feat: add spine-books model function with empty-prop nil handling

sample-books.org

@@ -39,7 +39,7 @@
 :ID:      5e8d-pir
 :END:
 
-* READING Use of Weapons
+* READING Use of Weapons                                                          :scifi:literary:
 :PROPERTIES:
 :AUTHOR:  Iain M. Banks
 :ISBN:    978-0316029193

spine.el

@@ -16,6 +16,7 @@
 (require 'simple-httpd)
 (require 'mustache)
 (require 'ht)
+(require 'cl-lib)
 
 ;; --- configuration ----------------------------------------------------
 
@@ -26,6 +27,9 @@
 nil means localhost only. Set to a string like \"0.0.0.0\" to listen on
 all interfaces.")
 
+(defvar spine-org-file "~/spine/books.org"
+  "Path to the spine.org data file.")
+
 (defvar spine-template-dir
   (expand-file-name "templates/"
                     (file-name-directory load-file-name))
@@ -43,6 +47,78 @@ Returns the rendered string."
      (buffer-string))
    context))
 
+(defun spine--h (text)
+  "HTML-escape TEXT."
+  (when text
+    (let ((s text))
+      (setq s (replace-regexp-in-string "&" "&" s))
+      (setq s (replace-regexp-in-string "<" "&lt;" s))
+      (setq s (replace-regexp-in-string ">" "&gt;" s))
+      (setq s (replace-regexp-in-string "\"" "&quot;" s))
+      s)))
+
+(defun spine--extract-notes (hl-begin hl-end)
+  "Extract reading notes from headline body between HL-BEGIN and HL-END.
+Returns list of (date-string text-string) pairs."
+  (let ((notes nil))
+    (save-excursion
+      (goto-char hl-begin)
+      ;; Skip past PROPERTIES and LOGBOOK drawers
+      (while (re-search-forward
+              "^[ \t]*:\\(PROPERTIES\\|LOGBOOK\\):" hl-end t)
+        (re-search-forward "^[ \t]*:END:" hl-end t))
+      ;; Collect note lines: "- [YYYY-MM-DD] text"
+      (while (re-search-forward
+              "^- \\[\\([0-9]\\{4\\}-[0-9]\\{2\\}-[0-9]\\{2\\}\\)\\] \\(.*\\)"
+              hl-end t)
+        (push (list (match-string 1) (match-string 2)) notes)))
+    (nreverse notes)))
+
+
+(defun spine--prop (pos prop)
+  "Get Org property PROP at headline position POS.
+Returns nil for empty or missing properties."
+  (let ((val (save-excursion
+               (goto-char pos)
+               (org-entry-get nil prop))))
+    (and val (> (length val) 0) val)))
+(defun spine-books ()
+  "Return a list of plists, one per top-level headline in `spine-org-file'.
+Returns nil if the file is missing or cannot be parsed."
+  (unless (file-exists-p spine-org-file)
+    (message "spine-books: file not found: %s" spine-org-file)
+    (cl-return-from spine-books nil))
+  (condition-case err
+      (with-temp-buffer
+        (insert-file-contents spine-org-file)
+        (org-mode)
+        (let ((books nil))
+          (org-element-map (org-element-parse-buffer 'headline) 'headline
+            (lambda (hl)
+              (when (= (org-element-property :level hl) 1)
+                (let ((pos (org-element-property :begin hl)))
+                  (push (list :id       (spine--prop pos "ID")
+                              :title    (org-element-property :title hl)
+                              :status   (org-element-property :todo-keyword hl)
+                              :author   (spine--prop pos "AUTHOR")
+                              :isbn     (spine--prop pos "ISBN")
+                              :cover    (spine--prop pos "COVER")
+                              :format   (spine--prop pos "FORMAT")
+                              :rec_by   (spine--prop pos "REC_BY")
+                              :rec_note (spine--prop pos "REC_NOTE")
+                              :rating   (spine--prop pos "RATING")
+                              :added    (spine--prop pos "ADDED")
+                              :tags     (org-element-property :tags hl)
+                              :notes    (spine--extract-notes
+                                         (org-element-property :begin hl)
+                                         (org-element-property :end hl)))
+                        books)))))
+          (nreverse books)))
+    (error
+     (message "spine-books: failed to parse %s: %s"
+              spine-org-file (error-message-string err))
+     nil)))
+
 (defvar spine-skip-server-start nil
   "When non-nil, do not start the HTTP server.
 Set by test harnesses that only need the model functions.")