◊(Local Yarn Code "Check-in [0b455f1f]")

#lang pollen/mode racket/base

;; Copyright (c) 2018 Joel Dueck.
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; A copy of the License is included with this source code, in the
;; file "LICENSE.txt".
;; You may also obtain a copy of the License at
;;
;;       http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.
;;
;; Author contact information:
;;   joel@jdueck.net
;;   https://joeldueck.com
;; -------------------------------------------------------------------------

;; Provides functions for fast preserving and fetching of article/series data.
;;  → Docs and metas go in (saved to SQLite database)
;;    HTML comes out →
;; Calling sites have no notion of the database or schema.

;; The functions provided by sqlite-tools.rkt are not safe for user-provided
;; data; a maliciously crafted input could bomb the database. This is acceptable
;; 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
         pollen/pagetree
         racket/string
         "sqlite-tools.rkt"
         "template-html.rkt"
         "dates.rkt")

;; ~~~ Provides ~~~

(provide spell-of-summoning!
         crystalize-article!)

;; ~~~ Private use ~~~

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

(define table_articles-fields
  '(pagenode
    title
    published
    updated
    doc_html
    author
    conceal
    series_pagenode
    noun_singular 
    note_count))

(define table_notes-fields
  '(pagenode
    note-id
    heading
    author
    date
    note_html))

(define table_series-fields
  '(pagenode
    title
    published
    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))

(define (optional-meta m)
  (or (select-from-metas m (current-metas)) ""))

(define (series-noun)
  (define series-pagenode (->pagenode (or (select-from-metas 'series (current-metas)) "")))
  (case series-pagenode
    ['|| ""] ; no series specified
    [else (or (select-from-metas 'noun-singular series-pagenode) "")]))

;; ~~~ 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 (using current-doc and current-metas) and its notes (if any)
;; to the database, and return the rendered HTML.
;;
(define (crystalize-article! pagenode doc)
  (define header (html-article-header))
  (define footer (html-article-footer))
  (define body (->html (cdr doc)))
  ;; TK: store notes separately

  (define saving-query (make-insert/replace-query 'articles table_articles-fields))
  (query! saving-query
          (symbol->string pagenode)
          (optional-meta 'title)
          (select-from-metas 'published (current-metas))
          (optional-meta 'updated)
          (string-append header body footer)
          (optional-meta 'author)
          (optional-meta 'conceal)
          (optional-meta 'series)
          (series-noun)
          0) ; note_count
          
  `(@ ,header ,body ,footer))

                     syntax/parse
                     pollen/setup))

(require pollen/tag
         pollen/setup
         racket/function
         "tags-html.rkt"
         "template-html.rkt"
         "crystalize.rkt")

(provide (all-defined-out)
         (all-from-out "crystalize.rkt" "template-html.rkt"))

(module setup racket/base
  (require syntax/modresolve)
  (provide (all-defined-out))
  (define poly-targets '(html))
  (define cache-watchlist
    (map resolve-module-path '("tags-html.rkt"
                               "template-html.rkt"
                               "dates.rkt"
                               "crystalize.rkt"))))

;; Macro for defining tag functions that automatically branch based on the 
;; current output format and the list of poly-targets in the setup module.
;; 
(define-syntax (poly-branch-tag stx)
  (syntax-parse stx
    [(_ TAG:id)

#lang racket/base

;; Copyright (c) 2018 Joel Dueck.
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; A copy of the License is included with this source code, in the
;; file "LICENSE.txt".
;; You may also obtain a copy of the License at
;;
;;       http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.
;;
;; Author contact information:
;;   joel@jdueck.net
;;   https://joeldueck.com
;; -------------------------------------------------------------------------

;; Provides a very light set of utility functions for a SQLite database.
;; These functions are completely agnostic as to the database schema.
;; These functions are NOT SAFE for use with data provided by untrusted users!

(require db/sqlite3
         db/base
         racket/list
         racket/match
         racket/function
         racket/contract
         sugar/coerce)

(module+ test
  (require rackunit))

(provide sqltools:dbc
         sqltools:log-queries?)

(provide
 (contract-out
  ;; Utility functions
  [log-query                 (string? . -> . void?)]
  [vector->hash              (vector? (listof symbolish?) . -> . hash?)]
  [backtick                  (stringish? . -> . string?)]
  [list->sql-fields          ((listof stringish?) . -> . string?)]
  [list->sql-parameters      ((listof any/c) . -> . string?)]

  ;; Simple SQL makers
  [make-table-schema         ((string? (listof stringish?))
                              (#:primary-key-cols (listof stringish?))
                              . ->* . string?)]
  [make-insert/replace-query (stringish? (listof stringish?) . -> . string?)]
  [make-select-query         (stringish? (listof stringish?) #:where string? . -> . string?)]

  ;; Database operations
  [init-db!                  ((pathish?) #:rest (listof string?) . ->* . void?)]
  [query!                    ((string?) #:rest (listof any/c) . ->* . void?)]
  [select-rows!              (case->
                              (stringish? (listof stringish?) any/c . -> . (or/c empty? hash?))
                              (string? (listof stringish?) . -> . (or/c empty? hash?)))]))

;; ~~~ Private use ~~~

(define uninitialized-connection "No DB connection!")
(define (weave xs ys)
  (for/fold [(woven null)
             #:result (reverse woven)]
            ([x (in-list xs)]
             [y (in-list ys)])
    (cons y (cons x woven))))

;; ~~~ Provided parameters ~~~

(define sqltools:dbc (make-parameter uninitialized-connection))
(define sqltools:log-queries? (make-parameter #f))

;; ~~~ Provided utility functions ~~~

(define (backtick str) (format "`~a`" str))
(define (list->sql-fields fields) (apply string-append (add-between (map backtick fields) ", ")))
(define (list->sql-parameters fields)
  (apply string-append (add-between (map (λ(x) (format "?~a" (add1 x))) (range (length fields))) ", ")))

;; TESTING: utility functions…
(module+ test
  (check-equal? (backtick "field") "`field`")
  (check-equal? (list->sql-fields '("f1" "f2" "f3")) "`f1`, `f2`, `f3`")
  (check-equal? (list->sql-fields '(f1 f2 f3)) "`f1`, `f2`, `f3`") ; Can use symbols too
  (check-equal? (list->sql-parameters '("name" "rank" "serial")) "?1, ?2, ?3")
  (check-equal? (list->sql-parameters '(name rank serial)) "?1, ?2, ?3")
  (check-equal? (weave '(x y z) '(1 2 3)) '(x 1 y 2 z 3)))

;; ~~~ Public functions ~~~

;; Prints to stdout if logging is on
(define (log-query q) (unless (not (sqltools:log-queries?)) (println q)))

;; Using a list of field names, convert a vector into a hash that uses the
;; field names (in symbol form) for keys.
;; Racket’s db functions all return vectors; hashes are much easier to use.
;; If fields and v are not equal in length, the unpairable elements are omitted
;; from the hash!
(define (vector->hash v fields)
  (cond [(zero? (vector-length v)) null]
        [else (let ([keys (map ->symbol fields)]
                    [vals (vector->list v)])
                (apply hash (weave keys vals)))]))

;; TESTING: vector->hash...
(module+ test
  (let ([test-row '#("Joe" "PFC" 123)]
        [test-cols-SYMBOL '(name rank serial)]
        [test-cols-STRING '("name" "rank" "serial")]
        [desired-result '#hash((serial . 123) (rank . "PFC") (name . "Joe"))])
    (check-equal? (vector->hash test-row test-cols-SYMBOL) desired-result)
    (check-equal? (vector->hash test-row test-cols-STRING) desired-result))

  ;; Behavior when v and fields are unequal in length:
  (check-equal? (vector->hash '#("foo" "bar") '(a b c))
                '#hash((a . "foo") (b . "bar")))
  (check-equal? (vector->hash '#("foo" "bar" "baz") '(a b))
                '#hash((a . "foo") (b . "bar"))))

;; Create a simple table schema from a list of fields, optionally specifying
;; primary key
(define (make-table-schema tablename fields #:primary-key-cols [primary-cols '()])
  (define primary-key
    (format "PRIMARY KEY (~a)"
            (list->sql-fields (if (empty? primary-cols) (list (first fields)) primary-cols))))
  (format "CREATE TABLE IF NOT EXISTS `~a` (~a, ~a);"
          tablename
          (list->sql-fields fields)
          primary-key))

;; Create a query that inserts a row if it doesn’t exist (based on the first
;; column only), or updates it if it does. The returned query is parameterized,
;; and must be used with a list of values equal in length to the number of
;; fields given.
(define (make-insert/replace-query tablename fields)
  (format "INSERT OR REPLACE INTO `~a` (`rowid`, ~a) values ((SELECT `rowid` FROM `~a` WHERE `~a`= ?1), ~a)"
          tablename
          (list->sql-fields fields)
          tablename
          (first fields)
          (list->sql-parameters fields)))

;; Simple row selection
(define (make-select-query table fields #:where where-clause)
  (format "SELECT ~a FROM `~a` WHERE ~a"
          (list->sql-fields fields)
          table
          where-clause))

;; TESTING: SQL query makers...
(module+ test
  (check-equal? (make-table-schema 'posts '(title date))
                "CREATE TABLE IF NOT EXISTS `posts` (`title`, `date`, PRIMARY KEY (`title`));")
  (check-equal? (make-table-schema "posts" '("title" "date"))
                "CREATE TABLE IF NOT EXISTS `posts` (`title`, `date`, PRIMARY KEY (`title`));")
  (check-equal? (make-table-schema 'posts '(title date) #:primary-key-cols '(author date))
                "CREATE TABLE IF NOT EXISTS `posts` (`title`, `date`, PRIMARY KEY (`author`, `date`));")

  (check-equal? (make-insert/replace-query 'posts '(author title))
                (string-append "INSERT OR REPLACE INTO `posts` (`rowid`, `author`, `title`) "
                               "values ((SELECT `rowid` FROM `posts` WHERE `author`= ?1), ?1, ?2)"))

  (check-equal? (make-select-query 'posts '(author title) #:where 1)
                "SELECT `author`, `title` FROM `posts` WHERE 1"))

(define (good-connection?)
  (and (connection? (sqltools:dbc)) (connected? (sqltools:dbc))))

;; Initialize the database connection, creating the database if it does not yet exist
;; and running any provided queries (e.g., "CREATE TABLE IF NOT EXISTS...")
(define (init-db! filename . qs)
  (sqltools:dbc (sqlite3-connect #:database filename #:mode 'create))
  (unless (empty? qs)
    (for ([q (in-list qs)])
         (query! q))))

;; Run a query with logging (if enabled) and return the result
(define (query! q . parameters)
  (unless (good-connection?) (error "(query!) DB not connected"))
  (log-query q)
  (apply query-exec (sqltools:dbc) q parameters))

;; Run a SELECT query, return a hash with field names as keys
(define select-rows!
  (case-lambda
    ;; Use arbitrary query
    [(query fieldnames)
     (unless (good-connection?) (error "(select-rows!) DB not connected"))
     (log-query query)
     (define result (query-rows (sqltools:dbc) query))
     (map (curryr vector->hash fieldnames) result)]
    
    ;; Use a simple SELECT FROM WHERE template
    [(table fields where-clause)
     (unless (good-connection?) (error "(select-rows!) DB not connected"))
     (define query (make-select-query table fields #:where where-clause))
     (log-query query)
     (define result (query-rows (sqltools:dbc) query))
     (map (curryr vector->hash fields) result)]))

;; TESTING: database connection state and queries
(module+ test
  (define TESTDB "SQLITE-TOOLS-TEST.sqlite")

  ;; Check that things start out uninitialized and that queries don’t work
  (check-equal? (sqltools:dbc) uninitialized-connection)
  (check-false (file-exists? TESTDB))
  (check-exn exn:fail? (lambda () (query! "-- nothing")))
  (check-exn exn:fail? (lambda () (select-rows! 'posts '(title) 1)))
  
  ;; Initialize db connection, create file with no schema
  (test-begin
   (check-equal? (init-db! TESTDB) (void))
   (check-true (file-exists? TESTDB))
   (delete-file TESTDB))

  ;; Initialize new db/connection, create file with schema, check that
  ;; simple queries return expected results
  (test-begin
   (check-equal? (init-db! TESTDB (make-table-schema 'posts '(title date))) (void))
   (check-true (file-exists? TESTDB))
   (check-equal? (select-rows! (make-select-query 'posts '(title date) #:where 1) '(title date)) null)
   (check-equal? (query! (make-insert/replace-query 'posts '(title date)) "Hello" "2018-08-10") (void))
   (check-equal? (select-rows! 'posts '(title date) "`date`='2018-08-10'")
                 '(#hash((title . "Hello") (date . "2018-08-10")))))

  ;; Clean up
  (disconnect (sqltools:dbc))
  (sqltools:dbc uninitialized-connection)
  (delete-file TESTDB))

;; Provides functions for displaying content in HTML templates.
(require pollen/core
         "dates.rkt")

(provide (all-defined-out))

(define (html-head [title #f])
  ◊@{<head>
     <title>The Local Yarn◊when/splice[title]{: ◊title}</title>
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <link rel="stylesheet" type="text/css" href="/web-extra/martin.css">
     </head>})

(define (html-page-top)
  ◊@{<body><main>
     <a href="/"><header>
     <img src="/web-extra/logo.png" height="103" width="129" class="logo">
     <h1>The Local Yarn</h1>
     </header></a>})

(define (html-article-header)
  (define title (select-from-metas 'title (current-metas)))
  (define published (select-from-metas 'published (current-metas)))
    (cond
      [title
       ◊string-append{<article class="with-title hentry">
          <h1 class="entry-title">◊|title|</h1>
          <p class="time"><a href="#" class="rel-bookmark">
          <time datetime="◊published" class="published">◊ymd->english[published]</time>
          </a></p>
          <section class="entry-content">}]
      [else
       ◊string-append{<article class="no-title hentry">
          <h1><a href="#" class="rel-bookmark">
          <time datetime="◊published" class="entry-title">◊ymd->english[published]</time>
          </a></h1>
          <section class="entry-content">}]))

(define (html-article-footer)
  ◊string-append{</section>
     <footer class="article-info"><span class="x">(</span>Part of ‘Talking About Poetry’. Once I threw a mudball at a birdhouse. I’m not exactly proud of it, though.<span class="x">)</span></footer>
     </article>})


(define (html-page-bottom)
  ◊@{<footer>By Joel Dueck</footer>
     </main></body>})

<!DOCTYPE html>
<html>
◊html-head[(select-from-metas 'title here)]

◊html-page-top[]

◊spell-of-summoning![]

◊crystalize-article![here doc]

◊html-page-bottom[]

</html>