import {
  getDay,
  getWeek,
  addDays,
  subDays,
  subYears,
  getYear,
  lightFormat,
  getDayOfYear,
  getDaysInYear,
  intervalToDuration,
} from "./deps.ts";

const format = "yyyy/MM/dd";

export const makeDiary = (date: Date): {
  title: string;
  header: string[];
  footer: string[];
} => {
  /** 井戸端で日記が始まってからの年数 */
  const intervalY = intervalToDuration({ start: new Date(2020, 9, 9), end: date }).years;
  
  return {
    title: toTitle(date),
    header: [
      `第${getWeek(date)}週: ${youbiLine(date)}`,
      `${getYear(date)}年 ${
        (getDayOfYear(date) * 100 / getDaysInYear(date)).toFixed(2)
      }％経過`,
    ],
    footer: [
      `[${lightFormat(subDays(date, 1), format)}.icon] ← ${
        lightFormat(date, format)
      } → [${lightFormat(addDays(date, 1), format)}.icon]`,
      `[/ [${lightFormat(date, "yyyy/MM")}.icon]]`,
    ],
  };
}

const youbiLine = (date: Date): string => {
  const day = getDay(date);
  return [..."日月火水木金土"].map(
    (char, i) => i === day ? `[[${char}]]` : char
  ).join("");
};
const dateRegExp = /^\d{4}\/\d{2}\/\d{2}$/;
export const isOldDiary = (title: string, today: Date): boolean => {
  if (!dateRegExp.test(title)) return false;
  return toTitle(today) !== title;
};

const toTitle = (date: Date): string => lightFormat(date, format);