!........................................................................
!
! Subroutine :  get_cl_input (con_file, con)  
!
! Description:  Gets command line parameters for BMADZ
!
! Arguments  :
!
! Mod/Commons:    
!
! Calls      :      
!
! Author     : R. Helms
!
! Modified   :     
!             
!........................................................................
!
!
! $Log$
! Revision 1.9  2007/01/30 16:15:13  dcs
! merged with branch_bmad_1.
!
! Revision 1.6  2003/11/10 17:01:53  dcs
! removed lat symmetry
!
! Revision 1.5  2003/09/23 18:31:28  dlr
! with carriage return, uses lattice in constraint file
!
! Revision 1.4  2003/06/18 20:43:30  helms
! Fixed bug with longitudinal position calculation and -p flag.
!
! Revision 1.3  2003/06/17 21:04:08  helms
! Fixed "-p" option.
! Changed plotdo_bmadz to effeciently calculate logitudinal positions of
! elements on the fly.
!
! Revision 1.2  2003/06/07 20:44:29  cesrulib
! conform to the lahey f95 standard
!
! Revision 1.1  2003/05/30 14:19:41  helms
! Improved line command parsing.
! Extended structures for damping lattices.
!
!........................................................................
!

subroutine get_cl_input (con_file, con)
!----------------------------------------------------------
! It works like this...
!
! You can enter nothing on the command line and bmadz will prompt you
! for a constraint file.  Then it will prompt you for a lattice file
! with the default found in the constraint file.
!
! You can enter only a constraint file and bmadz will use the lattice
! file from the constraint file automatically
!
! You can enter both a constraint and lattice file, and an optional
! third argument which will somehow control plotting

  use constraints_mod
  use sim_utils
  implicit none

  character*(*), intent(out) :: con_file
  type (constraint_struct), intent(out) :: con

  character*20, parameter :: default_con_file = 'cons_nochange.in'
  integer nargs, iargc
  character(80) arg, dummy

! setup some default stuff
  con%ele_names(1) = ' '

  nargs = command_argument_count()

! get constraint file
  if (nargs > 3) then
     print*, 'Usage: bmadz [cons_file [lattice_file [-p]]]'
     stop
  end if

  if (nargs == 0) then
     write(*,'("Enter constraint file <",A,">: ")',advance="no") &
           trim(default_con_file)
     read(*,'(A)') con_file
     if (con_file == '') con_file = default_con_file
     call read_constraints (con_file, con)
     write(*,'("Enter lattice file <",A,">: ")',advance="no") &
          trim(con%lat_file)
     read(*,'(A)') dummy
     if(dummy /= ' ')con%lat_file = dummy
     return
  end if

  if(nargs >= 1)then
     call get_command_argument(1, con_file)
     print*, "Using ", trim(con_file)
     call read_constraints (con_file, con)
! get lattice file (otherwise, use filename from constraint file
     if (nargs >= 2) then
        call get_command_argument(2, con%lat_file)
        print*, "Using ", trim(con%lat_file)
! look for '-p'
        if (nargs >=3) then
           call get_command_argument(3, arg)
           if (arg(:2) == '-p') then
              con%n_loops = 0
              con%plot = .true.
           else
              print*, "Unrecognized option: ", trim(arg)
           end if
        end if
     end if
  end if

  
end subroutine get_cl_input