日本の暦でカレンダーを表示する

jpcal.ts

import { parse } from "https://deno.land/std@0.95.0/flags/mod.ts"
import { TextDecoder } from 'https://cdn.skypack.dev/text-decoding'
const sjisDecoder = new TextDecoder("shift-jis")

const typeOptions = new Map([
    [0, "西暦から和暦へ変換"],
    [1, "和暦から西暦へ変換"],
    [2, "太陰太陽暦の朔日"],
])

const gengoOptions = new Map([
    ["a000", "西暦 (換算)"],
    ["b019", "允恭天皇"],
    ["b020", "安康天皇"],
    ["b021", "雄略天皇"],
    ["b022", "清寧天皇"],
    ["b023", "顕宗天皇"],
    ["b024", "仁賢天皇"],
    ["b025", "武烈天皇"],
    ["b026", "継体天皇"],
    ["b027", "安閑天皇"],
    ["b028", "宣化天皇"],
    ["b029", "欽明天皇"],
    ["b030", "敏達天皇"],
    ["b031", "用明天皇"],
    ["b032", "崇峻天皇"],
    ["b033", "推古天皇"],
    ["b034", "舒明天皇"],
    ["b035", "皇極天皇"],
    ["b036", "大化"],
    ["b037", "白雉"],
    ["b038", "斉明天皇"],
    ["b039", "天智天皇"],
    ["b040", "天武天皇"],
    ["b041", "朱鳥"],
    ["b042", "持統天皇"],
    ["b043", "文武天皇"],
    ["b044", "大宝"],
    ["b045", "慶雲"],
    ["b046", "和銅"],
    ["b047", "霊亀"],
    ["b048", "養老"],
    ["b049", "神亀"],
    ["b050", "天平"],
    ["b051", "天平感宝"],
    ["b052", "天平勝宝"],
    ["b053", "天平宝字"],
    ["b054", "天平神護"],
    ["b055", "神護景雲"],
    ["b056", "宝亀"],
    ["b057", "天応"],
    ["b058", "延暦"],
    ["b059", "大同"],
    ["b060", "弘仁"],
    ["b061", "天長"],
    ["b062", "承和"],
    ["b063", "嘉祥"],
    ["b064", "仁寿"],
    ["b065", "斉衡"],
    ["b066", "天安"],
    ["b067", "貞観"],
    ["b068", "元慶"],
    ["b069", "仁和"],
    ["b070", "寛平"],
    ["b071", "昌泰"],
    ["b072", "延喜"],
    ["b073", "延長"],
    ["b074", "承平"],
    ["b075", "天慶"],
    ["b076", "天暦"],
    ["b077", "天徳"],
    ["b078", "応和"],
    ["b079", "康保"],
    ["b080", "安和"],
    ["b081", "天禄"],
    ["b082", "天延"],
    ["b083", "貞元"],
    ["b084", "天元"],
    ["b085", "永観"],
    ["b086", "寛和"],
    ["b087", "永延"],
    ["b088", "永祚"],
    ["b089", "正暦"],
    ["b090", "長徳"],
    ["b091", "長保"],
    ["b092", "寛弘"],
    ["b093", "長和"],
    ["b094", "寛仁"],
    ["b095", "治安"],
    ["b096", "万寿"],
    ["b097", "長元"],
    ["b098", "長暦"],
    ["b099", "長久"],
    ["b100", "寛徳"],
    ["b101", "永承"],
    ["b102", "天喜"],
    ["b103", "康平"],
    ["b104", "治暦"],
    ["b105", "延久"],
    ["b106", "承保"],
    ["b107", "承暦"],
    ["b108", "永保"],
    ["b109", "応徳"],
    ["b110", "寛治"],
    ["b111", "嘉保"],
    ["b112", "永長"],
    ["b113", "承徳"],
    ["b114", "康和"],
    ["b115", "長治"],
    ["b116", "嘉承"],
    ["b117", "天仁"],
    ["b118", "天永"],
    ["b119", "永久"],
    ["b120", "元永"],
    ["b121", "保安"],
    ["b122", "天治"],
    ["b123", "大治"],
    ["b124", "天承"],
    ["b125", "長承"],
    ["b126", "保延"],
    ["b127", "永治"],
    ["b128", "康治"],
    ["b129", "天養"],
    ["b130", "久安"],
    ["b131", "仁平"],
    ["b132", "久寿"],
    ["b133", "保元"],
    ["b134", "平治"],
    ["b135", "永暦"],
    ["b136", "応保"],
    ["b137", "長寛"],
    ["b138", "永万"],
    ["b139", "仁安"],
    ["b140", "嘉応"],
    ["b141", "承安"],
    ["b142", "安元"],
    ["b143", "治承"],
    ["b144", "養和"],
    ["b145", "寿永"],
    ["b146", "元暦"],
    ["b147", "文治"],
    ["b148", "建久"],
    ["b149", "正治"],
    ["b150", "建仁"],
    ["b151", "元久"],
    ["b152", "建永"],
    ["b153", "承元"],
    ["b154", "建暦"],
    ["b155", "建保"],
    ["b156", "承久"],
    ["b157", "貞応"],
    ["b158", "元仁"],
    ["b159", "嘉禄"],
    ["b160", "安貞"],
    ["b161", "寛喜"],
    ["b162", "貞永"],
    ["b163", "天福"],
    ["b164", "文暦"],
    ["b165", "嘉禎"],
    ["b166", "暦仁"],
    ["b167", "延応"],
    ["b168", "仁治"],
    ["b169", "寛元"],
    ["b170", "宝治"],
    ["b171", "建長"],
    ["b172", "康元"],
    ["b173", "正嘉"],
    ["b174", "正元"],
    ["b175", "文応"],
    ["b176", "弘長"],
    ["b177", "文永"],
    ["b178", "建治"],
    ["b179", "弘安"],
    ["b180", "正応"],
    ["b181", "永仁"],
    ["b182", "正安"],
    ["b183", "乾元"],
    ["b184", "嘉元"],
    ["b185", "徳治"],
    ["b186", "延慶"],
    ["b187", "応長"],
    ["b188", "正和"],
    ["b189", "文保"],
    ["b190", "元応"],
    ["b191", "元亨"],
    ["b192", "正中"],
    ["b193", "嘉暦"],
    ["b194", "元徳"],
    ["b195", "元弘"],
    ["b196", "建武"],
    ["b197", "延元"],
    ["b198", "興国"],
    ["b199", "正平"],
    ["b200", "建徳"],
    ["b201", "文中"],
    ["b202", "天授"],
    ["b203", "弘和"],
    ["b204", "元中"],
    ["b205", "明徳"],
    ["b206", "応永"],
    ["b207", "正長"],
    ["b208", "永享"],
    ["b209", "嘉吉"],
    ["b210", "文安"],
    ["b211", "宝徳"],
    ["b212", "享徳"],
    ["b213", "康正"],
    ["b214", "長禄"],
    ["b215", "寛正"],
    ["b216", "文正"],
    ["b217", "応仁"],
    ["b218", "文明"],
    ["b219", "長享"],
    ["b220", "延徳"],
    ["b221", "明応"],
    ["b222", "文亀"],
    ["b223", "永正"],
    ["b224", "大永"],
    ["b225", "享禄"],
    ["b226", "天文"],
    ["b227", "弘治"],
    ["b228", "永禄"],
    ["b229", "元亀"],
    ["b230", "天正"],
    ["b231", "文禄"],
    ["b232", "慶長"],
    ["b233", "元和"],
    ["b234", "寛永"],
    ["b235", "正保"],
    ["b236", "慶安"],
    ["b237", "承応"],
    ["b238", "明暦"],
    ["b239", "万治"],
    ["b240", "寛文"],
    ["b241", "延宝"],
    ["b242", "天和"],
    ["b243", "貞享"],
    ["b244", "元禄"],
    ["b245", "宝永"],
    ["b246", "正徳"],
    ["b247", "享保"],
    ["b248", "元文"],
    ["b249", "寛保"],
    ["b250", "延享"],
    ["b251", "寛延"],
    ["b252", "宝暦"],
    ["b253", "明和"],
    ["b254", "安永"],
    ["b255", "天明"],
    ["b256", "寛政"],
    ["b257", "享和"],
    ["b258", "文化"],
    ["b259", "文政"],
    ["b260", "天保"],
    ["b261", "弘化"],
    ["b262", "嘉永"],
    ["b263", "安政"],
    ["b264", "万延"],
    ["b265", "文久"],
    ["b266", "元治"],
    ["b267", "慶応"],
    ["b268", "明治"],
    ["b269", "大正"],
    ["b270", "昭和"],
    ["b271", "平成"],
    ["b272", "令和"],
    ["c000", "正慶"],
    ["c001", "建武"],
    ["c002", "暦応"],
    ["c003", "康永"],
    ["c004", "貞和"],
    ["c005", "観応"],
    ["c006", "文和"],
    ["c007", "延文"],
    ["c008", "康安"],
    ["c009", "貞治"],
    ["c010", "応安"],
    ["c011", "永和"],
    ["c012", "康暦"],
    ["c013", "永徳"],
    ["c014", "至徳"],
    ["c015", "嘉慶"],
    ["c016", "康応"],
    ["c017", "明徳"],
])

const jgOptions = new Map([
    [0, "すべてユリウス暦"],
    [1, "すべてグレゴリオ暦"],
    [2, "デフォルト"],
])

function buildFormData(fields: {
    type: number;
    gengo: string;
    year: number;
    leap: boolean;
    month: number;
    day: number;
    jg: number;
    len: number;
}) {
    if (!typeOptions.has(fields.type)) throw new RangeError()
    if (!gengoOptions.has(fields.gengo)) throw new RangeError()
    if (!jgOptions.has(fields.jg)) throw new RangeError()
    // 間隔
    const div = 1
    // 間隔の単位: 3=日
    const divu = 3
    // 期間の単位: 3=日
    const lenu = 3
    // 年号の判断: 0=年単位, 1=日付単位
    const gen = 1
    const formData = new FormData()
    formData.set("type", String(fields.type))
    formData.set("gengo", fields.gengo)
    formData.set("year", String(fields.year))
    if (fields.leap) formData.set("leap", "1")
    formData.set("month", String(fields.month))
    formData.set("day", String(fields.day))
    formData.set("jg", String(fields.jg))
    formData.set("div", String(div))
    formData.set("divu", String(divu))
    formData.set("len", String(fields.len))
    formData.set("lenu", String(lenu))
    formData.set("gen", String(gen))
    formData.set("csv", "CSV")
    return formData
}

async function fetchCSV(year: number, leap: boolean, month: number, day: number) {
    const body = buildFormData({
        type: 1,
        gengo: "a000",
        year,
        leap,
        month,
        day,
        jg: 1,
        len: 31,
    })
    const f = await fetch("https://eco.mtk.nao.ac.jp/cgi-bin/koyomi/caldb.cgi", {
        method: "POST",
        body
    })
    if (!f.ok) throw new Error()
    const resBody = await f.arrayBuffer()
    const resText = sjisDecoder.decode(resBody)
    return resText
}

function* parseCSV(csv: string) {
    for (const line of csv.split(/\r?\n/g).slice(1)) {
        if (!line) continue
        const [
            西暦,
            和暦,
            神武紀元,
            _年の干支,
            _日の干支,
        ] = line.split(/,/g)
        const date = 西暦.replace(/\//g, "-")
        const weekday = new Date(date).getDay()
        const m = /(?<jera>\D+)(?<jyear>\d+)年(?<jleap>閏?)(?<jmonth>\d+)月(?<jday>\d+)日/.exec(和暦)
        if (!m) throw new Error()
        const { jera, jyear, jleap, jmonth, jday } = m.groups!
        yield {
            date,
            weekday,
            jinmu: parseInt(神武紀元, 10),
            jera,
            jyear: parseInt(jyear, 10),
            jleap: Boolean(jleap),
            jmonth: parseInt(jmonth, 10),
            jday: parseInt(jday, 10),
        }
    }
}

function monthlyCalendar(source: Generator<{
    date: string;
    weekday: number;
    jinmu: number;
    jera: string;
    jyear: number;
    jleap: boolean;
    jmonth: number;
    jday: number;
}>) {
    let output = ""
    const first = source.next()
    if (first.done) throw new Error()
    const { weekday, jera, jyear, jleap, jmonth } = first.value
    output += `${jera}${jyear}年${jleap ? "閏" : ""}${jmonth}月\n`
    output += `日 月 火 水 木 金 土\n`
    let line = []
    for (let i = 0; i < weekday; i++) {
        line.push("  ")
    }
    line.push(" 1")
    for (const row of source) {
        if (row.jday === 1) break
        if (line.length === 7) {
            output += line.join(" ")
            output += "\n"
            line = []
        }
        line.push(String(row.jday).padStart(2, " "))
    }
    output += line.join(" ")
    return output
}

const { _: args, leap } = parse(Deno.args, { boolean: ["leap"] })

if (args.length !== 2) throw new Error()

const year = Number(args[0])
const month = Number(args[1])
console.log(monthlyCalendar(parseCSV(await fetchCSV(year, leap, month, 1))))