open Qputils;;
open Qptypes;;
open Core.Std;;

let spec =
  let open Command.Spec in
  empty 
  +> flag "o" (optional string)
     ~doc:"file Name of the created EZFIO file."
  +> flag "b" (required string)
     ~doc:"string Name of basis set."
  +> flag "c" (optional_with_default 0 int)
     ~doc:"int Total charge of the molecule. Default is 0."
  +> flag "d" (optional_with_default 0. float)
     ~doc:"float Add dummy atoms. x * (covalent radii of the atoms)"
  +> flag "m" (optional_with_default 1 int)
     ~doc:"int Spin multiplicity (2S+1) of the molecule. Default is 1."
  +> flag "p" no_arg
     ~doc:" Using pseudopotentials"
  +> anon ("xyz_file" %: file )


let dummy_centers ~threshold ~molecule ~nuclei =
  let d =
    Molecule.distance_matrix molecule
  in
  let n =
    Array.length d
  in
  let nuclei =
    Array.of_list nuclei
  in
  let rec aux accu = function
  | (-1,_) -> accu
  | (i,-1) -> aux accu (i-1,i-1)
  | (i,j) when (i>j) ->
    let new_accu = 
      let x,y =
          Element.covalent_radius (nuclei.(i)).Atom.element |> Positive_float.to_float, 
          Element.covalent_radius (nuclei.(j)).Atom.element |> Positive_float.to_float
      in 
      let r =
        ( x +. y ) *. threshold
      in
      if d.(i).(j) < r then
        (i,x,j,y,d.(i).(j)) :: accu
      else
        accu
    in aux new_accu (i,j-1)
  | (i,j) when (i=j) -> aux accu (i,j-1)
  | _ -> assert false
  in
  aux [] (n-1,n-1)
  |> List.map ~f:(fun (i,x,j,y,r) ->
    let f = 
      x /. (x +. y)
    in
    let u = 
      Point3d.of_tuple ~units:Units.Bohr
      ( nuclei.(i).Atom.coord.Point3d.x +. 
          (nuclei.(j).Atom.coord.Point3d.x -. nuclei.(i).Atom.coord.Point3d.x) *. f, 
        nuclei.(i).Atom.coord.Point3d.y +. 
          (nuclei.(j).Atom.coord.Point3d.y -. nuclei.(i).Atom.coord.Point3d.y) *. f, 
        nuclei.(i).Atom.coord.Point3d.z +. 
          (nuclei.(j).Atom.coord.Point3d.z -. nuclei.(i).Atom.coord.Point3d.z) *. f) 
    in
    Atom.{ element = Element.X ; charge = Charge.of_int 0 ; coord = u }
    )
     
    
let list_basis () =
  let basis_list = 
    Qpackage.root ^ "/install/emsl/EMSL_api.py list_basis" 
    |> Unix.open_process_in 
    |> In_channel.input_lines
    |> List.map ~f:(fun x -> 
       match String.split x ~on:'\'' with
       | [] -> ""
       | a :: [] 
       | _ :: a :: _ -> String.strip a
      )
  in 
  List.sort basis_list ~cmp:String.ascending
  |> String.concat ~sep:"\t" 


let run ?o b c d m p xyz_file =

  (* Read molecule *)
  let molecule =
    (Molecule.of_xyz_file xyz_file ~charge:(Charge.of_int c)
      ~multiplicity:(Multiplicity.of_int m) )
  in
  let dummy =
    dummy_centers ~threshold:d ~molecule ~nuclei:molecule.Molecule.nuclei
  in
(*
  List.iter dummy ~f:(fun x ->
    Printf.printf "%s\n" (Atom.to_string ~units:Units.Angstrom x)
  );
*)
  let nuclei =
    molecule.Molecule.nuclei @ dummy
  in


  let basis_table =
     Hashtbl.Poly.create ()
  in

  (* Open basis set channels *)
  let basis_channel element =
    let key =
      Element.to_string element
    in
    match Hashtbl.find basis_table key with
    | Some in_channel -> 
        in_channel
    | None -> 
         let msg = 
           Printf.sprintf "%s is not defined in basis %s.%!"
           (Element.to_long_string element) b ;
         in
         failwith msg
  in
  
  let temp_filename =
    Filename.temp_file "qp_create_" ".basis"
  in
  let () = 
    Sys.remove temp_filename
  in

  let fetch_channel basis =
    let command =
        Qpackage.root ^ "/scripts/get_basis.sh \"" ^ temp_filename 
          ^ "." ^ basis ^ "\" \"" ^ basis ^"\""
    in
    match Sys.is_file basis with
    | `Yes -> 
          In_channel.create basis
    | _ -> 
      begin
        let filename = 
          Unix.open_process_in command
          |> In_channel.input_all
          |> String.strip
        in
        let new_channel =
          In_channel.create filename
        in
        Unix.unlink filename;
        new_channel
      end
  in

  let rec build_basis = function
  | [] -> ()
  | elem_and_basis_name :: rest -> 
    begin
      match (String.lsplit2 ~on:':' elem_and_basis_name) with
      | None -> (* Principal basis *)
        begin
          let basis = 
            elem_and_basis_name 
          in
          let new_channel =
            fetch_channel basis
          in
          List.iter nuclei ~f:(fun elem->
            let key = 
              Element.to_string elem.Atom.element
            in
            match Hashtbl.add basis_table ~key:key ~data:new_channel with
            | `Ok -> ()
            | `Duplicate -> ()
          )
        end
      | Some (key, basis) -> (*Aux basis *)
        begin
          let elem  = 
            Element.of_string key
          and basis =
            String.lowercase basis
          in
          let key = 
             Element.to_string elem
          in
          let new_channel =
            fetch_channel basis
          in
          begin
            match Hashtbl.add basis_table ~key:key ~data:new_channel with
            | `Ok -> ()
            | `Duplicate -> failwith ("Duplicate definition of basis for "^(Element.to_long_string elem))
          end
       end
    end;
    build_basis rest
  in
  String.split ~on:'|' b
  |> List.rev_map ~f:String.strip 
  |> build_basis;

  (* Build EZFIO File name *)
  let ezfio_file =
    match o with
    | Some x -> x
    | None ->
      begin
        match String.rsplit2 ~on:'.' xyz_file with
        | Some (x,"xyz") -> x^".ezfio"
        | _ -> xyz_file^".ezfio"
      end
  in
  if Sys.file_exists_exn ezfio_file then
    failwith (ezfio_file^" already exists");

  (* Create EZFIO *)
  Ezfio.set_file ezfio_file;

  (* Write Electrons *)
  Ezfio.set_electrons_elec_alpha_num ( Elec_alpha_number.to_int
    molecule.Molecule.elec_alpha ) ;
  Ezfio.set_electrons_elec_beta_num  ( Elec_beta_number.to_int
    molecule.Molecule.elec_beta  ) ;

  (* Write Nuclei *)
  let labels =
     List.map ~f:(fun x->Element.to_string x.Atom.element) nuclei
  and charges = 
     List.map ~f:(fun x-> Atom.(Charge.to_float x.charge)) nuclei 
  and coords  = 
    (List.map ~f:(fun x-> x.Atom.coord.Point3d.x) nuclei) @
    (List.map ~f:(fun x-> x.Atom.coord.Point3d.y) nuclei) @
    (List.map ~f:(fun x-> x.Atom.coord.Point3d.z) nuclei) in
  let nucl_num = (List.length labels) in
  Ezfio.set_nuclei_nucl_num nucl_num ;
  Ezfio.set_nuclei_nucl_label (Ezfio.ezfio_array_of_list 
    ~rank:1 ~dim:[| nucl_num |] ~data:labels);
  Ezfio.set_nuclei_nucl_charge (Ezfio.ezfio_array_of_list 
    ~rank:1 ~dim:[| nucl_num |] ~data:charges);
  Ezfio.set_nuclei_nucl_coord  (Ezfio.ezfio_array_of_list 
    ~rank:2 ~dim:[| nucl_num ; 3 |] ~data:coords);

  (* Write Basis set *)
  let basis =

    let nmax =
       Nucl_number.get_max ()
    in
    let rec do_work (accu:(Atom.t*Nucl_number.t) list) (n:int) = function
    | [] -> accu
    | e::tail ->
      let new_accu =
        (e,(Nucl_number.of_int ~max:nmax n))::accu
      in
      do_work new_accu (n+1) tail
    in
    let result = do_work [] 1  nuclei
    |> List.rev
    |> List.map ~f:(fun (x,i) ->
       try 
         let e =
           match x.Atom.element with
           | Element.X -> Element.H
           | e -> e
         in
         Basis.read_element (basis_channel x.Atom.element) i e
       with
       | End_of_file -> failwith
             ("Element "^(Element.to_string x.Atom.element)^" not found in basis set.")
       ) 
    |> List.concat
    in
    (* close all in_channels *)
    result
  in
  let long_basis = Long_basis.of_basis basis in
  let ao_num = List.length long_basis in
  Ezfio.set_ao_basis_ao_num ao_num;
  Ezfio.set_ao_basis_ao_basis b;
  let ao_prim_num = List.map long_basis ~f:(fun (_,g,_) -> List.length g.Gto.lc) 
  and ao_nucl = List.map long_basis ~f:(fun (_,_,n) -> Nucl_number.to_int n)
  and ao_power= 
    let l = List.map long_basis ~f:(fun (x,_,_) -> x) in
    (List.map l ~f:(fun t -> Positive_int.to_int Symmetry.Xyz.(t.x)) )@
    (List.map l ~f:(fun t -> Positive_int.to_int Symmetry.Xyz.(t.y)) )@
    (List.map l ~f:(fun t -> Positive_int.to_int Symmetry.Xyz.(t.z)) ) 
  in
  let ao_prim_num_max = List.fold ~init:0 ~f:(fun s x ->
    if x > s then x
    else s) ao_prim_num
  in
  let gtos = List.map long_basis ~f:(fun (_,x,_) -> x) in

  let create_expo_coef ec = 
      let coefs = 
        begin match ec with
        | `Coefs -> List.map gtos ~f:(fun x->
          List.map x.Gto.lc ~f:(fun (_,coef) -> AO_coef.to_float coef) )
        | `Expos -> List.map gtos ~f:(fun x->
          List.map x.Gto.lc ~f:(fun (prim,_) -> AO_expo.to_float
          prim.Primitive.expo) )
        end
      in
      let rec get_n n accu = function
        | [] -> List.rev accu  
        | h::tail ->
            let y =
            begin match List.nth h n with
            | Some x -> x
            | None -> 0.
            end
            in 
            get_n n (y::accu) tail
      in
      let rec build accu = function
        | n when n=ao_prim_num_max -> accu
        | n -> build ( accu @ (get_n n [] coefs) ) (n+1)
      in
      build [] 0
  in

  let ao_coef = create_expo_coef `Coefs
  and ao_expo = create_expo_coef `Expos
  in
  Ezfio.set_ao_basis_ao_prim_num (Ezfio.ezfio_array_of_list
    ~rank:1 ~dim:[| ao_num |] ~data:ao_prim_num) ;
  Ezfio.set_ao_basis_ao_nucl(Ezfio.ezfio_array_of_list
    ~rank:1 ~dim:[| ao_num |] ~data:ao_nucl) ;
  Ezfio.set_ao_basis_ao_power(Ezfio.ezfio_array_of_list
  ~rank:2 ~dim:[| ao_num ; 3 |] ~data:ao_power) ;
  Ezfio.set_ao_basis_ao_coef(Ezfio.ezfio_array_of_list
  ~rank:2 ~dim:[| ao_num ; ao_prim_num_max |] ~data:ao_coef) ;
  Ezfio.set_ao_basis_ao_expo(Ezfio.ezfio_array_of_list
  ~rank:2 ~dim:[| ao_num ; ao_prim_num_max |] ~data:ao_expo) ;


  (* Doesn't work... *)
  if (p) then 
    begin
      Qpackage.root ^ "/scripts/pseudo/put_pseudo_in_ezfio.py " ^ ezfio_file ^ " " ^ " BFD-Pseudo"
      |> Sys.command_exn
    end;

  match Input.Ao_basis.read () with
  | None -> failwith "Error in basis"
  | Some x -> Input.Ao_basis.write x
 


let command = 
    Command.basic 
    ~summary: "Quantum Package command"
    ~readme:(fun () -> "

=== Available basis sets ===

" ^ (list_basis ()) ^ "

============================

Creates an EZFIO directory from a standard xyz file.  The basis set is defined
as a single string if all the atoms are taken from the same basis set,
otherwise specific elements can be defined as follows:

 -b \"cc-pcvdz | H:cc-pvdz | C:6-31g\"

If a file with the same name as the basis set exists, this file will be read.
Otherwise, the basis set is obtained from the database.

" )
    spec
    (fun o b c d m p xyz_file () ->
       run ?o b c d m p xyz_file )


let () =
    Command.run command