import { Parser } from "../Parser.mjs";
import { mapValue, normalizeTwoDigitYear, parseNDigits } from "../utils.mjs";

// From http://www.unicode.org/reports/tr35/tr35-31/tr35-dates.html#Date_Format_Patterns
// | Year     |     y | yy |   yyy |  yyyy | yyyyy |
// |----------|-------|----|-------|-------|-------|
// | AD 1     |     1 | 01 |   001 |  0001 | 00001 |
// | AD 12    |    12 | 12 |   012 |  0012 | 00012 |
// | AD 123   |   123 | 23 |   123 |  0123 | 00123 |
// | AD 1234  |  1234 | 34 |  1234 |  1234 | 01234 |
// | AD 12345 | 12345 | 45 | 12345 | 12345 | 12345 |
export class YearParser extends Parser {
  priority = 130;
  incompatibleTokens = ["Y", "R", "u", "w", "I", "i", "e", "c", "t", "T"];

  parse(dateString, token, match) {
    const valueCallback = (year) => ({
      year,
      isTwoDigitYear: token === "yy",
    });

    switch (token) {
      case "y":
        return mapValue(parseNDigits(4, dateString), valueCallback);
      case "yo":
        return mapValue(
          match.ordinalNumber(dateString, {
            unit: "year",
          }),
          valueCallback,
        );
      default:
        return mapValue(parseNDigits(token.length, dateString), valueCallback);
    }
  }

  validate(_date, value) {
    return value.isTwoDigitYear || value.year > 0;
  }

  set(date, flags, value) {
    const currentYear = date.getFullYear();

    if (value.isTwoDigitYear) {
      const normalizedTwoDigitYear = normalizeTwoDigitYear(
        value.year,
        currentYear,
      );
      date.setFullYear(normalizedTwoDigitYear, 0, 1);
      date.setHours(0, 0, 0, 0);
      return date;
    }

    const year =
      !("era" in flags) || flags.era === 1 ? value.year : 1 - value.year;
    date.setFullYear(year, 0, 1);
    date.setHours(0, 0, 0, 0);
    return date;
  }
}