(* Copyright (C) 2002, 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/.
 *)

module T = MQGTypes
module U = MQGUtil
module G = MQueryGenerator
module C = MQIConn

open Http_types ;;

let debug = true;;
let debug_print s = if debug then prerr_endline s;;
Http_common.debug := true;;
(* Http_common.debug := true;; *)

open Printf;;

let daemon_name = "Search Engine";;

let string_tail s =
  let len = String.length s in
  String.sub s 1 (len-1)

  (* First of all we load the configuration *)
let _ =
 let configuration_file = "searchEngine.conf.xml" in
  Helm_registry.load_from configuration_file
;;

let port = Helm_registry.get_int "search_engine.port";;

let pages_dir = Helm_registry.get "search_engine.html_dir";;

  (** accepted HTTP servers for ask_uwobo method forwarding *)
let valid_servers= Helm_registry.get_string_list "search_engine.valid_servers";;

let interactive_user_uri_choice_TPL = pages_dir ^ "/moogle_chat1.html";;
let interactive_interpretation_choice_TPL = pages_dir ^ "/moogle_chat2.html";;
let constraints_choice_TPL = pages_dir ^ "/moogle_constraints_choice.html";;
(* let final_results_TPL = pages_dir ^ "/templateambigpdq3.html";; *)
let start_TPL = pages_dir ^ "/moogle.html";; 
let final_results_TPL = pages_dir ^ "/moogle.html";;  

let my_own_url =
 let ic = Unix.open_process_in "hostname -f" in
 let hostname = input_line ic in
 ignore (Unix.close_process_in ic);
 sprintf "http://%s:%d" hostname port
;;

exception Chat_unfinished
exception Invalid_action of string  (* invalid action for "/search" method *)

let javascript_quote s =
 let rex = Pcre.regexp "'" in
 let rex' = Pcre.regexp "\"" in
  Pcre.replace ~rex ~templ:"\\'"
   (Pcre.replace ~rex:rex' ~templ:"\\\"" s)
;;

  (* build a bool from a 1-character-string *)
let bool_of_string' = function
  | "0" -> false
  | "1" -> true
  | s -> failwith ("Can't parse a boolean from string: " ^ s)
;;

  (* build an int option from a string *)
let int_of_string' = function
  | "_" -> None
  | s ->
      try
        Some (int_of_string s)
      with Failure "int_of_string" ->
        failwith ("Can't parse an int option from string: " ^ s)
;;

  (* HTML pretty printers for mquery_generator types *)

let html_of_r_obj (pos, uri) =
  sprintf
    "<tr><td><input type='checkbox' name='constr_obj' checked='on'/></td><td>%s</td><td>%s</td><td>%s</td></tr>"
    uri (U.text_of_position pos)
    (if U.is_main_position pos then
      sprintf "<input name='obj_depth' size='2' type='text' value='%s' />"
        (U.text_of_depth pos "")
    else
      "<input type=\"hidden\" name=\"obj_depth\" />")
;;

let html_of_r_rel pos =
  sprintf
    "<tr><td><input type='checkbox' name='constr_rel' checked='on'/></td><td>%s</td><td><input name='rel_depth' size='2' type='text' value='%s' /></td></tr>"
    (U.text_of_position (pos:>T.full_position)) (U.text_of_depth (pos:>T.full_position) "")
;;

let html_of_r_sort (pos, sort) =
  sprintf
    "<tr><td><input type='checkbox' name='constr_sort' checked='on'/></td><td>%s</td><td>%s</td><td><input name='sort_depth' size='2' type='text' value='%s'/></td></tr>"
    (U.text_of_sort sort) (U.text_of_position (pos:>T.full_position)) (U.text_of_depth (pos:>T.full_position) "")
;;

  (** pretty print a MathQL query result to an HELM theory file *)
let theory_of_result result =
 let results_no = List.length result in
  if results_no > 0 then
   let mode = if results_no > 10 then "linkonly" else "typeonly" in
   let results =
    let idx = ref (results_no + 1) in
     List.fold_right
      (fun (uri,attrs) i ->
        decr idx ;
        "<tr><td valign=\"top\">" ^ string_of_int !idx ^ ".</td><td><ht:OBJECT uri=\"" ^ uri ^ "\" mode=\"" ^ mode ^ "\"/></td></tr>" ^  i
      ) result ""
   in
    "<b><font size=\"+1\">Query Results:</font></b><table xmlns:ht=\"http://www.cs.unibo.it/helm/namespaces/helm-theory\">" ^ results ^ "</table>"
  else
    "<b><font size=\"+1\">Query Results:</font></b><p>No results found!</p>"
;;

let pp_result result =
 "<html xmlns:ht=\"http://www.cs.unibo.it/helm/namespaces/helm-theory\">\n<head><title>Query Results</title><style> A { text-decoration: none } </style></head>\n<body>" ^ theory_of_result result ^ "</body></html>"
;;

  (** chain application of Pcre substitutions *)
let rec apply_substs substs line =
  match substs with
  | [] -> line
  | (rex, templ) :: rest -> apply_substs rest (Pcre.replace ~rex ~templ line)
  (** fold like function on files *)
let fold_file f init fname =
  let inchan = open_in fname in
  let rec fold_lines' value =
    try 
      let line = input_line inchan in 
      fold_lines' (f value line)
    with End_of_file -> value
  in
  let res = (try fold_lines' init with e -> (close_in inchan; raise e)) in
  close_in inchan;
  res
  (** iter like function on files *)
let iter_file f = fold_file (fun _ line -> f line) ()

let (expression_tag_RE,
     action_tag_RE,
     advanced_tag_RE,
     title_tag_RE, no_choices_tag_RE, current_choices_tag_RE,  
     choices_tag_RE, msg_tag_RE, id_to_uris_RE, id_RE, iden_tag_RE,
     interpretations_RE, interpretations_labels_RE, results_RE, new_aliases_RE,
     form_RE, variables_initialization_RE, search_engine_url_RE)
  =
  (Pcre.regexp "@EXPRESSION@", 
   Pcre.regexp "@ACTION@", 
   Pcre.regexp "@ADVANCED@",
   Pcre.regexp "@TITLE@", Pcre.regexp "@NO_CHOICES@",  
   Pcre.regexp "@CURRENT_CHOICES@",
   Pcre.regexp "@CHOICES@", Pcre.regexp "@MSG@",
   Pcre.regexp "@ID_TO_URIS@", Pcre.regexp "@ID@", Pcre.regexp "@IDEN@",
   Pcre.regexp "@INTERPRETATIONS@", Pcre.regexp "@INTERPRETATIONS_LABELS@",
   Pcre.regexp "@RESULTS@", Pcre.regexp "@NEW_ALIASES@", Pcre.regexp "@FORM@",
   Pcre.regexp "@VARIABLES_INITIALIZATION@", Pcre.regexp "@SEARCH_ENGINE_URL@")
let server_and_port_url_RE = Pcre.regexp "^http://([^/]+)/.*$"

let pp_error = sprintf "<html><body><h1>Error: %s</h1></body></html>";;

let bad_request body outchan =
  Http_daemon.respond_error ~code:(`Status (`Client_error `Bad_request)) ~body
    outchan
;;

let contype = "Content-Type", "text/html";;

(* SEARCH ENGINE functions *)

let get_constraints term =
 function
    | "/elim" ->
      None,
      (CGLocateInductive.get_constraints term),
      (None,None,None)
    | "/match" ->
     let constr_obj, constr_rel, constr_sort =
       CGSearchPattern.get_constraints term in
     (Some CGSearchPattern.universe),
     (constr_obj, constr_rel, constr_sort),
     (Some constr_obj, Some constr_rel, Some constr_sort)
    | "/hint" ->
     let list_of_must, only = CGMatchConclusion.get_constraints [] [] term in
(* FG: there is no way to choose the block number ***************************)
     let block = pred (List.length list_of_must) in 
      (Some CGMatchConclusion.universe), 
      (List.nth list_of_must block, [], []), (Some only, None, None)
    | _ -> assert false
;;

(*
  format:
    <must_obj> ':' <must_rel> ':' <must_sort> ':' <only_obj> ':' <only_rel> ':' <only_sort>

    <must_*> ::= ('0'|'1') ('_'|<int>) (',' ('0'|'1') ('_'|<int>))*
    <only> ::= '0'|'1'
*)
let add_user_constraints ~constraints
 ((obj, rel, sort), (only_obj, only_rel, only_sort))
=
  let parse_must s =
    let l = Pcre.split ~pat:"," s in
    (try
      List.map
        (fun s ->
          let subs = Pcre.extract ~pat:"^(.)(\\d+|_)$" s in
          (bool_of_string' subs.(1), int_of_string' subs.(2)))
        l
     with
      Not_found -> failwith ("Can't parse constraint string: " ^ constraints)
    )
  in
    (* to be used on "obj" *)
  let add_user_must33 user_must must =
    List.map2
     (fun (b, i) (p, u) ->
       if b then Some (U.set_full_position p i, u) else None)
     user_must must
  in
    (* to be used on "rel" *)
  let add_user_must22 user_must must =
    List.map2
     (fun (b, i) p -> if b then Some (U.set_main_position p i) else None)
     user_must must
  in
    (* to be used on "sort" *)
  let add_user_must32 user_must must =
    List.map2
     (fun (b, i) (p, s)-> if b then Some (U.set_main_position p i, s) else None)
     user_must must
  in
  match Pcre.split ~pat:":" constraints with
  | [user_obj;user_rel;user_sort;user_only_obj;user_only_rel;user_only_sort] ->
      let
       (user_obj,user_rel,user_sort,user_only_obj,user_only_rel,user_only_sort)
      =
        (parse_must user_obj,
        parse_must user_rel,
        parse_must user_sort,
        bool_of_string' user_only_obj,
        bool_of_string' user_only_rel,
        bool_of_string' user_only_sort)
      in
      let only' =
       (if user_only_obj  then only_obj else None),
       (if user_only_rel  then only_rel else None),
       (if user_only_sort then only_sort else None)
      in
      let must' =
       let rec filter_some =
        function
           [] -> []
         | None::tl -> filter_some tl
         | (Some x)::tl -> x::(filter_some tl) 
       in
        filter_some (add_user_must33 user_obj obj),
        filter_some (add_user_must22 user_rel rel),
        filter_some (add_user_must32 user_sort sort)
      in
      (must', only')
  | _ -> failwith ("Can't parse constraint string: " ^ constraints)
in

let send_results results
  ?(id_to_uris = DisambiguatingParser.EnvironmentP3.of_string "") 
   (req: Http_types.request) outchan
  =
  Http_daemon.send_basic_headers ~code:(`Code 200) outchan ;
  Http_daemon.send_header "Content-Type" "text/xml" outchan;
  Http_daemon.send_CRLF outchan ;
  let subst =
    (search_engine_url_RE, my_own_url) ::
    (results_RE, theory_of_result results)::
    (advanced_tag_RE, req#param "advanced")::
    (expression_tag_RE, req#param "expression")::
    (List.map
      (function (key,value) ->
        let key' = (Pcre.extract ~pat:"param\\.(.*)" key).(1) in
        Pcre.regexp ("@" ^ key' ^ "@"), value)
      (List.filter
	      (fun (key,_) as p-> Pcre.pmatch ~pat:"^param\\." key)
	      req#params))
    in
    iter_file
      (fun line ->
        let new_aliases =
          DisambiguatingParser.EnvironmentP3.to_string id_to_uris
        in
        let processed_line =
          apply_substs
            (* CSC: Bug here: this is a string, not an array! *)
            ((new_aliases_RE, "'" ^ javascript_quote new_aliases ^ "'")::subst) 
            line
        in
        output_string outchan (processed_line ^ "\n"))
      final_results_TPL
in

let exec_action mqi_handle (req: Http_types.request) outchan =
  let term_string = req#param "expression" in
  let (context, metasenv) = ([], []) in
  let id_to_uris_raw = 
    try req#param "aliases" 
    with Http_types.Param_not_found _ -> ""
  in
  let parse_interpretation_choices choices =
    List.map int_of_string (Pcre.split ~pat:" " choices) in
  let parse_choices choices_raw =
    let choices = Pcre.split ~pat:";" choices_raw in
      List.fold_left
        (fun f x ->
           match Pcre.split ~pat:"\\s" x with
             | ""::id::tail
             | id::tail when id<>"" ->
                 (fun id' ->
                    if id = id' then
                      Some (List.map (fun u -> Netencoding.Url.decode u) tail)
                    else
                      f id')
             | _ -> failwith "Can't parse choices")
        (fun _ -> None)
        choices
  in
  let id_to_uris =
    DisambiguatingParser.EnvironmentP3.of_string id_to_uris_raw in
  let id_to_choices =
    try
      let choices_raw = req#param "choices" in
        parse_choices choices_raw
    with Http_types.Param_not_found _ -> (fun _ -> None)
  in
  let interpretation_choices =
    try
      let choices_raw = req#param "interpretation_choices" in
      if choices_raw = "" then None 
      else Some (parse_interpretation_choices choices_raw)
    with Http_types.Param_not_found _ -> None
  in 
  let module Chat: DisambiguateTypes.Callbacks =
    struct

      let interactive_user_uri_choice
        ~selection_mode ?ok
        ?enable_button_for_non_vars ~(title: string) ~(msg: string)
        ~(id: string) (choices: string list)
        =
        (match id_to_choices id with
           | Some choices -> choices
           | None ->
              if req#param "advanced" = "no" then
                let isvar s =
		  let len = String.length s in
		  let suffix = String.sub s (len-4) 4 in
		    not (suffix  = ".var") in
		List.filter isvar choices
	      else 
               let msg = Pcre.replace ~pat:"\'" ~templ:"\\\'" msg in
               (match selection_mode with
                  | `SINGLE -> assert false
                  | `MULTIPLE ->
                      Http_daemon.send_basic_headers ~code:(`Code 200) outchan;
                      Http_daemon.send_CRLF outchan ;
                      let check_box uri =
			"<input type=\"checkbox\" name=\"param.choices\" 
                        value=\"" ^
			uri ^ "\" />" ^ "<b>" ^ uri ^ "</b>" in
(* aggiungere gli hyperlinks? *)
                      let check_boxes = 
			String.concat "<br />" 
			  (List.map check_box choices) in
		      iter_file
                        (fun line ->
                           let processed_line =
			     apply_substs
 			       [advanced_tag_RE, req#param "advanced";
                                choices_tag_RE, check_boxes;
                                no_choices_tag_RE, 
				   string_of_int (List.length choices);
                                iden_tag_RE, id;
                                current_choices_tag_RE, req#param "choices";  
                                expression_tag_RE, req#param "expression";
                                action_tag_RE, string_tail req#path ]
			       line
			   in
                             output_string outchan (processed_line ^ "\n"))
                        interactive_user_uri_choice_TPL;
			raise Chat_unfinished))

      let interactive_interpretation_choice interpretations =
        match interpretation_choices with
            Some l -> prerr_endline "CARRAMBA" ; l
          | None ->
              let html_interpretations =
		let radio_button n = 
		  "<input type=\"radio\" name=\"param.interp\" value=\"" ^
		  (string_of_int n) ^ "\" />" in
                let text interp =
		  String.concat "<br />" 
		    (List.map
                       (fun (id, value) -> 
			  sprintf "<span>%s = %s</span>" id value) 
		       interp) in
		let rec aux n = 
		  function
		      [] -> []
                    | interp::tl ->
			((radio_button n)^(text interp))::(aux (n+1) tl) in
                String.concat "<br />" (aux 0 interpretations)
              in
              Http_daemon.send_basic_headers ~code:(`Code 200) outchan ;
              Http_daemon.send_CRLF outchan ;
              iter_file
                (fun line ->
                   let processed_line =
                     apply_substs
                       [advanced_tag_RE, req#param "advanced";
                        interpretations_RE, html_interpretations;
                        current_choices_tag_RE, req#param "choices";
			expression_tag_RE, req#param "expression";
                        action_tag_RE, string_tail req#path ]
                        line
                   in
                   output_string outchan (processed_line ^ "\n"))
                interactive_interpretation_choice_TPL;
              raise Chat_unfinished

      let input_or_locate_uri ~title ?id () =
        assert false

    end
  in
  let module Disambiguate' = DisambiguatingParser.Make(Chat) in
  let (id_to_uris', metasenv', term') =
    match
      Disambiguate'.disambiguate_term mqi_handle
        context metasenv term_string id_to_uris
    with
        [id_to_uris',metasenv',term'] -> id_to_uris',metasenv',term'
      | _ -> assert false
        in
  let universe,
  ((must_obj, must_rel, must_sort) as must'),
  ((only_obj, only_rel, only_sort) as only) =
    get_constraints term' req#path
  in
  let must'', only' =
    (try
       add_user_constraints
         ~constraints:(req#param "constraints")
         (must', only)
     with Http_types.Param_not_found _ ->
       if req#param "advanced" = "no" then
	 (must',only)
       else
       let variables =
         "var aliases = '" ^ id_to_uris_raw ^ "';\n" ^
         "var constr_obj_len = " ^
         string_of_int (List.length must_obj) ^ ";\n" ^
         "var constr_rel_len = " ^
         string_of_int (List.length must_rel) ^ ";\n" ^
         "var constr_sort_len = " ^
         string_of_int (List.length must_sort) ^ ";\n" in
       let form =
         (if must_obj = [] then "" else
            "<h4>Obj constraints</h4>" ^
            "<table>" ^
            (String.concat "\n" (List.map html_of_r_obj must_obj)) ^
            "</table>" ^
            (* The following three lines to make Javascript create *)
            (* the constr_obj[] and obj_depth[] arrays even if we  *)
            (* have only one real entry.                           *)
            "<input type=\"hidden\" name=\"constr_obj\" />" ^
            "<input type=\"hidden\" name=\"obj_depth\" />") ^
         (if must_rel = [] then "" else
            "<h4>Rel constraints</h4>" ^
            "<table>" ^
            (String.concat "\n" (List.map html_of_r_rel must_rel)) ^
            "</table>" ^
            (* The following two lines to make Javascript create *)
            (* the constr_rel[] and rel_depth[] arrays even if   *)
            (* we have only one real entry.                      *)
            "<input type=\"hidden\" name=\"constr_rel\" />" ^
            "<input type=\"hidden\" name=\"rel_depth\" />") ^
         (if must_sort = [] then "" else
            "<h4>Sort constraints</h4>" ^
            "<table>" ^
            (String.concat "\n" (List.map html_of_r_sort must_sort)) ^
            "</table>" ^
            (* The following two lines to make Javascript create *)
            (* the constr_sort[] and sort_depth[] arrays even if *)
            (* we have only one real entry.                      *)
            "<input type=\"hidden\" name=\"constr_sort\" />" ^
            "<input type=\"hidden\" name=\"sort_depth\" />") ^
         "<h4>Only constraints</h4>" ^
         "Enforce Only constraints for objects: " ^
         "<input type='checkbox' name='only_obj'" ^
         (if only_obj = None then "" else " checked='yes'") ^
         " /><br />" ^
         "Enforce Rel constraints for objects: " ^
         "<input type='checkbox' name='only_rel'" ^
         (if only_rel = None then "" else " checked='yes'") ^
         " /><br />" ^
         "Enforce Sort constraints for objects: " ^
         "<input type='checkbox' name='only_sort'" ^
         (if only_sort = None then "" else " checked='yes'") ^
         " /><br />"
       in
       Http_daemon.send_basic_headers ~code:(`Code 200) outchan ;
       Http_daemon.send_CRLF outchan ;
       iter_file
         (fun line ->
            let processed_line =
              apply_substs
                [form_RE, form ;
                 variables_initialization_RE, variables;
                 advanced_tag_RE, req#param "advanced";
                 current_choices_tag_RE, req#param "choices";
                 interpretations_RE, req#param "interpretation_choices"; 
                 expression_tag_RE, req#param "expression";
                 action_tag_RE, string_tail req#path]  line
            in
              output_string outchan (processed_line ^ "\n"))
         constraints_choice_TPL; 
       raise Chat_unfinished)
  in
  let query =
    G.query_of_constraints universe must'' only'
  in
  let results = MQueryInterpreter.execute mqi_handle query in 
  send_results results ~id_to_uris:id_to_uris' req outchan
in

(* HTTP DAEMON CALLBACK *)

let build_dynamic_uri url params =
  let p = 
    String.concat "&" (List.map  (fun (key,value) -> (key ^ "=" ^ (Netencoding.Url.encode value))) params) in
  url ^ "?" ^ p
in

let build_uwobo_request (req: Http_types.request) outchan =
  prerr_endline ("ECCOLO: " ^ req#param "param.SEARCH_ENGINE_URL");
  let xmluri = build_dynamic_uri ((req#param "param.SEARCH_ENGINE_URL") ^ "/search") req#params in
  prerr_endline ("xmluri: " ^ xmluri);
  (*let xmluri = Netencoding.Url.encode xmluri in*)
  let server_and_port = req#param "param.processorURL" in
  let newreq = 
    build_dynamic_uri 
      (server_and_port ^ "apply") 
      (("xmluri",xmluri)::("keys",(req#param "param.thkeys"))::req#params) in
  (* if List.mem server_and_port valid_servers then *)
  prerr_endline newreq;
  if true then 
    Http_daemon.respond
      ~headers:["Content-Type", "text/html"]
      ~body:(Http_client.http_get newreq)
      outchan
  else
    Http_daemon.respond
      ~body:(pp_error ("Untrusted UWOBO server: " ^ server_and_port ^
      (String.concat "\n" valid_servers)))
      outchan
in

let proxy url outchan =
  let server_and_port =
    (Pcre.extract ~rex:server_and_port_url_RE url).(1)
  in
  if List.mem server_and_port valid_servers then
    Http_daemon.respond
      ~headers:["Content-Type", "text/html"]
      ~body:(Http_client.http_get url)
      outchan
  else
    Http_daemon.respond
      ~body:(pp_error ("Untrusted UWOBO server: " ^ server_and_port))
      outchan
in

let callback mqi_handle (req: Http_types.request) outchan =
  try
    debug_print (sprintf "Received request: %s" req#path);
    (match req#path with
    | "/help" -> Http_daemon.respond ~body:"HELM Search Engine" outchan
    | "/locate" ->
        let initial_expression =
          try req#param "expression" with Http_types.Param_not_found _ -> ""
        in
        let expression =
          Pcre.replace ~pat:"\\s*$"
            (Pcre.replace ~pat:"^\\s*" initial_expression)
        in
        if expression = "" then
          send_results [] req outchan
        else
          let results =
            let query = G.locate expression in
             MQueryInterpreter.execute mqi_handle query
          in
          send_results results req outchan
    | "/execute" ->
        let query_string = req#param "query" in
        let lexbuf = Lexing.from_string query_string in
        let query = MQueryUtil.query_of_text lexbuf in
        let result = MQueryInterpreter.execute mqi_handle query in
        let result_string = pp_result result in
        Http_daemon.respond ~body:result_string ~headers:[contype] outchan
(*  Http_daemon.respond ~headers:[contype] ~body:(pp_result result) outchan *)
    | "/unreferred" ->
        let target = req#param "target" in
        let source = req#param "source" in
        let query = G.unreferred target source in
        let result = MQueryInterpreter.execute mqi_handle query in
        Http_daemon.respond ~headers:[contype] ~body:(pp_result result) outchan
    | "/getpage" ->
        (* TODO implement "is_permitted" *)
        let _ = prerr_endline 
	  (Netencoding.Url.encode "http://mowgli.cs.unibo.it:38080/") in 
        (let is_permitted _ = true in
        let remove_fragment uri = Pcre.replace ~pat:"#.*" uri in
        let page = remove_fragment (req#param "url") in
        let preprocess =
          (try
            bool_of_string (req#param "preprocess")
          with Invalid_argument _ | Http_types.Param_not_found _ -> false)
        in
        (match page with
        | page when is_permitted page ->
            (let fname = sprintf "%s/%s" pages_dir (remove_fragment page) in
            Http_daemon.send_basic_headers ~code:(`Code 200) outchan;
            Http_daemon.send_header "Content-Type" "text/html" outchan;
            Http_daemon.send_CRLF outchan;
            if preprocess then begin
              iter_file
                (fun line ->
                  output_string outchan
                    ((apply_substs
                       ((search_engine_url_RE, my_own_url) ::
                        (advanced_tag_RE, "no") ::
                        (results_RE, "") ::
                       (List.map
                         (function (key,value) ->
                           let key' =
                            (Pcre.extract ~pat:"param\\.(.*)" key).(1)
                           in
                            Pcre.regexp ("@" ^ key' ^ "@"), value
                         )
                         (List.filter
                           (fun (key,_) as p-> Pcre.pmatch ~pat:"^param\\." key)
                           req#params)
                       ))
                       line) ^
                    "\n"))
                fname
            end else
              Http_daemon.send_file ~src:(FileSrc fname) outchan)
        | page -> Http_daemon.respond_forbidden ~url:page outchan))
    (* OLD | "/ask_uwobo" -> proxy (req#param "url") outchan *)
    | "/ask_uwobo" -> build_uwobo_request req outchan
    | "/hint"
    | "/match"
    | "/elim" ->
        exec_action mqi_handle req outchan
    | invalid_request ->
        Http_daemon.respond_error ~code:(`Status (`Client_error `Bad_request))
          outchan);
    debug_print (sprintf "%s done!" req#path)
  with
  | Chat_unfinished -> prerr_endline "Chat unfinished, Try again!"
  | Http_types.Param_not_found attr_name ->
      bad_request (sprintf "Parameter '%s' is missing" attr_name) outchan
  | exc ->
      let msg = sprintf "Uncaught exception: %s" (Printexc.to_string exc) in
       debug_print msg ;
       Http_daemon.respond ~body:(pp_error msg) outchan
in
printf "%s started and listening on port %d\n" daemon_name port;
printf "Current directory is %s\n" (Sys.getcwd ());
printf "HTML directory is %s\n" pages_dir;
flush stdout;
Unix.putenv "http_proxy" "";
let mqi_handle = C.init ~log:debug_print () in
Http_daemon.start' ~port (callback mqi_handle);
C.close mqi_handle;
printf "%s is terminating, bye!\n" daemon_name