;;; term-utils.el --- Common code used by term.el and comint.el  -*- lexical-binding: t; -*-

;; Copyright (C) 2018  Tino Calancha

;; Author: Tino Calancha <tino.calancha@gmail.com>
;; Keywords: processes, terminals

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;

;;; code:


;; Retrieve the right defvar value according with the buffer mode.
(defmacro term-utils--defvar-value (suffix)
  "Build a defvar with the `major-mode' and SUFFIX, return its value.
The buffer major mode must be `term-mode' or `comint-mode'."
  (declare (debug (symbolp)) (indent 0))
  `(symbol-value
    (intern-soft
     (format "%S%S" (if (derived-mode-p 'term-mode) 'term- 'comint-)
             ',suffix))))

;; AIX puts the name of the person being su'd to in front of the prompt.
;; kinit prints a prompt like `Password for devnull@GNU.ORG: '.
;; ksu prints a prompt like `Kerberos password for devnull/root@GNU.ORG: '.
;; ssh-add prints a prompt like `Enter passphrase: '.
;; plink prints a prompt like `Passphrase for key "root@GNU.ORG": '.
;; Ubuntu's sudo prompts like `[sudo] password for user:'
;; Some implementations of passwd use "Password (again)" as the 2nd prompt.
;; Something called "perforce" uses "Enter password:".
;; See M-x comint-testsuite--test-comint-password-prompt-regexp.
(defcustom term-utils-password-prompt-regexp
  (concat
   "\\(^ *\\|"
   (regexp-opt
    '("Enter" "enter" "Enter same" "enter same" "Enter the" "enter the"
      "Old" "old" "New" "new" "'s" "login"
      "Kerberos" "CVS" "UNIX" " SMB" "LDAP" "PEM" "SUDO"
      "[sudo]" "Repeat" "Bad" "Retype")
    t)
   " +\\)"
   "\\(?:" (regexp-opt password-word-equivalents) "\\|Response\\)"
   "\\(?:\\(?:, try\\)? *again\\| (empty for no passphrase)\\| (again)\\)?"
   ;; "[[:alpha:]]" used to be "for", which fails to match non-English.
   "\\(?: [[:alpha:]]+ .+\\)?[\\s  ]*[:：៖][\\s  ]*\\'")
  "Regexp matching prompts for passwords in the inferior process.
This is used by `term-utils-watch-for-password-prompt'."
  :version "27.1"
  :type 'regexp
  :group 'term-utils)

(declare-function comint-snapshot-last-prompt "comint")

(defun term-utils-send-invisible (&optional prompt)
  "Read a string without echoing with PROMPT.
Then send it to the process running in the current buffer.
The string is sent using `comint-input-sender' or `term-input-sender'
depending of the buffer mode.
Security bug: your string can still be temporarily recovered with
\\[view-lossage]; `clear-this-command-keys' can fix that."
  (interactive "P")			; Defeat snooping via C-x ESC ESC
  (let ((proc (get-buffer-process (current-buffer)))
	(prefix
	 (if (eq (window-buffer) (current-buffer))
	     ""
	   (format "(In buffer %s) "
		   (current-buffer)))))
    (if proc
	(let ((str (read-passwd (concat prefix
					(or prompt "Non-echoed text: ")))))
	  (if (stringp str)
	      (let ((input-sender-fun (term-utils--defvar-value input-sender)))
		(if (derived-mode-p 'comint-mode) (comint-snapshot-last-prompt))
		(funcall input-sender-fun proc str))
	    (message "Warning: text will be echoed")))
      (error "Buffer %s has no process" (current-buffer)))))

(defalias 'send-invisible 'term-utils-send-invisible)

(defvar term-raw-map) ; Defined in term.el
(defun term-utils-term-in-line-mode-p ()
  "Return non-nil if the buffer is in `term-mode' and line submode."
  (and (derived-mode-p 'term-mode) (eq (current-local-map) term-raw-map)))

(defun term-utils-watch-for-password-prompt (string)
  "Prompt in the minibuffer for password and send without echoing.
This function uses `send-invisible' to read and send a password to the buffer's
process if STRING contains a password prompt defined by
`term-utils-password-prompt-regexp'.

This function could be in the lists `comint-output-filter-functions'
and `term-output-filter-functions'."
  ;; Do nothing if buffer is in term-mode with line submode
  (unless (term-utils-term-in-line-mode-p)
    (when (let ((case-fold-search t))
	    (string-match term-utils-password-prompt-regexp string))
      (when (string-match "^[ \n\r\t\v\f\b\a]+" string)
        (setq string (replace-match "" t t string)))
      (term-utils-send-invisible string))))


(provide 'term-utils)
;;; term-utils.el ends here