;;; mastodon-tl.el --- HTTP request/response functions for mastodon.el

;; Copyright (C) 2017 Johnson Denen
;; Author: Johnson Denen <johnson.denen@gmail.com>
;; Homepage: https://github.com/jdenen/mastodon.el

;; This file is not part of GNU Emacs.

;; This file is part of mastodon.el.

;; mastodon.el 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.

;; mastodon.el 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 mastodon.el.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; mastodon-tl.el provides timeline functions.

;;; Code:

(require 'mastodon-http)

(defgroup mastodon-tl nil
  "Timelines in Mastodon."
  :prefix "mastodon-tl-"
  :group 'mastodon)

(defun mastodon-tl--get-federated-timeline ()
  "Opens federated timeline."
  (interactive)
  (mastodon-tl--get "public"))

(defun mastodon-tl--get-home-timeline ()
  "Opens home timeline."
  (interactive)
  (mastodon-tl--get "home"))

(defun mastodon-tl--get-local-timeline ()
  "Opens local timeline."
  (interactive)
  (mastodon-tl--get "public?local=true"))

(defun mastodon-tl--get-tag-timeline ()
  "Prompts for tag and opens its timeline."
  (interactive)
  (let ((tag (read-string "Tag: ")))
    (mastodon-tl--get (concat "tag/" tag))))

(defun mastodon-tl--goto-toot-pos (find-pos &optional pos)
  "Search for toot with FIND-POS. Optionally stat from POS."
  (let* ((npos (funcall find-pos
                        (or pos (point))
                        'toot-id
                        (current-buffer))))
    (when npos (if (not (get-text-property npos 'toot-id))
                   (mastodon-tl--goto-toot-pos find-pos npos)
                 (when npos (goto-char npos))))))

(defun mastodon-tl--goto-next-toot ()
  "Jump to next toot header."
  (interactive)
  (mastodon-tl--goto-toot-pos 'next-single-property-change))

(defun mastodon-tl--goto-prev-toot ()
  "Jump to last toot header."
  (interactive)
  (mastodon-tl--goto-toot-pos 'previous-single-property-change))

(defun mastodon-tl--timeline-name ()
  "Determine timeline from `buffer-name'."
  (replace-regexp-in-string "\*" ""
                            (replace-regexp-in-string "mastodon-" "" (buffer-name))))

(defun mastodon-tl--remove-html (toot)
  (let* ((t1 (replace-regexp-in-string "<\/p>" "\n\n" toot))
         (t2 (replace-regexp-in-string "<\/?span>" "" t1)))
    (replace-regexp-in-string "<span class=\"h-card\">" "" t2)))

(defun mastodon-tl--byline-author (toot)
  "Propertize author of TOOT."
  (let* ((account (cdr (assoc 'account toot)))
         (handle (cdr (assoc 'acct account)))
         (name (cdr (assoc 'display_name account))))
    (concat
     (propertize name 'face 'warning)
     " (@"
     handle
     ")")))

(defun mastodon-tl--byline-boosted (toot)
  "Add byline for boosted data from TOOT."
  (let ((reblog (cdr (assoc 'reblog toot))))
    (when reblog
      (concat
       " "
       (propertize "Boosted" 'face 'highlight)
       " "
       (mastodon-tl--byline-author reblog)))))

(defun mastodon-tl--byline (toot)
  (let ((id (cdr (assoc 'id toot)))
        (faved (or (cdr (assoc 'favourited toot))
                   (cdr (assoc 'favourited
                               (cdr (assoc 'reblog toot))))))
        (boosted (or (cdr (assoc 'reblogged toot))
                     (cdr (assoc 'reblogged
                                 (cdr (assoc 'reblog toot)))))))
    (propertize
     (concat (propertize "\n | " 'face 'default)
             (when boosted
               (format "(%s) " (propertize "B" 'face 'success)))
             (when faved
               (format "(%s) " (propertize "F" 'face 'success)))
             (mastodon-tl--byline-author toot)
             (mastodon-tl--byline-boosted toot)
             (propertize "\n  ------------" 'face 'default))
     'toot-id id)))

(defun mastodon-tl--content (toot)
  (let* ((reblog (cdr (assoc 'reblog toot)))
         (content (if reblog
                      (cdr (assoc 'content reblog))
                    (cdr (assoc 'content toot)))))
    (propertize (mastodon-tl--remove-html content)
                'face 'default)))

(defun mastodon-tl--toot (toot)
  (insert
   (concat
    (mastodon-tl--content toot)
    (mastodon-tl--byline toot)
    "\n\n")))

(defun mastodon-tl--timeline (toots)
  (mapcar 'mastodon-tl--toot toots)
  (html2text)
  (replace-regexp "\n\n\n" "\n" nil (point-min) (point-max)))

;; TODO
;; Look into the JSON returned here by Local
(defun mastodon-tl--updated-json (timeline id)
  "Return JSON for TIMELINE since ID."
  (let ((url (mastodon--api-for (concat "timelines/"
                                        timeline
                                        "?since_id="
                                        (number-to-string id)))))
    (mastodon-http--get-json url)))

(defun mastodon-tl--property (prop)
  "Get property PROP for toot at point."
  (or (get-text-property (point) prop)
      (progn
        (mastodon-tl--goto-next-toot)
        (get-text-property (point) prop))))

(defun mastodon-tl--newest-id ()
  "Return toot-id from the top of the buffer."
  (goto-char (point-min))
  (mastodon-tl--property 'toot-id))

(defun mastodon-tl--update ()
  "Update timeline with new toots."
  (interactive)
  (let* ((tl (mastodon-tl--timeline-name))
         (id (mastodon-tl--newest-id))
         (json (mastodon-tl--updated-json tl id)))
    (when json
      (with-current-buffer (current-buffer)
        (let ((inhibit-read-only t))
          (goto-char (point-min))
          (mastodon-tl--timeline json))))))

(defun mastodon-tl--get (timeline)
  "Display TIMELINE in buffer."
  (let* ((url (mastodon--api-for (concat "timelines/" timeline)))
         (buffer (concat "*mastodon-" timeline "*"))
         (json (mastodon-http--get-json url)))
    (with-output-to-temp-buffer buffer
      (switch-to-buffer buffer)
      (mastodon-tl--timeline json))
    (mastodon-mode)))

(provide 'mastodon-tl)
;;; mastodon-tl.el ends here