open Builtin_defs

let eval = ref (fun ppf err s -> assert false)

(* Types *)

let types =
  [ 
    "Empty",   Types.empty;
    "Any",     any;
    "Int",     int;
    "Char",    Types.char Chars.any;
    "Byte",    char_latin1;
    "Atom",    atom;
    "Pair",    Types.Product.any;
    "Arrow",   Types.Arrow.any;
    "Record",  Types.Record.any;
    "String",  string;
    "Latin1",  string_latin1;
    "Bool",    bool;
    "Float",   float;
  ]

let env =
  List.fold_left
    (fun accu (n,t) -> 
       let n = Ident.U.mk n in
       Types.Print.register_global n t;
       Typer.enter_type (Ident.ident n) t accu
    )
    Typer.empty_env
    types

(* Operators *)

open Operators

let binary_op_gen = register_binary

let unary_op_gen = register_unary


let binary_op name t1 t2 f run =
  binary_op_gen
    name
    (fun arg1 arg2 constr precise ->
       f (arg1 t1 true) (arg2 t2 true))
    run

let binary_op_cst = register_op2


let binary_op_warning2 name t1 t2 w2 t run =
  binary_op_gen name
    (fun arg1 arg2 constr precise ->
       ignore (arg1 t1 false); 
       let r = arg2 t2 true in
       if not (Types.subtype r w2) then
	 raise (Typer.Warning ("This operator may fail", t));
       t)
    run

let unary_op_warning name targ w t run =
  unary_op_gen name
    (fun arg constr precise ->
       let res = arg targ true in
       if not (Types.subtype res w) then
	 raise (Typer.Warning ("This operator may fail",t));
       t)
    run

open Ident

let exn_load_file_utf8 = 
  Value.CDuceExn (
    Value.Pair (
      Value.Atom (Atoms.V.mk_ascii "load_file_utf8"),
      Value.string_latin1 "File is not a valid UTF-8 stream"))

let exn_int_of = 
  Value.CDuceExn (
    Value.Pair (
      Value.Atom (Atoms.V.mk_ascii "Invalid_argument"),
      Value.string_latin1 "int_of"))

let exn_not_found =
  Value.CDuceExn (Value.Atom (Atoms.V.mk_ascii "Not_found"))

let eval_load_file ~utf8 e =
  Location.protect_op "load_file";
  let fn = Value.get_string_latin1 e in
  let s = match Url.process fn with 
    | Url.Filename fn ->
	let ic = open_in fn in
	let len = in_channel_length ic in
	let s = String.create len in
	really_input ic s 0 len;
	close_in ic;
	s
    | Url.Url txt ->
	txt
  in
  if utf8 then 
    match U.mk_check s with 
      | Some s -> Value.string_utf8 s 
      | None -> raise exn_load_file_utf8
  else Value.string_latin1 s


let () = ();;

(* Comparison operators *)

binary_op "=" 
  any any 
  (fun t1 t2 ->
     if Types.is_empty (Types.cap t1 t2) then false_type
     else bool)
  (fun v1 v2 ->
     Value.vbool (Value.compare v1 v2 == 0));;
  
binary_op_cst "<=" 
  any any bool
  (fun v1 v2 -> Value.vbool (Value.compare v1 v2 <= 0));;
  
binary_op_cst "<" 
  any any bool
  (fun v1 v2 -> Value.vbool (Value.compare v1 v2 < 0));;
  
binary_op_cst ">=" 
  any any bool
  (fun v1 v2 -> 
     Value.vbool (Value.compare v1 v2 >= 0));;
  
binary_op_cst ">" 
  any any bool
  (fun v1 v2 -> 
     Value.vbool (Value.compare v1 v2 > 0));;

(* I/O *)
  
register_fun "string_of" 
  any string_latin1
  (fun v -> 
     let b = Buffer.create 16 in
     let ppf = Format.formatter_of_buffer b in
     Value.print ppf v;
     Format.pp_print_flush ppf ();
     Value.string_latin1 (Buffer.contents b)
  );;

register_fun "load_xml"
  string_latin1 any
  (fun v -> Load_xml.load_xml (Value.get_string_latin1 v));;
  
register_fun "load_html"
  string_latin1 Sequence.any
  (fun v -> Load_xml.load_html  (Value.get_string_latin1 v));;

register_fun "load_file_utf8" 
  string_latin1 string 
  (eval_load_file ~utf8:true);;

register_fun "load_file" 
  string_latin1 string_latin1 
  (eval_load_file ~utf8:false);;

register_fun "getenv" string_latin1 string_latin1
  (fun e ->
     Location.protect_op "getenv";
     let var = Value.get_string_latin1 e in
     try Value.string_latin1 (Sys.getenv var)
     with Not_found -> raise exn_not_found);;

let argv = ref Value.Absent;;

register_fun "argv" nil (Sequence.star string_latin1)
  (fun e ->
     Location.protect_op "argv";
     !argv);;


register_fun "print_xml" 
  Types.any string_latin1
  (fun v -> Print_xml.print_xml ~utf8:false !Eval.ns_table v);;

register_fun "print_xml_utf8" 
  Types.any string
  (fun v -> Print_xml.print_xml ~utf8:true !Eval.ns_table v);;


register_fun "print"
  string_latin1 nil
  (fun v ->
     Location.protect_op "print";
     print_string (Value.get_string_latin1 v);
     flush stdout;
     Value.nil
  );;

register_fun "print_utf8"
  string nil
  (fun v ->
     Location.protect_op "print";
     let s = Value.cduce2ocaml_string_utf8 v in
     print_string (U.get_str s);
     flush stdout;
     Value.nil
  );;

unary_op_warning "int_of"
  string intstr int
  (fun v ->
     let (s,_) = Value.get_string_utf8 v in
     try Value.Integer (Intervals.V.mk (U.get_str s)) (* UTF-8 is ASCII compatible ! *)
     with Failure _ -> raise exn_int_of);;

register_fun "atom_of"
  string atom
  (fun v ->
     let (s,_) = Value.get_string_utf8 v in (* TODO: check that s is a correct Name wrt XML *)
     Value.Atom (Atoms.V.mk Ns.empty s));;

binary_op_warning2 "dump_to_file"
  string_latin1 string string_latin1 nil
  (fun f v ->
     Location.protect_op "dump_to_file";
     let oc = open_out (Value.get_string_latin1 f) in
     output_string oc (Value.get_string_latin1 v);
     close_out oc;
     Value.nil);;
    
binary_op_cst "dump_to_file_utf8"
  string_latin1 string nil
  (fun f v ->
     Location.protect_op "dump_to_file_utf8";
     let oc = open_out (Value.get_string_latin1 f) in
     let (v,_) = Value.get_string_utf8 v in
     output_string oc (U.get_str v);
     close_out oc;
     Value.nil);;

(* Integer operators *)

binary_op_gen "+"
  (fun arg1 arg2 constr precise ->
     let t1 = arg1 (Types.cup int Types.Record.any) true in
     if Types.subtype t1 int 
     then (
       let t2 = arg2 int true in
       Types.interval
	 (Intervals.add (Types.Int.get t1) (Types.Int.get t2))
     )
     else if Types.subtype t1 Types.Record.any 
     then (
       let t2 = arg2 Types.Record.any true in 
       Types.Record.merge t1 t2
     )
     else raise (Typer.Error "The first argument mixes integers and records"))
  (fun v1 v2 -> match (v1,v2) with
     | (Value.Integer x, Value.Integer y) -> Value.Integer (Intervals.V.add x y)
     | (Value.Record r1, Value.Record r2) -> Value.Record (LabelMap.merge (fun x y -> y) r1 r2)
     | _ -> assert false);;
      
binary_op "-"
  int int
  (fun t1 t2 ->
     Types.interval 
     (Intervals.sub (Types.Int.get t1) (Types.Int.get t2)))
  (fun v1 v2 -> match (v1,v2) with
     | (Value.Integer x, Value.Integer y) -> Value.Integer (Intervals.V.sub x y)
     | _ -> assert false);;

binary_op "*"
  int int
  (fun t1 t2 ->
     Types.interval 
     (Intervals.mul (Types.Int.get t1) (Types.Int.get t2)))
  (fun v1 v2 -> match (v1,v2) with
     | (Value.Integer x, Value.Integer y) -> Value.Integer (Intervals.V.mult x y)
     | _ -> assert false);;

binary_op_warning2 "/"
  int int non_zero_int int
  (fun v1 v2 -> match (v1,v2) with
     | (Value.Integer x, Value.Integer y) -> Value.Integer (Intervals.V.div x y)
     | _ -> assert false);;

binary_op_warning2 "mod"
  int int non_zero_int int
  (fun v1 v2 -> match (v1,v2) with
     | (Value.Integer x, Value.Integer y) -> Value.Integer (Intervals.V.modulo x y)
     | _ -> assert false);;


binary_op_gen "@"
  (fun arg1 arg2 constr precise ->
     let constr' = Sequence.star 
		     (Sequence.approx (Types.cap Sequence.any constr)) in
     let exact = Types.subtype constr' constr in
     if exact then
       let t1 = arg1 constr' precise
       and t2 = arg2 constr' precise in
       if precise then Sequence.concat t1 t2 else constr
     else
       (* Note:
	  the knownledge of t1 may makes it useless to
	  check t2 with 'precise' ... *)
       let t1 = arg1 constr' true
       and t2 = arg2 constr' true in
       Sequence.concat t1 t2)
  Value.concat;;

unary_op_gen "flatten"
  Typer.flatten
  Value.flatten;;
  

register_fun "raise" any Types.empty
  (fun v -> raise (Value.CDuceExn v));;