[emcas] Implement Boris' org-agenda speed up tricks!

emacs/.config/doom/config.org

@@ -200,12 +200,25 @@ We love auto-formatting, but not everything should be auto-formatted
 A handful of mods here clean up org mode. Line numbers don’t mean much when
 you’re folding and unfolding all the time. I also really enjoy the typography of
 a serif font when I’m writing a lot of words.
+
+There's also a really cool trick that I picked from [[https://d12frosted.io/posts/2021-01-16-task-management-with-roam-vol5.html][Boris]] where we dynamically
+look through org files to see if they have org todos rather than just processing
+them all every time.
+
 #+BEGIN_SRC emacs-lisp
+(load! "+agenda-fix")
+
+(defun vulpea-agenda-files-update (&rest _)
+  "Update the value of `org-agenda-files'."
+  (setq org-agenda-files (vulpea-project-files)))
+
+(advice-add 'org-agenda :before #'vulpea-agenda-files-update)
+(advice-add 'org-todo-list :before #'vulpea-agenda-files-update)
+
 (add-hook 'org-mode-hook #'doom-disable-line-numbers-h)
 
 (after! org
   (setq org-directory (expand-file-name "~/var/org/")
-        org-agenda-files (append '("~/var/org"))
         org-ellipsis "…"
         org-image-actual-width '(600)
         org-fontify-quote-and-verse-blocks t