(**************************************************************************)
(*                                                                        *)
(*  Heptagon                                                              *)
(*                                                                        *)
(*  Author : Marc Pouzet                                                  *)
(*  Organization : Demons, LRI, University of Paris-Sud, Orsay            *)
(*                                                                        *)
(**************************************************************************)

(* Translation from Minils to Obc. *)
open Misc
open Names
open Idents
open Signature
open Obc
open Types
open Control
open Static
open Obc_mapfold
open Initial

let fresh_it () = Idents.gen_var "mls2obc" "i"

let gen_obj_name n =
  (shortname n) ^ "_mem" ^ (gen_symbol ())

let op_from_string op = { qual = "Pervasives"; name = op; }

let rec lhs_of_idx_list e = function
  | [] -> e | idx :: l -> mk_lhs (Larray (lhs_of_idx_list e l, idx))

let array_elt_of_exp idx e =
  match e.e_desc with
    | Econst ({ se_desc = Sarray_power (c, _) }) ->
        mk_exp (Econst c)
    | _ ->
        mk_lhs_exp (Larray(lhs_of_exp e, mk_exp (Elhs idx)))

(** Creates the expression that checks that the indices
    in idx_list are in the bounds. If idx_list=[e1;..;ep]
    and bounds = [n1;..;np], it returns
    e1 <= n1 && .. && ep <= np *)
let rec bound_check_expr idx_list bounds =
  match (idx_list, bounds) with
    | [idx], [n] ->
        mk_exp (Eop (op_from_string "<",
                     [idx; mk_exp (Econst n)]))
    | (idx :: idx_list, n :: bounds) ->
        let e = mk_exp (Eop (op_from_string "<",
                             [idx; mk_exp (Econst n)])) in
          mk_exp (Eop (op_from_string "&",
                       [e; bound_check_expr idx_list bounds]))
    | (_, _) -> assert false

let reinit o =
  Acall ([], o, Mreset, [])

let rec translate_pat map = function
  | Minils.Evarpat x -> [ var_from_name map x ]
  | Minils.Etuplepat pat_list ->
      List.fold_right (fun pat acc -> (translate_pat map pat) @ acc)
        pat_list []

let translate_var_dec l =
  let one_var { Minils.v_ident = x; Minils.v_type = t; v_loc = loc } =
    mk_var_dec ~loc:loc x t
  in
  List.map one_var l

(* [translate e = c] *)
let rec translate map e =
  let desc = match e.Minils.e_desc with
    | Minils.Econst v -> Econst v
    | Minils.Evar n -> Elhs (var_from_name map n)
    | Minils.Eapp ({ Minils.a_op = Minils.Eequal }, e_list, _) ->
        Eop (op_from_string "=", List.map (translate map ) e_list)
    | Minils.Eapp ({ Minils.a_op = Minils.Efun n },
                   e_list, _) when Mls_utils.is_op n ->
        Eop (n, List.map (translate map ) e_list)
    | Minils.Ewhen (e, _, _) ->
        let e = translate map e in
          e.e_desc
    | Minils.Estruct f_e_list ->
        let type_name = (match e.Minils.e_ty with
                           | Tid name -> name
                           | _ -> assert false) in
        let f_e_list = List.map (fun (f, e) -> (f, (translate map e))) f_e_list in
          Estruct (type_name, f_e_list)
    | Minils.Eapp ({ Minils.a_op = Minils.Efield; Minils.a_params = params }, e_list, _) ->
        let f = match (assert_1 params).se_desc with Sfield f -> f | _ -> assert false in
        let e = translate map (assert_1 e_list) in
          Elhs (mk_lhs (Lfield (lhs_of_exp e, f)))
  (*Remaining array operators*)
    | Minils.Eapp ({ Minils.a_op = Minils.Earray }, e_list, _) ->
        Earray (List.map (translate map ) e_list)
    | Minils.Eapp ({ Minils.a_op = Minils.Eselect;
                     Minils.a_params = idx }, e_list, _) ->
        let e = translate map (assert_1 e_list) in
        let idx_list = List.map (fun idx -> mk_exp (Econst idx)) idx in
          Elhs (lhs_of_idx_list (lhs_of_exp e) idx_list)
    | _ ->
      Format.eprintf "%a@." Mls_printer.print_exp e;
      assert false
  in
    mk_exp ~ty:e.Minils.e_ty desc

(* [translate pat act = si, d] *)
and translate_act map pat
    ({ Minils.e_desc = desc } as act) =
    match pat, desc with
    | Minils.Etuplepat p_list,
      Minils.Eapp ({ Minils.a_op = Minils.Etuple }, act_list, _) ->
        List.flatten (List.map2 (translate_act map) p_list act_list)
    | Minils.Etuplepat p_list,
        Minils.Econst { se_desc = Stuple se_list } ->
        let const_list = Mls_utils.exp_list_of_static_exp_list se_list in
          List.flatten (List.map2 (translate_act map) p_list const_list)
    | pat, Minils.Ewhen (e, _, _) ->
        translate_act map pat e
    | pat, Minils.Emerge (x, c_act_list) ->
        let lhs = var_from_name map x in
        [Acase (mk_exp (Elhs lhs),
                translate_c_act_list map pat c_act_list)]

    | Minils.Evarpat x,
                Minils.Eapp ({ Minils.a_op = Minils.Econcat }, [e1; e2], _) ->
        let cpt1 = fresh_it () in
        let cpt2 = fresh_it () in
        let x = var_from_name map x in
        (match e1.Minils.e_ty, e2.Minils.e_ty with
           | Tarray (_, n1), Tarray (_, n2) ->
               let e1 = translate map e1 in
               let e2 = translate map e2 in
               let a1 =
                 Afor (cpt1, mk_static_int 0, n1,
                       mk_block [Aassgn (mk_lhs (Larray (x, mk_evar cpt1)),
                                         mk_lhs_exp (Larray (lhs_of_exp e1,
                                                        mk_evar cpt1)))] ) in
               let idx = mk_exp (Eop (op_from_string "+",
                                      [ mk_exp (Econst n1); mk_evar cpt2])) in
               let a2 =
                 Afor (cpt2, mk_static_int 0, n2,
                       mk_block [Aassgn (mk_lhs (Larray (x, idx)),
                                         mk_lhs_exp (Larray (lhs_of_exp e2,
                                                             mk_evar cpt2)))] )
               in
               [a1; a2]
           | _ -> assert false )

    | Minils.Evarpat x,
              Minils.Eapp ({ Minils.a_op = Minils.Earray_fill;
                             Minils.a_params = [n] }, [e], _) ->
        let cpt = fresh_it () in
        let e = translate map e in
          [ Afor (cpt, mk_static_int 0, n,
                  mk_block [Aassgn (mk_lhs (Larray (var_from_name map x,
                                                  mk_evar cpt)), e) ]) ]

    | Minils.Evarpat x,
        Minils.Eapp ({ Minils.a_op = Minils.Eselect_slice;
                       Minils.a_params = [idx1; idx2] }, [e], _) ->
        let cpt = fresh_it () in
        let e = translate map e in
        let idx = mk_exp (Eop (op_from_string "+",
                               [mk_evar cpt;
                                mk_exp (Econst idx1) ])) in
        (* bound = (idx2 - idx1) + 1*)
        let bound = mk_static_int_op (op_from_string "+")
                      [ mk_static_int 1;
                        mk_static_int_op (op_from_string "-") [idx2;idx1] ] in
         [ Afor (cpt, mk_static_int 0, bound,
                mk_block [Aassgn (mk_lhs (Larray (var_from_name map x,
                                                  mk_evar cpt)),
                      mk_lhs_exp (Larray (lhs_of_exp e, idx)))] ) ]

   | Minils.Evarpat x,
          Minils.Eapp ({ Minils.a_op = Minils.Eselect_dyn }, e1::e2::idx, _) ->
        let x = var_from_name map x in
        let bounds = Mls_utils.bounds_list e1.Minils.e_ty in
        let e1 = translate map e1 in
        let idx = List.map (translate map) idx in
        let true_act =
          Aassgn (x, mk_exp (Elhs (lhs_of_idx_list (lhs_of_exp e1) idx))) in
        let false_act = Aassgn (x, translate map e2) in
        let cond = bound_check_expr idx bounds in
          [ Acase (cond, [ ptrue, mk_block [true_act];
                                    pfalse, mk_block [false_act] ]) ]

    | Minils.Evarpat x,
            Minils.Eapp ({ Minils.a_op = Minils.Eupdate },
                         e1::e2::idx, _) ->
        let x = var_from_name map x in
        let bounds = Mls_utils.bounds_list e1.Minils.e_ty in
        let idx = List.map (translate map) idx in
        let action = Aassgn (lhs_of_idx_list x idx,
                            translate map e2) in
        let cond = bound_check_expr idx bounds in
        let action = Acase (cond, [ ptrue, mk_block [action] ]) in
        let copy = Aassgn (x, translate map e1) in
          [copy; action]

    | Minils.Evarpat x,
          Minils.Eapp ({ Minils.a_op = Minils.Efield_update;
                   Minils.a_params = [{ se_desc = Sfield f }] },
                  [e1; e2], _) ->
        let x = var_from_name map x in
        let copy = Aassgn (x, translate map e1) in
        let action = Aassgn (mk_lhs (Lfield (x, f)),
                             translate map e2) in
          [copy; action]

    | Minils.Evarpat n, _ ->
        [Aassgn (var_from_name map n, translate map act)]
    | _ ->
      Format.eprintf "%a The pattern %a should be a simple var to be translated to obc.@."
        Location.print_location act.Minils.e_loc Mls_printer.print_pat pat;
      assert false

and translate_c_act_list map pat c_act_list =
  List.map
    (fun (c, act) -> (c, mk_block (translate_act map pat act)))
    c_act_list

let mk_obj_call_from_context (o, _) n =
  match o with
    | Oobj _ -> Oobj n
    | Oarray (_, lhs) -> Oarray(n, lhs)

let size_from_call_context (_, n) = n

let empty_call_context = Oobj "n", None

(** [si] is the initialization actions used in the reset method.
    [j] obj decs
    [s] is the list of actions used in the step method.
    [v] var decs *)
let rec translate_eq map call_context { Minils.eq_lhs = pat; Minils.eq_rhs = e }
    (v, si, j, s) =
  let { Minils.e_desc = desc; Minils.e_ck = ck; Minils.e_loc = loc } = e in
  match (pat, desc) with
    | Minils.Evarpat n, Minils.Efby (opt_c, e) ->
        let x = var_from_name map n in
        let si = (match opt_c with
                    | None -> si
                    | Some c -> (Aassgn (x, mk_exp (Econst c))) :: si) in
        let action = Aassgn (var_from_name map n, translate map e) in
        v, si, j, (control map ck action) :: s

    | Minils.Etuplepat p_list,
        Minils.Eapp({ Minils.a_op = Minils.Etuple }, act_list, _) ->
        List.fold_right2
          (fun pat e ->
             translate_eq map call_context
               (Minils.mk_equation pat e))
          p_list act_list (v, si, j, s)

    | pat, Minils.Eapp({ Minils.a_op = Minils.Eifthenelse }, [e1;e2;e3], _) ->
        let cond = translate map e1 in
        let vt, si, j, true_act = translate_eq map call_context
          (Minils.mk_equation pat e2) (v, si, j, s) in
        let vf, si, j, false_act = translate_eq map call_context
          (Minils.mk_equation pat e3) (v, si, j, s) in
        let vf = translate_var_dec vf in
        let vt = translate_var_dec vt in
        let action =
          Acase (cond, [ptrue, mk_block ~locals:vt true_act;
                        pfalse, mk_block ~locals:vf false_act]) in
          v, si, j, (control map ck action) :: s

    | pat, Minils.Eapp ({ Minils.a_op = Minils.Efun _ | Minils.Enode _ } as app,
                        e_list, r) ->
        let name_list = translate_pat map pat in
        let c_list = List.map (translate map) e_list in
        let v', si', j', action = mk_node_call map call_context
          app loc name_list c_list in
        let action = List.map (control map ck) action in
        let s = (match r, app.Minils.a_op with
                   | Some r, Minils.Enode _ ->
                       let ck = Clocks.Con (ck, Initial.ptrue, r) in
                       let ra = List.map (control map ck) si' in
                       ra @ action @ s
                   | _, _ -> action @ s) in
        v' @ v, si'@si, j'@j, s

    | pat, Minils.Eiterator (it, app, n, e_list, reset) ->
        let name_list = translate_pat map pat in
        let c_list =
          List.map (translate map) e_list in
        let x = fresh_it () in
        let call_context = Oarray ("n", mk_lhs (Lvar x)), Some n in
        let si', j', action = translate_iterator map call_context it
          name_list app loc n x c_list in
        let action = List.map (control map ck) action in
        let s =
          (match reset, app.Minils.a_op with
             | Some r, Minils.Enode _ ->
                 let ck = Clocks.Con (ck, Initial.ptrue, r) in
                 let ra = List.map (control map ck) si' in
                   ra @ action @ s
             | _, _ -> action @ s)
        in (v, si' @ si, j' @ j, s)

    | (pat, _) ->
        let action = translate_act map pat e in
        let action = List.map (control map ck) action in
          v, si, j, action @ s

and translate_eq_list map call_context act_list =
  List.fold_right (translate_eq map call_context) act_list ([], [], [], [])

and mk_node_call map call_context app loc name_list args =
  match app.Minils.a_op with
    | Minils.Efun f when Mls_utils.is_op f ->
        let e = mk_exp (Eop(f, args)) in
        [], [], [], [Aassgn(List.hd name_list, e) ]

    | Minils.Enode f when Itfusion.is_anon_node f ->
        let add_input env vd =
          Env.add vd.Minils.v_ident (mk_lhs (Lvar vd.Minils.v_ident)) env in
        let build env vd a =
          Env.add vd.Minils.v_ident a env in
        let subst_act_list env act_list =
          let exp funs env e = match e.e_desc with
            | Elhs { pat_desc = Lvar x } ->
                let e =
                  (try Env.find x env
                  with Not_found -> e) in
                  e, env
            | _ -> Obc_mapfold.exp funs env e
          in
          let funs = { Obc_mapfold.defaults with exp = exp } in
          let act_list, _ = mapfold (Obc_mapfold.act_it funs) env act_list in
            act_list
        in

        let nd = Itfusion.find_anon_node f in
        let map = List.fold_left add_input map nd.Minils.n_input in
        let map = List.fold_left2 build map nd.Minils.n_output name_list in
        let map = List.fold_left add_input map nd.Minils.n_local in
        let v, si, j, s = translate_eq_list map call_context nd.Minils.n_equs in
        let env = List.fold_left2 build Env.empty nd.Minils.n_input args in
          v @ nd.Minils.n_local, si, j, subst_act_list env s

    | Minils.Enode f | Minils.Efun f ->
        let o = mk_obj_call_from_context call_context (gen_obj_name f) in
        let obj =
          { o_name = obj_ref_name o; o_class = f;
            o_params = app.Minils.a_params;
            o_size = size_from_call_context call_context; o_loc = loc } in
        let si =
          (match app.Minils.a_op with
             | Minils.Efun _ -> []
             | Minils.Enode _ -> [reinit o]
             | _ -> assert false) in
          [], si, [obj], [Acall (name_list, o, Mstep, args)]
    | _ -> assert false

and translate_iterator map call_context it name_list app loc n x c_list =
  let array_of_output name_list =
    List.map (fun l -> mk_lhs (Larray (l, mk_evar x))) name_list in
  let array_of_input c_list =
    List.map (array_elt_of_exp (mk_lhs (Lvar x))) c_list in

  match it with
    | Minils.Imap ->
        let c_list = array_of_input c_list in
        let name_list = array_of_output name_list in
        let v, si, j, action = mk_node_call map call_context
          app loc name_list c_list in
        let v = translate_var_dec v in
        let b = mk_block ~locals:v action in
          si, j, [ Afor (x, mk_static_int 0, n, b) ]

    | Minils.Imapfold ->
        let (c_list, acc_in) = split_last c_list in
        let c_list = array_of_input c_list in
        let (name_list, acc_out) = split_last name_list in
        let name_list = array_of_output name_list in
        let v, si, j, action = mk_node_call map call_context
          app loc (name_list @ [ acc_out ])
          (c_list @ [ mk_exp (Elhs acc_out) ]) in
        let v = translate_var_dec v in
        let b = mk_block ~locals:v action in
          si, j, [Aassgn (acc_out, acc_in);
                  Afor (x, mk_static_int 0, n, b)]

    | Minils.Ifold ->
        let (c_list, acc_in) = split_last c_list in
        let c_list = array_of_input c_list in
        let acc_out = last_element name_list in
        let v, si, j, action = mk_node_call map call_context
          app loc name_list (c_list @ [ mk_exp (Elhs acc_out) ]) in
        let v = translate_var_dec v in
        let b = mk_block ~locals:v action in
          si, j, [ Aassgn (acc_out, acc_in);
                   Afor (x, mk_static_int 0, n, b) ]

    | Minils.Ifoldi ->
        let (c_list, acc_in) = split_last c_list in
        let c_list = array_of_input c_list in
        let acc_out = last_element name_list in
        let v, si, j, action = mk_node_call map call_context
          app loc name_list (c_list @ [ mk_evar x; mk_exp (Elhs acc_out) ]) in
        let v = translate_var_dec v in
        let b = mk_block ~locals:v action in
          si, j, [ Aassgn (acc_out, acc_in);
                   Afor (x, mk_static_int 0, n, b) ]

let remove m d_list =
  List.filter (fun { Minils.v_ident = n } -> not (List.mem_assoc n m)) d_list

let translate_contract map mem_vars =
  function
    | None -> ([], [], [], [])
    | Some
        {
          Minils.c_eq = eq_list;
          Minils.c_local = d_list;
        } ->
        let (v, si, j, s_list) = translate_eq_list map
          empty_call_context eq_list in
        let d_list = translate_var_dec (v @ d_list) in
        let d_list = List.filter
          (fun vd -> not (List.mem vd.v_ident mem_vars)) d_list in
         (si, j, s_list, d_list)

(** Returns a map, mapping variables names to the variables
    where they will be stored. *)
let subst_map inputs outputs locals mems =
  (* Create a map that simply maps each var to itself *)
  let m =
    List.fold_left
      (fun m { Minils.v_ident = x } -> Env.add x (mk_lhs (Lvar x)) m)
      Env.empty (inputs @ outputs @ locals)
  in
  List.fold_left (fun m x -> Env.add x (mk_lhs (Lmem x)) m) m mems

let translate_node
    ({
      Minils.n_name = f;
      Minils.n_input = i_list;
      Minils.n_output = o_list;
      Minils.n_local = d_list;
      Minils.n_equs = eq_list;
      Minils.n_contract = contract;
      Minils.n_params = params;
      Minils.n_loc = loc;
    } as n) =
  let mem_vars = Mls_utils.node_memory_vars n in
  let subst_map = subst_map i_list o_list d_list mem_vars in
  let (v, si, j, s_list) = translate_eq_list subst_map
    empty_call_context eq_list in
  let (si', j', s_list', d_list') =
    translate_contract subst_map mem_vars contract in
  let i_list = translate_var_dec i_list in
  let o_list = translate_var_dec o_list in
  let d_list = translate_var_dec (v @ d_list) in
  let m, d_list = List.partition
    (fun vd -> List.mem vd.v_ident mem_vars) d_list in
  let s = joinlist (s_list @ s_list') in
  let j = j' @ j in
  let si = joinlist (si @ si') in
  let stepm = {
    m_name = Mstep; m_inputs = i_list; m_outputs = o_list;
    m_body = mk_block ~locals:(d_list' @ d_list) s } in
  let resetm = {
    m_name = Mreset; m_inputs = []; m_outputs = [];
    m_body = mk_block si } in
    { cd_name = f; cd_mems = m; cd_params = params;
      cd_objs = j; cd_methods = [stepm; resetm];
      cd_loc = loc }

let translate_ty_def { Minils.t_name = name; Minils.t_desc = tdesc;
                       Minils.t_loc = loc } =
  let tdesc = match tdesc with
    | Minils.Type_abs -> Type_abs
    | Minils.Type_alias ln -> Type_alias ln
    | Minils.Type_enum tag_name_list -> Type_enum tag_name_list
    | Minils.Type_struct field_ty_list ->
        Type_struct field_ty_list in
  { t_name = name; t_desc = tdesc; t_loc = loc }

let translate_const_def { Minils.c_name = name; Minils.c_value = se;
                          Minils.c_type = ty; Minils.c_loc = loc } =
  { c_name = name;
    c_value = se;
    c_type = ty;
    c_loc = loc }

let program {
  Minils.p_modname = p_modname;
  Minils.p_opened = p_module_list;
  Minils.p_types = p_type_list;
  Minils.p_nodes = p_node_list;
  Minils.p_consts = p_const_list
} =
    {
      p_modname = p_modname;
      p_opened = p_module_list;
      p_types = List.map translate_ty_def p_type_list;
      p_consts = List.map translate_const_def p_const_list;
      p_defs = List.map translate_node p_node_list;
    }