<?php

namespace sammo;

class VarTurn60
{
    const MonthAdjustOffset = 2;

    static array $min30ToTurn = [
        [0, 0, 120],   //00:00 2
        [0, 30, 120],  //00:30
        [0, 60, 120],  //01:00
        [0, 90, 120],  //01:30
        [1, 0, 120],   //02:00 3
        [1, 30, 120],  //02:30
        [1, 60, 120],  //03:00
        [1, 90, 120],  //03:30
        [2, 0, 120],   //04:00 4
        [2, 30, 120],  //04:30
        [2, 60, 120],  //05:00 
        [2, 90, 120],  //05:30
        [3, 0, 60],    //06:00 5
        [3, 30, 60],   //06:30
        [4, 0, 60],    //07:00 6
        [4, 30, 60],   //07:30 
        [5, 0, 60],    //08:00 7
        [5, 30, 60],   //08:30 
        [6, 0, 60],    //09:00 8
        [6, 30, 60],   //09:30 
        [7, 0, 60],    //10:00 9
        [7, 30, 60],   //10:30 
        [8, 0, 60],    //11:00 10
        [8, 30, 60],   //11:30 
        [9, 0, 60],    //12:00 11
        [9, 30, 60],   //12:30 
        [10, 0, 60],   //13:00 0(12)
        [10, 30, 60],  //13:30
        [11, 0, 60],   //14:00 1(13)
        [11, 30, 60],  //14:30
        [12, 0, 60],   //15:00 2(14)
        [12, 30, 60],  //15:30
        [13, 0, 60],   //16:00 3(15)
        [13, 30, 60],  //16:30
        [14, 0, 60],   //17:00 4(16)
        [14, 30, 60],  //17:30
        [15, 0, 60],   //18:00 5(17)
        [15, 30, 60],  //18:30
        [16, 0, 30],   //19:00 6(18)
        [17, 0, 30],   //19:30 7(19)
        [18, 0, 30],   //20:00 8(20)
        [19, 0, 30],   //20:30 9(21)
        [20, 0, 30],   //21:00 10(22)
        [21, 0, 30],   //21:30 11(23)
        [22, 0, 60],   //22:00 0
        [22, 30, 60],  //22:30 
        [23, 0, 60],   //23:00 1
        [23, 30, 60],  //23:30
        //[24, 0, 60],   //24:00 2
    ];

    static array $turnToHM = [
        [0, 0, 120], //0
        [2, 0, 120], //1
        [4, 0, 120], //2
        [6, 0, 60],  //3
        [7, 0, 60],  //4
        [8, 0, 60],  //5
        [9, 0, 60],  //6
        [10, 0, 60], //7
        [11, 0, 60], //8
        [12, 0, 60], //9
        [13, 0, 60], //10
        [14, 0, 60], //11
        [15, 0, 60], //12
        [16, 0, 60], //13
        [17, 0, 60], //14
        [18, 0, 60], //15
        [19, 0, 30], //16
        [19, 30, 30],//17
        [20, 0, 30], //18
        [20, 30, 30],//19
        [21, 0, 30], //20
        [21, 30, 30],//21
        [22, 0, 60], //22
        [23, 0, 60], //23
        //[24, 0, 60], //24(?)
    ];

    function __construct(
        public \DateTimeImmutable $baseDay,
        public int $turnIdx, //0~23
        public float $secOffset, ///turnTerm에 따라 최대치가 30*60, 60*60, 120*60 가변
    )
    {
        
    }

    static function fromDatetime(\DateTimeInterface $date): self {
        $baseDay = new \DateTimeImmutable($date->format('Y-m-d'));
        $totalSec = $date->getTimestamp() - $baseDay->getTimestamp();

        $min30 = intdiv($totalSec, 60 * 30);

        assert($min30 < 48);

        [$turnIdx, $minOffset, ] = static::$min30ToTurn[$min30];
        
        $secOffset = $totalSec - 60 * 30 * $min30 + $minOffset * 60;
        return new static($baseDay, $turnIdx, $secOffset);
    }

    /// $b - $a 의 턴차
    static function calcTurnDiff(\DateTimeInterface $a, \DateTimeInterface $b): int{
        $aObj = static::fromDatetime($a);
        $bObj = static::fromDatetime($b);

        $resDays = $aObj->baseDay->diff($bObj->baseDay)->days; //놀랍게도 절대값
        if($aObj->baseDay > $bObj->baseDay){
            $resDays *= -1;
        }

        $res = $resDays * 24 + $bObj->turnIdx - $aObj->turnIdx;

        return $res;
    }

    function cutTurn($withFraction = true): array{
        [$hour, $minOffset, $turnTerm] = static::$turnToHM[$this->turnIdx];
        $date = $this->baseDay->add(TimeUtil::secondsToDateInterval(($hour * 60 + $minOffset) * 60));
        return [TimeUtil::format($date, $withFraction), $turnTerm];
    }

    function toDateStr($withFraction = true): string{
        [$hour, $minOffset, ] = static::$turnToHM[$this->turnIdx];
        $date = $this->baseDay->add(TimeUtil::secondsToDateInterval(($hour * 60 + $minOffset) * 60 + $this->secOffset));
        return TimeUtil::format($date, $withFraction);
    }

    function cutDay($withFraction = true): array{
        //고정 시간 기준 cutDay()의 이식
        //상수 테이블이 이미 13:00에 1월이 되도록 맞춰져 있음.
        //다만 20:00인 경우 8월이 아니라 9월이 됨 ^^;
        $newMonth = ($this->turnIdx + static::MonthAdjustOffset) % 12 + 1;

        $yearPulled = $newMonth > 3;

        $obj = $yearPulled ? $this->addTurn(12): $this;
        [$date, ] = $obj->addTurn(-($newMonth - 1))->cutTurn($withFraction);


        return [$date, $yearPulled, $newMonth];
    }

    function addTurn(int $moreTurn): self{
        $dayDiff = intdiv($moreTurn, 24);
        $moreTurn %= 24;

        $nextTurnIdx = $this->turnIdx + $moreTurn;
        if($nextTurnIdx < 0){
            $dayDiff -= 1;
            $nextTurnIdx += 24;
        }
        else if($nextTurnIdx >= 24){
            $dayDiff += 1;
            $nextTurnIdx -= 24;
        }

        [, , $oldTurnTerm] = static::$turnToHM[$this->turnIdx];
        [, , $nextTurnTerm] = static::$turnToHM[$nextTurnIdx];

        $nextSecOffset = $this->secOffset;
        if($oldTurnTerm != $nextTurnTerm){
            $nextSecOffset *= $nextTurnTerm;
            $nextSecOffset /= $oldTurnTerm;
        }

        if($dayDiff == 0){
            return new static($this->baseDay, $nextTurnIdx, $nextSecOffset);
        }

        if($dayDiff > 0){
            $nextBaseDay = $this->baseDay->add(new \DateInterval("P{$dayDiff}D"));
        }
        else{
            $dayAbsDiff = abs($dayDiff);
            $nextBaseDay = $this->baseDay->sub(new \DateInterval("P{$dayAbsDiff}D"));
        }
        
        return new static($nextBaseDay, $nextTurnIdx, $nextSecOffset);
    }
}