import i18n, { t } from "i18next";

const A_DAY = 24 * 60 * 60 * 1000;

const dateTimeFullFormatter1 = new Intl.DateTimeFormat(i18n.language, {
    weekday: "short",
    month: "short",
    day: "numeric",
});

const dateTimeFullFormatter2 = new Intl.DateTimeFormat(i18n.language, {
    year: "numeric",
});
const dateTimeShortFormatter = new Intl.DateTimeFormat(i18n.language, {
    month: "short",
    day: "numeric",
    year: "numeric",
    hour: "2-digit",
    minute: "2-digit",
});

const timeFormatter = new Intl.DateTimeFormat(i18n.language, {
    timeStyle: "short",
});

export function formatDateFull(date: number | Date) {
    return [dateTimeFullFormatter1, dateTimeFullFormatter2]
        .map((f) => f.format(date))
        .join(" ");
}

export function formatDate(date: number | Date) {
    const withinYear =
        new Date().getFullYear() === new Date(date).getFullYear();
    const dateTimeFormat2 = !withinYear ? dateTimeFullFormatter2 : null;
    return [dateTimeFullFormatter1, dateTimeFormat2]
        .filter((f) => !!f)
        .map((f) => f.format(date))
        .join(" ");
}

export function formatDateTimeShort(date: number | Date) {
    return dateTimeShortFormatter.format(date);
}

export function formatTime(date: number | Date) {
    return timeFormatter.format(date).toUpperCase();
}

export function formatDateTimeFull(dateTime: number | Date): string {
    return [formatDateFull(dateTime), t("at"), formatTime(dateTime)].join(" ");
}

export function formatDateTime(dateTime: number | Date): string {
    return [formatDate(dateTime), t("at"), formatTime(dateTime)].join(" ");
}

export function formatDateRelative(date: number) {
    const units = {
        year: 24 * 60 * 60 * 1000 * 365,
        month: (24 * 60 * 60 * 1000 * 365) / 12,
        day: 24 * 60 * 60 * 1000,
        hour: 60 * 60 * 1000,
        minute: 60 * 1000,
        second: 1000,
    };
    const relativeDateFormat = new Intl.RelativeTimeFormat(i18n.language, {
        localeMatcher: "best fit",
        numeric: "always",
        style: "long",
    });
    const elapsed = date - Date.now(); // "Math.abs" accounts for both "past" & "future" scenarios

    for (const u in units)
        if (Math.abs(elapsed) > units[u] || u === "second")
            return relativeDateFormat.format(
                Math.round(elapsed / units[u]),
                u as Intl.RelativeTimeFormatUnit,
            );
}

export const isSameDay = (first, second) => {
    return (
        first.getFullYear() === second.getFullYear() &&
        first.getMonth() === second.getMonth() &&
        first.getDate() === second.getDate()
    );
};

export const getDate = (item) => {
    const currentDate = item.metadata.creationTime / 1000;
    const date = isSameDay(new Date(currentDate), new Date())
        ? t("TODAY")
        : isSameDay(new Date(currentDate), new Date(Date.now() - A_DAY))
          ? t("YESTERDAY")
          : formatDate(currentDate);

    return date;
};