#lang racket/base

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;; Wiki and user settings for the browser-side CMap workspace.
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(require db
         racket/string
         "database.rkt")

(provide read-cmap-settings
         save-start-cmap!
         save-cmap-page-guides!
         save-cmap-zoom!)

(define start-cmap-setting-key "cmap.start.v1")

(define (clean-context-key who context-key)
  (unless (and (string? context-key)
               (not (string=? (string-trim context-key) ""))
               (<= (string-length context-key) 200))
    (error who "invalid CMap context"))
  context-key)

(define (clean-zoom who zoom)
  (unless (and (exact-integer? zoom) (<= 25 zoom 300))
    (error who "zoom must be an integer between 25 and 300"))
  zoom)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; goal   : Read the wiki start CMap and one user's CMap view preferences.
; pre    : user-id identifies an authenticated wiki user.
; post   : The database is unchanged; missing preferences receive defaults.
; result : A JSON-compatible settings hash.
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(define (read-cmap-settings config user-id)
  (call-with-wiki-database
   config
   (λ (db)
     (define start-slug
       (or (query-maybe-value
            db
            "SELECT value FROM wiki_settings WHERE key = $1"
            start-cmap-setting-key)
           ""))
     (define page-guide-row
       (query-maybe-row
        db
        "SELECT page_guides_visible FROM user_cmap_preferences WHERE user_id = $1"
        user-id))
     (define page-guides-visible
       (if page-guide-row (vector-ref page-guide-row 0) #t))
     (define zoom-rows
       (query-rows
        db
        "SELECT cmap_slug, context_key, zoom_percent FROM user_cmap_zoom_levels WHERE user_id = $1 ORDER BY cmap_slug, context_key"
        user-id))
     (define zooms
       (for/list ((row (in-list zoom-rows)))
         (hash 'cmapSlug (vector-ref row 0)
               'contextKey (vector-ref row 1)
               'zoomPercent (vector-ref row 2))))
     (hash 'startCmapSlug start-slug
           'pageGuidesVisible page-guides-visible
           'zooms zooms))))

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; goal   : Select the wiki-wide start CMap.
; pre    : slug is empty, or identifies a current non-archived CMap.
; post   : The start setting is removed or updated atomically.
; result : The stored slug, or the empty string when cleared.
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(define (save-start-cmap! config slug)
  (define clean-slug (if (string? slug) (string-trim slug) ""))
  (call-with-wiki-database
   config
   (λ (db)
     (cond
       ((string=? clean-slug "")
        (query-exec db "DELETE FROM wiki_settings WHERE key = $1" start-cmap-setting-key))
       ((query-maybe-value
         db
         "SELECT 1 FROM concept_maps WHERE slug = $1 AND archived = FALSE"
         clean-slug)
        (query-exec
         db
         "INSERT INTO wiki_settings(key, value, updated_at) VALUES ($1, $2, $3) ON CONFLICT(key) DO UPDATE SET value = excluded.value, updated_at = excluded.updated_at"
         start-cmap-setting-key clean-slug (current-seconds)))
       (else
        (error 'save-start-cmap! "the selected start CMap does not exist")))))
  clean-slug)

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; goal   : Store one user's wiki-wide A4 page-guide preference.
; pre    : visible is a boolean and user-id identifies an authenticated user.
; post   : The user's preference is inserted or updated atomically.
; result : The stored boolean.
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(define (save-cmap-page-guides! config user-id visible)
  (unless (boolean? visible)
    (error 'save-cmap-page-guides! "pageGuidesVisible must be a boolean"))
  (call-with-wiki-database
   config
   (λ (db)
     (query-exec
      db
      "INSERT INTO user_cmap_preferences(user_id, page_guides_visible, updated_at) VALUES ($1, $2, $3) ON CONFLICT(user_id) DO UPDATE SET page_guides_visible = excluded.page_guides_visible, updated_at = excluded.updated_at"
      user-id visible (current-seconds))))
  visible)

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; goal   : Store one user's zoom for one CMap context.
; pre    : The CMap exists, context-key is non-empty and zoom is 25 through 300.
; post   : This single context preference is inserted or updated atomically.
; result : The normalized zoom percentage.
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(define (save-cmap-zoom! config user-id cmap-slug context-key zoom)
  (define clean-context (clean-context-key 'save-cmap-zoom! context-key))
  (define clean-zoom-percent (clean-zoom 'save-cmap-zoom! zoom))
  (call-with-wiki-database
   config
   (λ (db)
     (unless (query-maybe-value
              db
              "SELECT 1 FROM concept_maps WHERE slug = $1 AND archived = FALSE"
              cmap-slug)
       (error 'save-cmap-zoom! "the selected CMap does not exist"))
     (query-exec
      db
      "INSERT INTO user_cmap_zoom_levels(user_id, cmap_slug, context_key, zoom_percent, updated_at) VALUES ($1, $2, $3, $4, $5) ON CONFLICT(user_id, cmap_slug, context_key) DO UPDATE SET zoom_percent = excluded.zoom_percent, updated_at = excluded.updated_at"
      user-id cmap-slug clean-context clean-zoom-percent (current-seconds))))
  clean-zoom-percent)