(* Copyright (C) 2004-2005, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * HELM is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://helm.cs.unibo.it/
 *)

open Printf
open MatitaTypes 

let is_dir fname =
  try
    (Unix.stat fname).Unix.st_kind = Unix.S_DIR
  with Unix.Unix_error _ -> false

let is_regular fname =
  try
    (Unix.stat fname).Unix.st_kind = Unix.S_REG
  with Unix.Unix_error _ -> false

let input_file fname =
  let size = (Unix.stat fname).Unix.st_size in
  let buf = Buffer.create size in
  let ic = open_in fname in
  Buffer.add_channel buf ic size;
  close_in ic;
  Buffer.contents buf

let is_proof_script fname = true  (** TODO Zack *)
let is_proof_object fname = true  (** TODO Zack *)

let append_phrase_sep s =
  if not (Pcre.pmatch ~pat:(sprintf "%s$" BuildTimeConf.phrase_sep) s) then
    s ^ BuildTimeConf.phrase_sep
  else
    s

let strip_trailing_blanks =
  let rex = Pcre.regexp "\\s*$" in
  fun s -> Pcre.replace ~rex s

let strip_trailing_slash =
  let rex = Pcre.regexp "/$" in
  fun s -> Pcre.replace ~rex s

let empty_mathml () =
  DomMisc.domImpl#createDocument ~namespaceURI:(Some DomMisc.mathml_ns)
    ~qualifiedName:(Gdome.domString "math") ~doctype:None

let empty_boxml () =
  DomMisc.domImpl#createDocument ~namespaceURI:(Some DomMisc.boxml_ns) 
    ~qualifiedName:(Gdome.domString "box") ~doctype:None

exception History_failure

type 'a memento = 'a array * int * int * int  (* data, hd, tl, cur *)

class type ['a] history =
  object
    method add : 'a -> unit
    method next : 'a
    method previous : 'a
    method load: 'a memento -> unit
    method save: 'a memento
    method is_begin: bool
    method is_end: bool
  end

class basic_history (head, tail, cur) =
  object
    val mutable hd = head  (* insertion point *)
    val mutable tl = tail (* oldest inserted item *)
    val mutable cur = cur  (* current item for the history *)
    
    method is_begin = cur <= tl
    method is_end = cur >= hd
  end
  
  
class shell_history size =
  let size = size + 1 in
  let decr x = let x' = x - 1 in if x' < 0 then size + x' else x' in
  let incr x = (x + 1) mod size in
  object (self)
    val data = Array.create size ""

    inherit basic_history (0, -1 , -1)
    
    method add s =
      data.(hd) <- s;
      if tl = -1 then tl <- hd;
      hd <- incr hd;
      if hd = tl then tl <- incr tl;
      cur <- hd
    method previous =
      if cur = tl then raise History_failure;
      cur <- decr cur;
      data.(cur)
    method next =
      if cur = hd then raise History_failure;
      cur <- incr cur;
      if cur = hd then "" else data.(cur)
    method load (data', hd', tl', cur') =
      assert (Array.length data = Array.length data');
      hd <- hd'; tl <- tl'; cur <- cur';
      Array.blit data' 0 data 0 (Array.length data')
    method save = (Array.copy data, hd, tl, cur)
  end

class ['a] browser_history ?memento size init =
  object (self)
    initializer match memento with Some m -> self#load m | _ -> ()
    val data = Array.create size init

    inherit basic_history (0, 0, 0)
    
    method previous =
      if cur = tl then raise History_failure;
      cur <- cur - 1;
      if cur = ~-1 then cur <- size - 1;
      data.(cur)
    method next =
      if cur = hd then raise History_failure;
      cur <- cur + 1;
      if cur = size then cur <- 0;
      data.(cur)
    method add (e:'a) =
      if e <> data.(cur) then
        begin
          cur <- cur + 1;
          if cur = size then cur <- 0;
          if cur = tl then tl <- tl + 1;
          if tl = size then tl <- 0;
          hd <- cur;
          data.(cur) <- e
        end
    method load (data', hd', tl', cur') =
      assert (Array.length data = Array.length data');
      hd <- hd'; tl <- tl'; cur <- cur';
      Array.blit data' 0 data 0 (Array.length data')
    method save = (Array.copy data, hd, tl, cur)
  end

let singleton f =
  let instance = lazy (f ()) in
  fun () -> Lazy.force instance

let mkdir d =
  let errmsg = sprintf "Unable to create directory \"%s\"" d in
  try
    (match Unix.system ("mkdir -p " ^ d) with
    | Unix.WEXITED 0 -> ()
    | _ -> failwith errmsg)
  with Unix.Unix_error _ -> failwith errmsg

let get_proof_status status =
  match status.proof_status with
  | Incomplete_proof s -> s
  | _ -> statement_error "no ongoing proof"

let get_proof_metasenv status =
  match status.proof_status with
  | No_proof -> []
  | Incomplete_proof ((_, metasenv, _, _), _) -> metasenv
  | Proof (_, metasenv, _, _) -> metasenv
  | Intermediate m -> m

let get_proof_context status =
  match status.proof_status with
  | Incomplete_proof ((_, metasenv, _, _), goal) ->
      let (_, context, _) = CicUtil.lookup_meta goal metasenv in
      context
  | _ -> []
 
let get_proof_aliases status = status.aliases
  
let qualify status name = get_string_option status "baseuri" ^ "/" ^ name

let unopt = function None -> failwith "unopt: None" | Some v -> v

let image_path n = sprintf "%s/%s" BuildTimeConf.images_dir n

let end_ma_RE = Pcre.regexp "\\.ma$"
let obj_file_of_script f = Pcre.replace ~rex:end_ma_RE ~templ:".moo" f

let rec list_uniq = function 
  | [] -> []
  | h::[] -> [h]
  | h1::h2::tl when h1 = h2 -> list_uniq (h2 :: tl) 
  | h1::tl (* when h1 <> h2 *) -> h1 :: list_uniq tl

let end_ma_RE = Pcre.regexp "\\.ma$"