()
!
IMPLICIT NONE
LOGICAL :: exst
!
CALL seqopn( iunrec, 'recover', 'UNFORMATTED', exst )
!
CLOSE( UNIT = iunrec, STATUS = 'DELETE' )
!
END SUBROUTINE clean_recover

END MODULE recover_mod