/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 * @flow strict-local
 * @emails oncall+draft_js
 */
'use strict';

import type ContentState from "./ContentState";
import type SelectionState from "./SelectionState";

const applyEntityToContentBlock = require("./applyEntityToContentBlock");

const Immutable = require("immutable");

function applyEntityToContentState(contentState: ContentState, selectionState: SelectionState, entityKey: ?string): ContentState {
  const blockMap = contentState.getBlockMap();
  const startKey = selectionState.getStartKey();
  const startOffset = selectionState.getStartOffset();
  const endKey = selectionState.getEndKey();
  const endOffset = selectionState.getEndOffset();
  const newBlocks = blockMap.skipUntil((_, k) => k === startKey).takeUntil((_, k) => k === endKey).toOrderedMap().merge(Immutable.OrderedMap([[endKey, blockMap.get(endKey)]])).map((block, blockKey) => {
    const sliceStart = blockKey === startKey ? startOffset : 0;
    const sliceEnd = blockKey === endKey ? endOffset : block.getLength();
    return applyEntityToContentBlock(block, sliceStart, sliceEnd, entityKey);
  });
  return contentState.merge({
    blockMap: blockMap.merge(newBlocks),
    selectionBefore: selectionState,
    selectionAfter: selectionState
  });
}

module.exports = applyEntityToContentState;