import { EditorState, TextSelection } from "prosemirror-state";
import { Command, CommandPredicate } from "./types";
import { getCursor } from "./util";

export function filter(predicate: CommandPredicate, command: Command): Command {
  return (state, dispatch) => {
    return predicate(state) ? command(state, dispatch) : false;
  };
}

export function not(predicate: CommandPredicate): CommandPredicate {
  return state => !predicate(state);
}

export function startCursor(state: EditorState): boolean {
  const $cursor = getCursor(state);
  return $cursor != null && $cursor.parentOffset === 0;
}

export function textSelected(state: EditorState): boolean {
  const { selection } = state;
  return selection instanceof TextSelection && !selection.empty;
}