! Copyright (C) 2011 UNESCO-IHE, WL|Delft Hydraulics and Delft University !
! Dano Roelvink, Ap van Dongeren, Ad Reniers, Jamie Lescinski,            !
! Jaap van Thiel de Vries, Robert McCall                                  !
!                                                                         !
! d.roelvink@unesco-ihe.org                                               !
! UNESCO-IHE Institute for Water Education                                !
! P.O. Box 3015                                                           !
! 2601 DA Delft                                                           !
! The Netherlands                                                         !
!                                                                         !
! This library is free software; you can redistribute it and/or           !
! modify it under the terms of the GNU Lesser General Public              !
! License as published by the Free Software Foundation; either            !
! version 2.1 of the License, or (at your option) any later version.      !
!                                                                         !
! This library 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        !
! Lesser General Public License for more details.                         !
!                                                                         !
! You should have received a copy of the GNU Lesser General Public        !
! License along with this library; if not, write to the Free Software     !
! Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307     !
! USA                                                                     !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
module landslide_module
  implicit none
  type landslides
     ! landslide file names
     character*256                   :: lsinpfile
     ! landslide time stamps
     real*8                         :: lsinpt
     ! timestep of the landslide files
     real*8                          :: lsdt

  end type landslides

contains

  subroutine readlsfile(s,par)
    use params
    use xmpi_module
    use spaceparams
    use readkey_module
    use filefunctions
    use interp
    use logging_module, only: report_file_read_error

    IMPLICIT NONE

    type(parameters)                                :: par
    type(spacepars)                                 :: s
    type(landslides), dimension(:), pointer, save    :: ls

    integer                                     :: i,j,fid,ier,it,nls
    ! z coordinates
    real*8, dimension(:,:), pointer             :: dzbls
    ! counter of the used landslide file
    integer, save                               :: ls_ind
    character(1)                                :: ch


    allocate(ls(1:par%nslide))
    allocate(dzbls(1:par%nx+1,1:par%ny+1)) 
    s%dzblsdt = 0
    
    fid=create_new_fid()
    open(fid,file=par%slidefile)
    ier=0   

    ! read in times and landslide file names
    do i=1,par%nslide
       read(fid,*,iostat=ier) ls(i)%lsinpt, ls(i)%lsinpfile
       if (ier .ne. 0) then
          call report_file_read_error(par%slidefile)
       endif
    enddo
    close(fid)

    ! only update if there are still landslide files to be
    ! read in, otherwise s%dzblsdt remains zero
    if (par%t<=ls(par%nslide)%lsinpt) then

       ! find the landslide file for the actual hydrodynamic time
       ! and compute lsdt
       ls_ind=0
       do i=1,par%nslide-1
            if (ls(i)%lsinpt<=par%t) then  
                ls_ind=ls_ind+1                        
            endif
       end do
       ! add one afterwards because we want to update 
       ! towards the next timestep   
       ls_ind=ls_ind+1       
        if (ls_ind==1) then
             ! The first time stamp equals the first 
             ! time step/intervall 
             ls(ls_ind)%lsdt=ls(ls_ind)%lsinpt
        else
             ls(ls_ind)%lsdt=ls(ls_ind)%lsinpt-ls(ls_ind-1)%lsinpt
        endif   
       
       ! read in landslide file with the index ls_ind
       ! that corresponds to the actual hydrodynamic time

       fid=create_new_fid()
       open (fid,file=ls(ls_ind)%lsinpfile)
       do j=1,par%ny+1
           read(fid,*,iostat=ier)(dzbls(i,j),i=1,par%nx+1)
           if (ier .ne. 0) then
                call report_file_read_error(ls(ls_ind)%lsinpfile)
           endif
       end do
       close(fid)

       ! compute rate of bed change per second
       !(just in case time step between input files is not one second)

       s%dzblsdt=1/ls(ls_ind)%lsdt*dzbls
    
    endif
  deallocate(ls)
  deallocate(dzbls)
  
  end subroutine readlsfile

end module landslide_module