;;; livie-channel.el --- Auxiliary major mode for livie -*- lexical-binding: t; -*-

;; Copyright (C) 2018 - 2021

;;; Authors:

;; Charlie Ritter <chewzerita@posteo.net>
;; Jesus E. <heckyel@hyperbola.info>
;; Gabriele Rastello <gabriele.rastello@edu.unito.it>
;; Pablo BC <pablo.barraza@protonmail.com>

;;; Commentary:

;; livie grabs a list of youtube videos based on a search.
;; the user can then select a video to watch through `livie-player'

;;; Code:

(defcustom livie-channel-sort-criterion "newest"
  "Sort videos by 'newest', 'oldest', or 'popular', as used by `livie-channel-search'."
  :type 'string
  :options '("newest" "oldest" "popular")
  :group 'livie-channel)

(defvar livie-channel-mode-map
  (let ((map (make-sparse-keymap)))
    (set-keymap-parent map text-mode-map)
    (define-key map "h" #'describe-mode)
    (define-key map "q" #'livie--quit-channel-buffer)
    (define-key map ">" #'livie-channel-next-page)
    (define-key map "<" #'livie-channel-previous-page)
    (define-key map (kbd "<tab>") #'next-line)
    (define-key map (kbd "<backtab>") #'previous-line)
    (define-key map "S" #'livie-channel-sort-videos)
    (define-key map (kbd "RET") #'livie-open-entry)
    (define-key map "y" #'livie-watch-this-video)
    map)
  "Keymap for `livie-channel-mode'.")

(define-derived-mode livie-channel-mode livie-mode
  "livie-channel-mode"
  "Mode for displaying livie-channel-videos.
\\{livie-channel-mode-map}"
  (buffer-disable-undo)
  (make-local-variable 'livie-videos)
  (make-local-variable 'livie-channel-author)
  (setq-local livie-type-of-results "video")
  (setf	buffer-read-only t))

(defun livie--channel-query (uid n sort)
  "Query youtube for UID videos, return the Nth page of results, sorted bv SORT."
  (let ((videos (livie--API-call (concat "channels/videos/" uid)
				 `(("page" ,n)
				   ("sort_by" ,sort)
				   ("fields" ,livie-default-video-query-fields)))))
    (dotimes (i (length videos))
      (let ((v (aref videos i)))
	(aset videos i
	      (livie-video--create :title     (assoc-default 'title v)
				   :author    (assoc-default 'author v)
				   :authorId  (assoc-default 'authorId v)
				   :length    (assoc-default 'lengthSeconds v)
				   :id        (assoc-default 'videoId v)
				   :views     (assoc-default 'viewCount v)
				   :published (assoc-default 'published v)))))
    videos))

(defun livie-channel ()
  "Open a buffer for the channel of the current entry."
  (let* ((entry (livie-get-current-video))
	 (author (funcall (livie--get-author-function entry) entry))
	 (authorId (funcall (livie--get-authorId-function entry) entry)))
    (get-buffer-create author)
    (switch-to-buffer author)
    (unless (eq major-mode 'livie-channel-mode)
      (livie-channel-mode))
    (setf livie-channel-author author)
    (setf livie-search-term authorId)
    (livie-channel-get-videos authorId)))

(defun livie-channel-get-videos (authorId)
  "Fetch videos from AUTHORID."
  (setf livie-current-page 1)
  (setf livie-videos (livie--channel-query authorId livie-current-page livie-channel-sort-criterion))
  (livie--draw-channel-buffer))

(defun livie-channel-next-page ()
  "Fetch videos from AUTHORID."
  (interactive)
  (setf livie-current-page (1+ livie-current-page))
  (setf livie-videos (livie--channel-query livie-search-term livie-current-page livie-channel-sort-criterion))
  (livie--draw-channel-buffer))

(defun livie-channel-previous-page ()
  "Fetch videos from AUTHORID."
  (interactive)
  (when (> livie-current-page 1)
    (setf livie-current-page (1- livie-current-page))
    (setf livie-videos (livie--channel-query livie-search-term livie-current-page livie-channel-sort-criterion))
    (livie--draw-channel-buffer)))

(defun livie-channel-sort-videos ()
  "Sort videos from the current channel, either by newest (default), oldest, or popular."
  (interactive)
  (setf livie-channel-sort-criterion (completing-read "Sort videos by (default value is newest): " (get 'livie-channel-sort-criterion 'custom-options)))
  (setf livie-current-page 1)
  (setf livie-videos (livie--channel-query livie-search-term livie-current-page livie-channel-sort-criterion))
  (livie--draw-channel-buffer))

(defun livie--insert-channel-video (video)
  "Insert VIDEO in the current buffer."
  (insert (livie--format-video-published (livie-video-published video))
	  " "
	  (livie--format-title (livie-video-title video))
	  " "
	  (livie--format-video-length (livie-video-length video))
	  " "
	  (livie--format-video-views (livie-video-views video))))

(defun livie--draw-channel-buffer ()
  "Draws the livie channel buffer i.e. clear everything and write down all videos in `livie-videos'."
  (let ((inhibit-read-only t)
	(current-line (line-number-at-pos)))
    (erase-buffer)
    (setq header-line-format (concat "Displaying videos from " (propertize livie-channel-author 'face 'livie-parameter-face)
				     ", page "
				     (propertize (number-to-string livie-current-page) 'face 'livie-parameter-face)
				     ", sorted by: "
				     (propertize livie-channel-sort-criterion 'face 'livie-parameter-face)))
    (seq-do (lambda (v)
	      (livie--insert-channel-video v)
	      (insert "\n"))
	    livie-videos)
    (goto-char (point-min))))

(defun livie--quit-channel-buffer ()
  "Deletes the current buffer."
  (interactive)
  (kill-buffer (current-buffer)))

(provide 'livie-channel)

;; Local Variables:
;; byte-compile-warnings: (not free-vars)
;; End:
;;; livie-channel.el ends here