(* COCANWIKI scripts.
 * Written by Richard W.M. Jones <rich@merjis.com>.
 * Copyright (C) 2004 Merjis Ltd.
 * $Id: cocanwiki_template.ml,v 1.3 2004/09/08 15:46:52 rich Exp $
 *
 * This module wraps around the Template library.  It provides caching
 * of templates and fills in standard fields on a host-specific basis.
 *
 *)

open Unix

open Cocanwiki_files

let base =
  let base =
    try Sys.getenv "COCANWIKI_TEMPLATES"
    with Not_found -> "/usr/share/cocanwiki/templates" in
  let is_dir path =
    try (Unix.stat path).Unix.st_kind = Unix.S_DIR
    with Unix.Unix_error _ -> false in
  if not (is_dir base) then
    failwith ("environment variable $COCANWIKI_TEMPLATES " ^
	      "must be set to point to my 'templates' directory " ^
	      "(see README file for more details)");
  base

(* Cache of precompiled templates, arranged by full path. *)
let cache = Hashtbl.create 32

let _get_template filename =
  let path = base // filename in
  let stat = Unix.stat path in
  let mtime = stat.st_mtime in

  try
    let template, old_mtime = Hashtbl.find cache path in
    if old_mtime < mtime then (
      (* The template has changed on disk since it was compiled.  Reload. *)
      let template = Template.template path in
      Hashtbl.replace cache path (template, mtime);
      template
    ) else
      template
  with
      Not_found ->
	(* Template not seen before, so load it. *)
	let template = Template.template path in
	Hashtbl.replace cache path (template, mtime);
	template

let get_template (dbh : Dbi.connection) hostid filename =
  let template = _get_template filename in

  (* Get standard fields concerning this host from the database. *)
  (* XXX *)

  template