!
!     Shows FDF capabilities..
!
PROGRAM iochamp
  USE fdf
  USE prec
  implicit none
!--------------------------------------------------------------- Local Variables
  integer, parameter         :: maxa = 100
  logical                    :: doit, debug, check, val, logic(10)
  logical                    :: beginning, ending
  character(len=72)          :: fname, axis, status, filename, title
  character(len=72)          :: molecule_name, key, comment
  character(2)               :: symbol(maxa)
  character(len=20)          :: chunks(10), subblock(10)
  character(len=30)          :: keyword(5), argument(5)
  integer(sp)                :: i, j, ia, na, external_entry, number_of_atoms
  integer(sp)                :: isa(maxa)
  real(sp)                   :: wmix
  real(dp)                   :: cutoff, phonon_energy, factor
  real(dp)                   :: xa(3, maxa)
  real(dp)                   :: listr(maxa)
  type(block_fdf)            :: bfdf, bfdf2
  type(parsed_line), pointer :: pline, pline2
  !type(fdf_file)             :: fdffile 
  integer                    :: nextorb, nblk_max, nopt_iter, max_iteration, max_iter
  real(dp)                   :: energy_tol
  real(dp)                   :: sr_tau, sr_eps, sr_adiag 
  character(len=20)          :: real_format = '(A, T20, F8.5)'
  character(len=20)          :: int_format = '(A, T20, I8)'

!------------------------------------------------------------------------- BEGIN

! Initialize
  call fdf_init('test-champ.inp', 'test-champ.out')

! Handle/Use fdf structure
  if (fdf_defined('new-style')) write(6,*) 'New-style stuff'

! strings/characters
  fname = fdf_string('title', 'Default title')
  write(6,'(A)') 'title of the calculation :: ', fname

  molecule_name = fdf_string('molecule', 'default_filename.txt')
  write(6,'(A)') 'Name of the molecule file read from the file:', molecule_name


! Integer numbers (keyword, default_value). The variable is assigned default_value when keyword is not present
  nextorb = fdf_integer('nextorb', 0)
  write(6,fmt=int_format) 'Next Orb =', nextorb

  nblk_max = fdf_integer('nblk_max', 0)
  write(6,fmt=int_format) 'nblk max =', nblk_max

  nopt_iter = fdf_integer('nopt_iter', 0)
  write(6,fmt=int_format) 'nopt_iter =', nopt_iter


! floats (keyword, default_value) variable is assigned default_value when keyword is not present
  sr_tau = fdf_get('sr_tau', 0.025d0)
  write(6,fmt=real_format) 'sr_tau:', sr_tau

  sr_eps = fdf_get('sr_eps', 0.001d0)
  write(6,fmt=real_format) 'sr_eps:', sr_eps

  sr_adiag = fdf_get('sr_adiag', 0.01d0)
  write(6,fmt=real_format) 'sr_adiag:', sr_adiag

  energy_tol = fdf_get('energy_tol', 0.00001d0)
  write(6,fmt=real_format) 'energy_tol:', energy_tol

! logical :: true, .true., yes, T, and TRUE are equivalent
  debug = fdf_boolean('Debug', .TRUE.)
  write(6,'(A, L2)') 'Debug:', debug


! mixed types in one line (for example, reading a number with units)
  cutoff = fdf_physical('Energy_Cutoff', 8.d0, 'Ry')
  write(6,fmt=real_format) 'Energy CutOff:', cutoff, " eV"

  phonon_energy = fdf_physical('phonon-energy', 0.01d0, 'eV')
  write(6,fmt=real_format) 'Phonon Energy:', phonon_energy



! block containing other key-value pairs (currently not working)  
  if (fdf_block('optimization_flags', bfdf)) then
    write(*,*) "inside opt block"
    i = 1
    do while(fdf_bline(bfdf, pline))   
      write(*,*) "some debug info pline" , pline%ntokens, pline%line
      keyword(i) = fdf_bnames(pline, 1)
      argument(i) = fdf_bnames(pline, 2)
      i = i + 1
    enddo
  endif


  write(6,'(A,4X)') 'keywords', (keyword(i), i = 1, 4)
  write(6,'(A,4X)') 'arguments', (argument(i), i = 1, 4)

  do i = 1, 4
    write(*,*) "conversion" , fdf_boolean(argument(i), .false.)
  enddo
  
!  write(6,'(A,4X)') 'optimize_wavefunction using bline', (subblock(i), i = 1, 4)

  if (fdf_block('general', bfdf)) then
    write(*,*) "inside general block"
    i = 1
    do while(fdf_bline(bfdf, pline))    
      doit = fdf_bsearch(pline, "pool")    
      write(*,*) "pool found", doit      
      i = i + 1
    enddo
  endif

  


  doit = fdf_get("opt.optimize_wavefunction", .true.)
  write(6,*) 'outside  optimize_wavefunction', doit

  doit = fdf_get('opt.optimize_ci', .true.)
  write(6,*) 'outside  optimize_ci', doit

  doit = fdf_get('opt.optimize_jastrow', .true.)
  write(6,*) 'outside  optimize_jastrow:', doit

  doit = fdf_get('opt.optimize_orbitals', .true.)
  write(6,*) 'outside  optimize_orbitals:', doit




  max_iter = fdf_integer('max_iteration', 100)
  write(6,*) 'Examples: maximum_iter =', max_iter


  if (fdf_defined('molecule')) then
      write(6,*) "molecule block has been defined :: molecule's geometry in angstrom units"
!      molecule_name =  fdf_string('molecule', 'h2o.xyz')
!      write(6,*) 'Name of xyz file:', molecule_name
      na = 24 ! debug
      if (fdf_block('molecule', bfdf)) then
        ia = 1
        do while(fdf_bline(bfdf, pline))
!          na = fdf_bintegers(pline, 1)
!          write(*,*) na
          symbol(ia) = fdf_bnames(pline, 1)
          do i= 1, 3
            xa(i,ia) = fdf_breals(pline, i)
          enddo
          ia = ia + 1
        enddo
        na = ia - 1 
      endif
  endif
  
    write(6,*) 'Coordinates from an external file:'
    do ia = 1, 24
      write(6,'(A, 4x, 3F10.6)') symbol(ia), (xa(i,ia),i=1,3) 
    enddo
  



!  Molecule coordinate block begins here  

  if (fdf_block('Coordinates', bfdf)) then
    ia = 1
    do while(fdf_bline(bfdf, pline))
      symbol(ia) = fdf_bnames(pline, 1)
      do i= 1, 3
        xa(i,ia) = fdf_breals(pline, i)
      enddo
      ia = ia + 1
    enddo
    na = ia - 1 
  endif

  write(6,*) 'Coordinates:'
  do ia = 1, na
    write(6,'(A, 4x, 3F10.6)') symbol(ia), (xa(i,ia),i=1,3) 
  enddo

!  Molecule coordinate block ends here


  if (fdf_block('Other-Block', bfdf)) then

!   Forward reading 
    write(6,*) 'beginning of other block  '
    ia = 1
    write(*,*) "linecount", fdf_block_linecount("Other-Block")

    do while((fdf_bline(bfdf, pline)) .and. (ia .le. na))

      if (pline%ntokens == 1) then      
        number_of_atoms = fdf_bintegers(pline, 1)
        write(*,*) "number of atoms", number_of_atoms
      endif
      na = 3
      if (pline%ntokens == 4) then
        symbol(ia) = fdf_bnames(pline, 1)
        do i= 1, na
          xa(i,ia) = fdf_breals(pline, i)
        enddo
        ia = ia + 1
      endif
    enddo

    write(6,*) 'Other-Block (Forward):'
    do ia= 1, na
      write(6,'(A4,3F10.6)') symbol(ia), (xa(i,ia),i=1,3)
    enddo

!   Backward reading
    ia = 1
    do while((fdf_bbackspace(bfdf, pline)) .and. (ia .le. na))
      symbol(ia) = fdf_bnames(pline, 1)
      do i= 1, na
        xa(i,ia) = fdf_breals(pline, i)
      enddo
      ia = ia + 1
    enddo

    write(6,*) 'Other-Block (Backward):'
    do ia= 1, na
      write(6,'(A4,3F10.6)') symbol(ia), (xa(i,ia),i=1,3)
    enddo

!   Forward reading
    ia = 1
    do while((fdf_bline(bfdf, pline)) .and. (ia .le. na))
      symbol(ia) = fdf_bnames(pline, 1)
      do i= 1, na
        xa(i,ia) = fdf_breals(pline, i)
      enddo
      ia = ia + 1
    enddo

    write(6,*) 'Other-Block (Forward):'
    do ia= 1, na
      write(6,'(A4,3F10.6)') symbol(ia), (xa(i,ia),i=1,3)
    enddo

!   Forward reading with rewind
    call fdf_brewind(bfdf)
    ia = 1
    do while((fdf_bline(bfdf, pline)) .and. (ia .le. na))
      symbol(ia) = fdf_bnames(pline, 1)
      do i= 1, na
        xa(i,ia) = fdf_breals(pline, i)
      enddo
      ia = ia + 1
    enddo

    write(6,*) 'Other-Block (Forward-with-rewind):'
    do ia= 1, na
      write(6,'(A4,3F10.6)') symbol(ia), (xa(i,ia),i=1,3)
    enddo
  endif

  if ( fdf_block('ListBlock',bfdf) ) then
     i = 0
     do while ( fdf_bline(bfdf,pline) )
        i = i + 1
        na = fdf_bnlists(pline)
        write(*,'(2(a,i0),a)') 'Listblock line: ',i,' has ',na,' lists'
        do ia = 1 , na
           j = -1
           call fdf_bilists(pline,ia,j,isa)
           write(*,'(tr5,2(a,i0),a)') 'list ',ia,' has ',j,' entries'
           call fdf_bilists(pline,ia,j,isa)
           write(*,'(tr5,a,1000(tr1,i0))') 'list: ',isa(1:j)
        end do
     end do
  end if

  ! Check lists
  if ( fdf_islinteger('MyList') .and. fdf_islist('MyList') &
      .and. (.not. fdf_islreal('MyList')) ) then
     na = -1
     call fdf_list('MyList',na,isa)
     if ( na < 2 ) stop 1
     write(*,'(tr1,a,i0,a)') 'MyList has ',na,' entries'
     call fdf_list('MyList',na,isa)
     write(*,'(tr5,a,1000(tr1,i0))') 'MyList: ',isa(1:na)
   else
     write(*,*)'MyList was not recognized'
     stop 1
   end if

  if ( fdf_islinteger('MyListOne') .and. fdf_islist('MyListOne') &
      .and. (.not. fdf_islreal('MyListOne')) ) then
     na = -1
     call fdf_list('MyListOne',na,isa)
     if ( na /= 1 ) stop 1
     write(*,'(tr1,a,i0,a)') 'MyListOne has ',na,' entries'
     call fdf_list('MyListOne',na,isa)
     write(*,'(tr5,a,1000(tr1,i0))') 'MyListOne: ',isa(1:na)
  else
     write(*,*)'MyListOne was not recognized'
     stop 1
  end if

  if ( fdf_islreal('MyListR') .and. fdf_islist('MyListR') &
      .and. (.not. fdf_islinteger('MyListR')) ) then
    na = -1
    call fdf_list('MyListR',na,listr)
    write(*,'(tr1,a,i0,a)') 'MyListR has ',na,' entries'
    if ( na < 2 ) stop 1
    call fdf_list('MyListR',na,listr)
    write(*,'(tr5,a,1000(tr1,f4.1))') 'MyListR: ',listr(1:na)
  else
    write(*,*)'MyListR was not recognized'
    stop 1
  end if

  if ( fdf_islreal('MyListROne') .and. fdf_islist('MyListROne') &
      .and. (.not. fdf_islinteger('MyListROne')) ) then
    na = -1
    call fdf_list('MyListROne',na,listr)
    if ( na /= 1 ) stop 1
    write(*,'(tr1,a,i0,a)') 'MyListROne has ',na,' entries'
    call fdf_list('MyListROne',na,listr)
    write(*,'(tr5,a,1000(tr1,f4.1))') 'MyListROne: ',listr(1:na)
  else
    write(*,*)'MyListROne was not recognized'
    stop 1
  end if

  if ( fdf_islist('externalentry') ) then
     write(*,*) 'externalentry is a list'
  else
     write(*,*) 'externalentry is not a list'
  end if

  external_entry = fdf_integer('externalentry', 60)
  write(6,*) 'ExternalEntry:', external_entry

  axis   = fdf_string('AxisXY', 'Cartesian')
  status = fdf_string('StatusXY', 'Enabled')
  write(6,*) 'Axis: ', TRIM(axis), ' | ', TRIM(status)

! Shutdown and deallocates fdf structure
  call fdf_shutdown()

!----------------------------------------------------------------------------END
END PROGRAM iochamp