/**
 * Copyright (c) UXBOX Labs SL
 * 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.
 */
'use strict';

import {CharacterMetadata} from "draft-js";
import {Map} from "immutable";

function removeStylePrefix(chmeta, stylePrefix) {
  var withoutStyle = chmeta.set('style', chmeta.getStyle().filter((s) => !s.startsWith(stylePrefix)))
  return CharacterMetadata.create(withoutStyle);
};

export function removeInlineStylePrefix(contentState, selectionState, stylePrefix) {
  var blockMap = contentState.getBlockMap();
  var startKey = selectionState.getStartKey();
  var startOffset = selectionState.getStartOffset();
  var endKey = selectionState.getEndKey();
  var endOffset = selectionState.getEndOffset();
  var newBlocks = blockMap.skipUntil(function (_, k) {
    return k === startKey;
  }).takeUntil(function (_, k) {
    return k === endKey;
  }).concat(Map([[endKey, blockMap.get(endKey)]])).map(function (block, blockKey) {
    var sliceStart;
    var sliceEnd;

    if (startKey === endKey) {
      sliceStart = startOffset;
      sliceEnd = endOffset;
    } else {
      sliceStart = blockKey === startKey ? startOffset : 0;
      sliceEnd = blockKey === endKey ? endOffset : block.getLength();
    }

    var chars = block.getCharacterList();
    var current;

    while (sliceStart < sliceEnd) {
      current = chars.get(sliceStart);
      chars = chars.set(sliceStart, removeStylePrefix(current, stylePrefix));
      sliceStart++;
    }

    return block.set('characterList', chars);
  });

  return contentState.merge({
    blockMap: blockMap.merge(newBlocks),
    selectionBefore: selectionState,
    selectionAfter: selectionState
  });
}