var Dz = {
  remoteWindows: [],
  idx: -1,
  step: 0,
  html: null,
  slides: null,
  progressBar: null,
  params: {
    autoplay: "1"
  }
};

const SLIDE_TAG = "article"

Dz.init = function () {
  document.body.className = "loaded";
  this.slides = Array.prototype.slice.call($$(`body > ${SLIDE_TAG}`));
  this.progressBar = $("#progress-bar");
  this.html = document.body.parentNode;
  this.setupParams();
  this.onhashchange();
  this.setupTouchEvents();
  this.onresize();
  this.setupView();
}
Dz.setupParams = function () {
  var p = window.location.search.substr(1).split('&');
  p.forEach(function (e, i, a) {
    var keyVal = e.split('=');
    Dz.params[keyVal[0]] = decodeURIComponent(keyVal[1]);
  });
  // Specific params handling
  if (!+this.params.autoplay)
    $$.forEach($$("video"), function (v) {
      v.controls = true
    });
}
Dz.onkeydown = function (aEvent) {
  // Don't intercept keyboard shortcuts
  if (aEvent.altKey ||
    aEvent.ctrlKey ||
    aEvent.metaKey ||
    aEvent.shiftKey) {
    return;
  }
  if (aEvent.keyCode == 37 // left arrow
    ||
    aEvent.keyCode == 38 // up arrow
    ||
    aEvent.keyCode == 33 // page up
  ) {
    aEvent.preventDefault();
    this.back();
  }
  if (aEvent.keyCode == 39 // right arrow
    ||
    aEvent.keyCode == 40 // down arrow
    ||
    aEvent.keyCode == 34 // page down
  ) {
    aEvent.preventDefault();
    this.forward();
  }
  if (aEvent.keyCode == 35) { // end
    aEvent.preventDefault();
    this.goEnd();
  }
  if (aEvent.keyCode == 36) { // home
    aEvent.preventDefault();
    this.goStart();
  }
  if (aEvent.keyCode == 32) { // space
    aEvent.preventDefault();
    this.toggleContent();
  }
  if (aEvent.keyCode == 70) { // f
    aEvent.preventDefault();
    this.goFullscreen();
  }
  if (aEvent.keyCode == 79 //o
    ||
    aEvent.keyCode == 27 //Esc
  ) {
    aEvent.preventDefault();
    this.toggleView();
  }
}
/* Touch Events */
Dz.setupTouchEvents = function () {
  var orgX, newX;
  var tracking = false;
  var db = document.body;
  db.addEventListener("touchstart", start.bind(this), false);
  db.addEventListener("touchmove", move.bind(this), false);

  function start(aEvent) {
    aEvent.preventDefault();
    tracking = true;
    orgX = aEvent.changedTouches[0].pageX;
  }

  function move(aEvent) {
    if (!tracking) return;
    newX = aEvent.changedTouches[0].pageX;
    if (orgX - newX > 100) {
      tracking = false;
      this.forward();
    } else {
      if (orgX - newX < -100) {
        tracking = false;
        this.back();
      }
    }
  }
}
Dz.setupView = function () {
  document.body.addEventListener("click", function (e) {
    if (!Dz.html.classList.contains("view")) return;
    if (!e.target || e.target.nodeName != SLIDE_IDENTIFIER.toUpperCase) return;
    Dz.html.classList.remove("view");
    Dz.setCursor(Dz.slides.indexOf(e.target) + 1);
  }, false);
}
/* Adapt the size of the slides to the window */
Dz.onresize = function () {
  var db = document.body;
  var sx = db.clientWidth / window.innerWidth;
  var sy = db.clientHeight / window.innerHeight;
  var transform = "scale(" + (1 / Math.max(sx, sy)) + ")";
  db.style.transform = transform;
  db.style.marginTop = -db.clientHeight / 2 + "px";
  db.style.marginLeft = -db.clientWidth / 2 + "px";
}
Dz.getNotes = function (aIdx) {
  var s = $(`${SLIDE_TAG}:nth-of-type(${aIdx}$)`);
  var d = s.$("[role='note']");
  return d ? d.innerHTML : "";
}
Dz.onmessage = function (aEvent) {
  var argv = aEvent.data.split(" "),
    argc = argv.length;
  argv.forEach(function (e, i, a) {
    a[i] = decodeURIComponent(e)
  });
  var win = aEvent.source;
  if (argv[0] === "REGISTER" && argc === 1) {
    this.remoteWindows.push(win);
    this.postMsg(win, "REGISTERED", document.title, this.slides.length);
    this.postMsg(win, "CURSOR", this.idx + "." + this.step);
    return;
  }
  if (argv[0] === "BACK" && argc === 1)
    this.back();
  if (argv[0] === "FORWARD" && argc === 1)
    this.forward();
  if (argv[0] === "START" && argc === 1)
    this.goStart();
  if (argv[0] === "END" && argc === 1)
    this.goEnd();
  if (argv[0] === "TOGGLE_CONTENT" && argc === 1)
    this.toggleContent();
  if (argv[0] === "SET_CURSOR" && argc === 2)
    window.location.hash = "#" + argv[1];
  if (argv[0] === "GET_CURSOR" && argc === 1)
    this.postMsg(win, "CURSOR", this.idx + "." + this.step);
  if (argv[0] === "GET_NOTES" && argc === 1)
    this.postMsg(win, "NOTES", this.getNotes(this.idx));
}
Dz.toggleContent = function () {
  // If a Video is present in this new slide, play it.
  // If a Video is present in the previous slide, stop it.
  var s = $(`${SLIDE_TAG}[aria-selected]`);
  if (s) {
    var video = s.$("video");
    if (video) {
      if (video.ended || video.paused) {
        video.play();
      } else {
        video.pause();
      }
    }
  }
}
Dz.setCursor = function (aIdx, aStep) {
  // If the user change the slide number in the URL bar, jump
  // to this slide.
  aStep = (aStep != 0 && typeof aStep !== "undefined") ? "." + aStep : ".0";
  window.location.hash = "#" + aIdx + aStep;
}
Dz.onhashchange = function () {
  var cursor = window.location.hash.split("#"),
    newidx = 1,
    newstep = 0;
  if (cursor.length == 2) {
    newidx = ~~cursor[1].split(".")[0];
    newstep = ~~cursor[1].split(".")[1];
    if (newstep > Dz.slides[newidx - 1].$$('.next').length) {
      newstep = 0;
      newidx++;
    }
  }
  this.setProgress(newidx, newstep);
  if (newidx != this.idx) {
    this.setSlide(newidx);
  }
  if (newstep != this.step) {
    this.setIncremental(newstep);
  }
  for (var i = 0; i < this.remoteWindows.length; i++) {
    this.postMsg(this.remoteWindows[i], "CURSOR", this.idx + "." + this.step);
  }
}
Dz.back = function () {
  if (this.idx == 1) {
    return;
  }
  this.setCursor(this.idx - 1,
    this.slides[this.idx - 2].$$('.next[active]').length);
}
Dz.forward = function () {
  if (this.idx >= this.slides.length &&
    this.step >= this.slides[this.idx - 1].$$('.next').length) {
    return;
  }
  if (this.html.classList.contains("view") ||
    this.step >= this.slides[this.idx - 1].$$('.next').length) {
    this.setCursor(this.idx + 1,
      this.slides[this.idx].$$('.next[active]').length);
  } else {
    this.setCursor(this.idx, this.step + 1);
  }
}
Dz.goStart = function () {
  this.setCursor(1, 0);
}
Dz.goEnd = function () {
  var lastIdx = this.slides.length;
  var lastStep = this.slides[lastIdx - 1].$$('.next').length;
  this.setCursor(lastIdx, lastStep);
}
Dz.toggleView = function () {
  this.html.classList.toggle("view");
  if (this.html.classList.contains("view")) {
    $(`${SLIDE_TAG}[aria-selected]`).scrollIntoView(true);
  }
}
Dz.setSlide = function (aIdx) {
  this.idx = aIdx;
  var old = $(`${SLIDE_TAG}[aria-selected]`);
  var next = $(`${SLIDE_TAG}:nth-of-type(${this.idx})`);
  if (old) {
    old.removeAttribute("aria-selected");
    var video = old.$("video");
    if (video) {
      video.pause();
    }
  }
  if (next) {
    next.setAttribute("aria-selected", "true");
    if (this.html.classList.contains("view")) {
      next.scrollIntoView();
    } else {
      var video = next.$("video");
      if (video && !!+this.params.autoplay) {
        video.play();
      }
    }
  } else {
    // That should not happen
    this.idx = -1;
    // console.warn("Slide doesn't exist.");
  }
}
Dz.setIncremental = function (aStep) {
  this.step = aStep;
  var incrementals = Array.prototype.slice.call(this.slides[this.idx - 1].$$('.next')).sort(function (a, b) {
    return Number(a.getAttribute('next-order')) - Number(b.getAttribute('next-order'));
  });
  var next = incrementals[this.step - 1];
  if (next) {
    next.setAttribute('active', true);
  } else {
    this.setCursor(this.idx, 0);
  }
  return next;
}
Dz.goFullscreen = function () {
  var html = $('html'),
    requestFullscreen = html.requestFullscreen || html.requestFullScreen || html.mozRequestFullScreen || html.webkitRequestFullScreen;
  if (requestFullscreen) {
    requestFullscreen.apply(html);
  }
}

Dz.setProgress = function (aIdx, aStep) {
  var slide = $(`${SLIDE_TAG}:nth-of-type(${aIdx})`);
  if (!slide)
    return;
  var steps = slide.$$('.next').length + 1,
    slideSize = 100 / (this.slides.length - 1),
    stepSize = slideSize / steps;
  this.progressBar.style.width = ((aIdx - 1) * slideSize + aStep * stepSize) + '%';
}

Dz.postMsg = function (aWin, aMsg) { // [arg0, [arg1...]]
  aMsg = [aMsg];
  for (var i = 2; i < arguments.length; i++)
    aMsg.push(encodeURIComponent(arguments[i]));
  aWin.postMessage(aMsg.join(" "), "*");
}

function init() {
  Dz.init();
  window.onkeydown = Dz.onkeydown.bind(Dz);
  window.onresize = Dz.onresize.bind(Dz);
  window.onhashchange = Dz.onhashchange.bind(Dz);
  window.onmessage = Dz.onmessage.bind(Dz);
}
window.onload = init;
// Helpers
if (!Function.prototype.bind) {
  Function.prototype.bind = function (oThis) {
    // closest thing possible to the ECMAScript 5 internal IsCallable
    // function
    if (typeof this !== "function")
      throw new TypeError(
        "Function.prototype.bind - what is trying to be fBound is not callable"
      );
    var aArgs = Array.prototype.slice.call(arguments, 1),
      fToBind = this,
      fNOP = function () {},
      fBound = function () {
        return fToBind.apply(this instanceof fNOP ? this : oThis || window,
          aArgs.concat(Array.prototype.slice.call(arguments)));
      };
    fNOP.prototype = this.prototype;
    fBound.prototype = new fNOP();
    return fBound;
  };
}
var $ = (HTMLElement.prototype.$ = function (aQuery) {
  return this.querySelector(aQuery);
}).bind(document);
var $$ = (HTMLElement.prototype.$$ = function (aQuery) {
  return this.querySelectorAll(aQuery);
}).bind(document);
$$.forEach = function (nodeList, fun) {
  Array.prototype.forEach.call(nodeList, fun);
}