(* COCANWIKI - a wiki written in Objective CAML.
 * Written by Richard W.M. Jones <rich@merjis.com>.
 * Copyright (C) 2004 Merjis Ltd.
 * $Id: broken_links.ml,v 1.2 2006/03/27 18:09:46 rich Exp $
 *
 * This program 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.
 *
 * This program 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 this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *)

open Apache
open Registry
open Cgi
open Printf

open Cocanwiki
open Cocanwiki_template

let keys h = Hashtbl.fold (fun key _ xs -> key :: xs) h []

let run r (q : cgi) dbh hostid _ _ =
  let template = get_template dbh hostid "broken_links.html" in

  (* The links table (to_url) field can now point to a non-existant
   * page.  It's from this observation that we are able to retrieve
   * the complete list of broken links.  Links to empty template pages
   * aren't broken links either because some of the content is
   * synthesized.
   *)
  let rows =
    PGSQL(dbh)
      "select l.from_url, p.title, l.to_url
         from links l, pages p
        where l.hostid = $hostid
          and l.hostid = p.hostid and l.from_url = p.url
          and p.redirect is null
          and not exists (select id from pages
                           where hostid = l.hostid and url = l.to_url)
          and not exists (select id from templates
                           where l.to_url ~ url_regexp)
        order by 3, 1 desc" in

  (* Group the links together. *)
  let h = Hashtbl.create 32 in
  List.iter (
    fun (from_url, from_title, to_url) ->
      let a = try Hashtbl.find h to_url with Not_found -> [] in
      let a = (from_url, from_title) :: a in
      Hashtbl.replace h to_url a
  ) rows;

  let keys = List.sort compare (keys h) in
  let table =
    List.map
      (fun to_url ->
	 let values = Hashtbl.find h to_url in
	 let table =
	   List.map
	     (fun (from_url, from_title) ->
		[ "page", Template.VarString from_url;
		  "title", Template.VarString from_title ]) values in
	 [ "url", Template.VarString to_url;
	   "references", Template.VarTable table ]) keys in

  template#table "links" table;

  q#template template

let () =
  register_script ~restrict:[CanView] run