import { ExternalTokenizer } from '@lezer/lr';
import {
  AxisFormat,
  DateFormat,
  Excludes,
  InclusiveEndDates,
  Section,
  TickInterval,
  Title,
  TodayMarker,
  Weekday,
  text,
} from './gantt.grammar.terms';

const keywordMap: { [key: string]: number } = {
  axisFormat: AxisFormat,
  dateFormat: DateFormat,
  excludes: Excludes,
  inclusiveEndDates: InclusiveEndDates,
  section: Section,
  tickInterval: TickInterval,
  title: Title,
  todayMarker: TodayMarker,
  weekday: Weekday,
};

const keywords = Object.keys(keywordMap);

export const textToken = new ExternalTokenizer((input) => {
  if (input.next === 32 || input.next === 10 || input.next === -1) return;

  if (input.next === 37 && input.peek(1) === 37) {
    return;
  }

  let tokens = '';

  while (input.next !== 10 && input.next !== -1) {
    tokens += String.fromCodePoint(input.next);
    input.advance();
  }

  const activeKeyword = keywords.filter((keyword) => {
    if (keyword === tokens) {
      return tokens.startsWith(keyword);
    }
    return tokens.startsWith(keyword + ' ');
  });

  if (activeKeyword.length > 0) {
    input.acceptToken(
      keywordMap[activeKeyword[0]],
      activeKeyword[0].length - tokens.length
    );
    return;
  }

  input.acceptToken(text);
});