(use-package tramp
  :ensure nil ;; package is bundled with emacs

  :init
  ;; use ssh as transfer method
  (setq tramp-default-method "ssh")

  ;; workaround for long ControlPath on darwin
  ;; https://trac.macports.org/ticket/29794
  (when (eq system-type 'darwin)
    (setq tramp-ssh-controlmaster-options
          "-o ControlPath=/tmp/%%r@%%h:%%p -o ControlMaster=auto -o ControlPersist=no"))

  ;; disable vc integration for remote files
  (setq vc-ignore-dir-regexp
        (format "\\(%s\\)\\|\\(%s\\)"
                vc-ignore-dir-regexp
                tramp-file-name-regexp))

  :bind
  (("C-x +" . sudo-find-file)
   ("C-x !" . sudo-current-file))

  :config
  ;; make sudo:remote-host work as expected
  (add-to-list 'tramp-default-proxies-alist '(nil "\\`root\\'" "/ssh:%h:"))
  (add-to-list 'tramp-default-proxies-alist
               '((regexp-quote (system-name)) nil nil))

  (defun sudo-prefix-p (prefix)
    "Return t if PREFIX is a sudo prefix."
    (or (string-equal prefix "/sudo") (string-equal prefix "/sudo:")))

  (defun ssh-prefix-p (prefix)
    "Return t if PREFIX is a ssh prefix."
    (string-equal prefix "/ssh"))

  (defun sudo-file-name (filename)
    "Return FILENAME with a sudo prefix.

If FILENAME already has a sudo prefix, do nothing. If FILENAME is
accessed over SSH, prefix it with \"/sudo:\". Otherwise, assume
FILENAME is a local path and prefix it with \"/sudo::\"."
    (let* ((splitname (split-string filename ":"))
           (prefix (car splitname))
           (ssh-p (ssh-prefix-p prefix))
           (sudo-p (sudo-prefix-p prefix)))
      (if sudo-p
          filename
        (let ((sudo-prefix (if ssh-p "/sudo" "/sudo:"))
              (components (if ssh-p (cdr splitname) splitname)))
          (mapconcat 'identity (cons sudo-prefix components) ":")))))

  (defun sudo-find-file (&optional arg)
    "Find file and open it with sudo.
With a prefix ARG prompt edit currently visited file using sudo."
    (interactive "P")
    (if arg
        (find-alternate-file (sudo-file-name buffer-file-name))
      (find-file (sudo-file-name (ido-read-file-name "Find file with sudo: ")))))

  (defun sudo-current-file ()
    (interactive)
    (sudo-find-file t)))

(provide 'init-tramp)