(require 'epa)
(require 'dired)

(defvar epa-dired-map
  (let ((keymap (make-sparse-keymap)))
    (define-key keymap "d" 'epa-dired-do-decrypt)
    (define-key keymap "v" 'epa-dired-do-verify)
    (define-key keymap "s" 'epa-dired-do-sign)
    (define-key keymap "e" 'epa-dired-do-encrypt)
    keymap))

(fset 'epa-dired-prefix epa-dired-map)

(defun epa-dired-setup ()
  (add-hook 'dired-mode-hook 'epa-dired-mode-hook))

(defun epa-dired-mode-hook ()
  (define-key dired-mode-map ":" 'epa-dired-prefix))

(defun epa-dired-decrypt-file (file)
  (let ((context (epg-make-context)))
    (message "Decrypting %s..." (file-name-nondirectory file))
    (epg-decrypt-file context file)
    (message "Decrypting %s...done" (file-name-nondirectory file))))

(defun epa-dired-do-decrypt ()
  (interactive)
  (let ((file-list (dired-get-marked-files)))
    (while file-list
      (epa-dired-decrypt-file (car file-list))
      (setq file-list (cdr file-list)))))

(defun epa-dired-verify-file (file)
  (let* ((context (epg-make-context))
	 (plain (if (equal (file-name-extension file) "sig")
		    (file-name-sans-extension file))))
    (message "Verifying %s..." (file-name-nondirectory file))
    (epg-verify-file context file plain)
    (message "Verifying %s...done" (file-name-nondirectory file))))

(defun epa-dired-do-verify ()
  (interactive)
  (let ((file-list (dired-get-marked-files)))
    (while file-list
      (epa-dired-verify-file (car file-list))
      (setq file-list (cdr file-list)))))

(defun epa-dired-sign-file (file detached)
  (let ((signature (concat file (if detached ".sig" ".gpg")))
	(context (epg-make-context)))
    (message "Signing %s..." (file-name-nondirectory file))
    (epg-sign-file context file signature)
    (message "Signing %s...done" (file-name-nondirectory file))))

(defun epa-dired-do-sign (&optional detached)
  (interactive "p")
  (let ((file-list (dired-get-marked-files)))
    (while file-list
      (epa-dired-sign-file (expand-file-name (car file-list)) detached)
      (setq file-list (cdr file-list)))
    (revert-buffer)))

(defun epa-dired-encrypt-file (keys file)
  (let ((cipher (concat file ".gpg"))
	(context (epg-make-context)))
    (message "Encrypting %s..." (file-name-nondirectory file))
    (epg-encrypt-file context
		      file
		      (mapcar (lambda (key)
				(epg-sub-key-id
				 (car (epg-key-sub-key-list key))))
			      keys)
		      cipher)
    (message "Encrypting %s...done" (file-name-nondirectory file))))

(defun epa-dired-do-encrypt ()
  (interactive)
  (let ((file-list (dired-get-marked-files)))
    (while file-list
      (epa-ask-keys "Select keys for encryption.  \
If no keys are selected, symmetric encryption will be performed.  "
		    #'epa-dired-encrypt-file nil
		    (expand-file-name (car file-list)))
      (setq file-list (cdr file-list)))))

(provide 'epa-dired)

;;; epa-dired.el ends here