const toRect = function (rect) {
  return {
    left: Fun.constant(rect.left),
    top: Fun.constant(rect.top),
    right: Fun.constant(rect.right),
    bottom: Fun.constant(rect.bottom),
    width: Fun.constant(rect.width),
    height: Fun.constant(rect.height)
  };
};

  return Future.nu(function (callback) {
    const getCurrent = Fun.curry(getScrollTop, element);

    const update = function (newScroll) {
      element.dom().scrollTop = newScroll;
      Css.set(element, 'top', (getTop(element) + ANIMATION_STEP) + 'px');
    };

    const finish = function (/* dest */) {
      element.dom().scrollTop = destination;
      Css.set(element, 'top', finalTop + 'px');
      callback(destination);
    };

    animator.animate(getCurrent, destination, ANIMATION_STEP, update, finish, ANIMATION_RATE);
  });

const insertSpaceOrNbspAtSelection = (editor: Editor): boolean => {
  const pos = CaretPosition.fromRangeStart(editor.selection.getRng());
  const root = Element.fromDom(editor.getBody());

  if (editor.selection.isCollapsed()) {
    const isInlineTarget = Fun.curry(InlineUtils.isInlineTarget, editor);
    const caretPosition = CaretPosition.fromRangeStart(editor.selection.getRng());

    return BoundaryLocation.readLocation(isInlineTarget, editor.getBody(), caretPosition)
      .bind(locationToCaretPosition(root))
      .bind(insertInlineBoundarySpaceOrNbsp(root, pos))
      .exists(setSelection(editor));
  } else {
    return false;
  }
};

  const sTestScenario = function (rawScenario) {
    const scenario = ValueSchema.asRawOrDie('Checking scenario', ValueSchema.objOf([
      FieldSchema.strict('label'),
      FieldSchema.defaulted('content', ''),
      FieldSchema.defaulted('node', Element.fromText('')),
      FieldSchema.strictObjOf('fields', [
        FieldSchema.option('url'),
        FieldSchema.option('text'),
        FieldSchema.option('title'),
        FieldSchema.option('target')
      ]),
      FieldSchema.strict('expected'),
      FieldSchema.defaulted('beforeExecute', Step.pass),
      FieldSchema.defaulted('mutations', Fun.constant(Step.pass))
    ]), rawScenario);

    return Logger.t(
      scenario.label,
      GeneralSteps.sequence([
        tEditor.sPrepareState(scenario.node.dom(), scenario.content),
        sClickLink,
        TestUi.sSetFieldOptValue(scenario.fields.url),
        sClickNext,
        sAssertTextFocused,
        TestUi.sSetFieldOptValue(scenario.fields.text),
        sClickNext,
        sAssertTitleFocused,
        TestUi.sSetFieldOptValue(scenario.fields.title),
        sClickNext,
        sAssertTargetFocused,
        TestUi.sSetFieldOptValue(scenario.fields.target),
        sClickPrev,
        sAssertTitleFocused,
        sClickPrev,
        sAssertTextFocused,
        sClickPrev,
        sAssertUrlFocused,
        scenario.beforeExecute,
        Keyboard.sKeydown(doc, Keys.enter(), { }),
        tEditor.sAssertEq('Checking insert content', scenario.expected),
        scenario.mutations(scenario.node),
        tEditor.sClear

      ])
    );
  };

const setContent = (editor: Editor, content: Content, args: SetContentArgs = {}): Content => {
  args.format = args.format ? args.format : defaultFormat;
  args.set = true;
  args.content = isTreeNode(content) ? '' : content;

  if (!isTreeNode(content) && !args.no_events) {
    editor.fire('BeforeSetContent', args);
    content = args.content;
  }

  return Option.from(editor.getBody())
    .fold(
      Fun.constant(content),
      (body) => isTreeNode(content) ? setContentTree(editor, body, content, args) : setContentString(editor, body, content, args)
    );

};

const findLocationTraverse = function (forward, isInlineTarget, rootNode, fromLocation, pos) {
  const from = InlineUtils.normalizePosition(forward, pos);
  const to = CaretFinder.fromPosition(forward, rootNode, from).map(Fun.curry(InlineUtils.normalizePosition, forward));

  const location = to.fold(
    function () {
      return fromLocation.map(outside);
    },
    function (to) {
      return readLocation(isInlineTarget, rootNode, to)
        .map(Fun.curry(betweenInlines, forward, isInlineTarget, rootNode, from, to))
        .filter(Fun.curry(skipNoMovement, fromLocation));
    }
  );

  return location.filter(isValidLocation);
};

const deriveReplacing = (spec, component: AlloyComponent) => {
  if (component.hasConfigured(Representing)) {
    /* TODO type this

    [{
      dom: {
        tag: 'div',
        classes: [ 'my-class' ],
        innerHtml: text
      }
    } ... ];
    */
    return {
      updateButton: Fun.curry(Replacing.set, component)
    };
  }
};

export default function () {
  const store = TestStore();

  const editorState = {
    start: Cell(null),
    content: Cell('')
  };

  const sPrepareState = function (node, content) {
    return Step.sync(function () {
      editorState.start.set(node);
      editorState.content.set(content);
    });
  };

  const editor = {
    selection: {
      getStart: editorState.start.get,
      getContent: editorState.content.get,
      select: Fun.noop
    },

    insertContent (data) {
      store.adder({ method: 'insertContent', data })();
    },
    execCommand (name, ui, args) {
      store.adder({ method: 'execCommand', data: Objects.wrap(name, args) })();
    },
    dom: {
      createHTML (tag, attributes, innerText) {
        return { tag, attributes, innerText };
      },
      encode: Fun.identity
    },
    focus: Fun.noop
  };

  return {
    editor: Fun.constant(editor),
    adder: store.adder,
    assertEq: store.assertEq,
    sAssertEq: store.sAssertEq,
    sClear: store.sClear,
    sPrepareState
  };
}

      return getWinFromFrame(frame).map(function (win) {

        const html = Element.fromDom(doc.dom().documentElement);

        const getCursorBox = editor.getCursorBox.getOrThunk(function () {
          return function () {
            return WindowSelection.get(win).bind(function (sel) {
              return WindowSelection.getFirstRect(win, sel).orThunk(function () {
                return tryFallbackBox(win);
              });
            });
          };
        });

        const setSelection = editor.setSelection.getOrThunk(function () {
          return function (start, soffset, finish, foffset) {
            WindowSelection.setExact(win, start, soffset, finish, foffset);
          };
        });

        const clearSelection = editor.clearSelection.getOrThunk(function () {
          return function () {
            WindowSelection.clear(win);
          };
        });

        return {
          body: Fun.constant(body),
          doc: Fun.constant(doc),
          win: Fun.constant(win),
          html: Fun.constant(html),
          getSelection: Fun.curry(getSelectionFromFrame, frame),
          setSelection,
          clearSelection,
          frame: Fun.constant(frame),

          onKeyup: getOrListen(editor, doc, 'onKeyup', 'keyup'),
          onNodeChanged: getOrListen(editor, doc, 'onNodeChanged', 'selectionchange'),
          onDomChanged: editor.onDomChanged, // consider defaulting with MutationObserver

          onScrollToCursor: editor.onScrollToCursor,
          onScrollToElement: editor.onScrollToElement,
          onToReading: editor.onToReading,
          onToEditing: editor.onToEditing,

          onToolbarScrollStart: editor.onToolbarScrollStart,
          onTouchContent: editor.onTouchContent,
          onTapContent: editor.onTapContent,
          onTouchToolstrip: editor.onTouchToolstrip,

          getCursorBox
        };
      });