type t = 
{
  n_alfa       : int ;
  n_beta       : int ;
  mo_class     : MOClass.t ;
  mo_basis     : MOBasis.t ;
  determinants : Determinant.t array;
}

module Ss = Spindeterminant_space

let n_alfa t = t.n_alfa
let n_beta t = t.n_beta
let mo_class t = t.mo_class
let mo_basis t = t.mo_basis
let determinants t = t.determinants
let size     t = Array.length t.determinants

let fci_of_mo_basis ?(frozen_core=true) mo_basis =
  let s = MOBasis.simulation mo_basis in
  let e = Simulation.electrons s in
  let n_alfa = Electrons.n_alfa e 
  and n_beta = Electrons.n_beta e in
  let det_a =
    Ss.fci_of_mo_basis ~frozen_core mo_basis n_alfa
  and det_b =
    Ss.fci_of_mo_basis ~frozen_core mo_basis n_beta
  in
  let mo_class = Ss.mo_class det_a in
  let determinants =
    let a = Ss.spin_determinants det_a
    and b = Ss.spin_determinants det_b
    in
    let sb = Ss.size det_b in
    Array.to_list a
    |> List.map (fun a_i ->
        Array.init sb (fun j ->
            Determinant.of_spindeterminants a_i b.(j)) )
    |> Array.concat
  in
  { n_alfa ; n_beta ; mo_class ; mo_basis ; determinants }


let pp_det_space ppf t =
  Format.fprintf ppf "@[<v 2>[ ";
  Array.iteri (fun i d -> Format.fprintf ppf "@[<v>@[%8d@]@;@[%a@]@]@;" i
                    (Determinant.pp_det (MOBasis.size (mo_basis t))) d) t.determinants ;
  Format.fprintf ppf "]@]"