/**
 * Copyright (c) 2013-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule keyCommandMoveSelectionToStartOfBlock
 * @format
 * @flow
 */

'use strict';

var EditorState = require('./EditorState');

/**
 * Collapse selection at the start of the first selected block. This is used
 * for Firefox versions that attempt to navigate forward/backward instead of
 * moving the cursor. Other browsers are able to move the cursor natively.
 */
function keyCommandMoveSelectionToStartOfBlock(editorState: EditorState): EditorState {
  var selection = editorState.getSelection();
  var startKey = selection.getStartKey();
  return EditorState.set(editorState, {
    selection: selection.merge({
      anchorKey: startKey,
      anchorOffset: 0,
      focusKey: startKey,
      focusOffset: 0,
      isBackward: false
    }),
    forceSelection: true
  });
}

module.exports = keyCommandMoveSelectionToStartOfBlock;