;; Adds org-links for EMMS
;; Based on
;; https://orgmode.org/manual/Adding-Hyperlink-Types.html#Adding-Hyperlink-Types
;;
;; - (untested);;
;; (with-eval-afeter-load "org"
;;                        (add-to-list
;;                         'load-path
;;                         "/your/path/to/this/file.el")
;;                        (require 'ol-emms))
;;
;; - To load it with use-package:
;; (use-package ol-emms
;;   :after (ol)
;;   :load-path "~/.emacs.d/plugins/"
;;   :config
;;   (add-hook 'org-mode-hook
;;             #'(lambda ()
;;                 "Add `org-emms-open' to `org-add-link-type'"
;;                 (org-add-link-type "emms" 'org-emms-open))))

(require 'ol)
(require 'emms)

(defun org-emms-store-link ()
  "Store a link to a sound file."
  (when (eq major-mode 'emms-playlist-mode)
    ;; This is EMMS mode, we do make this link.
    (let* ((file (org-emms-get-file-name))
           (link (concat "emms:" file))
           (desc (emms-info-track-description (emms-playlist-track-at)))
           )
      (org-link-store-props
       :type "emms"
       :link link
       :decription desc))))

(defun org-emms-get-file-name ()
  "Get the file name from the current playlist line."
  (let ((fname (emms-track-simple-description (emms-playlist-track-at))))
    (if (file-exists-p fname)
        fname
      nil)))

(defun org-emms-export (link description format)
  "Export an EMMS link from Org files."
  (let ((desc (or link description)))
    (pcase format
      (`html (format "<a href=\"%s\">%s</a>" path desc))
      (`latex (format "\\href{%s}{%s}" path desc))
      (`texinfo (format "@uref{%s,%s}" path desc))
      (`ascii (format "%s (%s)" desc path))
      (_ path))))

(defun org-emms-open (link)
  "The EMMS command to be used to play a sound file."
  (if (file-exists-p link)
      ;; If the file is a playlist (based on extension), use
      ;; it as such. Otherwise, play the file
      (let ((fname (expand-file-name link))
            (buf nil))

        ;; Add file to playlist
        (if ;; Check if the extension of the file is in the
            ;; list of playlist extensions
            (member
             ;; Get the extension as a symbol
             ;;   https://emacsredux.com/blog/2014/12/05
             ;;   /converting-between-symbols-and-strings/
             (intern (file-name-extension link))
             emms-source-playlist-formats)
            ;; Add playlist
            (emms-play-playlist fname)
          ;; Add regular file
          (emms-play-file fname)))))

(defun org-emms-complete-link (&optional arg)
  "Use the existing file name completion for file.
Links to get the file name and append it. (Based on
`org-pdfview')."
  (replace-regexp-in-string "^file:" "emms:" (org-link-complete-file arg)))

(org-link-set-parameters "emms"
                         :follow #'org-emms-open
                         :export #'org-emms-export
                         :complete #'org-emms-complete-link
                         :store #'org-emms-store-link)

(provide 'ol-emms)

;;; ol-emms.el ends here