;;; emacsconf-ical.el ---  ical export  -*- lexical-binding: t; -*-

;; Copyright (C) 2021  Sacha Chua

;; Author: Sacha Chua <sacha@sachachua.com>
;; Keywords: multimedia

;; 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 3 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; 

;;; Code:

(defvar emacsconf-ical-public-directory (concat "/ssh:orga@media.emacsconf.org:/var/www/media.emacsconf.org/" emacsconf-year)
  "Directory to post ics files to.")

(defun emacsconf-ical-send-via-email ()
  (interactive)
  (let ((ical-file (expand-file-name
                    (concat (org-entry-get (point) "SLUG") ".ics")
                    (expand-file-name "ics" (file-name-directory emacsconf-org-file))))
        (ical-entry (emacsconf-ical-convert-entry-to-string (format-time-string "%Y%m%dT%H%M%SZ" nil t))))
    (with-temp-file ical-file
      (insert ical-entry))
    (emacsconf-mail-speaker "Calendar entry")
    (mml-attach-file ical-file)))

(defun emacsconf-ical-convert-entry-to-string (&optional updated)
  (string-join 
   (list
    "BEGIN:VCALENDAR"
    "VERSION:2.0"
    "PRODID:EmacsConf"
    (concat "X-WR-CALNAME:EmacsConf " emacsconf-year)
    "X-WR-CALNAME:EmacsConf"
    "CALSCALE:GREGORIAN"
    "METHOD:PUBLISH"
    (emacsconf-ical-format-talk (emacsconf-get-talk-info-for-subtree) updated)
    "END:VCALENDAR")
   "\r\n"))

(defun emacsconf-ical-format-talk (o &optional updated)
  (string-join
   (delq
    nil
    (list
     "BEGIN:VEVENT"
     (string-trim (org-icalendar-fold-string
                   (org-icalendar-cleanup-string
                    (concat "SUMMARY:" (plist-get o :title)
                            (if (plist-get o :speakers)
                                (concat " - " (plist-get o :speakers))
                              "")))))
     "ORGANIZER:EmacsConf"
     (concat "LOCATION:" "https://emacsconf.org/")
     ;; (concat "UID:emacsconf-" emacsconf-year "-" (plist-get o :slug))
     (concat "UID:" (plist-get o :uuid))
     (concat "URL:" "https://emacsconf.org/" emacsconf-year "/talks/" (plist-get o :slug))
     (concat "DTSTART:" (format-time-string "%Y%m%dT%H%M%SZ" (plist-get o :start-time) t))
     (concat "DTEND:" (format-time-string "%Y%m%dT%H%M%SZ" (plist-get o :end-time) t))
     (if updated (concat "DTSTAMP:" updated))
     (string-trim
      (org-icalendar-fold-string
       (org-icalendar-cleanup-string
        (concat "DESCRIPTION: Times are approximate and will probably change.\n"
                "https://emacsconf.org/" emacsconf-year "/talks/" (plist-get o :slug) "\n"
                (emacsconf-surround (if (length= (plist-get o :speakers) 1) "Speaker: " "Speakers: ")
                                    (plist-get o :speakers)
                                    "\n" "")
                (plist-get o :markdown)))))
     "END:VEVENT"))
   "\r\n"))

(defun emacsconf-format-as-ical (emacsconf-info)
  (require 'ox-icalendar)
  (let ((updated (format-time-string "%Y%m%dT%H%M%SZ" nil t)))
    (string-join 
     (list
      "BEGIN:VCALENDAR"
      "VERSION:2.0"
      "PRODID:EmacsConf"
      (concat "X-WR-CALNAME:EmacsConf " emacsconf-year)
      "X-WR-CALNAME:EmacsConf"
      "CALSCALE:GREGORIAN"
      "METHOD:PUBLISH"
      (mapconcat (lambda (o) (emacsconf-ical-format-talk o updated))
                 (seq-remove (lambda (o) (string= (plist-get o :status) "CANCELLED"))
                             (emacsconf-filter-talks emacsconf-info))
                 "\r\n")
      "END:VCALENDAR")
     "\r\n")))

(defun emacsconf-ical-generate-all ()
  (interactive)
  (let* ((emacsconf-talk-info-functions (append emacsconf-talk-info-functions (list 'emacsconf-get-abstract-from-wiki)))
         (info (emacsconf-get-talk-info)))
    (emacsconf-ical-generate-main info)
    (emacsconf-ical-generate-tracks info)))

(defun emacsconf-ical-generate-main (&optional info)
  (with-temp-file (expand-file-name "emacsconf.ics"
                                    (or emacsconf-ical-public-directory
                                        (expand-file-name emacsconf-year emacsconf-directory)))
    (insert (emacsconf-format-as-ical (emacsconf-prepare-for-display (or info (emacsconf-get-talk-info)))))))

(defun emacsconf-ical-generate-tracks (&optional info)
  (interactive)
  (mapc (lambda (entry)
          (let ((track (emacsconf-get-track (car entry))))
            (when track
              (with-temp-file (expand-file-name (format "emacsconf-%s.ics" (plist-get track :id))
                                                (or emacsconf-ical-public-directory
                                                    (expand-file-name emacsconf-year emacsconf-directory)))
                (insert (emacsconf-format-as-ical (cdr entry)))))))
        (seq-group-by (lambda (o) (plist-get o :track)) (emacsconf-prepare-for-display (or info (emacsconf-get-talk-info))))))

(provide 'emacsconf-ical)