From 77fdbf8552a0a2ff451bf9071f6646ac016cb262 Mon Sep 17 00:00:00 2001
From: stardiviner <numbchild@gmail.com>
Date: Sat, 1 Jul 2023 18:29:02 +0800
Subject: [PATCH] org: Improve the tags fast selection performance

* lisp/org.el (org-fast-tag-selection): Filter out only maximum number
limited tags has fast selection bound when `org-use-fast-tag-selection'
is 'auto and tags has fast select bound keys.
* lisp/org.el (org-fast-tag-selection-maximum-tags): Add new custom
option to set maximum tags number for fast tag selection.
* doc/org-manual.org (org-fast-tag-selection-maximum-tags): Add new
custom option document.
* etc/ORG-NEWS: declare this new custom option.
---
 doc/org-manual.org | 10 ++++++++++
 etc/ORG-NEWS       | 11 +++++++++++
 lisp/org.el        | 14 +++++++++++++-
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/doc/org-manual.org b/doc/org-manual.org
index 3a49917d7..30fcf32dc 100644
--- a/doc/org-manual.org
+++ b/doc/org-manual.org
@@ -5073,6 +5073,16 @@ effect: start selection with {{{kbd(C-c C-c C-c)}}} instead of
 the special window is not even shown for single-key tag selection, it
 comes up only when you press an extra {{{kbd(C-c)}}}.
 
+#+vindex: org-fast-tag-selection-maximum-tags
+Limit the tags table when you have many tags. You can set the maximum
+tags number for fast tag selection interface. When the variable
+~org-use-fast-tag-selection~ is ~auto~ and
+~org-fast-tag-selection-maximum-tags~ variable value number is smaller
+than single key bound tags number, the fast tag selection will only
+show single key bound tags, in contrary, will show the maximum number
+limited tags. If ~org-use-fast-tag-selection~ is other values, will
+show full tags.
+
 ** Tag Hierarchy
 :PROPERTIES:
 :DESCRIPTION: Create a hierarchy of tags.
diff --git a/etc/ORG-NEWS b/etc/ORG-NEWS
index cb4bc632b..dfabbfbed 100644
--- a/etc/ORG-NEWS
+++ b/etc/ORG-NEWS
@@ -322,6 +322,17 @@ special repeaters ~++~ and ~.+~ are skipped.
 A capture template can target ~(here)~ which is the equivalent of
 invoking a capture template with a zero prefix.
 
+*** Add new option ~org-fast-tag-selection-maximum-tags~ to limit fast tag selection interface displayed tags
+
+Limit the tags table when you have many tags. You can set the maximum
+tags number for fast tag selection interface. When the variable
+~org-use-fast-tag-selection~ is ~auto~ and
+~org-fast-tag-selection-maximum-tags~ variable value number is smaller
+than single key bound tags number, the fast tag selection will only
+show single key bound tags, in contrary, will show the maximum number
+limited tags. If ~org-use-fast-tag-selection~ is other values, will
+show full tags.
+
 ** Miscellaneous
 *** =org-crypt.el= now applies initial visibility settings to decrypted entries
 
diff --git a/lisp/org.el b/lisp/org.el
index fdb920864..f077cde12 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -2775,6 +2775,12 @@ displaying the tags menu is not even shown, until you press `C-c' again."
 	  (const :tag "Yes" t)
 	  (const :tag "Expert" expert)))
 
+(defcustom org-fast-tag-selection-maximum-tags 26
+  "Set the maximum tags number for fast tag selection."
+  :group 'org-tags
+  :type 'number
+  :safe #'numberp)
+
 (defvar org-fast-tag-selection-include-todo nil
   "Non-nil means fast tags selection interface will also offer TODO states.
 This is an undocumented feature, you should not rely on it.")
@@ -11929,7 +11935,13 @@ these have keys assigned to them.
 If the keys are nil, a-z are automatically assigned.
 Returns the new tags string, or nil to not change the current settings."
   (let* (;; Combined alist of all the tags and todo keywords.
-         (tag-alist (append tag-table todo-table))
+         (tag-alist (let* ((tags-table (append tag-table todo-table))
+                           (binding-tags (seq-filter 'cdr tags-table)))
+                      (cl-case org-use-fast-tag-selection
+                        (auto (if (length> binding-tags org-fast-tag-selection-maximum-tags)
+                                  binding-tags
+                                (seq-take tags-table org-fast-tag-selection-maximum-tags)))
+                        (t tags-table))))
          ;; Max width occupied by a single tag record in the completion buffer.
 	 (field-width
           (+ 3 ; keep space for "[c]" binding.
-- 
2.39.2 (Apple Git-143)