module readsediment_module
   !
   ! Conceptual possibilities: 
   !  - like waterlevels and interpolating linearly, but what about point sources?
   !  - constant on the boundaries, but what about cross-shore gradients?
   !   
   implicit none
   save 
   
      
   contains
   
   subroutine initsediment(s,par)       ! nog aansluiten in initialize
      use params
      use spaceparams
      use paramsconst
      use filefunctions
      use logging_module
      
      implicit none
      
      type(spacepars), target               :: s
      type(parameters), intent(in)          :: par
      
      logical                               :: exists
      integer                               :: i,j,ff,fid,fid2,ier
      character(slen)                       :: testline
      
      exists = .false.
      
      ! if there is a file with initial ccg list, then use that
      inquire(file=par%ccginitfile,exist=exists)       ! list of filenames with initial fields
      if (exists) then
         fid = create_new_fid()
         open(fid,file=par%ccginitfile)
         read(fid,*)testline
         if (trim(testline)=='INIFRACLIST') then       ! we assume the order of the file follows the order of the fractions in the params.txt file
            do ff = 1, par%ngd
               read(fid,*)testline                     ! read next initial field file
               inquire(file=trim(testline),exist=exists)
               if (exists) then
                  fid2 = create_new_fid()
                  ! read per fraction
                  do j=1,s%ny+1
                     read(fid2,*,iostat=ier)(s%ccg(i,j,ff),i=1,s%nx+1)
                     if (ier .ne. 0) then
                        call report_file_read_error(testline)
                     endif
                  enddo
               else
                  call writelog('lwse','','Error: Initial sediment concentration file '//trim(testline)//' does not exist.') 
                  call halt_program()
               endif
            end do
         else
            call writelog('lwse','','Error: List of initial concentration field files should start with INIFRACLIST,  ') 
            call writelog('lwse','','       followed by no_of_fractions filenames containing the concentration fields.') 
            call halt_program()
         end if
         close(fid)   
      else  ! no initial ccg0 file exists, ccg is assumed to be allocated and filled with zeros       
         do ff = 1, par%ngd
            do i = 1, s%nx+1
               do j = 1, s%ny+1
                 s%ccg(i,j,ff) = par%ccg0(ff)                  
               enddo
            enddo
         enddo
      endif
      
   end subroutine initsediment
    
   
end module readsediment_module