import { NodeType } from "prosemirror-model";
import { EditorState, Transaction } from "prosemirror-state";

export default function backspaceToParagraph(type: NodeType) {
  return (state: EditorState, dispatch: (tr: Transaction) => void) => {
    const { $from, from, to, empty } = state.selection;

    // if the selection has anything in it then use standard delete behavior
    if (!empty) return null;

    // check we're in a matching node
    if ($from.parent.type !== type) return null;

    // check if we're at the beginning of the heading
    const $pos = state.doc.resolve(from - 1);
    if ($pos.parent === $from.parent) return null;

    // okay, replace it with a paragraph
    dispatch(
      state.tr
        .setBlockType(from, to, type.schema.nodes.paragraph)
        .scrollIntoView()
    );
    return true;
  };
}