Tính Tam Nguyên Cửu Vận dựa vào năm

calculator.js

const THE_1ST_YEAR = 1864;
const CYCLE_YEARS = 180;
const NUM_OF_FATES = 9;
const NUM_OF_YEARS_FOR_FATE = 20;

const ORIGINS = ['Thượng Nguyên', 'Trung Nguyên', 'Hạ Nguyên'];
const NINE_FATES_FACILITIES = [
  'Khảm-Thủy',
  'Khôn-Thổ',
  'Chấn-Mộc',
  'Tốn-Mộc',
  'Trung cung-Thổ',
  'Cấn-Kim',
  'Đoài-Kim',
  'Cấn-Thổ',
  'Ly-Hỏa',
];

const calculateYearValue = (inputYear) => {
  if (!inputYear || inputYear < THE_1ST_YEAR)
    throw new Error(
      `Wrong year provided: ${inputYear}.\nShould input year from ${THE_1ST_YEAR}.`
    );

  const yearValue = (inputYear - THE_1ST_YEAR) % CYCLE_YEARS;

  return yearValue;
};

const calculateOriginAndFate = (inputYear) => {
  const yearValue = calculateYearValue(inputYear);
  const fateValue = Math.floor(yearValue / NUM_OF_YEARS_FOR_FATE) + 1;

  const originIndex = Math.max(Math.ceil(fateValue / ORIGINS.length) - 1, 0);
  const origin = ORIGINS[originIndex];

  console.log(`
  Year: ${inputYear}
  - Origin: ${origin}
  - Fate: ${fateValue}
  - Fate Facility: ${NINE_FATES_FACILITIES[fateValue - 1]}
  `);
};

const printFullThreeOriginsAndNineFates = (inputYear) => {
  const currentYear = new Date().getFullYear();
  const targetYear = inputYear || currentYear;

  console.log(`Printing full 3 origins and nine fates for year: ${targetYear}`);

  // If not provide input year use current year
  const yearValue = calculateYearValue(targetYear);
  let startYear = targetYear - yearValue;

  console.log(`The 1st for this cycle is: ${startYear}`);

  for (let originIndex in ORIGINS) {
    console.log(`Origin: ${ORIGINS[originIndex]}`);

    for (let fateIndex = 0; fateIndex < NUM_OF_FATES / 3; fateIndex++) {
      const fromYear = startYear;
      const endYear = startYear + NUM_OF_YEARS_FOR_FATE - 1;

      // Assign new start year for next Fate
      startYear = endYear + 1;

      const fateNo = originIndex * (NUM_OF_FATES / 3) + fateIndex + 1;

      console.log(`- Fate ${fateNo}: ${fromYear}-${endYear}`);
    }
  }
};

// calculateOriginAndFate();
calculateOriginAndFate(2022);

// printFullThreeOriginsAndNineFates();
// printFullThreeOriginsAndNineFates(2044);

// References:
// - https://blog.daothuba.com/2020/07/cuu-cung-phi-tinh-tam-nguyen-cuu-van.html
// - http://phongthuyhuyenkhonghoc.net/index.php/component/k2/item/33-tam-nguyen-cuu-van
// - Kim=>Thủy, Thủy=>Mộc, Mộc=>Hoả, Hoả=>Thổ, Thổ=>Kim

Year: 2022
  - Origin: Hạ Nguyên
  - Fate: 8
  - Fate Facility: Cấn-Thổ