From 12726d18487298907ff63374120d17ee733383a7 Mon Sep 17 00:00:00 2001
From: Hugo Heagren <hugo@heagren.com>
Date: Mon, 28 Mar 2022 23:18:45 +0100
Subject: [PATCH 1/2] ol.el: add description format parameter to
 org-link-parameters

* ol.el (org-link-parameters): add parameter `:default-description', a
string or a function.
* (org-insert-link): if no description is provided (pre-existing or as
an argument), next option is to use the `:default-description' (if
non-nil) parameter to generate one.

Default descriptions are predictable within a link type, but because
link types are quite diverse, are NOT predictable across many types. A
type-parameter is thus a good place to store information on the
default description.
---
 lisp/ol.el | 53 ++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 42 insertions(+), 11 deletions(-)

diff --git a/lisp/ol.el b/lisp/ol.el
index d4bd0e40c..00f3bce5c 100644
--- a/lisp/ol.el
+++ b/lisp/ol.el
@@ -141,6 +141,15 @@ link.
   Function that inserts a link with completion.  The function
   takes one optional prefix argument.
 
+`:default-description'
+
+  String or function used as a default when prompting users for a
+  link's description.  A string is used as-is, a function is
+  called with two arguments: the full link text, and the
+  description generated by `org-insert-link'.  It should return
+  the description to use (this reflects the behaviour of
+  `org-link-make-description-function').
+
 `:display'
 
   Value for `invisible' text property on the hidden parts of the
@@ -1804,11 +1813,14 @@ prefix negates `org-link-keep-stored-after-insertion'.
 If the LINK-LOCATION parameter is non-nil, this value will be used as
 the link location instead of reading one interactively.
 
-If the DESCRIPTION parameter is non-nil, this value will be used as the
-default description.  Otherwise, if `org-link-make-description-function'
-is non-nil, this function will be called with the link target, and the
-result will be the default link description.  When called non-interactively,
-don't allow to edit the default description."
+If the DESCRIPTION parameter is non-nil, this value will be used
+as the default description.  If not, and the chosen link type has
+a non-nil `:default-description' parameter, that is used to
+generate a description as described in `org-link-parameters'
+docstring. Otherwise, if `org-link-make-description-function' is
+non-nil, this function will be called with the link target, and
+the result will be the default link description.  When called
+non-interactively, don't allow to edit the default description."
   (interactive "P")
   (let* ((wcf (current-window-configuration))
 	 (origbuf (current-buffer))
@@ -1818,7 +1830,10 @@ don't allow to edit the default description."
 	 (desc region)
 	 (link link-location)
 	 (abbrevs org-link-abbrev-alist-local)
-	 entry all-prefixes auto-desc)
+	 (all-prefixes (append (mapcar #'car abbrevs)
+			       (mapcar #'car org-link-abbrev-alist)
+			       (org-link-types)))
+         entry auto-desc type)
     (cond
      (link-location)		      ; specified by arg, just use it.
      ((org-in-regexp org-link-bracket-re 1)
@@ -1859,9 +1874,6 @@ Use TAB to complete link prefixes, then RET for type-specific completion support
 	  (unless (pos-visible-in-window-p (point-max))
 	    (org-fit-window-to-buffer))
 	  (and (window-live-p cw) (select-window cw))))
-      (setq all-prefixes (append (mapcar #'car abbrevs)
-				 (mapcar #'car org-link-abbrev-alist)
-				 (org-link-types)))
       (unwind-protect
 	  ;; Fake a link history, containing the stored links.
 	  (let ((org-link--history
@@ -1893,6 +1905,13 @@ Use TAB to complete link prefixes, then RET for type-specific completion support
       (or entry (push link org-link--insert-history))
       (setq desc (or desc (nth 1 entry)))))
 
+    (setq type
+          (cond
+           ((string-match (rx-to-string `(: string-start (submatch (or ,@all-prefixes)) ":")) link)
+            (match-string 1 link))
+           ((file-name-absolute-p link) "file")
+           ((string-match "\\`\\.\\.?/" link) "file")))
+
     (when (funcall (if (equal complete-file '(64)) 'not 'identity)
 		   (not org-link-keep-stored-after-insertion))
       (setq org-stored-links (delq (assoc link org-stored-links)
@@ -1961,12 +1980,24 @@ Use TAB to complete link prefixes, then RET for type-specific completion support
       (let ((initial-input
 	     (cond
 	      (description)
-	      ((not org-link-make-description-function) desc)
+              (desc)
+              ((org-link-get-parameter type :default-description)
+               (let ((def (org-link-get-parameter type :default-description)))
+                 (condition-case nil
+                     (cond
+                      ((stringp def) def)
+                      ((functionp def)
+                       (funcall def link desc)))
+                   (error
+                    (message "Can't get link description from org link parameter `:default-description': %S"
+			     def)
+		    (sit-for 2)
+                    nil))))
 	      (t (condition-case nil
 		     (funcall org-link-make-description-function link desc)
 		   (error
 		    (message "Can't get link description from %S"
-			     (symbol-name org-link-make-description-function))
+		             org-link-make-description-function)
 		    (sit-for 2)
 		    nil))))))
 	(setq desc (if (called-interactively-p 'any)
-- 
2.20.1