class DateCaster

class DateCaster {
    private const PERIOD_LIMIT = 3;
    public static function castDateTime(\DateTimeInterface $d, array $a, Stub $stub, bool $isNested, int $filter) : array {
        $prefix = Caster::PREFIX_VIRTUAL;
        $location = $d->getTimezone() ? $d->getTimezone()
            ->getLocation() : null;
        $fromNow = (new \DateTimeImmutable())->diff($d);
        $title = $d->format('l, F j, Y') . "\n" . self::formatInterval($fromNow) . ' from now' . ($location ? $d->format('I') ? "\nDST On" : "\nDST Off" : '');
        unset($a[Caster::PREFIX_DYNAMIC . 'date'], $a[Caster::PREFIX_DYNAMIC . 'timezone'], $a[Caster::PREFIX_DYNAMIC . 'timezone_type']);
        $a[$prefix . 'date'] = new ConstStub(self::formatDateTime($d, $location ? ' e (P)' : ' P'), $title);
        $stub->class .= $d->format(' @U');
        return $a;
    }
    public static function castInterval(\DateInterval $interval, array $a, Stub $stub, bool $isNested, int $filter) : array {
        $now = new \DateTimeImmutable('@0', new \DateTimeZone('UTC'));
        $numberOfSeconds = $now->add($interval)
            ->getTimestamp() - $now->getTimestamp();
        $title = number_format($numberOfSeconds, 0, '.', ' ') . 's';
        $i = [
            Caster::PREFIX_VIRTUAL . 'interval' => new ConstStub(self::formatInterval($interval), $title),
        ];
        return $filter & Caster::EXCLUDE_VERBOSE ? $i : $i + $a;
    }
    private static function formatInterval(\DateInterval $i) : string {
        $format = '%R ';
        if (0 === $i->y && 0 === $i->m && ($i->h >= 24 || $i->i >= 60 || $i->s >= 60)) {
            $d = new \DateTimeImmutable('@0', new \DateTimeZone('UTC'));
            $i = $d->diff($d->add($i));
            // recalculate carry over points
            $format .= 0 < $i->days ? '%ad ' : '';
        }
        else {
            $format .= ($i->y ? '%yy ' : '') . ($i->m ? '%mm ' : '') . ($i->d ? '%dd ' : '');
        }
        $format .= $i->h || $i->i || $i->s || $i->f ? '%H:%I:' . self::formatSeconds($i->s, substr($i->f, 2)) : '';
        $format = '%R ' === $format ? '0s' : $format;
        return $i->format(rtrim($format));
    }
    public static function castTimeZone(\DateTimeZone $timeZone, array $a, Stub $stub, bool $isNested, int $filter) : array {
        $location = $timeZone->getLocation();
        $formatted = (new \DateTimeImmutable('now', $timeZone))->format($location ? 'e (P)' : 'P');
        $title = $location && \extension_loaded('intl') ? \Locale::getDisplayRegion('-' . $location['country_code']) : '';
        $z = [
            Caster::PREFIX_VIRTUAL . 'timezone' => new ConstStub($formatted, $title),
        ];
        return $filter & Caster::EXCLUDE_VERBOSE ? $z : $z + $a;
    }
    public static function castPeriod(\DatePeriod $p, array $a, Stub $stub, bool $isNested, int $filter) : array {
        $dates = [];
        foreach (clone $p as $i => $d) {
            if (self::PERIOD_LIMIT === $i) {
                $now = new \DateTimeImmutable('now', new \DateTimeZone('UTC'));
                $dates[] = \sprintf('%s more', ($end = $p->getEndDate()) ? ceil(($end->format('U.u') - $d->format('U.u')) / ((int) $now->add($p->getDateInterval())
                    ->format('U.u') - (int) $now->format('U.u'))) : $p->recurrences - $i);
                break;
            }
            $dates[] = \sprintf('%s) %s', $i + 1, self::formatDateTime($d));
        }
        $period = \sprintf('every %s, from %s%s %s', self::formatInterval($p->getDateInterval()), $p->include_start_date ? '[' : ']', self::formatDateTime($p->getStartDate()), ($end = $p->getEndDate()) ? 'to ' . self::formatDateTime($end) . ($p->include_end_date ? ']' : '[') : 'recurring ' . $p->recurrences . ' time/s');
        $p = [
            Caster::PREFIX_VIRTUAL . 'period' => new ConstStub($period, implode("\n", $dates)),
        ];
        return $filter & Caster::EXCLUDE_VERBOSE ? $p : $p + $a;
    }
    private static function formatDateTime(\DateTimeInterface $d, string $extra = '') : string {
        return $d->format('Y-m-d H:i:' . self::formatSeconds($d->format('s'), $d->format('u')) . $extra);
    }
    private static function formatSeconds(string $s, string $us) : string {
        return \sprintf('%02d.%s', $s, 0 === ($len = \strlen($t = rtrim($us, '0'))) ? '0' : ($len <= 3 ? str_pad($t, 3, '0') : $us));
    }

}