import { SelectionState } from 'draft-js';

class SelectionStateUtil {
  constructor() {}

  createEmpty(blockKey) {
    return SelectionState.createEmpty(blockKey);
  }

  getOffsets(selectionState) {
    return {
      startOffset: selectionState.getStartOffset(),
      endOffset: selectionState.getEndOffset(),
    };
  }

  updateRange(selectionState, newStartOffset, newEndOffset) {
    return new SelectionState({
      anchorKey: selectionState.anchorKey,
      anchorOffset: newStartOffset,
      focusKey: selectionState.focusKey,
      focusOffset: newEndOffset,
      hasFocus: selectionState.hasFocus,
      isBackward: false,
    })
  }

  selectTextRange(blockKey, anchorOffset, focusOffset) {
    return new SelectionState({
      anchorKey: blockKey,
      anchorOffset,
      focusKey: blockKey,
      focusOffset,
      hasFocus: false,
      isBackward: false,
    })
  }

  selectEntireBlock(selectionState, block) {
    // Used to apply default inline styles to any blocks that have them
    return new SelectionState({
      anchorKey: selectionState.anchorKey,
      anchorOffset: 0,
      focusKey: selectionState.focusKey,
      focusOffset: block.getCharacterList().size,
      hasFocus: selectionState.hasFocus,
      isBackward: false,
    });
  }

  selectBlockByKey(blockKey) {
    return new SelectionState({
      anchorKey: blockKey,
      anchorOffset: 0,
      focusKey: blockKey,
      focusOffset: 1,
      hasFocus: true,
      isBackward: false
    });
  }
}

export default new SelectionStateUtil();