Add previous inputs to defaults in multi-selection

Close #714

Co-authored-by: Rahguzar <[email protected]>

README.org

@@ -216,6 +216,8 @@ You then have two ways to access these strings from the completion prompt:
 1. by using =M-n= from the prompt, which will cycle through the strings
 2. by calling =citar-insert-preset= with a keybinding, and then selecting the string
 
+If you want to select multiple candidates using the same search term =M-n= also recalls the previous input, so you can use =TAB= to select one candidate then press =M-n= to quickly insert the previous search term again (see notes below for some caveats).
+
 =citar= also preserves the history of your selections (see caveat below about multiple candidate selection though), which are also accessible in your completion UI, but by using =M-p=.
 You can save this history across sessions by adding =citar-history= to =savehist-additional-variables=.
 
@@ -238,6 +240,14 @@ The ~citar-notes-sources~ variable configures note backends, and ~citar-notes-so
 A backend primarily specifies functions to update the Citar display, to create the completion candidates, and to open existing and new notes.
 See the ~citar-notes-sources~ docstring for details, and the =citar-register-notes-source= and =citar-remove-notes-source= convenience functions.
 
+Using =M-n= to recall the previous input only works when selecting multiple candidates during a single =citar-command=. If you use =vertico=, =vertico-repeat= provides similar functionality for rerunning the commands with the last input.
+
+By default =Emacs= leaves the point at the beginning of input if you press =M-n= with minibuffer empty. If you want to change this behavior and instead leave the point at the end of input use,
+
+#+BEGIN_SRC emacs-lisp
+(advice-add 'goto-history-element :after (defun my-end-of-buffer (&rest _) (goto-char (point-max))))
+#+END_SRC
+
 ** Files, file association and file-field parsing
 
 If you have ~citar-library-paths~ set, the relevant open commands will look in those directories for file names of =CITEKEY.EXTENSION=.

citar.el

@@ -584,10 +584,17 @@ to filter them."
 SEL is the key which should be used for selection. EXIT is the key which
 is used for exiting the minibuffer during completing read.")
 
+(defvar citar--multiple-last-input nil
+  "Variable used to track the input so that it can be restored subsequently.")
+
 (defun citar--multiple-exit ()
   "Exit with the currently selected candidates."
   (interactive)
-  (setq unread-command-events (listify-key-sequence (kbd (car citar--multiple-setup)))))
+  (funcall-interactively (key-binding (kbd (car citar--multiple-setup)))))
+
+(defun citar--multiple-record-input ()
+  "Record the current minibuffer input."
+  (setq citar--multiple-last-input (minibuffer-contents-no-properties)))
 
 (defun citar--setup-multiple-keymap ()
   "Make a keymap suitable for `citar--select-multiple'."
@@ -596,29 +603,34 @@ is used for exiting the minibuffer during completing read.")
         (kbdexit (kbd (cdr citar--multiple-setup))))
     (define-key keymap kbdselect (lookup-key keymap kbdexit))
     (define-key keymap kbdexit #'citar--multiple-exit)
-    (use-local-map keymap)))
+    (use-local-map keymap))
+  (add-hook 'post-command-hook #'citar--multiple-record-input nil t))
 
 (defun citar--select-multiple (prompt candidates &optional filter history def)
   "Select multiple CANDIDATES with PROMPT.
 HISTORY is the `completing-read' history argument."
   ;; Because completing-read-multiple just does not work for long candidate
   ;; strings, and IMO is a poor UI.
-  (let* ((selected-hash (make-hash-table :test 'equal)))
-    (while (let ((initial-history (symbol-value history))
-                 (item (minibuffer-with-setup-hook #'citar--setup-multiple-keymap
-                         (completing-read
-                          (format "%s (%s/%s): " prompt
-                                  (hash-table-count selected-hash)
-                                  (hash-table-count candidates))
-                          (citar--multiple-completion-table selected-hash candidates filter)
-                          nil t nil history `("" . ,def)))))
-             (unless (string-empty-p item)
+  (let* ((selected-hash (make-hash-table :test 'equal))
+         (command this-command))
+    (push (setq citar--multiple-last-input "") def)
+    (while (let* ((initial-history (symbol-value history))
+                  (item (minibuffer-with-setup-hook #'citar--setup-multiple-keymap
+                          (completing-read
+                           (format "%s (%s/%s): " prompt
+                                   (hash-table-count selected-hash)
+                                   (hash-table-count candidates))
+                           (citar--multiple-completion-table selected-hash candidates filter)
+                           nil t nil history def))))
+             (push citar--multiple-last-input def)
+             (unless (string-blank-p citar--multiple-last-input)
                (if (not (gethash item selected-hash))
                    (puthash item t selected-hash)
                  (remhash item selected-hash)
                  (set history initial-history)))
-             (not (or (eq last-command #'citar--multiple-exit)
-                      (string-empty-p item)))))
+             (not (or (eq this-command #'citar--multiple-exit)
+                      (string-blank-p citar--multiple-last-input))))
+      (setq this-command command))
     (hash-table-keys selected-hash)))
 
 (cl-defun citar--get-resource-candidates (citekeys &key files links notes create-notes)