File: public/js/tinymce/src/themes/mobile/src/main/js/android/core/AndroidSetup.js

define(
  'tinymce.themes.mobile.android.core.AndroidSetup',

  [
    'ephox.katamari.api.Fun',
    'ephox.katamari.api.Option',
    'ephox.sugar.api.events.DomEvent',
    'ephox.sugar.api.node.Element',
    'ephox.sugar.api.properties.Attr',
    'global!Math',
    'tinymce.themes.mobile.android.focus.ResumeEditing',
    'tinymce.themes.mobile.style.Styles',
    'tinymce.themes.mobile.util.DataAttributes',
    'tinymce.themes.mobile.util.Rectangles'
  ],

  function (Fun, Option, DomEvent, Element, Attr, Math, ResumeEditing, Styles, DataAttributes, Rectangles) {
    // This amount is added to the minimum scrolling distance when calculating how much to scroll
    // because the soft keyboard has appeared.
    var EXTRA_SPACING = 50;

    var data = 'data-' + Styles.resolve('last-outer-height');

    var setLastHeight = function (cBody, value) {
      Attr.set(cBody, data, value);
    };

    var getLastHeight = function (cBody) {
      return DataAttributes.safeParse(cBody, data);
    };

    var getBoundsFrom = function (rect) {
      return {
        top: Fun.constant(rect.top()),
        bottom: Fun.constant(rect.top() + rect.height())
      };
    };

    var getBounds = function (cWin) {
      var rects = Rectangles.getRectangles(cWin);
      return rects.length > 0 ? Option.some(rects[0]).map(getBoundsFrom) : Option.none();
    };

    var findDelta = function (outerWindow, cBody) {
      var last = getLastHeight(cBody);
      var current = outerWindow.innerHeight;
      return last > current ? Option.some(last - current) : Option.none();
    };

    var calculate = function (cWin, bounds, delta) {
      // The goal here is to shift as little as required.
      var isOutside = bounds.top() > cWin.innerHeight || bounds.bottom() > cWin.innerHeight;
      return isOutside ? Math.min(delta, bounds.bottom() - cWin.innerHeight + EXTRA_SPACING) : 0;
    };

    var setup = function (outerWindow, cWin) {
      var cBody = Element.fromDom(cWin.document.body);

      var toEditing = function () {
        // TBIO-3816 throttling the resume was causing keyboard hide/show issues with undo/redo
        // throttling was introduced to work around a different keyboard hide/show issue, where
        // async uiChanged in Processor in polish was causing keyboard hide, which no longer seems to occur
        ResumeEditing.resume(cWin);
      };

      var onResize = DomEvent.bind(Element.fromDom(outerWindow), 'resize', function () {

        findDelta(outerWindow, cBody).each(function (delta) {
          getBounds(cWin).each(function (bounds) {
            // If the top is offscreen, scroll it into view.
            var cScrollBy = calculate(cWin, bounds, delta);
            if (cScrollBy !== 0) {
              cWin.scrollTo(cWin.pageXOffset, cWin.pageYOffset + cScrollBy);
            }
          });
        });
        setLastHeight(cBody, outerWindow.innerHeight);
      });

      setLastHeight(cBody, outerWindow.innerHeight);

      var destroy = function () {
        onResize.unbind();
      };

      return {
        toEditing: toEditing,
        destroy: destroy
      };
    };

    return {
      setup: setup
    };
  }
);