type t = Contracted_shell.t array

(** Returns an array of the basis set per atom *)
let of_nuclei_and_general_basis n b =
  let result = 
    Array.map (fun (e, center) ->
      List.assoc e b
      |> Array.map (fun (totAngMom, shell) ->
        let expo = Array.map (fun General_basis.{exponent ; coefficient} ->
          exponent) shell
        and coef = Array.map (fun General_basis.{exponent ; coefficient} ->
          coefficient) shell
        in
        Contracted_shell.create ~expo ~coef ~totAngMom ~center ~indice:0)
    ) n
    |> Array.to_list
    |> Array.concat
  in
  Array.iteri (fun i x ->
    if (i > 0) then
      result.(i) <- {x with Contracted_shell.indice= (
    result.(i-1).Contracted_shell.indice + (Array.length result.(i-1).Contracted_shell.powers)) }
    ) result ;
  result


let to_string b =
  let line ="
-----------------------------------------------------------------------
" in 
  "
                          Atomic Basis set
                          ----------------

-----------------------------------------------------------------------
 #   Angular   Coordinates (Bohr)       Exponents       Coefficients
    Momentum  X        Y        Z
-----------------------------------------------------------------------
"
  ^
    ( Array.map (fun i -> 
          Contracted_shell.to_string i) b
      |> Array.to_list
      |> String.concat line
    )
    ^ line

let file : string option ref = ref None

let set_file f =
  file := Some f

let general_basis = lazy(
  match !file with
  | None -> failwith "basis set file not defined"
  | Some filename -> Gamess_reader.read ~filename
)   


let basis = lazy (
  of_nuclei_and_general_basis
    (Lazy.force Nuclei.nuclei) (Lazy.force general_basis)
)