;;; ido-ubiquitous.el --- Use ido (nearly) everywhere.

;; Author: Ryan C. Thompson
;; URL: https://github.com/DarwinAwardWinner/ido-ubiquitous
;; Version: 1.1
;; Created: 2011-09-01
;; Keywords: convenience
;; EmacsWiki: InteractivelyDoThings

;; This file is NOT part of GNU Emacs.

;;; Commentary:

;; You may have seen the `ido-everywhere' variable in ido.el and got
;; excited that you could use ido completion for everything. Then you
;; were probably disappointed when you realized that it only applied
;; to *file names* and nothing else. Well, ido-ubiquitous is here to
;; fulfill the original promise and let you use ido completion for
;; (almost) any command that uses `completing-read' to offer you a
;; choice of several alternatives.

;; This even works in M-x, but for that, you might prefer the "smex"
;; package instead.

;; As of version 0.7, this package also makes a small modification to
;; ido's behavior so as to support a strange corner case of
;; `completing-read' that some functions rely on. Since the goal of
;; this package is to replace `completing-read' everywhere instead of
;; just selectively (as ido itself does), compatibility with all the
;; quriks of `completing-read' is important here.

;; If you find a case where enabling ido-ubiquitous causes a command
;; not to work correctly, please report it by creating an issue on
;; GitHub: https://github.com/DarwinAwardWinner/ido-ubiquitous/issues

;;; License:

;; 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, 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Code:

(require 'ido)

;;;###autoload
(defgroup ido-ubiquitous nil
  "Use ido for (almost) all completion."
  :group 'ido)

;;;###autoload
(define-minor-mode ido-ubiquitous-mode
  "Use `ido-completing-read' instead of `completing-read' almost everywhere.

  This mode has no effect unles `ido-mode' is also enabled.

  If this mode causes problems for a function, you can force the
  function to use the original completing read by using the macro
  `ido-ubiquitous-disable-in'. For example, if a
  function `foo' cannot work with ido-style completion, evaluate
  the following (for example by putting it in your .emacs file):

    (ido-ubiquitous-disable-in foo)"

  nil
  :global t
  :group 'ido-ubiquitous)

;;;###autoload
(define-obsolete-variable-alias 'ido-ubiquitous
  'ido-ubiquitous-mode "0.8")
;;;###autoload
(define-obsolete-function-alias 'ido-ubiquitous
  'ido-ubiquitous-mode "0.8")

;;;###autoload
(defcustom ido-ubiquitous-command-exceptions '()
  "List of commands that should not be affected by `ido-ubiquitous'.

Even when `ido-ubiquitous' mode is enabled, these commands will
continue to use `completing-read' instead of
`ido-completing-read'.

Only *interactive* commands should go here. To disable
ido-ubiquitous in non-interactive functions, customize
`ido-ubiquitous-function-exceptions'."
  :type '(repeat (symbol :tag "Command"))
  :group 'ido-ubiquitous)

;;;###autoload
(define-obsolete-variable-alias 'ido-ubiquitous-exceptions
  'ido-ubiquitous-command-exceptions "0.4")

(defadvice completing-read (around ido-ubiquitous activate)
  (if (or (not ido-mode)
          (not ido-ubiquitous-mode)
          (memq this-command ido-ubiquitous-command-exceptions)
          ;; Avoid infinite recursion from ido calling completing-read
          (boundp 'ido-cur-item))
      ad-do-it
    (let ((allcomp (all-completions "" collection predicate)))
      ;; Only use ido completion if there are actually any completions
      ;; to offer.
      (if allcomp
          (setq ad-return-value
                (ido-completing-read prompt allcomp
                                     nil require-match initial-input hist def))
        ad-do-it))))

(defmacro ido-ubiquitous-disable-in (func)
  "Disable ido-ubiquitous in FUNC."
  (let ((docstring
         (format "Disable ido-ubiquitous in %s" func)))
    `(defadvice ,func (around disable-ido-ubiquitous activate)
       ,docstring
       (let (ido-ubiquitous-mode) ad-do-it))))

(define-obsolete-function-alias
  'disable-ido-ubiquitous-in
  'ido-ubiquitous-disable-in
  "0.4")

(defmacro ido-ubiquitous-enable-in (func)
  "Re-enable ido-ubiquitous in FUNC.

  This reverses the effect of `ido-ubiquitous-disable-in'."
  ;; In my experience, simply using `ad-remove-advice' or
  ;; `ad-disable-advice' doesn't work correctly (in Emacs 23).
  ;; Instead, I've found that one must redefine the advice under the
  ;; same name ("disable-ido-ubiquitous") to simply call the original
  ;; function with no modifications. This has the same effect
  ;; (disables the advice), but is presumably less efficient.
  (let ((docstring
         (format "DO NOT disable ido-ubiquitous in %s" func)))
    `(defadvice ,func (around disable-ido-ubiquitous activate)
       ,docstring
       ad-do-it)))

(define-obsolete-function-alias
  'enable-ido-ubiquitous-in
  'ido-ubiquitous-enable-in
  "0.4")

;; Always disable ido-ubiquitous in `find-file' and similar functions,
;; because they are not supposed to use ido.
(defvar ido-ubiquitous-permanent-function-exceptions
  '(read-file-name
    gnus-emacs-completing-read
    gnus-iswitchb-completing-read
    man)
  "Functions in which ido-ubiquitous should always be disabled.

If you want to disable ido in a specific function or command, do
not modify this variable. Instead, try `M-x customize-group
ido-ubiquitous.")

(dolist (func ido-ubiquitous-permanent-function-exceptions)
  (eval `(ido-ubiquitous-disable-in ,func)))

(defun ido-ubiquitous--set-difference (list1 list2)
  "Replacement for `set-difference' from `cl'."
  (apply #'nconc
         (mapcar (lambda (elt) (unless (memq elt list2) (list elt)))
                 list1)))

(defun ido-ubiquitous-set-function-exceptions (sym newval)
  (let* ((oldval (when (boundp sym) (eval sym))))
    ;; Filter out permanent fixtures
    (setq oldval (ido-ubiquitous--set-difference oldval ido-ubiquitous-permanent-function-exceptions))
    (setq newval (ido-ubiquitous--set-difference newval ido-ubiquitous-permanent-function-exceptions))
    ;; Re-enable ido-ubiquitous on all old functions, in case they
    ;; were removed from the list.
    (dolist (oldfun oldval)
      (eval `(ido-ubiquitous-enable-in ,oldfun)))
    ;; Set the new value
    (set-default sym newval)
    ;; Disable ido-ubiquitous on all new functions
    (dolist (newfun newval)
      (eval `(ido-ubiquitous-disable-in ,newfun)))))

;;;###autoload
(defcustom ido-ubiquitous-function-exceptions
  '(grep-read-files)
  "List of functions in which to disable ido-ubiquitous.

If you need to add a function to this list, please also file a
bug report at
https://github.com/DarwinAwardWinner/ido-ubiquitous/issues

Note that certain functions, such as `read-file-name', must
always have ido-ubiquitous disabled, and cannot be added
here. (They are effectively a permanent part of this list
already.)"
  :group 'ido-ubiquitous
  :type '(repeat :tag "Functions"
                 (symbol :tag "Function"))
  :set 'ido-ubiquitous-set-function-exceptions)

(defcustom ido-ubiquitous-enable-compatibility t
  "Emulate a quirk of `completing-read'.

In the past, the `completing-read' function had no way of
specifying a default item, so instead the convention was to
request the default by returning an empty string. This occurrs in
standard emacs completion system when you press \"RET\" without
typing anything first. This is a problem for ido completion
because when ido is used this way, it does not know which item is
the default, so it cannot put the default at the head of the
list. Hence, simply pressing \"RET\" will not properly select the
advertised default. Setting this variable to non-nil will force
ido to emulate this quirk of the standard emacs completion system
in order to maintain compatibility with old functions that still
use the empty-string-as-default convention.

Specifically, when this variable is non-nil, ido will return an
empty string (thereby requesting the default) if you press \"RET\"
without entering any text or cycling through the offered choices.
This replaces the standard ido behavior of returning the first
item on the list. Enabling this option improves compatibility
with many older functions that use `completing-read' in this way,
but may also break compatibility with others, since it changes
what ido returns.

If you want this enabled most of the time but once in a while you
really want to select the first item on the list, you can do so
by prefixing \"RET\" with \"C-u\".

This has no effect when ido is completing buffers or files."
  :type 'boolean
  :group 'ido-ubiquitous)

(defvar ido-ubiquitous-initial-item nil
  "The first item selected when ido starts.")

(defadvice ido-read-internal (before clear-initial-item activate)
  (setq ido-ubiquitous-initial-item nil))

(defadvice ido-make-choice-list (after set-initial-item activate)
  (when (and ad-return-value (listp ad-return-value))
    (setq ido-ubiquitous-initial-item (car ad-return-value))))

(defadvice ido-next-match (after clear-initial-item activate)
  (setq ido-ubiquitous-initial-item nil))

(defadvice ido-prev-match (after clear-initial-item activate)
  (setq ido-ubiquitous-initial-item nil))

(defadvice ido-exit-minibuffer (around required-allow-empty-string activate)
  "Emulate a quirk of `completing-read'.

Apparently, `completing-read' used to request the default item by
returning an empty string when RET was pressed with an empty input.
This forces `ido-completing-read' to do the same (instead of returning
the first choice in the list).

This has no effect when ido is completing buffers or files."
  (if (and ido-ubiquitous-enable-compatibility
           (eq ido-cur-item 'list)
           ido-require-match
           (null ido-default-item)
           (not current-prefix-arg)
           (string= ido-text "")
           (string= (car ido-cur-list)
                    ido-ubiquitous-initial-item))
      (ido-select-text)
    ad-do-it))

(defadvice bookmark-completing-read (around disable-ido-compatibility activate)
  "`bookmark-completing-read' uses `completing-read' in an odd
  way that conflicts with the compatibilty mode of
  ido-ubiquitous."
  (let (ido-ubiquitous-enable-compatibility)
    ad-do-it))

(provide 'ido-ubiquitous) ;;; ido-ubiquitous.el ends here