let basis_file : string option ref = ref None
let coord_file : string option ref = ref None
let out_file   : string option ref = ref None


let speclist = [
  ( "-b" , Arg.String (fun x -> basis_file := Some x) ,
    "File containing the atomic basis set") ;
  ( "-c" , Arg.String (fun x -> coord_file := Some x) ,
    "File containing the nuclear coordinates") ;
  ( "-o" , Arg.String (fun x -> out_file := Some x) ,
    "Output file") ;
]

let run ~coord ~basis ~out =
  let coord_file = 
    match coord with 
    | None -> raise (Invalid_argument "Coordinate file should be specified with -c")
    | Some x -> x
  and basis_file = 
    match basis with 
    | None -> raise (Invalid_argument "Basis set file should be specified with -b")
    | Some x -> x
  and out_file = 
    match out with 
    | None -> raise (Invalid_argument "Output file should be specified with -o")
    | Some x -> x
  in

  let nuclei = 
    Nuclei.of_xyz_file ~filename:coord_file
  in
  print_endline @@ Nuclei.to_string nuclei;

  let basis =
    let general_basis =
      Gamess_reader.read ~filename:basis_file
    in
    Basis.of_nuclei_and_general_basis nuclei general_basis
  in
  print_endline @@ Basis.to_string basis;

  ERI.to_file ~filename:out_file basis



let () =
  let usage_msg = "Available options:" in
  Arg.parse speclist (fun _ -> ()) usage_msg;
  try
    run ~coord:!coord_file ~basis:!basis_file ~out:!out_file
  with
  | Invalid_argument e ->
    begin
      print_string "Error: " ; print_endline e; print_newline ();
      Arg.usage speclist usage_msg
    end