Helm: Add "Add to EMMS playlist" find-file action

.emacs.d/lisp/init-helm.el

@@ -310,6 +310,19 @@ With prefix argument, UPDATE the databases with custom uptions thanks to the
      (and (not (string-match-p ffap-url-regexp candidate))
           helm-ff-default-directory
           (locate-dominating-file helm-ff-default-directory ".git")))
+   1)
+  (helm-source-add-action-to-source-if
+   "Add to EMMS playlist"
+   (lambda (_candidate)
+     (when (require 'emms nil 'noerror)
+       (dolist (c (helm-marked-candidates))
+         (emms-add-directory-tree c))))
+   source
+   (lambda (candidate)
+     (or (file-directory-p candidate)
+         (and (file-name-extension candidate)
+              (string-match-p (concat (regexp-opt '("mp3" "mp4" "m4a" "ogg" "flac" "spx" "wma" "wv")) "$")
+                              (file-name-extension candidate)))))
    1))
 
 (provide 'init-helm)