◊(Local Yarn Code "Diff")

    noun_plural
    noun_singular))

(define table_articles (make-table-schema "articles" table_articles-fields))
(define table_notes (make-table-schema "notes" table_notes-fields #:primary-key-cols '(pagenode note_id)))
(define table_series (make-table-schema "series" table_series-fields))

;; Split all ◊note tags out of the Pollen doc
(define (doc->body/notes doc)
  (define (is-note? tx) (and (txexpr? tx) (equal? 'note (get-tag tx))))
  (splitf-txexpr doc is-note?))

;; ~~~ Provided functions: Initializing; Saving posts and notes

;; Initialize the database connection, creating the database if it doesn’t
;; exist, and executing the table schema queries
;;
(define (spell-of-summoning!)
  (init-db! DBFILE table_articles table_notes table_series))

;; Save an article and its notes (if any) to the database, and return the
;; rendered HTML of the complete article.
;;
(define (crystalize-article! pagenode doc)
  (define pubdate (select-from-metas 'published (current-metas)))
  (define-values (body-txpr note-txprs) (doc->body/notes doc))
  (define doc-html (->html (cdr body-txpr)))
  
  (define-values
    (doc2 maybe-title) (splitf-txexpr doc (make-tag-predicate 'title)))
  (define-values 
    (body-txpr note-txprs) (splitf-txexpr doc2 (make-tag-predicate 'note)))
  (define-values (disposition disp-note-id)
    (notes->last-disposition-values note-txprs))
  
  (let* ([pubdate (select-from-metas 'published (current-metas))]
         [doc-html    (->html (cdr body-txpr))]
  (define title-specified? (non-empty-string? (maybe-meta 'title)))
  (define-values (title-plain title-html-flow)
    (title-plain+html-values body-txpr disposition))
  (define series-node (maybe-meta 'series))
  (define header (html$-article-open title-specified? title-html-flow pubdate))
         [title-specified? (not (equal? '() maybe-title))]
         [title-val   (if (not (null? maybe-title)) (car maybe-title) maybe-title)]
         [title-tx    (make-article-title title-val body-txpr disposition disp-note-id)]
         [title-html  (->html title-tx)]
         [title-plain (tx-strs title-tx)]
         [series-node (series-pagenode)]
         [header      (html$-article-open title-specified? title-tx pubdate)]

  (define footertext (make-article-footertext pagenode series-node disposition disp-note-id (length note-txprs)))
  (define footer (html$-article-close footertext))
         [footertext (make-article-footertext pagenode series-node disposition disp-note-id (length note-txprs))]
         [footer (html$-article-close footertext)]
  
  (define notes-section-html (crystalize-notes! pagenode title-plain note-txprs))
         [notes-section-html (crystalize-notes! pagenode title-plain note-txprs)])

  ;; Values must come in the order defined in table_article_fields
  (define article-record
    (list (symbol->string pagenode)
          title-plain
          title-html-flow
          (bool->int title-specified?)
          pubdate
          (maybe-meta 'updated)
          (maybe-meta 'author default-authorname)
          (maybe-meta 'conceal)
          series-node
          (maybe-meta 'noun (series-noun))
          (length note-txprs)
          doc-html
          disposition
          disp-note-id
          (string-append header doc-html footer)
          "" ; listing_excerpt_html: Not yet used
          "")) ; listing_short_html: Not yet used
    ;; Values must come in the order defined in table_article_fields
    (define article-record
      (list (symbol->string pagenode)
            title-plain
            title-html
            (bool->int title-specified?)
            pubdate
            (maybe-meta 'updated)
            (maybe-meta 'author default-authorname)
            (maybe-meta 'conceal)
            (symbol->string series-node)
            (maybe-meta 'noun (series-noun))
            (length note-txprs)
            doc-html
            disposition
            disp-note-id
            (string-append header doc-html footer)
            "" ; listing_excerpt_html: Not yet used
            "")) ; listing_short_html: Not yet used

  (apply query! (make-insert/replace-query 'articles table_articles-fields) article-record)
    (apply query! (make-insert/replace-query 'articles table_articles-fields) article-record)
          
  (string-append header doc-html notes-section-html footer))
    (string-append header doc-html notes-section-html footer)))

;; ~~~ Article-related helper functions ~~~
;;

;; Return both a plain-text and HTML version of a title for the current article,
;; supplying a default if no title was specified in the metas.
(define (title-plain+html-values body-tx disposition)
;; Return a title txexpr for the current article, constructing a default if no title text was specified.
(define (make-article-title supplied-title body-tx disposition disp-note-id)
  (define title (maybe-meta 'title ""))
  (define title-val
    (cond [(and (string? title) (string=? title ""))
  (define title-elems
    (cond [(null? supplied-title) (list (default-title (get-elements body-tx)))]
           (format "“~a…”" (first-words (tx-strs body-tx) 5))]
          [else title]))
          [else (get-elements supplied-title)]))
  
  (define disposition-part
    (cond [(non-empty-string? disposition)
           (define-values (mark _) (disposition-values disposition))
           (format "<span class=\"disposition-mark\">~a</span>" mark)]
           `(span [[class "disposition-mark"]] (a [[href ,(string-append "#" disp-note-id)]] ,mark))]
          [else ""]))
  
  ;; Returns a txexpr, the tag will be discarded by the template/snippets
  (cond [(txexpr? title-val)
         (values (apply string-append (tx-strs title-val))
                 (string-append (->html title-val) disposition-part))]
  `(title ,@title-elems ,disposition-part))
        [else (values title-val (string-append title-val disposition-part))]))

  
;; Convert a bunch of information about an article into some nice English and links.
(define (make-article-footertext pagenode series disposition disp-note-id note-count)
  (define s-title (series-title))
  (define s-noun (series-noun))
  (define series-part
    (cond [(non-empty-string? s-title)
           (format "This is ~a, part of <a href=\"/~a\">‘~a’</a>."