(*
 * Copyright (C)2005-2013 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *)

open Common
open Type

type with_type =
	| NoValue
	| Value
	| WithType of t
	| WithTypeResume of t

type type_patch = {
	mutable tp_type : Ast.complex_type option;
	mutable tp_remove : bool;
	mutable tp_meta : Ast.metadata;
}

type current_fun =
	| FunMember
	| FunStatic
	| FunConstructor
	| FunMemberAbstract
	| FunMemberClassLocal
	| FunMemberAbstractLocal

type macro_mode =
	| MExpr
	| MBuild
	| MMacroType


type typer_pass =
	| PBuildModule			(* build the module structure and setup module type parameters *)
	| PBuildClass			(* build the class structure *)
	| PTypeField			(* type the class field, allow access to types structures *)
	| PCheckConstraint		(* perform late constraint checks with inferred types *)
	| PForce				(* usually ensure that lazy have been evaluated *)
	| PFinal				(* not used, only mark for finalize *)

type typer_globals = {
	types_module : (path, path) Hashtbl.t;
	modules : (path , module_def) Hashtbl.t;
	mutable delayed : (typer_pass * (unit -> unit) list) list;
	mutable debug_delayed : (typer_pass * ((unit -> unit) * string * typer) list) list;
	doinline : bool;
	mutable core_api : typer option;
	mutable macros : ((unit -> unit) * typer) option;
	mutable std : module_def;
	mutable hook_generate : (unit -> unit) list;
	type_patches : (path, (string * bool, type_patch) Hashtbl.t * type_patch) Hashtbl.t;
	mutable global_metadata : (string list * Ast.metadata_entry * (bool * bool * bool)) list;
	mutable get_build_infos : unit -> (module_type * t list * Ast.class_field list) option;
	delayed_macros : (unit -> unit) DynArray.t;
	mutable global_using : tclass list;
	(* api *)
	do_inherit : typer -> Type.tclass -> Ast.pos -> Ast.class_flag -> bool;
	do_create : Common.context -> typer;
	do_macro : typer -> macro_mode -> path -> string -> Ast.expr list -> Ast.pos -> Ast.expr option;
	do_load_module : typer -> path -> pos -> module_def;
	do_optimize : typer -> texpr -> texpr;
	do_build_instance : typer -> module_type -> pos -> ((string * t) list * path * (t list -> t));
}

and typer_module = {
	curmod : module_def;
	mutable module_types : module_type list;
	mutable module_using : tclass list;
	mutable module_globals : (string, (module_type * string)) PMap.t;
	mutable wildcard_packages : string list list;
}

and typer = {
	(* shared *)
	com : context;
	t : basic_types;
	g : typer_globals;
	mutable meta : metadata;
	mutable this_stack : texpr list;
	mutable with_type_stack : with_type list;
	mutable call_argument_stack : Ast.expr list list;
	(* variable *)
	mutable pass : typer_pass;
	(* per-module *)
	mutable m : typer_module;
	(* per-class *)
	mutable curclass : tclass;
	mutable tthis : t;
	mutable type_params : (string * t) list;
	(* per-function *)
	mutable curfield : tclass_field;
	mutable untyped : bool;
	mutable in_super_call : bool;
	mutable in_loop : bool;
	mutable in_display : bool;
	mutable in_macro : bool;
	mutable macro_depth : int;
	mutable curfun : current_fun;
	mutable ret : t;
	mutable locals : (string, tvar) PMap.t;
	mutable opened : anon_status ref list;
	mutable vthis : tvar option;
	(* events *)
	mutable on_error : typer -> string -> pos -> unit;
}

type call_error =
	| Not_enough_arguments
	| Too_many_arguments
	| Could_not_unify of error_msg
	| Cannot_skip_non_nullable of string

and error_msg =
	| Module_not_found of path
	| Type_not_found of path * string
	| Unify of unify_error list
	| Custom of string
	| Unknown_ident of string
	| Stack of error_msg * error_msg
	| Call_error of call_error

exception Fatal_error of string * Ast.pos

exception Forbid_package of (string * path * pos) * pos list * string

exception Error of error_msg * pos

exception DisplayTypes of t list

exception DisplayPosition of Ast.pos list

let make_call_ref : (typer -> texpr -> texpr list -> t -> pos -> texpr) ref = ref (fun _ _ _ _ _ -> assert false)
let type_expr_ref : (typer -> Ast.expr -> with_type -> texpr) ref = ref (fun _ _ _ -> assert false)
let type_module_type_ref : (typer -> module_type -> t list option -> pos -> texpr) ref = ref (fun _ _ _ _ -> assert false)
let unify_min_ref : (typer -> texpr list -> t) ref = ref (fun _ _ -> assert false)
let match_expr_ref : (typer -> Ast.expr -> (Ast.expr list * Ast.expr option * Ast.expr option) list -> Ast.expr option option -> with_type -> Ast.pos -> decision_tree) ref = ref (fun _ _ _ _ _ _ -> assert false)
let get_pattern_locals_ref : (typer -> Ast.expr -> Type.t -> (string, tvar * pos) PMap.t) ref = ref (fun _ _ _ -> assert false)
let get_constructor_ref : (typer -> tclass -> t list -> Ast.pos -> (t * tclass_field)) ref = ref (fun _ _ _ _ -> assert false)
let cast_or_unify_ref : (typer -> t -> texpr -> Ast.pos -> texpr) ref = ref (fun _ _ _ _ -> assert false)
let find_array_access_raise_ref : (typer -> tabstract -> tparams -> texpr -> texpr option -> pos -> (tclass_field * t * t * texpr * texpr option)) ref = ref (fun _ _ _ _ _ _ -> assert false)

(* Source: http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Levenshtein_distance#OCaml *)
let levenshtein a b =
	let x = Array.init (String.length a) (fun i -> a.[i]) in
	let y = Array.init (String.length b) (fun i -> b.[i]) in
	let minimum (x:int) y z =
		let m' (a:int) b = if a < b then a else b in
		m' (m' x y) z
	in
	let init_matrix n m =
		let init_col = Array.init m in
			Array.init n (function
			| 0 -> init_col (function j -> j)
			| i -> init_col (function 0 -> i | _ -> 0)
		)
	in
	match Array.length x, Array.length y with
		| 0, n -> n
		| m, 0 -> m
		| m, n ->
			let matrix = init_matrix (m + 1) (n + 1) in
			for i = 1 to m do
				let s = matrix.(i) and t = matrix.(i - 1) in
				for j = 1 to n do
					let cost = abs (compare x.(i - 1) y.(j - 1)) in
					s.(j) <- minimum (t.(j) + 1) (s.(j - 1) + 1) (t.(j - 1) + cost)
				done
			done;
			matrix.(m).(n)

let string_error_raise s sl msg =
	if sl = [] then msg else
	let cl = List.map (fun s2 -> s2,levenshtein s s2) sl in
	let cl = List.sort (fun (_,c1) (_,c2) -> compare c1 c2) cl in
	let rec loop sl = match sl with
		| (s2,i) :: sl when i <= (min (String.length s) (String.length s2)) / 3 -> s2 :: loop sl
		| _ -> []
	in
	match loop cl with
		| [] -> raise Not_found
		| [s] -> Printf.sprintf "%s (Suggestion: %s)" msg s
		| sl -> Printf.sprintf "%s (Suggestions: %s)" msg (String.concat ", " sl)

let string_error s sl msg =
	try string_error_raise s sl msg
	with Not_found -> msg

let string_source t = match follow t with
	| TInst(c,_) -> List.map (fun cf -> cf.cf_name) c.cl_ordered_fields
	| TAnon a -> PMap.fold (fun cf acc -> cf.cf_name :: acc) a.a_fields []
	| TAbstract({a_impl = Some c},_) -> List.map (fun cf -> cf.cf_name) c.cl_ordered_statics
	| _ -> []

let short_type ctx t =
	let tstr = s_type ctx t in
	if String.length tstr > 150 then String.sub tstr 0 147 ^ "..." else tstr

let unify_error_msg ctx = function
	| Cannot_unify (t1,t2) ->
		s_type ctx t1 ^ " should be " ^ s_type ctx t2
	| Invalid_field_type s ->
		"Invalid type for field " ^ s ^ " :"
	| Has_no_field (t,n) ->
		string_error n (string_source t) (short_type ctx t ^ " has no field " ^ n)
	| Has_no_runtime_field (t,n) ->
		s_type ctx t ^ "." ^ n ^ " is not accessible at runtime"
	| Has_extra_field (t,n) ->
		short_type ctx t ^ " has extra field " ^ n
	| Invalid_kind (f,a,b) ->
		(match a, b with
		| Var va, Var vb ->
			let name, stra, strb = if va.v_read = vb.v_read then
				"setter", s_access false va.v_write, s_access false vb.v_write
			else if va.v_write = vb.v_write then
				"getter", s_access true va.v_read, s_access true vb.v_read
			else
				"access", "(" ^ s_access true va.v_read ^ "," ^ s_access false va.v_write ^ ")", "(" ^ s_access true vb.v_read ^ "," ^ s_access false vb.v_write ^ ")"
			in
			"Inconsistent " ^ name ^ " for field " ^ f ^ " : " ^ stra ^ " should be " ^ strb
		| _ ->
			"Field " ^ f ^ " is " ^ s_kind a ^ " but should be " ^ s_kind b)
	| Invalid_visibility n ->
		"The field " ^ n ^ " is not public"
	| Not_matching_optional n ->
		"Optional attribute of parameter " ^ n ^ " differs"
	| Cant_force_optional ->
		"Optional parameters can't be forced"
	| Invariant_parameter _ ->
		"Type parameters are invariant"
	| Constraint_failure name ->
		"Constraint check failure for " ^ name
	| Missing_overload (cf, t) ->
		cf.cf_name ^ " has no overload for " ^ s_type ctx t
	| Unify_custom msg ->
		msg

let rec error_msg = function
	| Module_not_found m -> "Class not found : " ^ Ast.s_type_path m
	| Type_not_found (m,t) -> "Module " ^ Ast.s_type_path m ^ " does not define type " ^ t
	| Unify l ->
		let ctx = print_context() in
		String.concat "\n" (List.map (unify_error_msg ctx) l)
	| Unknown_ident s -> "Unknown identifier : " ^ s
	| Custom s -> s
	| Stack (m1,m2) -> error_msg m1 ^ "\n" ^ error_msg m2
	| Call_error err -> s_call_error err

and s_call_error = function
	| Not_enough_arguments -> "Not enough arguments"
	| Too_many_arguments -> "Too many arguments"
	| Could_not_unify err -> error_msg err
	| Cannot_skip_non_nullable s -> "Cannot skip non-nullable argument " ^ s

let pass_name = function
	| PBuildModule -> "build-module"
	| PBuildClass -> "build-class"
	| PTypeField -> "type-field"
	| PCheckConstraint -> "check-constraint"
	| PForce -> "force"
	| PFinal -> "final"

let display_error ctx msg p = ctx.on_error ctx msg p

let error msg p = raise (Error (Custom msg,p))

let make_call ctx e el t p = (!make_call_ref) ctx e el t p

let type_expr ctx e with_type = (!type_expr_ref) ctx e with_type

let unify_min ctx el = (!unify_min_ref) ctx el

let match_expr ctx e cases def with_type p = !match_expr_ref ctx e cases def with_type p

let make_static_call ctx c cf map args t p =
	let ta = TAnon { a_fields = c.cl_statics; a_status = ref (Statics c) } in
	let ethis = mk (TTypeExpr (TClassDecl c)) ta p in
	let monos = List.map (fun _ -> mk_mono()) cf.cf_params in
	let map t = map (apply_params cf.cf_params monos t) in
	let ef = mk (TField (ethis,(FStatic (c,cf)))) (map cf.cf_type) p in
	make_call ctx ef args (map t) p

let unify ctx t1 t2 p =
	try
		Type.unify t1 t2
	with
		Unify_error l ->
			if not ctx.untyped then display_error ctx (error_msg (Unify l)) p

let unify_raise ctx t1 t2 p =
	try
		Type.unify t1 t2
	with
		Unify_error l ->
			(* no untyped check *)
			raise (Error (Unify l,p))

let save_locals ctx =
	let locals = ctx.locals in
	(fun() -> ctx.locals <- locals)

let add_local ctx n t =
	let v = alloc_var n t in
	ctx.locals <- PMap.add n v ctx.locals;
	v

let gen_local_prefix = "`"

let gen_local ctx t =
	(* ensure that our generated local does not mask an existing one *)
	let rec loop n =
		let nv = (if n = 0 then gen_local_prefix else gen_local_prefix ^ string_of_int n) in
		if PMap.mem nv ctx.locals then
			loop (n+1)
		else
			nv
	in
	add_local ctx (loop 0) t

let is_gen_local v =
	String.unsafe_get v.v_name 0 = String.unsafe_get gen_local_prefix 0

let not_opened = ref Closed
let mk_anon fl = TAnon { a_fields = fl; a_status = not_opened; }

let delay ctx p f =
	let rec loop = function
		| [] -> [p,[f]]
		| (p2,l) :: rest ->
			if p2 = p then
				(p, f :: l) :: rest
			else if p2 < p then
				(p2,l) :: loop rest
			else
				(p,[f]) :: (p2,l) :: rest
	in
	ctx.g.delayed <- loop ctx.g.delayed

let rec flush_pass ctx p (where:string) =
	match ctx.g.delayed with
	| (p2,l) :: rest when p2 <= p ->
		(match l with
		| [] ->
			ctx.g.delayed <- rest;
		| f :: l ->
			ctx.g.delayed <- (p2,l) :: rest;
			f());
		flush_pass ctx p where
	| _ ->
		()

let make_pass ctx f = f

let init_class_done ctx =
	ctx.pass <- PTypeField

let exc_protect ctx f (where:string) =
	let rec r = ref (fun() ->
		try
			f r
		with
			| Error (m,p) ->
				raise (Fatal_error ((error_msg m),p))
	) in
	r

let fake_modules = Hashtbl.create 0
let create_fake_module ctx file =
	let file = Common.unique_full_path file in
	let mdep = (try Hashtbl.find fake_modules file with Not_found ->
		let mdep = {
			m_id = alloc_mid();
			m_path = (["$DEP"],file);
			m_types = [];
			m_extra = module_extra file (Common.get_signature ctx.com) (file_time file) MFake;
		} in
		Hashtbl.add fake_modules file mdep;
		mdep
	) in
	Hashtbl.replace ctx.g.modules mdep.m_path mdep;
	mdep

(* -------------- debug functions to activate when debugging typer passes ------------------------------- *)
(*/*

let delay_tabs = ref ""

let context_ident ctx =
	if Common.defined ctx.com Common.Define.CoreApi then
		" core "
	else if Common.defined ctx.com Common.Define.Macro then
		"macro "
	else
		"  out "

let debug ctx str =
	if Common.raw_defined ctx.com "cdebug" then prerr_endline (context_ident ctx ^ !delay_tabs ^ str)

let init_class_done ctx =
	debug ctx ("init_class_done " ^ Ast.s_type_path ctx.curclass.cl_path);
	init_class_done ctx

let ctx_pos ctx =
	let inf = Ast.s_type_path ctx.m.curmod.m_path in
	let inf = (match snd ctx.curclass.cl_path with "" -> inf | n when n = snd ctx.m.curmod.m_path -> inf | n -> inf ^ "." ^ n) in
	let inf = (match ctx.curfield.cf_name with "" -> inf | n -> inf ^ ":" ^ n) in
	inf

let pass_infos ctx p =
	let inf = pass_name p ^ " ("  ^ ctx_pos ctx ^ ")" in
	let inf = if ctx.pass > p then inf ^ " ??CURPASS=" ^ pass_name ctx.pass else inf in
	inf

let delay ctx p f =
	let inf = pass_infos ctx p in
	let rec loop = function
		| [] -> [p,[f,inf,ctx]]
		| (p2,l) :: rest ->
			if p2 = p then
				(p, (f,inf,ctx) :: l) :: rest
			else if p2 < p then
				(p2,l) :: loop rest
			else
				(p,[f,inf,ctx]) :: (p2,l) :: rest
	in
	ctx.g.debug_delayed <- loop ctx.g.debug_delayed;
	debug ctx ("add " ^ inf)

let pending_passes ctx =
	let rec loop acc = function
		| (p,l) :: pl when p < ctx.pass -> loop (acc @ l) pl
		| _ -> acc
	in
	match loop [] ctx.g.debug_delayed with
	| [] -> ""
	| l -> " ??PENDING[" ^ String.concat ";" (List.map (fun (_,i,_) -> i) l) ^ "]"

let display_error ctx msg p =
	debug ctx ("ERROR " ^ msg);
	display_error ctx msg p

let make_pass ?inf ctx f =
	let inf = (match inf with None -> pass_infos ctx ctx.pass | Some inf -> inf) in
	(fun v ->
		debug ctx ("run " ^ inf ^ pending_passes ctx);
		let old = !delay_tabs in
		delay_tabs := !delay_tabs ^ "\t";
		let t = (try
			f v
		with
			| Fatal_error (e,p) ->
				delay_tabs := old;
				raise (Fatal_error (e,p))
			| exc when not (Common.raw_defined ctx.com "stack") ->
				debug ctx ("FATAL " ^ Printexc.to_string exc);
				delay_tabs := old;
				raise exc
		) in
		delay_tabs := old;
		t
	)

let rec flush_pass ctx p where =
	let rec loop() =
		match ctx.g.debug_delayed with
		| (p2,l) :: rest when p2 <= p ->
			(match l with
			| [] ->
				ctx.g.debug_delayed <- rest
			| (f,inf,ctx2) :: l ->
				ctx.g.debug_delayed <- (p2,l) :: rest;
				match p2 with
				| PTypeField | PBuildClass -> f()
				| _ -> (make_pass ~inf ctx f)());
			loop()
		| _ ->
			()
	in
	match ctx.g.debug_delayed with
	| (p2,_) :: _ when p2 <= p ->
		let old = !delay_tabs in
		debug ctx ("flush " ^ pass_name p ^ "(" ^ where ^ ")");
		delay_tabs := !delay_tabs ^ "\t";
		loop();
		delay_tabs := old;
		debug ctx "flush-done";
	| _ ->
		()

let make_where ctx where =
	where ^ " (" ^ ctx_pos ctx ^ ")"

let exc_protect ctx f (where:string) =
	let f = make_pass ~inf:(make_where ctx where) ctx f in
	let rec r = ref (fun() ->
		try
			f r
		with
			| Error (m,p) ->
				raise (Fatal_error (error_msg m,p))
	) in
	r

*/*)
(* --------------------------------------------------- *)