let frames = {}
function activate(event, element) {
  if (element.target) {
    return
  }
  event.preventDefault()

  let parent = element.parentElement
  for (let e of parent.getElementsByClassName("active")) {
    e.classList.remove("active")
  }
  element.classList.add("active")
  let href = element.href
  let app = document.querySelector("#app")

  let frame = frames[href]
  if (frame) {
    frame.dispatchEvent(new Event("load"))
  } else {
    frame = app.appendChild(document.createElement("iframe"))
    frame.addEventListener("load", e => frameLoaded(frame))
    frame.src = href
    frames[href] = frame
  }

  for (let fhref in frames) {
    let f = frames[fhref]
    if (fhref == href) {
      f.classList.remove("hidden")
    } else {
      f.classList.add("hidden")
    }
  }
}


function frameLoaded(frame) {
  let doc = frame.contentDocument
  if (doc.title.length > 0) {
    document.title = doc.title
  }
  let icon = document.querySelector("link[rel~='icon']")
  let dicon = doc.querySelector("link[rel~='icon']")
  if (dicon) {
    icon.href = dicon.href
  } else {
    icon.href = defaultIcon
  }
}

let defaultIcon = null
function init() {
  let doc = document.querySelector("iframe").contentDocument

  defaultIcon = document.querySelector("link[rel~='icon']").href

  for (let l of document.head.querySelectorAll("style")) {
    doc.head.appendChild(l.cloneNode(true))
  }
  for (let l of document.head.querySelectorAll("link[rel='stylesheet']")) {
    doc.head.appendChild(l.cloneNode())
  }
  for (let f of document.querySelectorAll("#app iframe")) {
    frames[f.src] = f
  }


  let icons = doc.body.appendChild(doc.createElement("section"))
  icons.classList.add("icons")

  for (let link of document.querySelectorAll("nav a")) {
    let dlink = icons.appendChild(link.cloneNode(true))
    dlink.textContent = ""

    if (link.dataset.icon) {
      let icon = dlink.appendChild(doc.createElement("img"))
      icon.src = link.dataset.icon
      icon.style.objectFit = "cover"
    } else {
      let text = dlink.appendChild(doc.createElement("div"))
      text.textContent = link.textContent
    }

    // Make both of them update the selected tab
    link.addEventListener("click", event => activate(event, link))
    dlink.addEventListener("click", event => activate(event, link))
  }
}

if (document.readyState === "loading") {
  document.addEventListener("DOMContentLoaded", init)
} else {
  init()
}