import { HDate } from '@hebcal/hdate';
import { Event } from './event';
/**
 * Plug-in registry for daily learning calendars such as Daf Yomi (Bavli),
 * Yerushalmi Yomi, Mishna Yomi, Nach Yomi, etc.
 *
 * `@hebcal/core` itself contains no learning schedules — they are provided
 * by the {@link https://github.com/hebcal/hebcal-learning @hebcal/learning}
 * package, which calls {@link DailyLearning.addCalendar} on import. After
 * `@hebcal/learning` is loaded, `HebrewCalendar.calendar()` will emit
 * learning events when the corresponding `options.dailyLearning` flag is set.
 *
 * @example
 * import '@hebcal/learning';
 * import {DailyLearning, HDate} from '@hebcal/core';
 *
 * const ev = DailyLearning.lookup('dafYomi', new HDate(), false);
 * console.log(ev?.render('en')); // e.g. 'Berakhot 2'
 */
export declare class DailyLearning {
    /**
     * Registers a new learning calendar.
     *
     * The provided function is called whenever a caller asks for an event
     * from this calendar; if no learning occurs that day (e.g. the date is
     * before the cycle's start) it should return `null`.
     * @example
     * DailyLearning.addCalendar(
     *   'myCalendar',
     *   (hd, il) => new Event(hd, 'Today\'s learning', 0),
     *   new HDate(1, 'Tishrei', 5780),
     * );
     * @param name case insensitive
     * @param calendar a function that returns an `Event` or `null`
     * @param startDate the first date for which this calendar is valid
     */
    static addCalendar(name: string, calendar: (hd: HDate, il: boolean) => Event | null, startDate?: HDate): void;
    /**
     * Returns the learning event for the given date from the named calendar,
     * or `null` if there is no learning that day (or the named calendar is
     * not registered).
     * @example
     * import '@hebcal/learning';
     * import {DailyLearning, HDate} from '@hebcal/core';
     * DailyLearning.lookup('dafYomi', new HDate(2024, 1, 15), false);
     * @param name case insensitive
     * @param hd Hebrew Date
     * @param il true for Israel, false for Diaspora
     */
    static lookup(name: string, hd: HDate, il: boolean): Event | null;
    /**
     * Returns the first Hebrew date for which the named learning calendar
     * is valid (as registered by {@link addCalendar}), or `undefined` if the
     * calendar was not registered with a start date or is not registered at all.
     * @param name case insensitive
     */
    static getStartDate(name: string): HDate | undefined;
    /**
     * Returns `true` if a learning calendar with the given name has been
     * registered via {@link addCalendar}.
     * @param name case insensitive
     */
    static has(name: string): boolean;
    /**
     * Returns the (lower-cased) names of all currently-registered learning
     * calendars.
     */
    static getCalendars(): string[];
}