type unit =
    | 'ms'
    | 'millisecond'
    | 's'
    | 'second'
    | 'm'
    | 'minute'
    | 'h'
    | 'hour'
    | 'd'
    | 'day'
    | 'w'
    | 'week';

/**
 * convert time into another unit
 */
function convert(val: number, sourceUnitName: unit, destinationUnitName: unit = 'ms') {
    return (val * getUnit(sourceUnitName)) / getUnit(destinationUnitName);
}

// TODO: maybe extract to a separate module
/**
 * Gets multiplier for given unit.
 */
function getUnit(unitName: unit) {
    switch (unitName) {
        case 'ms':
        case 'millisecond':
            return 1;
        case 's':
        case 'second':
            return 1000;
        case 'm':
        case 'minute':
            return 60000;
        case 'h':
        case 'hour':
            return 3600000;
        case 'd':
        case 'day':
            return 86400000;
        case 'w':
        case 'week':
            return 604800000;
        default:
            throw new Error(`"${unitName}" is not a valid unit`);
    }
}

export default convert;