(*
 *  Copyright (C) 2003, 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://cs.unibo.it/helm/.
 *)

open Http_getter_types;;
open Printf;;
open Pxp_document;;
open Pxp_types;;
open Pxp_yacc;;

type setting_src =
  | Environment (* read setting from environment variables *)
  | Conffile    (* read setting from configuration file *)
  | Both        (* read setting from both; environment override config file *)

let conf_file_tree = ref None

let (conf_file, conf_dir) =
  try
    let conf_dir =
      Pcre.replace ~pat:"/$" (Sys.getenv "HELM_CONFIGURATION_DIR")
    in
    (conf_dir ^ "/configuration.xml", conf_dir)
  with Not_found -> failwith "HELM_CONFIGURATION_DIR undefined"

let safe_getenv ?(from = Both) var =
  (let rec read_from_file () =
    (match !conf_file_tree with
    | None ->
        conf_file_tree :=
          Some
            (parse_wfcontent_entity
              default_config (from_file conf_file) default_spec);
        read_from_file ()
    | Some t ->
        (try
          Some (find_element (String.lowercase var) t)#data
        with Not_found -> None))
  in
  let read_from_env () = try Some (Sys.getenv var) with Not_found -> None in
  let return_value name = function
    | Some v -> v
    | None -> failwith ("Setting " ^ name ^ " is not defined")
  in
  (match from with
  | Environment -> return_value var (read_from_env ())
  | Conffile -> return_value var (read_from_file ())
  | Both ->
      (match read_from_env () with
      | None -> return_value var (read_from_file ())
      | v -> return_value var v)))

let servers_file = safe_getenv "HTTP_GETTER_SERVERS_FILE"
let servers =
  let cons hd tl = hd @ [ tl ] in
  Http_getter_misc.fold_file cons [] servers_file

let xml_dbm = safe_getenv "HTTP_GETTER_XML_DBM"
let rdf_dbm = safe_getenv "HTTP_GETTER_RDF_DBM"
let xsl_dbm = safe_getenv "HTTP_GETTER_XSL_DBM"
let xml_index = safe_getenv "HTTP_GETTER_XML_INDEXNAME"
let rdf_index = safe_getenv "HTTP_GETTER_RDF_INDEXNAME"
let xsl_index = safe_getenv "HTTP_GETTER_XSL_INDEXNAME"
let xml_dir = safe_getenv "HTTP_GETTER_XML_DIR"
let rdf_dir = safe_getenv "HTTP_GETTER_RDF_DIR"
let dtd_dir = safe_getenv "HTTP_GETTER_DTD_DIR"

let port =
  let port = safe_getenv "HTTP_GETTER_PORT" in
  try
    int_of_string port
  with Failure "int_of_string" ->
    failwith ("Invalid port value: " ^ port)
let host =
  let buf = Buffer.create 20 in
  Shell.call ~stdout:(Shell.to_buffer buf) [Shell.cmd "hostname" ["-f"]];
  Pcre.replace ~pat:"\n+$" (Buffer.contents buf)
let my_own_url =
  sprintf
    "http://%s%s" (* without trailing '/' *)
    host
    (if port = 80 then "" else (sprintf ":%d" port))
let dtd_base_url = safe_getenv "HTTP_GETTER_DTD_BASE_URL"

let cache_mode =
  match String.lowercase (safe_getenv "HTTP_GETTER_CACHE_MODE") with
  | "normal" -> Enc_normal
  | "gz" -> Enc_gzipped
  | mode -> failwith ("Invalid cache mode: " ^ mode)

let dump_env () =
  printf
"xml_dbm:\t%s
rdf_dbm:\t%s
xsl_dbm:\t%s
xml_index:\t%s
rdf_index:\t%s
xsl_index:\t%s
xml_dir:\t%s
rdf_dir:\t%s
dtd_dir:\t%s
servers_file:\t%s
host:\t\t%s
port:\t\t%d
my_own_url:\t%s
dtd_base_url:\t%s
cache_mode:\t%s
conf_file:\t%s
conf_dir:\t%s
servers:
\t%s
"
    xml_dbm rdf_dbm xsl_dbm xml_index rdf_index xsl_index
    xml_dir rdf_dir dtd_dir servers_file host port
    my_own_url dtd_base_url
    (match cache_mode with Enc_normal -> "Normal" | Enc_gzipped -> "GZipped")
    conf_file conf_dir (String.concat "\n\t" servers);
  flush stdout