/**
 * Various date helper methods.
 *
 * Copyright (c) 2022 Markus Sipilä.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/**
 * Exports.
 */
module.exports = {
    getEntsoStart: getEntsoStart,
    getEntsoEnd: getEntsoEnd,
    getCurrentHour: getCurrentHour,
    getMidnight: getMidnight
};

/**
 * Returns the start datetime for Entso API request.
 *
 * Nordpool publishes the day ahead prices at 12:45 CET/CEST = 13:45 EET/EEST. If the script is
 * executed at 14:00 or later (local time), tomorrow's prices will be requested.
 * Otherwise today's prices will be requested.
 *
 * @return string
 *   Start datetime for the API call in format YYYYMMDD0000.
 */
function getEntsoStart() {
    let date = new Date();
    if (date.getHours() >= 14) {
	date.setDate(date.getDate() + 1);
    }
    return date.toLocaleDateString('en-GB').replaceAll('-','') + '0000';
}

/**
 * Returns the end datetime for Entso API request.
 *
 * Nordpool publishes the day ahead prices at 12:45 CET/CEST = 13:45 EET/EEST. If the script is
 * executed at 14:00 or later (local time), tomorrow's prices will be requested.
 * Otherwise today's prices will be requested.
 *
 * @return string
 *   End datetime for the API call in in format YYYYMMDD2200.
 */
function getEntsoEnd() {
    let date = new Date();
    if (date.getHours() >= 14) {
	date.setDate(date.getDate() + 1);
    }
    // Entso API uses CET/CEST. 23.00 EET/EEST = 22.00 CET/CEST.
    return date.toLocaleDateString('en-GB').replaceAll('-','') + '2200';
}

/**
 * Returns current hour.
 *
 * @return Date
 *   Current date with minutes, seconds and milliseconds set to 0.
 */
function getCurrentHour() {
    let date = new Date();
    date.setMinutes(0);
    date.setSeconds(0);
    date.setMilliseconds(0);
    return date;
}

/**
 * Returns the start/stop midnight.
 *
 * Nordpool publishes the day ahead prices at 12:45 CET/CEST = 13:45 EET/EEST. If the script is
 * executed at 14:00 or later (local time), 'start' midnight will be tomorrow 00:00 local time.
 * Otherwise 'start' midnight will be today 00:00 local time.
 *
 * Stop midnight: 24 hours afer the start midnight.
 *
 * @param string type
 *   'start' or 'stop.
 *
 * @return Date
 */
function getMidnight(type) {
    let date = new Date();
    if (date.getHours() >= 14) {
	date.setDate(date.getDate() + 1);
    }
    // Set time to 00:00:00.000
    date.setHours(0);
    date.setMinutes(0);
    date.setSeconds(0);
    date.setMilliseconds(0);
    
    if (type == 'stop') {
	date.setDate(date.getDate() + 1);
    }

    return date;
}