!+ 
! Program bmad_to_opal
!
! Example program to make an OPAL input file from a Bmad lattice
!
! Input (command line)
!   bmad_to_opal_params namelist
!		lat_filename lat.bmad
!    
!
! Output
!   lat_opal.in
!-

program bmad_to_opal

use bmad
use beam_mod
use opal_interface_mod
use time_tracker_mod
use write_lat_file_mod

implicit none

type (lat_struct), target  :: lat
type (ele_struct), pointer :: ele(:)
character(100) in_filename
character(100) lat_filename, lat2_filename, lat_path, basename
type (beam_init_struct) beam_init
type (beam_struct) beam
type (ele_struct), pointer :: ele1
character(100) opal_filename, opal_particle_filename, time_particle_filename
character(40)	:: r_name = 'bmad_to_opal'
integer :: n_arg, n_char
integer :: nmlfile, outfile, iu, ios, i
logical :: write_time_particles, write_opal_particles, write_phasing_info
logical :: err

namelist / bmad_to_opal_params / lat_filename, lat2_filename,   &
 write_time_particles, write_opal_particles, write_phasing_info, beam_init

!------------------------------------------
!Setup

!Get units for files
nmlfile = lunget()
outfile = lunget()

!Get input file from command line						   
n_arg = command_argument_count()
if (n_arg > 1) then
  print *, 'Usage: bmad_to_opal <input_file>'
  print *, 'Default: <input_file> = bmad_to_opal.in'
  stop
endif

in_filename = 'bmad_to_opal.in' !default
if (n_arg == 1) call get_command_argument(1, in_filename)

! Defaults of input file
lat_filename = 'lat.bmad'
lat2_filename = ''
write_time_particles = .false.
write_opal_particles = .false.
write_phasing_info   = .false. 
beam_init%n_particle = 1
beam_init%n_bunch = 1


!read input file
print *, 'Opening: ', trim(in_filename)
open (nmlfile, file = in_filename, status = "old")
read (nmlfile, nml = bmad_to_opal_params)
close (nmlfile)

!Trim filename
n_char= SplitFileName(lat_filename, lat_path, basename) 

!Prepare OPAL file
call file_suffixer (basename, opal_filename, 'opal', .true.)
iu = lunget()	
open (iu, file = opal_filename, iostat = ios)
if (ios /= 0) then
	call out_io (s_error$, r_name, 'CANNOT OPEN FILE: ' // trim(opal_filename))
  	stop
endif


!Print info to screen
print *, '--------------------------------------'
write (*, '(2a)'), 'Bmad lattice:      ', lat_filename
write (*, '(2a)'), 'OPAL input file =  ', opal_filename
print *, '--------------------------------------'

!------------------------------------------
!Bmad to OPAL

!Parse Lattice
call bmad_parser (lat_filename, lat)

!Parse additional settings
if (lat2_filename /= '') then
  print *, 'Parsing: '//trim(lat2_filename)
  call bmad_parser2 (lat2_filename, lat)
endif

!Fudge
ele => lat%ele

if (write_phasing_info) then
  do i = 1, lat%n_ele_track
	write (*, '(2a, es20.7)') trim(ele(i)%name), ' entrance ref time: ', ele(i-1)%ref_time
  enddo
endif


!Finally make OPAL input file
call write_opal_lattice_file(iu, lat)

!-------------------------------------------
!Cleanup

print *, "Written: ", opal_filename

!Close file
close(iu)

! Stop if no particles are to be written
if ( (.not. write_time_particles) .and. (.not. write_opal_particles) ) then
  stop
endif

!-------------------------------------------
!Particle distribution
!Write particle file if more than one particle is defined
if (beam_init%n_particle > 1 ) then
  !set ele1 to be the init_ele
  ele1 => lat%ele(0)

  !Initialize beam
  call init_beam_distribution (ele1, lat%param, beam_init, beam)
  beam%bunch(1)%particle(:)%p0c = ele1%value(p0c_start$)
  call out_io (s_info$, r_name, 'Initialized bunch with p0c = \es13.3\', ele1%value(p0c_start$) )

  !Prepare OPAL file
  call file_suffixer (basename, opal_particle_filename, 'opal_particles', .true.)
  call file_suffixer (basename, time_particle_filename, 'time_particles', .true.)
  
  if (write_opal_particles) then
    open (iu, file = opal_particle_filename, iostat = ios)
    if (ios /= 0) then
	    call out_io (s_error$, r_name, 'CANNOT OPEN FILE: ' // trim(opal_particle_filename))
  	    stop
    endif

    !Write the first bunch only
    call write_time_particle_distribution (iu, beam%bunch(1), ele1, style = 'OPAL')
    print *, beam%bunch(1)%particle(27)%vec
    print *, "Written: ", opal_particle_filename
    close(iu)
  endif
  
  if (write_time_particles) then
    open (iu, file = time_particle_filename, iostat = ios)
    if (ios /= 0) then
	    call out_io (s_error$, r_name, 'CANNOT OPEN FILE: ' // trim(time_particle_filename))
  	    stop
    endif

    !Write the first bunch only
    call write_time_particle_distribution (iu, beam%bunch(1), ele1)
    print *, beam%bunch(1)%particle(27)%vec
    print *, "Written: ", time_particle_filename
    close(iu)
    
    ! Track to the end, write to file for reference
    print *, beam%bunch(1)%particle(27)%vec
    call track_beam (lat, beam, err=err)
    print *, beam%bunch(1)%particle(27)%vec
    call file_suffixer (basename, time_particle_filename, 'end_opal_particles', .true.)
    open (iu, file = time_particle_filename, iostat = ios)
    call write_time_particle_distribution (iu, beam%bunch(1), ele1, style = 'OPAL')
    print *, "Written: ", time_particle_filename
    close(iu)   
    
  endif

endif

	
	
end program