(* COCANWIKI - a wiki written in Objective CAML.
 * Written by Richard W.M. Jones <rich@merjis.com>.
 * Copyright (C) 2004 Merjis Ltd.
 * $Id: cocanwiki_ext_calendar.ml,v 1.2 2004/10/07 18:56:53 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 ExtList

open GregorianDate

open Cocanwiki
open Cocanwiki_template
open Cocanwiki_strings
open Cocanwiki_date

let day_template = _get_template "calendar_day.html"
let month_template = _get_template "calendar_month.html"
let year_template = _get_template "calendar_year.html"
let year_1m_template = _get_template "calendar_year_1m.html"

let rec range a b =
  if a <= b then
    a :: range (a+1) b
  else
    []

let extension (dbh : Dbi.connection) hostid url =
  (* Validate a date in the form "yyyy[/mm[/dd]]".  Returns a (yyyy, mm, dd)
   * tuple with missing fields set to 0.  If the string doesn't parse or the
   * date isn't valid, then raises Not_found.
   *)
  let valid_date str =
    if String.length str = 4 &&
      isdigit str.[0] && isdigit str.[1] &&
      isdigit str.[2] && isdigit str.[3] then (
	let yyyy = int_of_string (String.sub str 0 4) in
	(yyyy, 0, 0)
      )
    else if String.length str = 7 &&
      isdigit str.[0] && isdigit str.[1] &&
      isdigit str.[2] && isdigit str.[3] &&
      str.[4] = '/' &&
      isdigit str.[5] && isdigit str.[6] then (
	let yyyy = int_of_string (String.sub str 0 4) in
	let mm = int_of_string (String.sub str 5 2) in
	if mm >= 1 && mm <= 12 then (yyyy, mm, 0) else raise Not_found
      )
    else if String.length str = 10 &&
      isdigit str.[0] && isdigit str.[1] &&
      isdigit str.[2] && isdigit str.[3] &&
      str.[4] = '/' &&
      isdigit str.[5] && isdigit str.[6] &&
      str.[7] = '/' &&
      isdigit str.[8] && isdigit str.[9] then (
	let yyyy = int_of_string (String.sub str 0 4) in
	let mm = int_of_string (String.sub str 5 2) in
	let dd = int_of_string (String.sub str 8 2) in
	let date = (yyyy, mm, dd) in
	if GregorianDate.check_date date then date else raise Not_found
      )
    else
      raise Not_found
  in

  (* From the links table, find all links to this page, or sub-calendar pages.
   * This query overselects.  We then filter the real pages in OCaml.
   *)
  let sth =
    dbh#prepare_cached
      "select li.from_url, p.title, li.to_url
         from links li, pages p
        where li.hostid = ? and li.to_url like ?
          and li.hostid = p.hostid and li.from_url = p.url" in
  sth#execute [`Int hostid; `String (url ^ "%")];

  let pages =
    let results =
      sth#map (function [`String from_url; `String title; `String to_url] ->
		 from_url, title, to_url
		 | _ -> assert false) in
    List.filter_map
      (fun (from_url, title, to_url) ->
	 try let date = valid_date to_url in Some (date, (title, from_url))
	 with Not_found -> None) results in
  let pages = List.sort pages in

  (* Validate the date in the URL itself. *)
  let date =
    try Some (valid_date url)
    with Not_found -> None in

  match date with
    | None ->				(* Not a valid date. *)
	"<p>" ^ url ^ " is not an actual date.</p>"
    | Some (yyyy, 0, 0) ->		(* Year view. *)
	let template = year_template in

	template#set "yyyy" (string_of_int yyyy);
	template#set "prev_yyyy" (string_of_int (yyyy - 1));
	template#set "next_yyyy" (string_of_int (yyyy + 1));

	(* Return true if there are any events on a particular day. *)
	let has_events date = List.exists (fun (d, _) -> date = d) pages in

	(* Generate each month template separately ...
	 * Wow, finally found a place I can use a for loop.
	 *)
	for mm = 1 to 12 do
	  let str =
	    let template = year_1m_template in
	    template#set "yyyy" (string_of_int yyyy);
	    template#set "mm" (sprintf "%02d" mm);
	    template#set "month_name" (long_month mm);
	    let dow = GregorianDate.day_of_week (yyyy, mm, 1) in
	    let dow = if dow = 7 then 0 else dow in
	    let max_dd = GregorianDate.days_in_month yyyy mm in
	    let dd = ref (1-dow) in
	    let rows = ref [] in
	    for r = 0 to 5 do		(* up to 5 rows ... *)
	      let cols = ref [] in
	      for c = 0 to 6 do		(* 7 columns, Sunday - Saturday *)
		let is_day = !dd >= 1 && !dd <= max_dd in
		let clasz =
		  if is_day then (
		    let date = yyyy, mm, !dd in
		    let is_weekend = GregorianDate.day_of_week date >= 6 in
		    let events = has_events date in
		    (if is_weekend then "cal_year_1m_weekend " else "") ^
		    (if events then "cal_year_1m_events" else "")
		  ) else
		    "cal_year_1m_empty" in
		let col =
		  [ "is_day", Template.VarConditional is_day;
		    "dd", Template.VarString (sprintf "%02d" !dd);
		    "class", Template.VarString clasz ] in
		cols := col :: !cols;
		incr dd
	      done;
	      rows := [ "cols", Template.VarTable (List.rev !cols) ] :: !rows;
	      cols := []
	    done;

	    template#table "rows" (List.rev !rows);

	    template#to_string in
	  template#set ("month" ^ string_of_int mm) str
	done;

	(* Annual events. *)
	let events =
	  List.filter (function ((_, 0, 0), _) -> true | _ -> false) pages in

	let table =
	  List.map (fun (_, (title, page)) ->
		      [ "title", Template.VarString title;
			"page", Template.VarString page ]) events in
	template#table "events" table;

	template#to_string

    | Some (yyyy, mm, 0) ->		(* Month view. *)
	let template = month_template in

	template#set "month_name" (long_month mm);
	template#set "yyyy" (string_of_int yyyy);
	template#set "mm" (sprintf "%02d" mm);

	let prev_yyyy, prev_mm =
	  if mm = 1 then yyyy - 1, 12
	  else yyyy, mm - 1 in
	let next_yyyy, next_mm =
	  if mm = 12 then yyyy + 1, 1
	  else yyyy, mm + 1 in
	template#set "prev_yyyy" (string_of_int prev_yyyy);
	template#set "prev_mm" (sprintf "%02d" prev_mm);
	template#set "next_yyyy" (string_of_int next_yyyy);
	template#set "next_mm" (sprintf "%02d" next_mm);

	(* Get all monthly events and all daily events. *)
	let monthly_events, daily_events =
	  List.partition (function ((_, _, 0), _) -> true | _ -> false)
	    pages in

	(* Table of monthly events. *)
	let table =
	  List.map (fun (_, (title, page)) ->
		      [ "title", Template.VarString title;
			"page", Template.VarString page ]) monthly_events in
	template#table "monthly_events" table;

	(* How many days in this month? *)
	let max_dd = GregorianDate.days_in_month yyyy mm in
	let days = range 1 max_dd in

	let table =
	  List.map (fun dd ->
		      let events =
			List.filter (fun ((_, _, d), _) -> d = dd)
			  daily_events in
		      let table =
			List.map (fun (_, (title, page)) ->
				    [ "title", Template.VarString title;
				      "page", Template.VarString page ])
			  events in
		      let is_weekend =
			GregorianDate.day_of_week (yyyy, mm, dd) >= 6 in
		      [ "dd", Template.VarString (sprintf "%02d" dd);
			"is_weekend", Template.VarConditional is_weekend;
			"events", Template.VarTable table ])
	    days in
	template#table "days" table;

	template#to_string

    | Some (yyyy, mm, dd) ->		(* Single day view. *)
	let template = day_template in
	failwith "not impl";












	template#to_string

(* Register the extension. *)
let () =
  extensions := ("calendar", extension) :: !extensions