(* 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/
 *)

(* $Id$ *)

open Printf

(** Functions "imported" from Http_getter_misc *)

let normalize_dir = Http_getter_misc.normalize_dir
let strip_suffix ~suffix s = 
  try 
    Http_getter_misc.strip_suffix ~suffix s
  with Invalid_argument _ -> s

let absolute_path file =
  if file.[0] = '/' then file else Unix.getcwd () ^ "/" ^ file
  
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

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

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

let list_tl_at ?(equality=(==)) e l =
  let rec aux =
    function
    | [] -> raise Not_found
    | hd :: tl as l when equality hd e -> l
    | hd :: tl -> aux tl
  in
  aux l

let shutup () = 
  HLog.set_log_callback (fun _ _ -> ());
(*
  let out = open_out "/dev/null" in
  Unix.dup2 (Unix.descr_of_out_channel out) (Unix.descr_of_out_channel stderr)
*)