◊(Local Yarn Code "Diff")

;; since the database is merely a disposable cache, and since all the input
;; will be coming from me.

(require pollen/setup
         pollen/core
         pollen/template
         racket/string
         racket/function
         txexpr
         db/base
         "sqlite-tools.rkt"
         "snippets-html.rkt"
         "dust.rkt")

;; ~~~ Provides ~~~

(provide spell-of-summoning!
         crystalize-article!
         article-plain-title
         list-short/articles
         list-full/articles
         list-full/articles+notes
         unfence
         preheat-series!)

;; ~~~ Private use ~~~

(define DBFILE (build-path (current-project-root) "vitreous.sqlite"))

;; Since the DB exists to serve as a high-speed cache, the tables are constructed so that

    note_id
    title_html_flow
    author
    author_url
    date
    disposition
    content_html
    series_pagenode
    listing_full_html
    listing_excerpt_html  ; Not used for now
    listing_short_html))

(define table_series-fields
  '(pagenode
    title

    (notes->last-disposition-values note-txprs))
  
  (let* ([pubdate (select-from-metas 'published (current-metas))]
         [doc-html    (->html (cdr body-txpr))]
         [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  (apply string-append (map ->html (get-elements title-tx)))]
         [title-plain (tx-strs title-tx)]
         [series-node (series-pagenode)]
         [header      (html$-article-open title-specified? title-tx pubdate)]
         [footertext (make-article-footertext pagenode series-node disposition disp-note-id (length note-txprs))]
         [footer (html$-article-close footertext)]
         [notes-section-html (crystalize-notes! pagenode title-plain note-txprs)])

            (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
            (html$-article-listing-short (symbol->string pagenode) pubdate title-plain))) ; listing_short_html: Not yet used

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

;; ~~~ Retrieve listings of articles and notes ~~~
;; ~~~ (Mainly for use on Series pages         ~~~

;; (private) Create a WHERE clause matching a single series or list of series
(define (where/series s)
  (cond [(list? s)
         (let ([series (map (curry (format "~a/~a.html" series-path)) s)])
           (format "WHERE `series_pagenode` IN ~a" (list->sql-values series)))]
        [(string? s)
         (format "WHERE `series_pagenode` IS \"~a/~a.html\"" series-path s)]
        [(equal? s #t)
         (format "WHERE `series_pagenode` IS \"~a\"" (here-output-path))]
        [else ""]))

;; (private) Return a combined list of articles and notes sorted by date
(define (list/articles+notes type #:series [s #t] #:limit [limit -1] [order "DESC"])
  (define select #<<@@@@@
     SELECT `~a` FROM
       (SELECT `~a`, `published` FROM `articles`
        UNION SELECT
        `~a`,`date` AS `published` FROM `notes`
        ~a ORDER BY `published` ~a LIMIT ~a)
@@@@@
    )
  (query-list (sqltools:dbc) (format select type type type (where/series s) order limit)))

;; (private) Return a list of articles only, sorted by date
(define (list/articles type #:series [s #t] #:limit [limit -1] [order "DESC"])
  (define select "SELECT `~a` FROM `articles` ~a ORDER BY `published` ~a LIMIT ~a")
  (query-list (sqltools:dbc) (format select type (where/series s) order limit)))

;; ~~~~
;; Return cached HTML of articles and/or notes, fenced within a style txexpr to prevent it being
;; escaped by ->html. See also: definition of `unfence`

(define (list-short/articles #:series [s #t] #:limit [limit -1] [order "DESC"])
  `(style "<ul class=\"article-list\">"
          ,@(list/articles "listing_short_html" #:series s #:limit limit order)
          "</ul>"))

(define (list-full/articles #:series [s #t] #:limit [limit -1] [order "DESC"])
  `(style ,@(list/articles "listing_full_html" #:series s #:limit limit order)))

;; Return a combined list of articles and notes (“full content” version) sorted by date
(define (list-full/articles+notes #:series [s #t] #:limit [limit -1] [order "DESC"])
  `(style ,@(list/articles+notes "listing_full_html" #:series s #:limit limit order)))

;; Remove "<style>" and "</style>" introduced by using ->html on docs containing output from
;; listing functions
(define (unfence html-str)
  (regexp-replace* #px"<[\\/]{0,1}style>" html-str ""))

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

;; 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-elems
    (cond [(null? supplied-title) (list (default-title (get-elements body-tx)))]

          note-id
          title-html-flow
          author
          author-url
          note-date
          disposition-attr
          content-html
          (symbol->string (series-pagenode))
          listing-full-html
          "" ; listing_excerpt_html: Not used for now
          "")) ; listing_short_html: Not used for now
  
  ;; save to db
  (define save-note-query
    (format (string-append "INSERT OR REPLACE INTO `notes` (`rowid`, ~a) "