From 9184756c07f6141803c263708b5d8078ba90c82c Mon Sep 17 00:00:00 2001
From: Daniel Borchmann <daniel@algebra20.de>
Date: Thu, 5 May 2022 22:08:02 +0200
Subject: [PATCH] Refactor function to return backlinks to item at point

Extract function to return actual list of backlinks, to later use it for
extracting backlinks of item at point and all its parents.
---
 site-lisp/db-org.el | 53 ++++++++++++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/site-lisp/db-org.el b/site-lisp/db-org.el
index acd076f..2f0b421 100644
--- a/site-lisp/db-org.el
+++ b/site-lisp/db-org.el
@@ -955,6 +955,35 @@ Show _b_acklinks to current item."
   ("O" (db/org-add-link-to-other-item t))
   ("b" db/org-find-links-to-current-item))
 
+(defun db/org--backlinks-for-id (item-id &optional org-ql-match archives)
+  "Return list of ID properties of Org Mode items linking to ITEM-ID.
+
+If the optional ORG-QL-MATCH is given and is a valid `org-ql' query in
+sexp syntax, filter the list for all items matching this query.
+If ARCHIVES is given, also include archive files.
+
+The search is conducted over all files returned by
+`org-agenda-files' including archives, as well as all files
+referenced in `org-agenda-text-search-extra-files'."
+
+  (let ((extra-files org-agenda-text-search-extra-files)
+        files)
+
+    ;; Determine files to search through; ignore `agenda-archive' in
+    ;; `org-agenda-text-search-extra-files', as we already handle this when
+    ;; calling `org-agenda-files'.
+    (setq files (org-agenda-files t archives))
+    (when (eq (car extra-files) 'agenda-archives)
+      (pop extra-files))
+    (setq files (append files extra-files))
+
+    (org-ql-query :select '(org-id-get-create)
+                  :from files
+                  :where (let ((link-expression `(link :target ,item-id)))
+                           (if org-ql-match
+                               `(and ,link-expression ,org-ql-match)
+                             link-expression)))))
+
 (defun db/org-backlinks-to-item-at-point (&optional org-ql-match archives)
   "Return list of Org links to item at point.
 
@@ -967,28 +996,18 @@ If ARCHIVES is given, also include archive files.
 The search is conducted over all files returned by
 `org-agenda-files' including archives, as well as all files
 referenced in `org-agenda-text-search-extra-files'."
-  (let ((id-of-item-at-point (org-id-get))
-        (extra-files org-agenda-text-search-extra-files)
-        files)
+
+  (let ((id-of-item-at-point (org-id-get)))
 
     (unless id-of-item-at-point
       (user-error "Item at point does not have an ID property set, cannot determine backlinks"))
 
-    ;; Determine files to search through; ignore `agenda-archive' in
-    ;; `org-agenda-text-search-extra-files', as we already handle this when
-    ;; calling `org-agenda-files'.
-    (setq files (org-agenda-files t archives))
-    (when (eq (car extra-files) 'agenda-archives)
-      (pop extra-files))
-    (setq files (append files extra-files))
+    (mapcar #'(lambda (id)
+                (list (org-link-make-string (format "id:%s" id)
+                                            (org-entry-get (org-id-find id 'marker) "ITEM"))))
+            (db/org--backlinks-for-id id-of-item-at-point org-ql-match archives))))
 
-    (org-ql-query :select '(list (org-link-make-string (format "id:%s" (org-id-get-create))
-                                                       (org-entry-get (point) "ITEM")))
-                  :from files
-                  :where (let ((link-expression `(link :target ,id-of-item-at-point)))
-                           (if org-ql-match
-                               `(and ,link-expression ,org-ql-match)
-                             link-expression)))))
+;; TODO: function to return links to all backlinks of self and parents
 
 
 ;;; End