export class TimeUnit {
    public constructor(
        public readonly milliseconds: number,
        public readonly longName: string,
        public readonly shortName: string,
    ) {
    }
}

export default class Time {
    public static readonly UNITS = {
        MILLISECOND: {
            milliseconds: 1,
            longName: 'millisecond',
            shortName: 'ms',
        },
        SECOND: {
            milliseconds: 1000,
            longName: 'second',
            shortName: 's',
        },
        MINUTE: {
            milliseconds: 60 * 1000,
            longName: 'minute',
            shortName: 'm',
        },
        HOUR: {
            milliseconds: 60 * 60 * 1000,
            longName: 'hour',
            shortName: 'h',
        },
        DAY: {
            milliseconds: 24 * 60 * 60 * 1000,
            longName: 'day',
            shortName: 'd',
        },
        MONTH: {
            milliseconds: 30 * 24 * 60 * 60 * 1000,
            longName: 'month',
            shortName: 'M',
        },
        YEAR: {
            milliseconds: 365 * 24 * 60 * 60 * 1000,
            longName: 'year',
            shortName: 'y',
        },
    };

    public static humanizeTimeSince(
        since: Date,
        short?: boolean,
        skipOneUnitNumber?: boolean,
        units?: TimeUnit[],
    ): string {
        return this.humanizeDuration(Date.now() - since.getTime(), short, skipOneUnitNumber, units);
    }

    public static humanizeTimeTo(
        to: Date,
        short?: boolean,
        skipOneUnitNumber?: boolean,
        units?: TimeUnit[],
    ): string {
        return this.humanizeDuration(to.getTime() - Date.now(), short, skipOneUnitNumber, units);
    }

    public static humanizeDuration(
        duration: number,
        short: boolean = false,
        skipOneUnitNumber: boolean = false,
        units: TimeUnit[] = [
            this.UNITS.SECOND,
            this.UNITS.MINUTE,
            this.UNITS.HOUR,
            this.UNITS.DAY,
            this.UNITS.MONTH,
            this.UNITS.YEAR,
        ],
    ): string {
        for (let i = units.length - 1; i > 0; i--) {
            if (duration >= units[i - 1].milliseconds && duration < units[i].milliseconds) {
                const amount = Math.floor(duration / units[i - 1].milliseconds);
                const unit = short ?
                    units[i - 1].shortName :
                    ' ' + units[i - 1].longName + (amount > 1 ? 's' : '');
                return (amount > 1 || !skipOneUnitNumber ? amount : '') + unit;
            }
        }

        return 'now';
    }

}