program import_integrals_mo
  PROVIDE mo_num
  call run
end

subroutine run
  use map_module
  implicit none
  BEGIN_DOC
! Program to import integrals in the MO basis.
!
! one-electron integrals : format is : i j value
! two-electron integrals : format is : i j k l value
!  Dirac's notation is used : <ij|kl> is <r1 r2|r1 r2>
!
! These files are read:
!
! E.qp : Contains the nuclear repulsion energy
!
! T_mo.qp : kinetic energy integrals
!
! P_mo.qp : pseudopotential integrals
!
! V_mo.qp : electron-nucleus potential
!
! H_mo.qp : core hamiltonian. If hmo exists, the other 1-e files are not read
!
! W_mo.qp : electron repulsion integrals
!
  END_DOC

  integer                        :: iunit
  integer                        :: getunitandopen

  integer                        :: i,j,k,l
  double precision               :: integral
  double precision, allocatable  :: A(:,:)

  integer                        :: n_integrals
  logical                        :: exists
  integer(key_kind), allocatable :: buffer_i(:)
  real(integral_kind), allocatable :: buffer_values(:)

  allocate(buffer_i(mo_num**3), buffer_values(mo_num**3))
  allocate (A(mo_num,mo_num))
  PROVIDE mo_integrals_map
  PROVIDE mo_integrals_threshold

  ! Nuclear repulsion

  A(1,1) = huge(1.d0)
  iunit = getunitandopen('E.qp','r')
  read (iunit,*,end=9) A(1,1)
  9 continue
  close(iunit)
  if (A(1,1) /= huge(1.d0)) then
    call ezfio_set_nuclei_nuclear_repulsion(A(1,1))
    call ezfio_set_nuclei_io_nuclear_repulsion('Read')
  endif

  ! One-electron integrals

  exists = .False.
  inquire(file='H_mo.qp',exist=exists)
  if (exists) then

    A = 0.d0
    i = 1
    j = 1
    iunit = getunitandopen('H_mo.qp','r')
    do
      read (iunit,*,end=8) i,j, integral
      if (i<0 .or. i>mo_num) then
        print *, i
        stop 'i out of bounds in H_mo.qp'
      endif
      if (j<0 .or. j>mo_num) then
        print *, j
        stop 'j out of bounds in H_mo.qp'
      endif
      A(i,j) = integral
    enddo
    8 continue
    close(iunit)
    call ezfio_set_mo_one_e_ints_mo_one_e_integrals(A)
    call ezfio_set_mo_one_e_ints_io_mo_one_e_integrals('Read')
    call ezfio_set_mo_one_e_ints_io_mo_integrals_kinetic('None')
    call ezfio_set_mo_one_e_ints_io_mo_integrals_pseudo('None')
    call ezfio_set_mo_one_e_ints_io_mo_integrals_n_e('None')

  else

    call ezfio_set_mo_one_e_ints_io_mo_one_e_integrals('None')

    A = 0.d0
    i = 1
    j = 1
    iunit = getunitandopen('T_mo.qp','r')
    do
      read (iunit,*,end=10) i,j, integral
      if (i<0 .or. i>mo_num) then
        print *, i
        stop 'i out of bounds in T_mo.qp'
      endif
      if (j<0 .or. j>mo_num) then
        print *, j
        stop 'j out of bounds in T_mo.qp'
      endif
      A(i,j) = integral
    enddo
    10 continue
    close(iunit)
    call ezfio_set_mo_one_e_ints_mo_integrals_kinetic(A)
    call ezfio_set_mo_one_e_ints_io_mo_integrals_kinetic('Read')

    A = 0.d0
    i = 1
    j = 1
    iunit = getunitandopen('P_mo.qp','r')
    do
      read (iunit,*,end=14) i,j, integral
      if (i<0 .or. i>mo_num) then
        print *, i
        stop 'i out of bounds in P_mo.qp'
      endif
      if (j<0 .or. j>mo_num) then
        print *, j
        stop 'j out of bounds in P_mo.qp'
      endif
      A(i,j) = integral
    enddo
    14 continue
    close(iunit)
    call ezfio_set_mo_one_e_ints_mo_integrals_pseudo(A)
    call ezfio_set_mo_one_e_ints_io_mo_integrals_pseudo('Read')

    A = 0.d0
    i = 1
    j = 1
    iunit = getunitandopen('V_mo.qp','r')
    do
      read (iunit,*,end=12) i,j, integral
      if (i<0 .or. i>mo_num) then
        print *, i
        stop 'i out of bounds in V_mo.qp'
      endif
      if (j<0 .or. j>mo_num) then
        print *, j
        stop 'j out of bounds in V_mo.qp'
      endif
      A(i,j) = integral
    enddo
    12 continue
    close(iunit)
    call ezfio_set_mo_one_e_ints_mo_integrals_n_e(A)
    call ezfio_set_mo_one_e_ints_io_mo_integrals_n_e('Read')

  end if


  ! Two-electron integrals

  iunit = getunitandopen('W_mo.qp','r')
  n_integrals=0
  i = 1
  j = 1
  k = 1
  l = 1
  buffer_values = 0.d0
  do
    read (iunit,*,end=13) i,j,k,l, integral
    if (i<0 .or. i>mo_num) then
       print *, i
       stop 'i out of bounds in W_mo.qp'
    endif
    if (j<0 .or. j>mo_num) then
       print *, j
       stop 'j out of bounds in W_mo.qp'
    endif
    if (k<0 .or. k>mo_num) then
       print *, k
       stop 'k out of bounds in W_mo.qp'
    endif
    if (l<0 .or. l>mo_num) then
       print *, l
       stop 'l out of bounds in W_mo.qp'
    endif
    n_integrals += 1
    call mo_two_e_integrals_index(i, j, k, l, buffer_i(n_integrals) )
    buffer_values(n_integrals) = integral
    if (n_integrals == size(buffer_i)) then
      call map_append(mo_integrals_map, buffer_i, buffer_values, n_integrals)
      n_integrals = 0
    endif
  enddo
  13 continue
  close(iunit)

  if (n_integrals > 0) then
    call map_append(mo_integrals_map, buffer_i, buffer_values, n_integrals)
  endif

  call map_sort(mo_integrals_map)
  call map_unique(mo_integrals_map)

  call map_save_to_disk(trim(ezfio_filename)//'/work/mo_ints',mo_integrals_map)
  call ezfio_set_mo_two_e_ints_io_mo_two_e_integrals('Read')

end