dom_server.clj

(ns com.fulcrologic.fulcro.dom-server
  "Support for rendering DOM from CLJ. Must be separate to enable same-named macros in CLJS for performance.

  Usage: Create your UI in CLJC files, and require with conditional reader tags:

  (ns app.ui
    (:require
      #?(:clj [com.fulcrologic.fulcro.dom-server :as dom] :cljs [com.fulcrologic.fulcro.dom :as dom])))"
  (:refer-clojure :exclude [map meta time mask select use set symbol filter])
  (:require
    [com.fulcrologic.fulcro.dom-common :as cdom]
    [com.fulcrologic.fulcro.components :refer [component-instance?]]
    [clojure.string :as str]
    [com.fulcrologic.fulcro.algorithms.do-not-use :as util]
    [clojure.spec.alpha :as s]
    [clojure.core.reducers :as r]
    [com.fulcrologic.fulcro.components :as comp]
    [taoensso.encore :as encore]))

(definterface IReactDOMElement
  (^StringBuilder renderToString [react-id ^StringBuilder sb]))

(declare render-element!)

(defrecord Element [tag attrs react-key children]
  IReactDOMElement
  (renderToString [this react-id sb]
    (render-element! this react-id sb)))

(defn element?
  "Returns true if the given arg is a server-side react element."
  [x]
  (instance? IReactDOMElement x))

(s/def ::dom-element-args
  (s/cat
    :css (s/? keyword?)
    :attrs (s/? (s/or
                  :nil nil?
                  :map #(and (map? %)
                          (not (component-instance? %))
                          (not (element? %)))))
    :children (s/* (s/or
                     :nil nil?
                     :string string?
                     :number number?
                     :collection #(or (vector? %) (seq? %))
                     :component component-instance?
                     :element element?))))

(declare a abbr address altGlyph altGlyphDef altGlyphItem animate animateColor animateMotion animateTransform area
  article aside audio b base bdi bdo big blockquote body br button canvas caption circle cite clipPath code
  col colgroup color-profile cursor data datalist dd defs del desc details dfn dialog discard div dl dt
  ellipse em embed feBlend feColorMatrix feComponentTransfer feComposite feConvolveMatrix feDiffuseLighting
  feDisplacementMap feDistantLight feDropShadow feFlood feFuncA feFuncB feFuncG feFuncR feGaussianBlur
  feImage feMerge feMergeNode feMorphology feOffset fePointLight feSpecularLighting feSpotLight feTile feTurbulence
  fieldset figcaption figure filter font font-face font-face-format font-face-name font-face-src font-face-uri
  footer foreignObject form g glyph glyphRef h1 h2 h3 h4 h5 h6 hatch hatchpath head header hkern hr html
  i iframe image img input ins kbd keygen label legend li line linearGradient link main map mark marker mask
  menu menuitem mesh meshgradient meshpatch meshrow meta metadata meter missing-glyph
  mpath nav noscript object ol optgroup option output p param path pattern picture polygon polyline pre progress q radialGradient
  rect rp rt ruby s samp script section select set small solidcolor source span stop strong style sub summary
  sup svg switch symbol table tbody td text textPath textarea tfoot th thead time title tr track tref tspan
  u ul unknown use var video view vkern wbr)

;; https://github.com/facebook/react/blob/57ae3b/src/renderers/dom/shared/SVGDOMPropertyConfig.js
;; https://github.com/facebook/react/blob/57ae3b/src/renderers/dom/shared/HTMLDOMPropertyConfig.js
(def no-suffix
  #{"animationIterationCount" "boxFlex" "boxFlexGroup" "boxOrdinalGroup"
    "columnCount" "fillOpacity" "flex" "flexGrow" "flexPositive" "flexShrink"
    "flexNegative" "flexOrder" "fontWeight" "lineClamp" "lineHeight" "opacity"
    "order" "orphans" "stopOpacity" "strokeDashoffset" "strokeOpacity"
    "strokeWidth" "tabSize" "widows" "zIndex" "zoom"})

(def lower-case-attrs
  #{"accessKey" "allowFullScreen" "allowTransparency" "as" "autoComplete"
    "autoFocus" "autoPlay" "contentEditable" "contextMenu" "crossOrigin"
    "cellPadding" "cellSpacing" "charSet" "classID" "colSpan" "dateTime"
    "encType" "formAction" "formEncType" "formMethod" "formNoValidate"
    "formTarget" "frameBorder" "hrefLang" "inputMode" "keyParams"
    "keyType" "marginHeight" "marginWidth" "maxLength" "mediaGroup"
    "minLength" "noValidate" "playsInline" "radioGroup" "readOnly" "rowSpan"
    "spellCheck" "srcDoc" "srcLang" "srcSet" "tabIndex" "useMap"
    "autoCapitalize" "autoCorrect" "autoSave" "itemProp" "itemScope"
    "itemType" "itemID" "itemRef"})

(def kebab-case-attrs
  #{"acceptCharset" "httpEquiv" "accentHeight" "alignmentBaseline" "arabicForm"
    "baselineShift" "capHeight" "clipPath" "clipRule" "colorInterpolation"
    "colorInterpolationFilters" "colorProfile" "colorRendering" "dominantBaseline"
    "enableBackground" "fillOpacity" "fillRule" "floodColor" "floodOpacity"
    "fontFamily" "fontSize" "fontSizeAdjust" "fontStretch" "fontStyle"
    "fontVariant" "fontWeight" "glyphName" "glyphOrientationHorizontal"
    "glyphOrientationVertical" "horizAdvX" "horizOriginX" "imageRendering"
    "letterSpacing" "lightingColor" "markerEnd" "markerMid" "markerStart"
    "overlinePosition" "overlineThickness" "paintOrder" "panose1" "pointerEvents"
    "renderingIntent" "shapeRendering" "stopColor" "stopOpacity" "strikethroughPosition"
    "strikethroughThickness" "strokeDasharray" "strokeDashoffset" "strokeLinecap"
    "strokeLinejoin" "strokeMiterlimit" "strokeOpacity" "strokeWidth" "textAnchor"
    "textDecoration" "textRendering" "underlinePosition" "underlineThickness"
    "unicodeBidi" "unicodeRange" "unitsPerEm" "vAlphabetic" "vHanging" "vIdeographic"
    "vMathematical" "vectorEffect" "vertAdvY" "vertOriginX" "vertOriginY" "wordSpacing"
    "writingMode" "xHeight"})

(def colon-between-attrs
  #{"xlinkActuate" "xlinkArcrole" "xlinkHref" "xlinkRole" "xlinkShow" "xlinkTitle"
    "xlinkType" "xmlBase" "xmlnsXlink" "xmlLang" "xmlSpace"})

(declare render-element!)

(defn append!
  ([^StringBuilder sb s0] (.append sb s0))
  ([^StringBuilder sb s0 s1]
   (.append sb s0)
   (.append sb s1))
  ([^StringBuilder sb s0 s1 s2]
   (.append sb s0)
   (.append sb s1)
   (.append sb s2))
  ([^StringBuilder sb s0 s1 s2 s3]
   (.append sb s0)
   (.append sb s1)
   (.append sb s2)
   (.append sb s3))
  ([^StringBuilder sb s0 s1 s2 s3 s4]
   (.append sb s0)
   (.append sb s1)
   (.append sb s2)
   (.append sb s3)
   (.append sb s4))
  ([^StringBuilder sb s0 s1 s2 s3 s4 & rest]
   (.append sb s0)
   (.append sb s1)
   (.append sb s2)
   (.append sb s3)
   (.append sb s4)
   (doseq [s rest]
     (.append sb s))))

(def ^:dynamic *css-mode* false)

(defn escape-html ^String [^String s]
  (if *css-mode*
    s
    (let [len (count s)]
      (loop [^StringBuilder sb nil
             i                 (int 0)]
        (if (< i len)
          (let [char (.charAt s i)
                repl (case char
                       \& "&amp;"
                       \< "&lt;"
                       \> "&gt;"
                       \" "&quot;"
                       \' "&#x27;"
                       nil)]
            (if (nil? repl)
              (if (nil? sb)
                (recur nil (inc i))
                (recur (doto sb
                         (.append char))
                  (inc i)))
              (if (nil? sb)
                (recur (doto (StringBuilder.)
                         (.append s 0 i)
                         (.append repl))
                  (inc i))
                (recur (doto sb
                         (.append repl))
                  (inc i)))))
          (if (nil? sb) s (str sb)))))))

(defrecord Text [s]
  IReactDOMElement
  (renderToString [this react-id sb]
    (append! sb (escape-html s))))

(defrecord ReactText [text]
  IReactDOMElement
  (renderToString [this react-id sb]
    (append! sb "<!-- react-text: " @react-id " -->" (escape-html text) "<!-- /react-text -->")
    (vswap! react-id inc)
    sb))

(defrecord ReactEmpty []
  IReactDOMElement
  (renderToString [this react-id sb]
    (append! sb "<!-- react-empty: " @react-id " -->")
    (vswap! react-id inc)
    sb))

(defn text-node
  "HTML text node"
  [s]
  (map->Text {:s s}))

(defn react-text-node
  "HTML text node"
  [s]
  (map->ReactText {:text s}))

(defn- react-empty-node []
  (map->ReactEmpty {}))

(defn- render-component [c]
  (if (or (nil? c) (element? c))
    c
    (encore/when-let [render (comp/component-options c :render)
                      output (render c)]
      (if (vector? output)
        (mapv render-component output)
        (recur output)))))

(defn element
  "Creates a dom node."
  [{:keys [tag attrs react-key children] :as elem}]
  (assert (name tag))
  (assert (or (nil? attrs) (map? attrs)) (format "elem %s attrs invalid" elem))
  (let [children         (flatten children)
        child-node-count (count children)
        reduce-fn        (if (> child-node-count 1)
                           r/reduce
                           reduce)
        children         (reduce-fn
                           (fn [res c]
                             (let [c' (cond
                                        (element? c) c

                                        (component-instance? c) (let [rendered (if-let [element (render-component c)]
                                                                                 element
                                                                                 (react-empty-node))]
                                                                  (assoc rendered :react-key
                                                                                  (some-> (:props c) :fulcro$reactKey)))

                                        (or (string? c) (number? c))
                                        (let [c (cond-> c (number? c) str)]
                                          (if (> child-node-count 1)
                                            (react-text-node c)
                                            (text-node c)))

                                        (nil? c) nil

                                        :else
                                        (throw (IllegalArgumentException. (str "Invalid child element: ") c)))]
                               (cond-> res
                                 (some? c') (conj c'))))
                           [] children)]
    (map->Element {:tag       (name tag)
                   :attrs     attrs
                   :react-key react-key
                   :children  children})))

(defn camel->other-case [^String sep]
  (fn ^String [^String s]
    (-> s
      (str/replace #"([A-Z0-9])" (str sep "$1"))
      str/lower-case)))

(def camel->kebab-case
  (camel->other-case "-"))

(def camel->colon-between
  (camel->other-case ":"))

(defn coerce-attr-key ^String [^String k]
  (cond
    (contains? lower-case-attrs k) (str/lower-case k)
    (contains? kebab-case-attrs k) (camel->kebab-case k)
    ;; special cases
    (= k "className") "class"
    (= k "htmlFor") "for"
    (contains? colon-between-attrs k) (camel->colon-between k)
    :else k))

(defn render-xml-attribute! [sb name value]
  (let [name (coerce-attr-key (clojure.core/name name))]
    (append! sb " " name "=\""
      (cond-> value
        (string? value) escape-html) "\"")))

(defn normalize-styles! [sb styles]
  (letfn [(coerce-value [k v]
            (cond-> v
              (string? v)
              escape-html
              (and (number? v)
                (not (contains? no-suffix k))
                (pos? v))
              (str "px")))]
    (run! (fn [[k v]]
            (let [k (name k)]
              (append! sb (camel->kebab-case k) ":" (coerce-value k v) ";")))
      styles)))

(defn render-styles! [sb styles]
  (when-not (empty? styles)
    (append! sb " style=\"")
    (normalize-styles! sb styles)
    (append! sb "\"")))

(defn render-attribute! [sb [key value]]
  (cond
    (or (fn? value)
      (not value))
    nil

    (identical? key :style)
    (render-styles! sb value)

    (or (true? value) (string? value) (number? value))
    (if (true? value)
      (append! sb " " (coerce-attr-key (name key)))
      (render-xml-attribute! sb key value))

    :else nil))

;; some props assigned first in input and option. see:
;; https://github.com/facebook/react/blob/680685/src/renderers/dom/client/wrappers/ReactDOMOption.js#L108
;; https://github.com/facebook/react/blob/680685/src/renderers/dom/client/wrappers/ReactDOMInput.js#L63
(defn render-attr-map! [sb tag attrs]
  (letfn [(sorter [order]
            (fn [[k _]]
              (get order k (->> (vals order)
                             (apply max)
                             inc))))]
    (let [attrs (cond->> attrs
                  (= tag "input") (sort-by (sorter {:type 0 :step 1
                                                    :min  2 :max 3}))
                  (= tag "option") (sort-by (sorter {:selected 0})))]
      (run! (partial render-attribute! sb) attrs))))

(def ^{:doc     "A list of elements that must be rendered without a closing tag."
       :private true}
  void-tags
  #{"area" "base" "br" "col" "command" "embed" "hr" "img" "input" "keygen" "link"
    "meta" "param" "source" "track" "wbr"})

(defn render-unescaped-html! [sb m]
  (if-not (contains? m :__html)
    (throw (IllegalArgumentException. "`props.dangerouslySetInnerHTML` must be in the form `{:__html ...}`")))
  (when-let [html (:__html m)]
    (append! sb html)))

(defn container-tag?
  "Returns true if the tag has content or is not a void tag. In non-HTML modes,
   all contentless tags are assumed to be void tags."
  [tag content]
  (or content (and (not (void-tags tag)))))

(defn render-element!
  "Render a tag vector as a HTML element string."
  [{:keys [tag attrs children]} react-id ^StringBuilder sb]
  (binding [*css-mode* (= "style" tag)]
    (append! sb "<" tag)
    (render-attr-map! sb tag attrs)
    (let [react-id-val @react-id]
      (when (= react-id-val 1)
        (append! sb " data-reactroot=\"\""))
      (append! sb " data-reactid=\"" react-id-val "\"")
      (vswap! react-id inc)
      sb)
    (if (container-tag? tag (seq children))
      (do
        (append! sb ">")
        (if-let [html-map (:dangerouslySetInnerHTML attrs)]
          (render-unescaped-html! sb html-map)
          (run! #(.renderToString % react-id sb) children))
        (append! sb "</" tag ">"))
      (append! sb "/>"))))

(def key-escape-lookup
  {"=" "=0"
   ":" "=2"})

(defn- is-element? [e]
  (or
    (comp/component-instance? e)
    (instance? com.fulcrologic.fulcro.dom_server.IReactDOMElement e)))

(defn- render-to-str* ^StringBuilder [x]
  {:pre [(or
           (vector? x)
           (is-element? x))]}
  (if (vector? x)
    (StringBuilder. (str/join " " (map render-to-str* x)))
    (let [element ^com.fulcrologic.fulcro.dom_server.IReactDOMElement (if-let [element (cond-> x
                                                                                         (component-instance? x) render-component)]
                                                                        element
                                                                        (react-empty-node))
          sb      (StringBuilder.)]
      (if (vector? element)
        (doseq [e element]
          (.renderToString e (volatile! 1) sb))
        (.renderToString element (volatile! 1) sb))
      sb)))

;; ===================================================================
;; Checksums (data-react-checksum)

(def MOD 65521)

;; Adapted from https://github.com/tonsky/rum
(defn adler32 [^StringBuilder sb]
  (let [l (.length sb)
        m (bit-and l -4)]
    (loop [a (int 1)
           b (int 0)
           i 0
           n (min (+ i 4096) m)]
      (cond
        (< i n)
        (let [c0 (int (.charAt sb i))
              c1 (int (.charAt sb (+ i 1)))
              c2 (int (.charAt sb (+ i 2)))
              c3 (int (.charAt sb (+ i 3)))
              b  (+ b a c0
                   a c0 c1
                   a c0 c1 c2
                   a c0 c1 c2 c3)
              a  (+ a c0 c1 c2 c3)]
          (recur (rem a MOD) (rem b MOD) (+ i 4) n))

        (< i m)
        (recur a b i (min (+ i 4096) m))

        (< i l)
        (let [c0 (int (.charAt sb i))]
          (recur (+ a c0) (+ b a c0) (+ i 1) n))

        :else
        (let [a (rem a MOD)
              b (rem b MOD)]
          (bit-or (int a) (unchecked-int (bit-shift-left b 16))))))))

(defn assign-react-checksum [^StringBuilder sb]
  (.insert sb (.indexOf sb ">") (str " data-react-checksum=\"" (adler32 sb) "\"")))

(defn render-to-str ^String [x]
  (let [sb (render-to-str* x)]
    (assign-react-checksum sb)
    (.toString sb)))

(defn node
  "Returns the dom node associated with a component's React ref.

  This is a NO-OP function for completion, and is not supported for SSR"
  ([component])
  ([component name]))

(defn create-element
  "Create a DOM element for which there exists no corresponding function.
   Useful to create DOM elements not included in React.DOM. Equivalent
   to calling `js/React.createElement`"
  ([tag]
   (create-element tag nil))
  ([tag opts & children]
   (element {:tag       tag
             :attrs     (dissoc opts :ref :key)
             :react-key (:key opts)
             :children  children})))

(defn gen-tag-fn [tag]
  `(defn ~tag ~(cdom/gen-docstring tag false)
     [& ~'args]
     (let [conformed-args# (util/conform! ::dom-element-args ~'args)
           {attrs#    :attrs
            children# :children
            css#      :css} conformed-args#
           children#       (mapv second children#)
           attrs-value#    (or (second attrs#) {})]
       (element {:tag       '~tag
                 :attrs     (-> (cdom/interpret-classes attrs-value#)
                              (dissoc :ref :key)
                              (cdom/add-kwprops-to-props css#))
                 :react-key (:key attrs-value#)
                 :children  children#}))))

(defmacro gen-all-tags []
  (when-not (boolean (:ns &env))
    `(do
       ~@(clojure.core/map gen-tag-fn cdom/tags))))

(gen-all-tags)