From fdb80d05c0a1e37d94b8bea1cb4333e2a00176c9 Mon Sep 17 00:00:00 2001
From: Adam Porter <adam@alphapapa.net>
Date: Sat, 5 Aug 2017 02:30:58 -0500
Subject: [PATCH] WIP

---
 org-agenda-ng.el | 115 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 org-agenda-ng.el

diff --git a/org-agenda-ng.el b/org-agenda-ng.el
new file mode 100644
index 0000000..7f466fb
--- /dev/null
+++ b/org-agenda-ng.el
@@ -0,0 +1,115 @@
+(require 'org)
+(require 'org-agenda)
+(require 'dash)
+(require 'cl-lib)
+
+(defun org-agenda-ng--filter-tree (tree &key filter-fns)
+  (let* ((types '(headline))
+         (info nil)
+         (first-match nil)
+         (fun (lambda (element)
+                (when (--all? (cl-typecase it
+                                (function (funcall it element))
+                                (cons (apply (car it) element (cdr it))))
+                              filter-fns)
+                  element))))
+    (org-element-map tree types fun info first-match)))
+
+
+(defun org-agenda-ng--test ()
+  (let ((tree (cddr (org-element-parse-buffer 'headline)))
+        (filter-fns '((org-agenda-ng--todo-p "TODO")
+                      (org-agenda-ng--scheduled-p < "2017-08-04"))))
+    (org-agenda-ng--filter-tree tree :filter-fns filter-fns)))
+
+
+
+(defun org-agenda-ng--todo-p (element &optional keyword)
+  "Return non-nil if ELEMENT is a TODO item.
+With KEYWORD, return non-nil if it has the same TODO keyword."
+  (when-let ((element-keyword (org-element-property :todo-keyword element)))
+    (pcase keyword
+      ('nil t)
+      ((pred stringp)
+       (string= element-keyword keyword))
+      (otherwise (error "Invalid keyword argument: %s" otherwise)))))
+
+(defun org-agenda-ng--scheduled-p (entry &optional comparator target-date)
+  "Return non-nil if ENTRY is scheduled.
+With COMPARATOR and DATE, return non-nil if entry's scheduled
+date compares with TARGET-DATE according to COMPARATOR."
+
+  (when-let ((scheduled-date (org-element-property :scheduled entry)))
+    ;; Append time to target-date because `date-to-day' requires it
+    (setq target-date (concat target-date " 00:00"))
+    (setq target-day-number (date-to-day target-date))
+    (pcase comparator
+      ('nil t)
+      ((and (pred functionp) (guard target-day-number))
+       (pcase (org-element-property :type scheduled-date)
+         ((or 'active 'inactive)
+          (funcall comparator
+                   (org-time-string-to-absolute
+                    (org-element-timestamp-interpreter scheduled-date 'ignore))
+                   target-day-number))))
+      (otherwise (error "COMPARATOR (%s) must be a function, and DATE (%s) must be a string" comparator target-date)))))
+
+(defun org-agenda-ng--add-scheduled-faces (entry)
+  "Add faces to ENTRY for its scheduled status."
+  (if-let ((today-day-number (org-today))
+           (scheduled-date (org-element-property :scheduled entry))
+           (scheduled-day-number (org-time-string-to-absolute
+                                  (org-element-timestamp-interpreter scheduled-date 'ignore)))
+           (todo-keyword (org-element-property :todo-keyword))
+           (done-p (member todo-keyword org-done-keywords))
+           (today-p (= today-day-number scheduled-day-number))
+           (face (cond
+                  (donep 'org-agenda-done)
+                  (today-p 'org-scheduled-today)
+                  (t 'org-scheduled))))
+      (org-add-props entry nil
+        'face face)
+    entry))
+
+(defun org-agenda-ng--add-text-properties (element)
+  "Return ELEMENT as a string with its text-properties set according to its property list.
+Its property list should be the second item in the list, as returned by `org-element-parse-buffer'."
+  (let* ((string (org-element-property :title element))
+         (properties (second element))
+         (properties (seq-subseq properties 0 24))  ;; FIXME
+         (properties (cl-loop for (key val) on properties by #'cddr
+                              for key = (intern (cl-subseq (symbol-name key) 1))
+                              unless (equal key 'raw-value)
+
+                              append (list key val))))
+    (setq string (org-add-props string properties))
+    (setq string (org-agenda-ng--add-scheduled-faces string))
+    string))
+
+(find-file-noselect "~/org/main.org")
+(let ((buffer (find-buffer-visiting "~/org/main.org")))
+  (with-current-buffer buffer
+    (length (org-agenda-ng--test))))
+
+(defun argh ()
+  (interactive)
+  (with-current-buffer (find-buffer-visiting "~/org/main.org")
+    (let* ((entries (cl-subseq (org-agenda-ng--test) 0 2))
+           (result-string (org-agenda-finalize-entries (mapcar #'org-agenda-ng--add-text-properties
+                                                               entries)
+                                                       'agenda))
+           (target-buffer (get-buffer-create "test-agenda-ng")))
+      (with-current-buffer target-buffer
+        (read-only-mode -1)
+        (erase-buffer)
+        (insert result-string)
+        (read-only-mode 1)
+        (pop-to-buffer (current-buffer))))))
+
+;; (with-current-buffer (find-file "~/src/org-agenda-ng/org-agenda-ng.el")
+;;   (eval-buffer))
+
+;; (decode-time (days-to-time 730119))
+;; (date-to-day "2017-08-04")
+
+;; (date-to-day "2017-08-03")