(*
 * Copyright (C)2005-2012 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 Lexing
open Ast

type error_msg =
	| Invalid_character of char
	| Unterminated_string
	| Unterminated_regexp
	| Unclosed_comment
	| Unclosed_code
	| Invalid_escape
	| Invalid_option

exception Error of error_msg * pos

let error_msg = function
	| Invalid_character c when int_of_char c > 32 && int_of_char c < 128 -> Printf.sprintf "Invalid character '%c'" c
	| Invalid_character c -> Printf.sprintf "Invalid character 0x%.2X" (int_of_char c)
	| Unterminated_string -> "Unterminated string"
	| Unterminated_regexp -> "Unterminated regular expression"
	| Unclosed_comment -> "Unclosed comment"
	| Unclosed_code -> "Unclosed code string"
	| Invalid_escape -> "Invalid escape sequence"
	| Invalid_option -> "Invalid regular expression option"

type lexer_file = {
	lfile : string;
	mutable lline : int;
	mutable lmaxline : int;
	mutable llines : (int * int) list;
	mutable lalines : (int * int) array;
	mutable lstrings : int list;
}

let make_file file =
	{
		lfile = file;
		lline = 1;
		lmaxline = 1;
		llines = [0,1];
		lalines = [|0,1|];
		lstrings = [];
	}


let cur = ref (make_file "")

let all_files = Hashtbl.create 0

let buf = Buffer.create 100

let error e pos =
	raise (Error (e,{ pmin = pos; pmax = pos; pfile = !cur.lfile }))

let keywords =
	let h = Hashtbl.create 3 in
	List.iter (fun k -> Hashtbl.add h (s_keyword k) k)
		[Function;Class;Static;Var;If;Else;While;Do;For;
		Break;Return;Continue;Extends;Implements;Import;
		Switch;Case;Default;Public;Private;Try;Untyped;
		Catch;New;This;Throw;Extern;Enum;In;Interface;
		Cast;Override;Dynamic;Typedef;Package;
		Inline;Using;Null;True;False;Abstract;Macro];
	h

let init file do_add =
	let f = make_file file in
	cur := f;
	if do_add then Hashtbl.replace all_files file f

let save() =
	!cur

let restore c =
	cur := c

let newline lexbuf =
	let cur = !cur in
	cur.lline <- cur.lline + 1;
	cur.llines <- (lexeme_end lexbuf,cur.lline) :: cur.llines

let fmt_pos p =
	p.pmin + (p.pmax - p.pmin) * 1000000

let add_fmt_string p =
	let file = (try
		Hashtbl.find all_files p.pfile
	with Not_found ->
		let f = make_file p.pfile in
		Hashtbl.replace all_files p.pfile f;
		f
	) in
	file.lstrings <- (fmt_pos p) :: file.lstrings

let fast_add_fmt_string p =
	let cur = !cur in
	cur.lstrings <- (fmt_pos p) :: cur.lstrings

let is_fmt_string p =
	try
		let file = Hashtbl.find all_files p.pfile in
		List.mem (fmt_pos p) file.lstrings
	with Not_found ->
		false

let remove_fmt_string p =
	try
		let file = Hashtbl.find all_files p.pfile in
		file.lstrings <- List.filter ((<>) (fmt_pos p)) file.lstrings
	with Not_found ->
		()

let find_line p f =
	(* rebuild cache if we have a new line *)
	if f.lmaxline <> f.lline then begin
		f.lmaxline <- f.lline;
		f.lalines <- Array.of_list (List.rev f.llines);
	end;
	let rec loop min max =
		let med = (min + max) lsr 1 in
		let lp, line = Array.unsafe_get f.lalines med in
		if med = min then
			line, p - lp
		else if lp > p then
			loop min med
		else
			loop med max
	in
	loop 0 (Array.length f.lalines)

(* resolve a position within a non-haxe file by counting newlines *)
let resolve_pos file =
	let ch = open_in_bin file in
	let f = make_file file in
	let rec loop p =
		let inc i () =
			f.lline <- f.lline + 1;
			f.llines <- (p + i,f.lline) :: f.llines;
			i
		in
		let i = match input_char ch with
			| '\n' -> inc 1
			| '\r' ->
				ignore(input_char ch);
				inc 2
			| _ -> fun () -> 1
		in
		loop (p + i())
	in
	try
		loop 0
	with End_of_file ->
		close_in ch;
		f

let find_file file =
	try Hashtbl.find all_files file with Not_found -> try resolve_pos file with Sys_error _ -> make_file file

let find_pos p =
	find_line p.pmin (find_file p.pfile)

let get_error_line p =
	let l, _ = find_pos p in
	l

let get_error_pos printer p =
	if p.pmin = -1 then
		"(unknown)"
	else
		let file = find_file p.pfile in
		let l1, p1 = find_line p.pmin file in
		let l2, p2 = find_line p.pmax file in
		if l1 = l2 then begin
			let s = (if p1 = p2 then Printf.sprintf " %d" p1 else Printf.sprintf "s %d-%d" p1 p2) in
			Printf.sprintf "%s character%s" (printer p.pfile l1) s
		end else
			Printf.sprintf "%s lines %d-%d" (printer p.pfile l1) l1 l2

let reset() = Buffer.reset buf
let contents() = Buffer.contents buf
let store lexbuf = Buffer.add_string buf (lexeme lexbuf)
let add c = Buffer.add_string buf c

let mk_tok t pmin pmax =
	t , { pfile = !cur.lfile; pmin = pmin; pmax = pmax }

let mk lexbuf t =
	mk_tok t (lexeme_start lexbuf) (lexeme_end lexbuf)

let mk_ident lexbuf =
	let s = lexeme lexbuf in
	mk lexbuf (try Kwd (Hashtbl.find keywords s) with Not_found -> Const (Ident s))

let invalid_char lexbuf =
	error (Invalid_character (lexeme_char lexbuf 0)) (lexeme_start lexbuf)

}

let ident = ('_'* ['a'-'z'] ['_' 'a'-'z' 'A'-'Z' '0'-'9']* | '_'+ | '_'+ ['0'-'9'] ['_' 'a'-'z' 'A'-'Z' '0'-'9']* )
let idtype = '_'* ['A'-'Z'] ['_' 'a'-'z' 'A'-'Z' '0'-'9']*
let integer = ['1'-'9'] ['0'-'9']* | '0'

rule skip_header = parse
	| "\239\187\191" { skip_header lexbuf }
	| "#!" [^'\n' '\r']* { skip_header lexbuf }
	| "" | eof { }

and token = parse
	| eof { mk lexbuf Eof }
	| [' ' '\t']+ { token lexbuf }
	| "\r\n" { newline lexbuf; token lexbuf }
	| '\n' | '\r' { newline lexbuf; token lexbuf }
	| "0x" ['0'-'9' 'a'-'f' 'A'-'F']+ { mk lexbuf (Const (Int (lexeme lexbuf))) }
	| integer { mk lexbuf (Const (Int (lexeme lexbuf))) }
	| integer '.' ['0'-'9']+ { mk lexbuf (Const (Float (lexeme lexbuf))) }
	| '.' ['0'-'9']+ { mk lexbuf (Const (Float (lexeme lexbuf))) }
	| integer ['e' 'E'] ['+' '-']? ['0'-'9']+ { mk lexbuf (Const (Float (lexeme lexbuf))) }
	| integer '.' ['0'-'9']* ['e' 'E'] ['+' '-']? ['0'-'9']+ { mk lexbuf (Const (Float (lexeme lexbuf))) }
	| integer "..." {
			let s = lexeme lexbuf in
			mk lexbuf (IntInterval (String.sub s 0 (String.length s - 3)))
		}
	| "//" [^'\n' '\r']*  {
			let s = lexeme lexbuf in
			mk lexbuf (CommentLine (String.sub s 2 ((String.length s)-2)))
		}
	| "++" { mk lexbuf (Unop Increment) }
	| "--" { mk lexbuf (Unop Decrement) }
	| "~"  { mk lexbuf (Unop NegBits) }
	| "%=" { mk lexbuf (Binop (OpAssignOp OpMod)) }
	| "&=" { mk lexbuf (Binop (OpAssignOp OpAnd)) }
	| "|=" { mk lexbuf (Binop (OpAssignOp OpOr)) }
	| "^=" { mk lexbuf (Binop (OpAssignOp OpXor)) }
	| "+=" { mk lexbuf (Binop (OpAssignOp OpAdd)) }
	| "-=" { mk lexbuf (Binop (OpAssignOp OpSub)) }
	| "*=" { mk lexbuf (Binop (OpAssignOp OpMult)) }
	| "/=" { mk lexbuf (Binop (OpAssignOp OpDiv)) }
	| "<<=" { mk lexbuf (Binop (OpAssignOp OpShl)) }
(*//| ">>=" { mk lexbuf (Binop (OpAssignOp OpShr)) } *)
(*//| ">>>=" { mk lexbuf (Binop (OpAssignOp OpUShr)) } *)
	| "==" { mk lexbuf (Binop OpEq) }
	| "!=" { mk lexbuf (Binop OpNotEq) }
	| "<=" { mk lexbuf (Binop OpLte) }
(*//| ">=" { mk lexbuf (Binop OpGte) }*)
	| "&&" { mk lexbuf (Binop OpBoolAnd) }
	| "||" { mk lexbuf (Binop OpBoolOr) }
	| "<<" { mk lexbuf (Binop OpShl) }
	| "->" { mk lexbuf Arrow }
	| "..." { mk lexbuf (Binop OpInterval) }
	| "=>" { mk lexbuf (Binop OpArrow)}
	| "!" { mk lexbuf (Unop Not) }
	| "<" { mk lexbuf (Binop OpLt) }
	| ">" { mk lexbuf (Binop OpGt) }
	| ";" { mk lexbuf Semicolon }
	| ":" { mk lexbuf DblDot }
	| "," { mk lexbuf Comma }
	| "." { mk lexbuf Dot }
	| "%" { mk lexbuf (Binop OpMod) }
	| "&" { mk lexbuf (Binop OpAnd) }
	| "|" { mk lexbuf (Binop OpOr) }
	| "^" { mk lexbuf (Binop OpXor) }
	| "+" { mk lexbuf (Binop OpAdd) }
	| "*" { mk lexbuf (Binop OpMult) }
	| "/" { mk lexbuf (Binop OpDiv) }
	| "-" { mk lexbuf (Binop OpSub) }
	| "=" { mk lexbuf (Binop OpAssign) }
	| "[" { mk lexbuf BkOpen }
	| "]" { mk lexbuf BkClose }
	| "{" { mk lexbuf BrOpen }
	| "}" { mk lexbuf BrClose }
	| "(" { mk lexbuf POpen }
	| ")" { mk lexbuf PClose }
	| "?" { mk lexbuf Question }
	| "@" { mk lexbuf At }
	| "/*" {
			reset();
			let pmin = lexeme_start lexbuf in
			let pmax = (try comment lexbuf with Exit -> error Unclosed_comment pmin) in
			mk_tok (Comment (contents())) pmin pmax;
		}
	| '"' {
			reset();
			let pmin = lexeme_start lexbuf in
			let pmax = (try string lexbuf with Exit -> error Unterminated_string pmin) in
			let str = (try unescape (contents()) with Exit -> error Invalid_escape pmin) in
			mk_tok (Const (String str)) pmin pmax;
		}
	| "'" {
			reset();
			let pmin = lexeme_start lexbuf in
			let pmax = (try string2 lexbuf with Exit -> error Unterminated_string pmin) in
			let str = (try unescape (contents()) with Exit -> error Invalid_escape pmin) in
			let t = mk_tok (Const (String str)) pmin pmax in
			fast_add_fmt_string (snd t);
			t
		}
	| "~/" {
			reset();
			let pmin = lexeme_start lexbuf in
			let options, pmax = (try regexp lexbuf with Exit -> error Unterminated_regexp pmin) in
			let str = contents() in
			mk_tok (Const (Regexp (str,options))) pmin pmax;
		}
	| '#' ident {
			let v = lexeme lexbuf in
			let v = String.sub v 1 (String.length v - 1) in
			mk lexbuf (Sharp v)
		}
	| '$' ['_' 'a'-'z' 'A'-'Z' '0'-'9']* {
			let v = lexeme lexbuf in
			let v = String.sub v 1 (String.length v - 1) in
			mk lexbuf (Dollar v)
		}
	| ident { mk_ident lexbuf }
	| idtype { mk lexbuf (Const (Ident (lexeme lexbuf))) }
	| _ { invalid_char lexbuf }

and comment = parse
	| eof { raise Exit }
	| '\n' | '\r' | "\r\n" { newline lexbuf; store lexbuf; comment lexbuf }
	| "*/" { lexeme_end lexbuf }
	| '*' { store lexbuf; comment lexbuf }
	| [^'*' '\n' '\r']+ { store lexbuf; comment lexbuf }

and string = parse
	| eof { raise Exit }
	| '\n' | '\r' | "\r\n" { newline lexbuf; store lexbuf; string lexbuf }
	| "\\\"" { store lexbuf; string lexbuf }
	| "\\\\" { store lexbuf; string lexbuf }
	| '\\' { store lexbuf; string lexbuf }
	| '"' { lexeme_end lexbuf }
	| [^'"' '\\' '\r' '\n']+ { store lexbuf; string lexbuf }

and string2 = parse
	| eof { raise Exit }
	| '\n' | '\r' | "\r\n" { newline lexbuf; store lexbuf; string2 lexbuf }
	| '\\' { store lexbuf; string2 lexbuf }
	| "\\\\" { store lexbuf; string2 lexbuf }
	| "\\'" { store lexbuf; string2 lexbuf }
	| "'" { lexeme_end lexbuf }
	| "$$" | "\\$" | '$' { store lexbuf; string2 lexbuf }
	| "${" {
		let pmin = lexeme_start lexbuf in
		store lexbuf;
		(try code_string lexbuf with Exit -> error Unclosed_code pmin);
		string2 lexbuf;
	}
	| [^'\'' '\\' '\r' '\n' '$']+ { store lexbuf; string2 lexbuf }

and code_string = parse
	| eof { raise Exit }
	| '\n' | '\r' | "\r\n" { newline lexbuf; store lexbuf; code_string lexbuf }
	| '{' | '/' { store lexbuf; code_string lexbuf }
	| '}' { store lexbuf; (* stop *) }
	| '"' {
		add "\"";
		let pmin = lexeme_start lexbuf in
		(try ignore(string lexbuf) with Exit -> error Unterminated_string pmin);
		add "\"";
		code_string lexbuf;
	}
	| "'" {
		add "'";
		let pmin = lexeme_start lexbuf in
		let pmax = (try string2 lexbuf with Exit -> error Unterminated_string pmin) in
		add "'";
		fast_add_fmt_string { pfile = !cur.lfile; pmin = pmin; pmax = pmax };
		code_string lexbuf;
	}
	| "/*" {
		let pmin = lexeme_start lexbuf in
		(try ignore(comment lexbuf) with Exit -> error Unclosed_comment pmin);
		code_string lexbuf;
	}
	| "//" [^'\n' '\r']* { store lexbuf; code_string lexbuf; }
	| [^'/' '"' '\'' '{' '}' '\n' '\r']+  { store lexbuf; code_string lexbuf; }

and regexp = parse
	| eof | '\n' | '\r' { raise Exit }
	| '\\' '/' { add "/"; regexp lexbuf }
	| '\\' 'r' { add "\r"; regexp lexbuf }
	| '\\' 'n' { add "\n"; regexp lexbuf }
	| '\\' 't' { add "\t"; regexp lexbuf }
	| '\\' ['\\' '$' '.' '*' '+' '^' '|' '{' '}' '[' ']' '(' ')' '?' '-' '0'-'9'] { add (lexeme lexbuf); regexp lexbuf }
	| '\\' ['w' 'W' 'b' 'B' 's' 'S' 'd' 'D' 'x'] { add (lexeme lexbuf); regexp lexbuf }
	| '\\' ['u' 'U'] ['0'-'9' 'a'-'f' 'A'-'F'] ['0'-'9' 'a'-'f' 'A'-'F'] ['0'-'9' 'a'-'f' 'A'-'F'] ['0'-'9' 'a'-'f' 'A'-'F'] { add (lexeme lexbuf); regexp lexbuf }
	| '\\' [^ '\\'] { error (Invalid_character (lexeme lexbuf).[1]) (lexeme_end lexbuf - 1) }
	| '/' { regexp_options lexbuf, lexeme_end lexbuf }
	| [^ '\\' '/' '\r' '\n']+ { store lexbuf; regexp lexbuf }

and regexp_options = parse
	| 'g' | 'i' | 'm' | 's' | 'u' {
			let l = lexeme lexbuf in
			l ^ regexp_options lexbuf
		}
	| ['a' - 'z'] { error Invalid_option (lexeme_start lexbuf) }
	| "" { "" }