Manage daily todo files on Emacs

todo.el

(defun create-directory (directory)
  "Creates the todo directory."
  (if (file-exists-p directory) (message "Director exists")
    (make-directory directory)
    (message "Directory created")
    ))

(defun create-todo-file (directory filename)
  "Checks if the todo file exists if not creates it."
  (create-directory directory)
  (if (file-exists-p filename) (message "Todo exists for the day")
    (write-region "" nil filename)))

(defun open-todo-file (directory)
  "Opens a todo file for the current day."
  (let (
       (filename
         (concat directory "/" (format-time-string "%Y-%m-%d") ".org")))
    (create-todo-file directory filename)
    (find-file filename)))

(defun open-todo-file-interactive ()
  "Creates a daily todo file.
  Track what needs to be done for the day.
  Plan your day better.
  See what you have accomplished at the end of the day."
  (interactive)
  (open-todo-file "~/todo"))

(global-set-key (kbd "C-c C-t") 'open-todo-file-interactive)