roman-time.js

'use strict';

/**
 * @param {String} time – время в формате HH:MM (например, 09:05)
 * @returns {String} – время римскими цифрами (IX:V)
 */
function romanTime(time) {
    var typeError = new TypeError('Неверное время');
    checkFormat(time);
    time = time.split(':');
    if (Number(time[0]) < 0 || Number(time[0]) > 23 ||
    Number(time[1]) < 0 || Number(time[1]) > 59) {
        throw typeError;
    }
    changeTime(time);
    time = time[0] + ':' + time[1];

    return time;
}

function checkFormat(time) {
    var typeError = new TypeError('Неверное время');
    if (time === null || time === undefined ||
    time.length !== 5) {
        throw typeError;
    }
    time = time.split(':');
    if (isNaN(time[0]) || isNaN(time[1])) {
        throw typeError;
    }
}

function changeTime(time) {
    if (Number(time[0]) === 0) {
        time[0] = 'N';
    } else {
        time[0] = getRomeHours(time[0]);
    }
    if (Number(time[1]) === 0) {
        time[1] = 'N';
    } else {
        time[1] = getRomeMinutes(time[1]);
    }
}

function getRomeHours(hours) {
    var romeHours = '';
    for (var i = 0; i < Math.floor(hours / 10); i++) {
        romeHours += 'X';
    }
    romeHours += getUnits(hours);

    return romeHours;
}

function getRomeMinutes(minutes) {
    var romeMinutes = '';
    if (minutes < 40) {
        for (var i = 0; i < Math.floor(minutes / 10); i++) {
            romeMinutes += 'X';
        }
    } else if (Math.floor(minutes / 10) === 4) {
        romeMinutes += 'XL';
    } else {
        romeMinutes += 'L';
    }
    romeMinutes += getUnits(minutes);

    return romeMinutes;
}

function getUnits(time) {
    var unit = '';
    if (time % 10 < 4) {
        for (var i = 0; i < time % 10; i++) {
            unit += 'I';
        }

        return unit;
    } else if (time % 10 === 4) {
        unit += 'IV';

        return unit;
    } else if (time % 10 < 9) {
        unit += 'V';
        for (var k = 0; k < (time % 10 - 5); k++) {
            unit += 'I';
        }

        return unit;
    }
    unit += 'IX';

    return unit;
}

module.exports = romanTime;