MODULE backup_core
!-----------------------------------------------------------------------
! NAME
!     backup_core
!
! DESCRIPTION
!     Intermediate backups of the PEM/PCM restart files.
!
! AUTHORS & DATE
!     JB Clement, 03/2026
!
! NOTES
!
!-----------------------------------------------------------------------

! DEPENDENCIES
! ------------
use numerics, only: di, k4

! DECLARATION
! -----------
implicit none

! PARAMETERS
! ----------
integer(di), protected :: backup_rate = 0_di ! Backup rate in PEM timesteps (0 disables intermediate backups)

! VISIBILITY
! ----------
private :: copy_restart_if_present, suffix2filename

contains
!+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

!=======================================================================
SUBROUTINE set_backup_config(backup_rate_in)
!-----------------------------------------------------------------------
! NAME
!     set_backup_config
!
! DESCRIPTION
!     Setter for "backup" configuration parameters.
!
! AUTHORS & DATE
!     JB Clement, 03/2026
!
! NOTES
!
!-----------------------------------------------------------------------

! DEPENDENCIES
! ------------
use utility,  only: int2str
use display,  only: print_msg, LVL_NFO
use stoppage, only: stop_clean

! DECLARATION
! -----------
implicit none

! ARGUMENTS
! ---------
integer(di), intent(in) :: backup_rate_in

! CODE
! ----
backup_rate = backup_rate_in
call print_msg('backup_rate = '//int2str(backup_rate),LVL_NFO)
if (backup_rate < 0) call stop_clean(__FILE__,__LINE__,'''backup_rate'' must be >= 0!',1)

END SUBROUTINE set_backup_config
!=======================================================================

!=======================================================================
SUBROUTINE backup_restarts(backup_idt)
!-----------------------------------------------------------------------
! NAME
!     backup_restarts
!
! DESCRIPTION
!     Duplicate restart files to timestep-tagged backup files.
!
! AUTHORS & DATE
!     JB Clement, 03/2026
!
! NOTES
!
!-----------------------------------------------------------------------

! DEPENDENCIES
! ------------
use geometry,  only: ngrid
use io_netcdf, only: start_name, start1D_name, startfi_name, startevo_name
use display,   only: print_msg, LVL_NFO
use utility,   only: int2str

! DECLARATION
! -----------
implicit none

! ARGUMENTS
! ---------
integer(di), intent(in) :: backup_idt

! LOCAL VARIABLES
! ---------------
character(:), allocatable :: suffix

! CODE
! ----
suffix = '_ts'//int2str(backup_idt)

call print_msg('> Saving "restart" files at iteration = '//int2str(backup_idt),LVL_NFO)
call copy_restart_if_present('re'//startevo_name,suffix2filename(startevo_name,suffix))
call copy_restart_if_present('re'//startfi_name,suffix2filename(startfi_name,suffix))
if (ngrid == 1) then
    call copy_restart_if_present('re'//start1D_name,suffix2filename(start1D_name,suffix))
else
    call copy_restart_if_present('re'//start_name,suffix2filename(start_name,suffix))
end if

END SUBROUTINE backup_restarts
!=======================================================================

!=======================================================================
SUBROUTINE copy_restart_if_present(src_name,dst_name)
!-----------------------------------------------------------------------
! NAME
!     copy_restart_if_present
!
! DESCRIPTION
!     Copy file if present. Used for restart backup files.
!
! AUTHORS & DATE
!     JB Clement, 03/2026
!
! NOTES
!
!-----------------------------------------------------------------------

! DEPENDENCIES
! ------------
use stoppage, only: stop_clean

! DECLARATION
! -----------
implicit none

! ARGUMENTS
! ---------
character(*), intent(in) :: src_name, dst_name

! LOCAL VARIABLES
! ---------------
logical(k4) :: here
integer(di) :: cstat

! CODE
! ----
inquire(file = src_name,exist = here)
if (.not. here) return

call execute_command_line('\cp -f '//src_name//' '//dst_name,cmdstat = cstat)
if (cstat > 0) then
    call stop_clean(__FILE__,__LINE__,'command execution failed!',1)
else if (cstat < 0) then
    call stop_clean(__FILE__,__LINE__,'command execution not supported!',1)
end if

END SUBROUTINE copy_restart_if_present
!=======================================================================

!=======================================================================
FUNCTION suffix2filename(filename,suffix_in) RESULT(name_out)
!-----------------------------------------------------------------------
! NAME
!     suffix2filename
!
! DESCRIPTION
!     Insert suffix before the extension of a filename.
!
! AUTHORS & DATE
!     JB Clement, 03/2026
!
! NOTES
!
!-----------------------------------------------------------------------

! DECLARATION
! -----------
implicit none

! ARGUMENTS
! ---------
character(*), intent(in) :: filename, suffix_in

! RESULT
! ------
character(:), allocatable :: name_out ! Filename with the suffix inserted

! LOCAL VARIABLES
! ---------------
integer(di) :: ipos

! CODE
! ----
ipos = index(filename,'.',back = .true.)
if (ipos > 0) then
    name_out = filename(:ipos - 1)//suffix_in//filename(ipos:)
else
    name_out = filename//suffix_in
end if

END FUNCTION suffix2filename
!=======================================================================

END MODULE backup_core