<?php

/**
 * This file is part of the Carbon package.
 *
 * (c) Brian Nesbitt <brian@nesbot.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Carbon\Traits;

use Carbon\Carbon;
use Carbon\CarbonImmutable;
use Carbon\CarbonInterface;
use Carbon\CarbonInterval;
use Carbon\CarbonPeriod;
use Carbon\Translator;
use Closure;
use DateInterval;
use DateTimeInterface;
use ReturnTypeWillChange;

/**
 * Trait Difference.
 *
 * Depends on the following methods:
 *
 * @method bool lessThan($date)
 * @method static copy()
 * @method static resolveCarbon($date = null)
 * @method static Translator translator()
 */
trait Difference
{
    /**
     * @codeCoverageIgnore
     *
     * @param CarbonInterval $diff
     */
    protected static function fixNegativeMicroseconds(CarbonInterval $diff)
    {
        if ($diff->s !== 0 || $diff->i !== 0 || $diff->h !== 0 || $diff->d !== 0 || $diff->m !== 0 || $diff->y !== 0) {
            $diff->f = (round($diff->f * 1000000) + 1000000) / 1000000;
            $diff->s--;

            if ($diff->s < 0) {
                $diff->s += 60;
                $diff->i--;

                if ($diff->i < 0) {
                    $diff->i += 60;
                    $diff->h--;

                    if ($diff->h < 0) {
                        $diff->h += 24;
                        $diff->d--;

                        if ($diff->d < 0) {
                            $diff->d += 30;
                            $diff->m--;

                            if ($diff->m < 0) {
                                $diff->m += 12;
                                $diff->y--;
                            }
                        }
                    }
                }
            }

            return;
        }

        $diff->f *= -1;
        $diff->invert();
    }

    /**
     * @param DateInterval $diff
     * @param bool         $absolute
     *
     * @return CarbonInterval
     */
    protected static function fixDiffInterval(DateInterval $diff, $absolute, array $skip = [])
    {
        $diff = CarbonInterval::instance($diff, $skip);

        // Work-around for https://bugs.php.net/bug.php?id=77145
        // @codeCoverageIgnoreStart
        if ($diff->f > 0 && $diff->y === -1 && $diff->m === 11 && $diff->d >= 27 && $diff->h === 23 && $diff->i === 59 && $diff->s === 59) {
            $diff->y = 0;
            $diff->m = 0;
            $diff->d = 0;
            $diff->h = 0;
            $diff->i = 0;
            $diff->s = 0;
            $diff->f = (1000000 - round($diff->f * 1000000)) / 1000000;
            $diff->invert();
        } elseif ($diff->f < 0) {
            static::fixNegativeMicroseconds($diff);
        }
        // @codeCoverageIgnoreEnd

        if ($absolute && $diff->invert) {
            $diff->invert();
        }

        return $diff;
    }

    /**
     * Get the difference as a DateInterval instance.
     * Return relative interval (negative if $absolute flag is not set to true and the given date is before
     * current one).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return DateInterval
     */
    #[ReturnTypeWillChange]
    public function diff($date = null, $absolute = false)
    {
        $other = $this->resolveCarbon($date);

        // Work-around for https://bugs.php.net/bug.php?id=81458
        // It was initially introduced for https://bugs.php.net/bug.php?id=80998
        // The very specific case of 80998 was fixed in PHP 8.1beta3, but it introduced 81458
        // So we still need to keep this for now
        // @codeCoverageIgnoreStart
        if (version_compare(PHP_VERSION, '8.1.0-dev', '>=') && $other->tz !== $this->tz) {
            $other = $other->avoidMutation()->tz($this->tz);
        }
        // @codeCoverageIgnoreEnd

        return parent::diff($other, (bool) $absolute);
    }

    /**
     * Get the difference as a CarbonInterval instance.
     * Return relative interval (negative if $absolute flag is not set to true and the given date is before
     * current one).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return CarbonInterval
     */
    public function diffAsCarbonInterval($date = null, $absolute = true, array $skip = [])
    {
        return static::fixDiffInterval($this->diff($this->resolveCarbon($date), $absolute), $absolute, $skip);
    }

    /**
     * Get the difference in years
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInYears($date = null, $absolute = true)
    {
        return (int) $this->diff($this->resolveCarbon($date), $absolute)->format('%r%y');
    }

    /**
     * Get the difference in quarters rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInQuarters($date = null, $absolute = true)
    {
        return (int) ($this->diffInMonths($date, $absolute) / static::MONTHS_PER_QUARTER);
    }

    /**
     * Get the difference in months rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInMonths($date = null, $absolute = true)
    {
        $date = $this->resolveCarbon($date)->avoidMutation()->tz($this->tz);

        [$yearStart, $monthStart, $dayStart] = explode('-', $this->format('Y-m-dHisu'));
        [$yearEnd, $monthEnd, $dayEnd] = explode('-', $date->format('Y-m-dHisu'));

        $diff = (((int) $yearEnd) - ((int) $yearStart)) * static::MONTHS_PER_YEAR +
            ((int) $monthEnd) - ((int) $monthStart);

        if ($diff > 0) {
            $diff -= ($dayStart > $dayEnd ? 1 : 0);
        } elseif ($diff < 0) {
            $diff += ($dayStart < $dayEnd ? 1 : 0);
        }

        return $absolute ? abs($diff) : $diff;
    }

    /**
     * Get the difference in weeks rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInWeeks($date = null, $absolute = true)
    {
        return (int) ($this->diffInDays($date, $absolute) / static::DAYS_PER_WEEK);
    }

    /**
     * Get the difference in days rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInDays($date = null, $absolute = true)
    {
        return $this->getIntervalDayDiff($this->diff($this->resolveCarbon($date), $absolute));
    }

    /**
     * Get the difference in days using a filter closure rounded down.
     *
     * @param Closure                                                $callback
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInDaysFiltered(Closure $callback, $date = null, $absolute = true)
    {
        return $this->diffFiltered(CarbonInterval::day(), $callback, $date, $absolute);
    }

    /**
     * Get the difference in hours using a filter closure rounded down.
     *
     * @param Closure                                                $callback
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInHoursFiltered(Closure $callback, $date = null, $absolute = true)
    {
        return $this->diffFiltered(CarbonInterval::hour(), $callback, $date, $absolute);
    }

    /**
     * Get the difference by the given interval using a filter closure.
     *
     * @param CarbonInterval                                         $ci       An interval to traverse by
     * @param Closure                                                $callback
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffFiltered(CarbonInterval $ci, Closure $callback, $date = null, $absolute = true)
    {
        $start = $this;
        $end = $this->resolveCarbon($date);
        $inverse = false;

        if ($end < $start) {
            $start = $end;
            $end = $this;
            $inverse = true;
        }

        $options = CarbonPeriod::EXCLUDE_END_DATE | ($this->isMutable() ? 0 : CarbonPeriod::IMMUTABLE);
        $diff = $ci->toPeriod($start, $end, $options)->filter($callback)->count();

        return $inverse && !$absolute ? -$diff : $diff;
    }

    /**
     * Get the difference in weekdays rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInWeekdays($date = null, $absolute = true)
    {
        return $this->diffInDaysFiltered(static function (CarbonInterface $date) {
            return $date->isWeekday();
        }, $this->resolveCarbon($date)->avoidMutation()->modify($this->format('H:i:s.u')), $absolute);
    }

    /**
     * Get the difference in weekend days using a filter rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInWeekendDays($date = null, $absolute = true)
    {
        return $this->diffInDaysFiltered(static function (CarbonInterface $date) {
            return $date->isWeekend();
        }, $this->resolveCarbon($date)->avoidMutation()->modify($this->format('H:i:s.u')), $absolute);
    }

    /**
     * Get the difference in hours rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInHours($date = null, $absolute = true)
    {
        return (int) ($this->diffInSeconds($date, $absolute) / static::SECONDS_PER_MINUTE / static::MINUTES_PER_HOUR);
    }

    /**
     * Get the difference in hours rounded down using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInRealHours($date = null, $absolute = true)
    {
        return (int) ($this->diffInRealSeconds($date, $absolute) / static::SECONDS_PER_MINUTE / static::MINUTES_PER_HOUR);
    }

    /**
     * Get the difference in minutes rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInMinutes($date = null, $absolute = true)
    {
        return (int) ($this->diffInSeconds($date, $absolute) / static::SECONDS_PER_MINUTE);
    }

    /**
     * Get the difference in minutes rounded down using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInRealMinutes($date = null, $absolute = true)
    {
        return (int) ($this->diffInRealSeconds($date, $absolute) / static::SECONDS_PER_MINUTE);
    }

    /**
     * Get the difference in seconds rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInSeconds($date = null, $absolute = true)
    {
        $diff = $this->diff($date);

        if ($diff->days === 0) {
            $diff = static::fixDiffInterval($diff, $absolute);
        }

        $value = (((($diff->m || $diff->y ? $diff->days : $diff->d) * static::HOURS_PER_DAY) +
            $diff->h) * static::MINUTES_PER_HOUR +
            $diff->i) * static::SECONDS_PER_MINUTE +
            $diff->s;

        return $absolute || !$diff->invert ? $value : -$value;
    }

    /**
     * Get the difference in microseconds.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInMicroseconds($date = null, $absolute = true)
    {
        $diff = $this->diff($date);
        $value = (int) round(((((($diff->m || $diff->y ? $diff->days : $diff->d) * static::HOURS_PER_DAY) +
            $diff->h) * static::MINUTES_PER_HOUR +
            $diff->i) * static::SECONDS_PER_MINUTE +
            ($diff->f + $diff->s)) * static::MICROSECONDS_PER_SECOND);

        return $absolute || !$diff->invert ? $value : -$value;
    }

    /**
     * Get the difference in milliseconds rounded down.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInMilliseconds($date = null, $absolute = true)
    {
        return (int) ($this->diffInMicroseconds($date, $absolute) / static::MICROSECONDS_PER_MILLISECOND);
    }

    /**
     * Get the difference in seconds using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInRealSeconds($date = null, $absolute = true)
    {
        /** @var CarbonInterface $date */
        $date = $this->resolveCarbon($date);
        $value = $date->getTimestamp() - $this->getTimestamp();

        return $absolute ? abs($value) : $value;
    }

    /**
     * Get the difference in microseconds using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInRealMicroseconds($date = null, $absolute = true)
    {
        /** @var CarbonInterface $date */
        $date = $this->resolveCarbon($date);
        $value = ($date->timestamp - $this->timestamp) * static::MICROSECONDS_PER_SECOND +
            $date->micro - $this->micro;

        return $absolute ? abs($value) : $value;
    }

    /**
     * Get the difference in milliseconds rounded down using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return int
     */
    public function diffInRealMilliseconds($date = null, $absolute = true)
    {
        return (int) ($this->diffInRealMicroseconds($date, $absolute) / static::MICROSECONDS_PER_MILLISECOND);
    }

    /**
     * Get the difference in seconds as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInSeconds($date = null, $absolute = true)
    {
        return (float) ($this->diffInMicroseconds($date, $absolute) / static::MICROSECONDS_PER_SECOND);
    }

    /**
     * Get the difference in minutes as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInMinutes($date = null, $absolute = true)
    {
        return $this->floatDiffInSeconds($date, $absolute) / static::SECONDS_PER_MINUTE;
    }

    /**
     * Get the difference in hours as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInHours($date = null, $absolute = true)
    {
        return $this->floatDiffInMinutes($date, $absolute) / static::MINUTES_PER_HOUR;
    }

    /**
     * Get the difference in days as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInDays($date = null, $absolute = true)
    {
        $hoursDiff = $this->floatDiffInHours($date, $absolute);
        $interval = $this->diff($date, $absolute);

        if ($interval->y === 0 && $interval->m === 0 && $interval->d === 0) {
            return $hoursDiff / static::HOURS_PER_DAY;
        }

        $daysDiff = $this->getIntervalDayDiff($interval);

        return $daysDiff + fmod($hoursDiff, static::HOURS_PER_DAY) / static::HOURS_PER_DAY;
    }

    /**
     * Get the difference in weeks as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInWeeks($date = null, $absolute = true)
    {
        return $this->floatDiffInDays($date, $absolute) / static::DAYS_PER_WEEK;
    }

    /**
     * Get the difference in months as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInMonths($date = null, $absolute = true)
    {
        $start = $this;
        $end = $this->resolveCarbon($date);
        $ascending = ($start <= $end);
        $sign = $absolute || $ascending ? 1 : -1;
        if (!$ascending) {
            [$start, $end] = [$end, $start];
        }
        $monthsDiff = $start->diffInMonths($end);
        /** @var Carbon|CarbonImmutable $floorEnd */
        $floorEnd = $start->avoidMutation()->addMonths($monthsDiff);

        if ($floorEnd >= $end) {
            return $sign * $monthsDiff;
        }

        /** @var Carbon|CarbonImmutable $startOfMonthAfterFloorEnd */
        $startOfMonthAfterFloorEnd = $floorEnd->avoidMutation()->addMonth()->startOfMonth();

        if ($startOfMonthAfterFloorEnd > $end) {
            return $sign * ($monthsDiff + $floorEnd->floatDiffInDays($end) / $floorEnd->daysInMonth);
        }

        return $sign * ($monthsDiff + $floorEnd->floatDiffInDays($startOfMonthAfterFloorEnd) / $floorEnd->daysInMonth + $startOfMonthAfterFloorEnd->floatDiffInDays($end) / $end->daysInMonth);
    }

    /**
     * Get the difference in year as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInYears($date = null, $absolute = true)
    {
        $start = $this;
        $end = $this->resolveCarbon($date);
        $ascending = ($start <= $end);
        $sign = $absolute || $ascending ? 1 : -1;
        if (!$ascending) {
            [$start, $end] = [$end, $start];
        }
        $yearsDiff = $start->diffInYears($end);
        /** @var Carbon|CarbonImmutable $floorEnd */
        $floorEnd = $start->avoidMutation()->addYears($yearsDiff);

        if ($floorEnd >= $end) {
            return $sign * $yearsDiff;
        }

        /** @var Carbon|CarbonImmutable $startOfYearAfterFloorEnd */
        $startOfYearAfterFloorEnd = $floorEnd->avoidMutation()->addYear()->startOfYear();

        if ($startOfYearAfterFloorEnd > $end) {
            return $sign * ($yearsDiff + $floorEnd->floatDiffInDays($end) / $floorEnd->daysInYear);
        }

        return $sign * ($yearsDiff + $floorEnd->floatDiffInDays($startOfYearAfterFloorEnd) / $floorEnd->daysInYear + $startOfYearAfterFloorEnd->floatDiffInDays($end) / $end->daysInYear);
    }

    /**
     * Get the difference in seconds as float (microsecond-precision) using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInRealSeconds($date = null, $absolute = true)
    {
        return $this->diffInRealMicroseconds($date, $absolute) / static::MICROSECONDS_PER_SECOND;
    }

    /**
     * Get the difference in minutes as float (microsecond-precision) using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInRealMinutes($date = null, $absolute = true)
    {
        return $this->floatDiffInRealSeconds($date, $absolute) / static::SECONDS_PER_MINUTE;
    }

    /**
     * Get the difference in hours as float (microsecond-precision) using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInRealHours($date = null, $absolute = true)
    {
        return $this->floatDiffInRealMinutes($date, $absolute) / static::MINUTES_PER_HOUR;
    }

    /**
     * Get the difference in days as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInRealDays($date = null, $absolute = true)
    {
        $date = $this->resolveUTC($date);
        $utc = $this->avoidMutation()->utc();
        $hoursDiff = $utc->floatDiffInRealHours($date, $absolute);

        return ($hoursDiff < 0 ? -1 : 1) * $utc->diffInDays($date) + fmod($hoursDiff, static::HOURS_PER_DAY) / static::HOURS_PER_DAY;
    }

    /**
     * Get the difference in weeks as float (microsecond-precision).
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInRealWeeks($date = null, $absolute = true)
    {
        return $this->floatDiffInRealDays($date, $absolute) / static::DAYS_PER_WEEK;
    }

    /**
     * Get the difference in months as float (microsecond-precision) using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInRealMonths($date = null, $absolute = true)
    {
        $start = $this;
        $end = $this->resolveCarbon($date);
        $ascending = ($start <= $end);
        $sign = $absolute || $ascending ? 1 : -1;
        if (!$ascending) {
            [$start, $end] = [$end, $start];
        }
        $monthsDiff = $start->diffInMonths($end);
        /** @var Carbon|CarbonImmutable $floorEnd */
        $floorEnd = $start->avoidMutation()->addMonths($monthsDiff);

        if ($floorEnd >= $end) {
            return $sign * $monthsDiff;
        }

        /** @var Carbon|CarbonImmutable $startOfMonthAfterFloorEnd */
        $startOfMonthAfterFloorEnd = $floorEnd->avoidMutation()->addMonth()->startOfMonth();

        if ($startOfMonthAfterFloorEnd > $end) {
            return $sign * ($monthsDiff + $floorEnd->floatDiffInRealDays($end) / $floorEnd->daysInMonth);
        }

        return $sign * ($monthsDiff + $floorEnd->floatDiffInRealDays($startOfMonthAfterFloorEnd) / $floorEnd->daysInMonth + $startOfMonthAfterFloorEnd->floatDiffInRealDays($end) / $end->daysInMonth);
    }

    /**
     * Get the difference in year as float (microsecond-precision) using timestamps.
     *
     * @param \Carbon\CarbonInterface|\DateTimeInterface|string|null $date
     * @param bool                                                   $absolute Get the absolute of the difference
     *
     * @return float
     */
    public function floatDiffInRealYears($date = null, $absolute = true)
    {
        $start = $this;
        $end = $this->resolveCarbon($date);
        $ascending = ($start <= $end);
        $sign = $absolute || $ascending ? 1 : -1;
        if (!$ascending) {
            [$start, $end] = [$end, $start];
        }
        $yearsDiff = $start->diffInYears($end);
        /** @var Carbon|CarbonImmutable $floorEnd */
        $floorEnd = $start->avoidMutation()->addYears($yearsDiff);

        if ($floorEnd >= $end) {
            return $sign * $yearsDiff;
        }

        /** @var Carbon|CarbonImmutable $startOfYearAfterFloorEnd */
        $startOfYearAfterFloorEnd = $floorEnd->avoidMutation()->addYear()->startOfYear();

        if ($startOfYearAfterFloorEnd > $end) {
            return $sign * ($yearsDiff + $floorEnd->floatDiffInRealDays($end) / $floorEnd->daysInYear);
        }

        return $sign * ($yearsDiff + $floorEnd->floatDiffInRealDays($startOfYearAfterFloorEnd) / $floorEnd->daysInYear + $startOfYearAfterFloorEnd->floatDiffInRealDays($end) / $end->daysInYear);
    }

    /**
     * The number of seconds since midnight.
     *
     * @return int
     */
    public function secondsSinceMidnight()
    {
        return $this->diffInSeconds($this->avoidMutation()->startOfDay());
    }

    /**
     * The number of seconds until 23:59:59.
     *
     * @return int
     */
    public function secondsUntilEndOfDay()
    {
        return $this->diffInSeconds($this->avoidMutation()->endOfDay());
    }

    /**
     * Get the difference in a human readable format in the current locale from current instance to an other
     * instance given (or now if null given).
     *
     * @example
     * ```
     * echo Carbon::tomorrow()->diffForHumans() . "\n";
     * echo Carbon::tomorrow()->diffForHumans(['parts' => 2]) . "\n";
     * echo Carbon::tomorrow()->diffForHumans(['parts' => 3, 'join' => true]) . "\n";
     * echo Carbon::tomorrow()->diffForHumans(Carbon::yesterday()) . "\n";
     * echo Carbon::tomorrow()->diffForHumans(Carbon::yesterday(), ['short' => true]) . "\n";
     * ```
     *
     * @param Carbon|\DateTimeInterface|string|array|null $other   if array passed, will be used as parameters array, see $syntax below;
     *                                                             if null passed, now will be used as comparison reference;
     *                                                             if any other type, it will be converted to date and used as reference.
     * @param int|array                                   $syntax  if array passed, parameters will be extracted from it, the array may contains:
     *                                                             - 'syntax' entry (see below)
     *                                                             - 'short' entry (see below)
     *                                                             - 'parts' entry (see below)
     *                                                             - 'options' entry (see below)
     *                                                             - 'skip' entry, list of units to skip (array of strings or a single string,
     *                                                             ` it can be the unit name (singular or plural) or its shortcut
     *                                                             ` (y, m, w, d, h, min, s, ms, µs).
     *                                                             - 'aUnit' entry, prefer "an hour" over "1 hour" if true
     *                                                             - 'join' entry determines how to join multiple parts of the string
     *                                                             `  - if $join is a string, it's used as a joiner glue
     *                                                             `  - if $join is a callable/closure, it get the list of string and should return a string
     *                                                             `  - if $join is an array, the first item will be the default glue, and the second item
     *                                                             `    will be used instead of the glue for the last item
     *                                                             `  - if $join is true, it will be guessed from the locale ('list' translation file entry)
     *                                                             `  - if $join is missing, a space will be used as glue
     *                                                             - 'other' entry (see above)
     *                                                             - 'minimumUnit' entry determines the smallest unit of time to display can be long or
     *                                                             `  short form of the units, e.g. 'hour' or 'h' (default value: s)
     *                                                             if int passed, it add modifiers:
     *                                                             Possible values:
     *                                                             - CarbonInterface::DIFF_ABSOLUTE          no modifiers
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_NOW   add ago/from now modifier
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_OTHER add before/after modifier
     *                                                             Default value: CarbonInterface::DIFF_ABSOLUTE
     * @param bool                                        $short   displays short format of time units
     * @param int                                         $parts   maximum number of parts to display (default value: 1: single unit)
     * @param int                                         $options human diff options
     *
     * @return string
     */
    public function diffForHumans($other = null, $syntax = null, $short = false, $parts = 1, $options = null)
    {
        /* @var CarbonInterface $this */
        if (\is_array($other)) {
            $other['syntax'] = \array_key_exists('syntax', $other) ? $other['syntax'] : $syntax;
            $syntax = $other;
            $other = $syntax['other'] ?? null;
        }

        $intSyntax = &$syntax;
        if (\is_array($syntax)) {
            $syntax['syntax'] = $syntax['syntax'] ?? null;
            $intSyntax = &$syntax['syntax'];
        }
        $intSyntax = (int) ($intSyntax ?? static::DIFF_RELATIVE_AUTO);
        $intSyntax = $intSyntax === static::DIFF_RELATIVE_AUTO && $other === null ? static::DIFF_RELATIVE_TO_NOW : $intSyntax;

        $parts = min(7, max(1, (int) $parts));
        $skip = \is_array($syntax) ? ($syntax['skip'] ?? []) : [];

        return $this->diffAsCarbonInterval($other, false, (array) $skip)
            ->setLocalTranslator($this->getLocalTranslator())
            ->forHumans($syntax, (bool) $short, $parts, $options ?? $this->localHumanDiffOptions ?? static::getHumanDiffOptions());
    }

    /**
     * @alias diffForHumans
     *
     * Get the difference in a human readable format in the current locale from current instance to an other
     * instance given (or now if null given).
     *
     * @param Carbon|\DateTimeInterface|string|array|null $other   if array passed, will be used as parameters array, see $syntax below;
     *                                                             if null passed, now will be used as comparison reference;
     *                                                             if any other type, it will be converted to date and used as reference.
     * @param int|array                                   $syntax  if array passed, parameters will be extracted from it, the array may contains:
     *                                                             - 'syntax' entry (see below)
     *                                                             - 'short' entry (see below)
     *                                                             - 'parts' entry (see below)
     *                                                             - 'options' entry (see below)
     *                                                             - 'join' entry determines how to join multiple parts of the string
     *                                                             `  - if $join is a string, it's used as a joiner glue
     *                                                             `  - if $join is a callable/closure, it get the list of string and should return a string
     *                                                             `  - if $join is an array, the first item will be the default glue, and the second item
     *                                                             `    will be used instead of the glue for the last item
     *                                                             `  - if $join is true, it will be guessed from the locale ('list' translation file entry)
     *                                                             `  - if $join is missing, a space will be used as glue
     *                                                             - 'other' entry (see above)
     *                                                             if int passed, it add modifiers:
     *                                                             Possible values:
     *                                                             - CarbonInterface::DIFF_ABSOLUTE          no modifiers
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_NOW   add ago/from now modifier
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_OTHER add before/after modifier
     *                                                             Default value: CarbonInterface::DIFF_ABSOLUTE
     * @param bool                                        $short   displays short format of time units
     * @param int                                         $parts   maximum number of parts to display (default value: 1: single unit)
     * @param int                                         $options human diff options
     *
     * @return string
     */
    public function from($other = null, $syntax = null, $short = false, $parts = 1, $options = null)
    {
        return $this->diffForHumans($other, $syntax, $short, $parts, $options);
    }

    /**
     * @alias diffForHumans
     *
     * Get the difference in a human readable format in the current locale from current instance to an other
     * instance given (or now if null given).
     */
    public function since($other = null, $syntax = null, $short = false, $parts = 1, $options = null)
    {
        return $this->diffForHumans($other, $syntax, $short, $parts, $options);
    }

    /**
     * Get the difference in a human readable format in the current locale from an other
     * instance given (or now if null given) to current instance.
     *
     * When comparing a value in the past to default now:
     * 1 hour from now
     * 5 months from now
     *
     * When comparing a value in the future to default now:
     * 1 hour ago
     * 5 months ago
     *
     * When comparing a value in the past to another value:
     * 1 hour after
     * 5 months after
     *
     * When comparing a value in the future to another value:
     * 1 hour before
     * 5 months before
     *
     * @param Carbon|\DateTimeInterface|string|array|null $other   if array passed, will be used as parameters array, see $syntax below;
     *                                                             if null passed, now will be used as comparison reference;
     *                                                             if any other type, it will be converted to date and used as reference.
     * @param int|array                                   $syntax  if array passed, parameters will be extracted from it, the array may contains:
     *                                                             - 'syntax' entry (see below)
     *                                                             - 'short' entry (see below)
     *                                                             - 'parts' entry (see below)
     *                                                             - 'options' entry (see below)
     *                                                             - 'join' entry determines how to join multiple parts of the string
     *                                                             `  - if $join is a string, it's used as a joiner glue
     *                                                             `  - if $join is a callable/closure, it get the list of string and should return a string
     *                                                             `  - if $join is an array, the first item will be the default glue, and the second item
     *                                                             `    will be used instead of the glue for the last item
     *                                                             `  - if $join is true, it will be guessed from the locale ('list' translation file entry)
     *                                                             `  - if $join is missing, a space will be used as glue
     *                                                             - 'other' entry (see above)
     *                                                             if int passed, it add modifiers:
     *                                                             Possible values:
     *                                                             - CarbonInterface::DIFF_ABSOLUTE          no modifiers
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_NOW   add ago/from now modifier
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_OTHER add before/after modifier
     *                                                             Default value: CarbonInterface::DIFF_ABSOLUTE
     * @param bool                                        $short   displays short format of time units
     * @param int                                         $parts   maximum number of parts to display (default value: 1: single unit)
     * @param int                                         $options human diff options
     *
     * @return string
     */
    public function to($other = null, $syntax = null, $short = false, $parts = 1, $options = null)
    {
        if (!$syntax && !$other) {
            $syntax = CarbonInterface::DIFF_RELATIVE_TO_NOW;
        }

        return $this->resolveCarbon($other)->diffForHumans($this, $syntax, $short, $parts, $options);
    }

    /**
     * @alias to
     *
     * Get the difference in a human readable format in the current locale from an other
     * instance given (or now if null given) to current instance.
     *
     * @param Carbon|\DateTimeInterface|string|array|null $other   if array passed, will be used as parameters array, see $syntax below;
     *                                                             if null passed, now will be used as comparison reference;
     *                                                             if any other type, it will be converted to date and used as reference.
     * @param int|array                                   $syntax  if array passed, parameters will be extracted from it, the array may contains:
     *                                                             - 'syntax' entry (see below)
     *                                                             - 'short' entry (see below)
     *                                                             - 'parts' entry (see below)
     *                                                             - 'options' entry (see below)
     *                                                             - 'join' entry determines how to join multiple parts of the string
     *                                                             `  - if $join is a string, it's used as a joiner glue
     *                                                             `  - if $join is a callable/closure, it get the list of string and should return a string
     *                                                             `  - if $join is an array, the first item will be the default glue, and the second item
     *                                                             `    will be used instead of the glue for the last item
     *                                                             `  - if $join is true, it will be guessed from the locale ('list' translation file entry)
     *                                                             `  - if $join is missing, a space will be used as glue
     *                                                             - 'other' entry (see above)
     *                                                             if int passed, it add modifiers:
     *                                                             Possible values:
     *                                                             - CarbonInterface::DIFF_ABSOLUTE          no modifiers
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_NOW   add ago/from now modifier
     *                                                             - CarbonInterface::DIFF_RELATIVE_TO_OTHER add before/after modifier
     *                                                             Default value: CarbonInterface::DIFF_ABSOLUTE
     * @param bool                                        $short   displays short format of time units
     * @param int                                         $parts   maximum number of parts to display (default value: 1: single unit)
     * @param int                                         $options human diff options
     *
     * @return string
     */
    public function until($other = null, $syntax = null, $short = false, $parts = 1, $options = null)
    {
        return $this->to($other, $syntax, $short, $parts, $options);
    }

    /**
     * Get the difference in a human readable format in the current locale from current
     * instance to now.
     *
     * @param int|array $syntax  if array passed, parameters will be extracted from it, the array may contains:
     *                           - 'syntax' entry (see below)
     *                           - 'short' entry (see below)
     *                           - 'parts' entry (see below)
     *                           - 'options' entry (see below)
     *                           - 'join' entry determines how to join multiple parts of the string
     *                           `  - if $join is a string, it's used as a joiner glue
     *                           `  - if $join is a callable/closure, it get the list of string and should return a string
     *                           `  - if $join is an array, the first item will be the default glue, and the second item
     *                           `    will be used instead of the glue for the last item
     *                           `  - if $join is true, it will be guessed from the locale ('list' translation file entry)
     *                           `  - if $join is missing, a space will be used as glue
     *                           if int passed, it add modifiers:
     *                           Possible values:
     *                           - CarbonInterface::DIFF_ABSOLUTE          no modifiers
     *                           - CarbonInterface::DIFF_RELATIVE_TO_NOW   add ago/from now modifier
     *                           - CarbonInterface::DIFF_RELATIVE_TO_OTHER add before/after modifier
     *                           Default value: CarbonInterface::DIFF_ABSOLUTE
     * @param bool      $short   displays short format of time units
     * @param int       $parts   maximum number of parts to display (default value: 1: single unit)
     * @param int       $options human diff options
     *
     * @return string
     */
    public function fromNow($syntax = null, $short = false, $parts = 1, $options = null)
    {
        $other = null;

        if ($syntax instanceof DateTimeInterface) {
            [$other, $syntax, $short, $parts, $options] = array_pad(\func_get_args(), 5, null);
        }

        return $this->from($other, $syntax, $short, $parts, $options);
    }

    /**
     * Get the difference in a human readable format in the current locale from an other
     * instance given to now
     *
     * @param int|array $syntax  if array passed, parameters will be extracted from it, the array may contains:
     *                           - 'syntax' entry (see below)
     *                           - 'short' entry (see below)
     *                           - 'parts' entry (see below)
     *                           - 'options' entry (see below)
     *                           - 'join' entry determines how to join multiple parts of the string
     *                           `  - if $join is a string, it's used as a joiner glue
     *                           `  - if $join is a callable/closure, it get the list of string and should return a string
     *                           `  - if $join is an array, the first item will be the default glue, and the second item
     *                           `    will be used instead of the glue for the last item
     *                           `  - if $join is true, it will be guessed from the locale ('list' translation file entry)
     *                           `  - if $join is missing, a space will be used as glue
     *                           if int passed, it add modifiers:
     *                           Possible values:
     *                           - CarbonInterface::DIFF_ABSOLUTE          no modifiers
     *                           - CarbonInterface::DIFF_RELATIVE_TO_NOW   add ago/from now modifier
     *                           - CarbonInterface::DIFF_RELATIVE_TO_OTHER add before/after modifier
     *                           Default value: CarbonInterface::DIFF_ABSOLUTE
     * @param bool      $short   displays short format of time units
     * @param int       $parts   maximum number of parts to display (default value: 1: single part)
     * @param int       $options human diff options
     *
     * @return string
     */
    public function toNow($syntax = null, $short = false, $parts = 1, $options = null)
    {
        return $this->to(null, $syntax, $short, $parts, $options);
    }

    /**
     * Get the difference in a human readable format in the current locale from an other
     * instance given to now
     *
     * @param int|array $syntax  if array passed, parameters will be extracted from it, the array may contains:
     *                           - 'syntax' entry (see below)
     *                           - 'short' entry (see below)
     *                           - 'parts' entry (see below)
     *                           - 'options' entry (see below)
     *                           - 'join' entry determines how to join multiple parts of the string
     *                           `  - if $join is a string, it's used as a joiner glue
     *                           `  - if $join is a callable/closure, it get the list of string and should return a string
     *                           `  - if $join is an array, the first item will be the default glue, and the second item
     *                           `    will be used instead of the glue for the last item
     *                           `  - if $join is true, it will be guessed from the locale ('list' translation file entry)
     *                           `  - if $join is missing, a space will be used as glue
     *                           if int passed, it add modifiers:
     *                           Possible values:
     *                           - CarbonInterface::DIFF_ABSOLUTE          no modifiers
     *                           - CarbonInterface::DIFF_RELATIVE_TO_NOW   add ago/from now modifier
     *                           - CarbonInterface::DIFF_RELATIVE_TO_OTHER add before/after modifier
     *                           Default value: CarbonInterface::DIFF_ABSOLUTE
     * @param bool      $short   displays short format of time units
     * @param int       $parts   maximum number of parts to display (default value: 1: single part)
     * @param int       $options human diff options
     *
     * @return string
     */
    public function ago($syntax = null, $short = false, $parts = 1, $options = null)
    {
        $other = null;

        if ($syntax instanceof DateTimeInterface) {
            [$other, $syntax, $short, $parts, $options] = array_pad(\func_get_args(), 5, null);
        }

        return $this->from($other, $syntax, $short, $parts, $options);
    }

    /**
     * Get the difference in a human readable format in the current locale from current instance to an other
     * instance given (or now if null given).
     *
     * @return string
     */
    public function timespan($other = null, $timezone = null)
    {
        if (!$other instanceof DateTimeInterface) {
            $other = static::parse($other, $timezone);
        }

        return $this->diffForHumans($other, [
            'join' => ', ',
            'syntax' => CarbonInterface::DIFF_ABSOLUTE,
            'options' => CarbonInterface::NO_ZERO_DIFF,
            'parts' => -1,
        ]);
    }

    /**
     * Returns either day of week + time (e.g. "Last Friday at 3:30 PM") if reference time is within 7 days,
     * or a calendar date (e.g. "10/29/2017") otherwise.
     *
     * Language, date and time formats will change according to the current locale.
     *
     * @param Carbon|\DateTimeInterface|string|null $referenceTime
     * @param array                                 $formats
     *
     * @return string
     */
    public function calendar($referenceTime = null, array $formats = [])
    {
        /** @var CarbonInterface $current */
        $current = $this->avoidMutation()->startOfDay();
        /** @var CarbonInterface $other */
        $other = $this->resolveCarbon($referenceTime)->avoidMutation()->setTimezone($this->getTimezone())->startOfDay();
        $diff = $other->diffInDays($current, false);
        $format = $diff < -6 ? 'sameElse' : (
            $diff < -1 ? 'lastWeek' : (
                $diff < 0 ? 'lastDay' : (
                    $diff < 1 ? 'sameDay' : (
                        $diff < 2 ? 'nextDay' : (
                            $diff < 7 ? 'nextWeek' : 'sameElse'
                        )
                    )
                )
            )
        );
        $format = array_merge($this->getCalendarFormats(), $formats)[$format];
        if ($format instanceof Closure) {
            $format = $format($current, $other) ?? '';
        }

        return $this->isoFormat((string) $format);
    }

    private function getIntervalDayDiff(DateInterval $interval): int
    {
        $daysDiff = (int) $interval->format('%a');
        $sign = $interval->format('%r') === '-' ? -1 : 1;

        if (\is_int($interval->days) &&
            $interval->y === 0 &&
            $interval->m === 0 &&
            version_compare(PHP_VERSION, '8.1.0-dev', '<') &&
            abs($interval->d - $daysDiff) === 1
        ) {
            $daysDiff = abs($interval->d); // @codeCoverageIgnore
        }

        return $daysDiff * $sign;
    }
}