(defun my-set-theme-on-mode ()
  (let* ((mode (cond
                ((memq major-mode '(clojure-mode clojurescript-mode))
                 'zenburn)
                ((memq major-mode '(elisp-mode emacs-lisp-mode))
                 'dracula)
                ((memq major-mode '(python-mode octave-mode))
                 'solarized-dark)
                ((memq major-mode '(org-mode))
                 'nord))))
    (when mode
      (load-theme mode))))

(defadvice switch-to-buffer (after activate)
  (when buffer-file-name (my-set-theme-on-mode)))
(defadvice other-window (after other-window-now activate)
  (when buffer-file-name (my-set-theme-on-mode)))
(defadvice other-frame (after other-frame-now activate)
  (when buffer-file-name (my-set-theme-on-mode)))

(add-hook 'after-change-major-mode-hook 'my-set-theme-on-mode)