(* COCANWIKI - a wiki written in Objective CAML.
 * Written by Richard W.M. Jones <rich@merjis.com>.
 * Copyright (C) 2004 Merjis Ltd.
 * $Id: links.ml,v 1.2 2004/11/02 18:47:54 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
open Cocanwiki_links

(* This script produces the links database for the whole site (if
 * called without the 'page' parameter), or else just for a particular
 * page.  If called with 'page' and 'type' parameters together, then it
 * can show inbound or outbound links only.  The format in all cases is a
 * simple machine-parsable text file.
 *)
let run r (q : cgi) (dbh : Dbi.connection) hostid _ _ =
  let template = get_template dbh hostid "links.txt" in

  if q#param_exists "page" then (
    let page = q#param "page" in
    let page = if page = "" then "index" else page in

    if q#param_exists "type" then (
      let type_ = q#param "type" in

      if type_ = "inbound" then (
	(* This is "what links here".  We're interested in indirect
	 * links too, so use Cocanwiki_links.what_links_here function.
	 *)
	let links = what_links_here dbh hostid page in
	let links = List.map fst links in

	q#header ~content_type:"text/plain" ();

	List.iter (fun url -> ignore (print_endline r url)) links

      ) else if type_ = "outbound" then (
	(* Display a list of links outbound from this page. *)
	let sth =
	  dbh#prepare_cached "select to_url from links
                               where hostid = ? and from_url = ?" in

	sth#execute [`Int hostid; `String page];

	q#header ~content_type:"text/plain" ();

	sth#iter (function [`String url] -> ignore (print_endline r url)
		    | _ -> assert false)

      ) else
	failwith "'type' parameter should be 'inbound' or 'outbound'"

    ) else (
      (* Just return the single-row "links database" relating to this
       * page.
       *)
      let sth = dbh#prepare_cached "select to_url from links
                                     where hostid = ? and from_url = ?" in
      sth#execute [`Int hostid; `String page];

      let table =
	sth#map (function [`String to_url] ->
		   [ "to", Template.VarString to_url ]
		   | _ -> assert false) in
      let table =
	[ [ "from", Template.VarString page;
	    "to", Template.VarTable table ] ] in
      template#table "links" table;

      q#template ~content_type:"text/plain" template
    )
  ) else (
    (* Links database for whole site in the simple format required by
     * the TouchGraph application.  We don't know anything about external
     * links, so we don't include them.  However we do include links to
     * non-existant internal pages.
     *)
    let h = Hashtbl.create 1024 in
    let add_link from_url to_url =
      let xs = try Hashtbl.find h from_url with Not_found -> [] in
      let xs = to_url :: xs in
      Hashtbl.replace h from_url xs
    in

    let sth = dbh#prepare_cached "select from_url, to_url from links
                                   where hostid = ?" in
    sth#execute [`Int hostid];

    sth#iter (function [`String from_url; `String to_url] ->
		add_link from_url to_url
		| _ -> assert false);

    (* Don't forget redirects!  They're kinda like links ... *)
    let sth = dbh#prepare_cached "select url, redirect from pages
                                   where hostid = ? and url is not null
                                     and redirect is not null" in
    sth#execute [`Int hostid];

    sth#iter (function [`String url; `String redirect] ->
		add_link url redirect
		| _ -> assert false);

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

    let table =
      List.map
	(fun from ->
	   let xs = Hashtbl.find h from in
	   let table =
	     List.map (fun to_ -> [ "to", Template.VarString to_ ]) xs in
	   [ "from", Template.VarString from;
	     "to", Template.VarTable table ]
	) (keys h) in
    template#table "links" table;

    q#template ~content_type:"text/plain" template
  )

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