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import scala.scalajs.js
import scala.scalajs.js.annotation.JSExport
import org.scalajs.dom
import org.scalajs.dom.extensions._
import scala.collection.mutable
import scalatags.JsDom.all._
object Renderer{
import japgolly.scalajs.react._ // React
import vdom.ReactVDom._ // Scalatags → React virtual DOM
import vdom.ReactVDom.all._ // Scalatags html & css (div, h1, textarea, etc.)
val Menu = ReactComponentB[Int]("Menu").render{ p =>
}.build
}
case class Tree[T](name: T, children: Vector[Tree[T]])
@JSExport
object Controller{
def munge(name: String) = {
name.replace(" ", "")
}
def addClass(el: dom.HTMLElement, cls: String) = {
removeClass(el, cls)
el.className = el.className + " " + cls
}
def removeClass(el: dom.HTMLElement, cls: String) = {
el.className = el.className.split(' ').filter(_ != cls).mkString(" ")
}
def toggleClass(el: dom.HTMLElement, cls: String) = {
val frags = el.className.split(' ')
if (!frags.contains(cls)) addClass(el, cls)
else removeClass(el, cls)
}
@JSExport
def main(data: scala.scalajs.js.Any) = {
val structure = upickle.readJs[Tree[String]](upickle.json.readJs(data))
val Seq(main, menu, layout, menuLink) = Seq(
"main", "menu", "layout", "menuLink"
).map(dom.document.getElementById)
val snippets = dom.document.getElementsByClassName("highlight-me")
snippets.foreach(js.Dynamic.global.hljs.highlightBlock(_))
val contentTree = {
def rec(current: Tree[String], depth: Int): Tree[dom.HTMLElement] = {
val myCls =
"menu-item" +
(if (depth <= 1) " menu-item-divided" else "")
val frag =
li(
paddingLeft := s"${depth * 15}px",
a(
current.name,
href:="#"+munge(current.name),
cls:=myCls
)
).render
Tree(frag, current.children.map(rec(_, depth + 1)))
}
rec(structure, 0)
}
val contentList = {
def rec(current: Tree[dom.HTMLElement]): Seq[dom.HTMLElement] = {
current.name +: current.children.flatMap(rec)
}
rec(contentTree).toVector
}
val frag = div(cls:="pure-menu pure-menu-open")(
a(cls:="pure-menu-heading", href:="#")(
"Contents"
),
ul(cls:="menu-item-list")(
contentList.drop(1)
)
)
menu.appendChild(frag.render)
val headers = {
def offset(el: dom.HTMLElement, parent: dom.HTMLElement): Double = {
if (el == parent) 0
else el.offsetTop + offset(el.offsetParent.asInstanceOf[dom.HTMLElement], parent)
}
val menuItems = {
def rec(current: Tree[String]): Seq[String] = {
current.name +: current.children.flatMap(rec)
}
rec(structure).tail
}
menuItems.map(munge)
.map(dom.document.getElementById)
.map(offset(_, main))
.toVector
}
scrollSpy(main, headers, contentList, contentTree)
menuLink.onclick = (e: dom.MouseEvent) => {
toggleClass(layout, "active")
toggleClass(menu, "active")
toggleClass(menuLink, "active")
}
}
/**
* Needs to be done in a sketchy imperative fashion for performance:
* onscroll gets called quite a lot, so any additional work makes it
* noticeable jerky
*/
def scrollSpy(main: dom.HTMLElement,
headers: Vector[Double],
contentList: Vector[dom.HTMLElement],
contentTree: Tree[dom.HTMLElement]) = {
var scrolling = false
var lastIndex = -1
def run() = {
scrolling = false
val threshold = main.scrollTop + main.clientHeight
var index = 0
while(index < headers.length && index >= 0){
index += 1
if (headers(index) > threshold) index *= -1
}
index = -index
if (index != lastIndex){
updateSideBar(lastIndex, index, contentList, contentTree)
lastIndex = index
}
}
run()
main.onscroll = (e: dom.UIEvent) => {
if (!scrolling){
scrolling = true
dom.requestAnimationFrame((d: Double) => run())
}
}
}
def isElementInViewport(el: dom.HTMLElement) = {
val rect = el.getBoundingClientRect()
rect.top >= 0 && rect.bottom <= dom.innerHeight
}
val lastShown = new js.Array[dom.HTMLElement](0)
val lastLined = new js.Array[dom.HTMLElement](0)
def updateSideBar(lastIndex: Int,
index: Int,
contentList: Vector[dom.HTMLElement],
contentTree: Tree[dom.HTMLElement]) = {
println(s"MOVING $lastIndex -> $index")
if (!isElementInViewport(contentList(index))) {
contentList(index).scrollIntoView(lastIndex > index)
}
val shown = new js.Array[dom.HTMLElement](0)
val lined = new js.Array[dom.HTMLElement](0)
/**
* Makes two passes over the children list; once to determine if
* the current element is a parent of the current header, and another
* to mark all the children of the current element with the correct
* CSS classes.
*/
def rec(curr: Tree[dom.HTMLElement]): Boolean = {
var found = false
var i = 0
var j = 0
while (j < curr.children.length){
val x = curr.children(j)
j+= 1
val f = rec(x)
found |= f
if (!found) i += 1
}
if (found || curr.name == contentList(index)){
var j = 0
while (j < curr.children.length){
val x = curr.children(j)
if (found && i > 0){
lined.push(x.name)
i -= 1
}
j+= 1
shown.push(x.name)
}
lined.push(curr.name)
true
}else false
}
rec(contentTree)
for(el <- contentList){
if (shown.indexOf(el) != -1) removeClass(el, "hide")
else addClass(el, "hide")
if (lined.indexOf(el) == -1) removeClass(el, "lined")
else addClass(el, "lined")
}
if (lastIndex != -1) removeClass(contentList(lastIndex), "pure-menu-selected")
addClass(contentList(index), "pure-menu-selected")
}
}
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