d12frosted/agenda.el

## agenda.el
(defun vulpea-project-p ()
  "Return non-nil if current buffer has any todo entry.

TODO entries marked as done are ignored, meaning the this
function returns nil if current buffer contains only completed
tasks."
  (seq-find                                 ; (3)
   (lambda (type)
     (eq type 'todo))
   (org-element-map                         ; (2)
       (org-element-parse-buffer 'headline) ; (1)
       'headline
     (lambda (h)
       (org-element-property :todo-type h)))))

(defun vulpea-project-update-tag ()
    "Update PROJECT tag in the current buffer."
    (when (and (not (active-minibuffer-window))
               (vulpea-buffer-p))
      (save-excursion
        (goto-char (point-min))
        (let* ((tags (vulpea-buffer-tags-get))
               (original-tags tags))
          (if (vulpea-project-p)
              (setq tags (cons "project" tags))
            (setq tags (remove "project" tags)))

          ;; cleanup duplicates
          (setq tags (seq-uniq tags))

          ;; update tags if changed
          (when (or (seq-difference tags original-tags)
                    (seq-difference original-tags tags))
            (apply #'vulpea-buffer-tags-set tags))))))

(defun vulpea-buffer-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 org-roam-directory))
        (file-name-directory buffer-file-name))))

(defun vulpea-project-files ()
    "Return a list of note files containing 'project' tag." ;
    (seq-uniq
     (seq-map
      #'car
      (org-roam-db-query
       [:select [nodes:file]
        :from tags
        :left-join nodes
        :on (= tags:node-id nodes:id)
        :where (like tag (quote "%\"project\"%"))]))))

(defun vulpea-agenda-files-update (&rest _)
  "Update the value of `org-agenda-files'."
  (setq org-agenda-files (vulpea-project-files)))

(add-hook 'find-file-hook #'vulpea-project-update-tag)
(add-hook 'before-save-hook #'vulpea-project-update-tag)

(advice-add 'org-agenda :before #'vulpea-agenda-files-update)
(advice-add 'org-todo-list :before #'vulpea-agenda-files-update)

;; functions borrowed from `vulpea' library
;; https://github.com/d12frosted/vulpea/blob/6a735c34f1f64e1f70da77989e9ce8da7864e5ff/vulpea-buffer.el

(defun vulpea-buffer-tags-get ()
  "Return filetags value in current buffer."
  (vulpea-buffer-prop-get-list "filetags" "[ :]"))

(defun vulpea-buffer-tags-set (&rest tags)
  "Set TAGS in current buffer.

If filetags value is already set, replace it."
  (if tags
      (vulpea-buffer-prop-set
       "filetags" (concat ":" (string-join tags ":") ":"))
    (vulpea-buffer-prop-remove "filetags")))

(defun vulpea-buffer-tags-add (tag)
  "Add a TAG to filetags in current buffer."
  (let* ((tags (vulpea-buffer-tags-get))
         (tags (append tags (list tag))))
    (apply #'vulpea-buffer-tags-set tags)))

(defun vulpea-buffer-tags-remove (tag)
  "Remove a TAG from filetags in current buffer."
  (let* ((tags (vulpea-buffer-tags-get))
         (tags (delete tag tags)))
    (apply #'vulpea-buffer-tags-set tags)))

(defun vulpea-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 vulpea-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-default-separators', normally
\"[ \f\t\n\r\v]+\", and OMIT-NULLS is forced to t.
If the property is already set, replace its value."
  (vulpea-buffer-prop-set
   name (combine-and-quote-strings values separators)))

(defun vulpea-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 vulpea-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 (vulpea-buffer-prop-get name)))
    (when (and value (not (string-empty-p value)))
      (split-string-and-unquote value separators))))

(defun vulpea-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 vulpea-project-p ()
	"Return non-nil if current buffer has any todo entry.

	TODO entries marked as done are ignored, meaning the this
	function returns nil if current buffer contains only completed
	tasks."
	(seq-find ; (3)
	(lambda (type)
	(eq type 'todo))
	(org-element-map ; (2)
	(org-element-parse-buffer 'headline) ; (1)
	'headline
	(lambda (h)
	(org-element-property :todo-type h)))))

	(defun vulpea-project-update-tag ()
	"Update PROJECT tag in the current buffer."
	(when (and (not (active-minibuffer-window))
	(vulpea-buffer-p))
	(save-excursion
	(goto-char (point-min))
	(let* ((tags (vulpea-buffer-tags-get))
	(original-tags tags))
	(if (vulpea-project-p)
	(setq tags (cons "project" tags))
	(setq tags (remove "project" tags)))

	;; cleanup duplicates
	(setq tags (seq-uniq tags))

	;; update tags if changed
	(when (or (seq-difference tags original-tags)
	(seq-difference original-tags tags))
	(apply #'vulpea-buffer-tags-set tags))))))

	(defun vulpea-buffer-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 org-roam-directory))
	(file-name-directory buffer-file-name))))

	(defun vulpea-project-files ()
	"Return a list of note files containing 'project' tag." ;
	(seq-uniq
	(seq-map
	#'car
	(org-roam-db-query
	[:select [nodes:file]
	:from tags
	:left-join nodes
	:on (= tags:node-id nodes:id)
	:where (like tag (quote "%\"project\"%"))]))))

	(defun vulpea-agenda-files-update (&rest _)
	"Update the value of `org-agenda-files'."
	(setq org-agenda-files (vulpea-project-files)))

	(add-hook 'find-file-hook #'vulpea-project-update-tag)
	(add-hook 'before-save-hook #'vulpea-project-update-tag)

	(advice-add 'org-agenda :before #'vulpea-agenda-files-update)
	(advice-add 'org-todo-list :before #'vulpea-agenda-files-update)

	;; functions borrowed from `vulpea' library
	;; https://github.com/d12frosted/vulpea/blob/6a735c34f1f64e1f70da77989e9ce8da7864e5ff/vulpea-buffer.el

	(defun vulpea-buffer-tags-get ()
	"Return filetags value in current buffer."
	(vulpea-buffer-prop-get-list "filetags" "[ :]"))

	(defun vulpea-buffer-tags-set (&rest tags)
	"Set TAGS in current buffer.

	If filetags value is already set, replace it."
	(if tags
	(vulpea-buffer-prop-set
	"filetags" (concat ":" (string-join tags ":") ":"))
	(vulpea-buffer-prop-remove "filetags")))

	(defun vulpea-buffer-tags-add (tag)
	"Add a TAG to filetags in current buffer."
	(let* ((tags (vulpea-buffer-tags-get))
	(tags (append tags (list tag))))
	(apply #'vulpea-buffer-tags-set tags)))

	(defun vulpea-buffer-tags-remove (tag)
	"Remove a TAG from filetags in current buffer."
	(let* ((tags (vulpea-buffer-tags-get))
	(tags (delete tag tags)))
	(apply #'vulpea-buffer-tags-set tags)))

	(defun vulpea-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 vulpea-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-default-separators', normally
	\"[ \f\t\n\r\v]+\", and OMIT-NULLS is forced to t.
	If the property is already set, replace its value."
	(vulpea-buffer-prop-set
	name (combine-and-quote-strings values separators)))

	(defun vulpea-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 vulpea-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 (vulpea-buffer-prop-get name)))
	(when (and value (not (string-empty-p value)))
	(split-string-and-unquote value separators))))

	(defun vulpea-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 ""))))