agenda now dynamically based on files with tag "agenda"

config.org

@@ -1182,6 +1182,144 @@ https://github.com/jwiegley/use-package/issues/319
          :map org-mode-map ("S-<right>" . org-shiftright)
        ("S-<left>" . org-shiftleft))
   :init
+  (defun my--org-files-with-tag (dir tag)
+         "Return a list of .org files in DIR recursively that have a #+FILETAGS: TAG."
+         (let ((files (directory-files-recursively dir "\\.org$"))
+               (tag-re (format "^#\\+filetags:.*\\:%s\\:" (regexp-quote tag))))
+           (seq-filter
+            (lambda (file)
+              (with-temp-buffer
+                (insert-file-contents file nil 0 1000)
+                (goto-char (point-min))
+                (re-search-forward tag-re nil t)))
+            files)))
+
+  (defun my--org-agenda-files-update ()
+    "Update `org-agenda-files` from MY--PATH_ORG_FILES based on file tag :agenda:."
+    (when (derived-mode-p 'org-mode)
+      (setq org-agenda-files (my--org-files-with-tag MY--PATH_ORG_FILES "agenda"))))
+                           
+    (defun my--todo-p ()
+      "Return non-nil if current buffer has any todo entry.
+
+TODO entries marked as done are ignored, meaning this function
+returns nil if current buffer contains only completed tasks."
+      (seq-find
+       (lambda (type)
+         (eq type 'todo))
+       (org-element-map
+           (org-element-parse-buffer 'headline)
+           'headline
+         (lambda (h)
+           (org-element-property :todo-type h)))))
+
+    (defun my--todo-update-tag ()
+      "Update AGENDA tag in the current buffer."
+      (when (and (not (active-minibuffer-window))
+                 (my--buffer-note-p))
+        (save-excursion
+          (goto-char (point-min))
+          (let* ((tags (my--buffer-tags-get))
+                 (original-tags tags))
+            (if (my--todo-p)
+                (setq tags (cons "agenda" tags))
+              (setq tags (remove "agenda" tags)))
+
+            ;;cleanup duplicates
+            (when (or (seq-difference tags original-tags)
+                      (seq-difference original-tags tags))
+              (apply #'my--buffer-tags-set tags))))))
+    
+    (defun my--buffer-note-p ()
+      "Return non-nil if the currently visited buffer is a note."
+      (and buffer-file-name
+           (string-prefix-p
+            (expand-file-name (file-name-as-directory MY--PATH_ORG_FILES)) 
+            (file-name-directory buffer-file-name))))
+
+    (defun my--buffer-tags-get ()
+      "Return filetags value in current buffer."
+      (my--buffer-prop-get-list "filetags" "[ :]"))
+
+    (defun my--buffer-tags-set (&rest tags)
+      "Set TAGS in current buffer.
+If filetags value is already set, replace it."
+      (if tags
+          (my--buffer-prop-set
+           "filetags" (concat ":" (string-join tags ":") ":"))
+        (my--buffer-prop-remove "filetags")))
+
+    (defun my--buffer-tags-add (tag)
+      "Add a TAG to filetags in current buffer."
+      (let* ((tags (my--buffer-tags-get))
+             (tags (append tags (list tag))))
+        (apply #'my--buffer-tags-set tags)))
+    
+    (defun my--buffer-tags-remove (tag)
+      "Remove a TAG from filetags in current buffer."
+      (let* ((tags (my--buffer-tags-get))
+             (tags (delete tag tags)))
+        (apply #'my--buffer-tags-set tags)))
+    
+    (defun my--buffer-prop-set (name value)
+      "Set a file property called NAME to VALUE in buffer file.
+If the property is already set, replace its value."
+      (setq name (downcase name))
+      (org-with-point-at 1
+        (let ((case-fold-search t))
+          (if (re-search-forward (concat "^#\\+" name ":\\(.*\\)")
+                                 (point-max) t)
+              (replace-match (concat "#+" name ": " value) 'fixedcase)
+            (while (and (not (eobp))
+                        (looking-at "^[#:]"))
+              (if (save-excursion (end-of-line) (eobp))
+                  (progn
+                    (end-of-line)
+                    (insert "\n"))
+                (forward-line)
+                (beginning-of-line)))
+            (insert "#+" name ": " value "\n")))))
+
+    (defun my--buffer-prop-set-list (name values &optional separators)
+      "Set a file property called NAME to VALUES in current buffer.
+VALUES are quoted and combined into single string using
+`combine-and-quote-strings'.
+If SEPARATORS is non-nil, it should be a regular expression
+matching text that separates, but is not part of, the substrings.
+If nil it defaults to `split-string-and-unquote', normally
+\"[ \f\t\n\r\v]+\", and OMIT-NULLS is forced to t.
+If the property is already set, replace its value."
+      (my--buffer-prop-set
+       name (combine-and-quote-strings values separators)))
+    
+    (defun my--buffer-prop-get (name)
+      "Get a buffer property called NAME as a string."
+      (org-with-point-at 1
+        (when (re-search-forward (concat "^#\\+" name ": \\(.*\\)")
+                                 (point-max) t)
+          (buffer-substring-no-properties
+           (match-beginning 1)
+           (match-end 1)))))
+    
+    (defun my--buffer-prop-get-list (name &optional separators)
+      "Get a buffer property NAME as a list using SEPARATORS.
+If SEPARATORS is non-nil, it should be a regular expression
+matching text that separates, but is not part of, the substrings.
+If nil it defaults to `split-string-default-separators', normally
+\"[ \f\t\n\r\v]+\", and OMIT-NULLS is forced to t."
+      (let ((value (my--buffer-prop-get name)))
+        (when (and value (not (string-empty-p value)))
+          (split-string-and-unquote value separators))))
+    
+    (defun my--buffer-prop-remove (name)
+      "Remove a buffer property called NAME."
+      (org-with-point-at 1
+        (when (re-search-forward (concat "\\(^#\\+" name ":.*\n?\\)")
+                                 (point-max) t)
+          (replace-match ""))))
+    
+
+  
 ;;   (defun my--org-agenda-files-set ()
 ;;     "Sets default agenda files.
 ;; Necessary when updating roam agenda todos."
@@ -1192,14 +1330,14 @@ https://github.com/jwiegley/use-package/issues/319
 ;;       (nconc org-agenda-files
 ;;    (directory-files-recursively MY--PATH_ORG_FILES_MOBILE "\\.org$"))))
 ;;  (my--org-agenda-files-set)
-  (setq org-agenda-files
-        (cl-remove-if (lambda (file)
-                        ;; exclude some subdirs
-                        (let ((excluded-dirs '("notes" "dummy")))
-                          (cl-some (lambda (dir) (string-match-p (concat "/" dir "/") file))
-                                   excluded-dirs)))
-;;                        (string-match-p "/notes/" file))
-                      (directory-files-recursively MY--PATH_ORG_FILES "\\.org$")))
+  (setq org-agenda-files (my--org-files-with-tag MY--PATH_ORG_FILES "agenda"))
+;;         (cl-remove-if (lambda (file)
+;;                         ;; exclude some subdirs
+;;                         (let ((excluded-dirs '("notes" "dummy")))
+;;                           (cl-some (lambda (dir) (string-match-p (concat "/" dir "/") file))
+;;                                    excluded-dirs)))
+;; ;;                        (string-match-p "/notes/" file))
+;                      (directory-files-recursively MY--PATH_ORG_FILES "\\.org$")) ;;)
 
   (defun my--org-skip-subtree-if-priority (priority)
       "Skip an agenda subtree if it has a  priority of PRIORITY.
@@ -1211,6 +1349,14 @@ https://github.com/jwiegley/use-package/issues/319
         (if (= pri-value pri-current)
   subtree-end
 nil)))
+  (add-hook 'find-file-hook #'my--todo-update-tag)
+  (add-hook 'before-save-hook #'my--todo-update-tag)
+  (add-hook 'after-save-hook #'my--org-agenda-files-update)
+;;  (add-to-list 'org-tags-exclude-from-inheritance "agenda") ;;removed in org 9.5
+  ;; use inheritance except for "agenda"
+  (setq org-use-tag-inheritance
+        (lambda (tags) (remove "agenda" tags)))
+
   :config
   (when *work_remote*
     (org-add-link-type "outlook" 'my--org-outlook-open)