package kr.co.vividnext.sodalive.point

import org.springframework.stereotype.Service
import java.time.LocalDateTime

@Service
class PointUsageService(
    private val memberPointRepository: MemberPointRepository,
    private val usePointRepository: UsePointRepository
) {
    fun usePoint(memberId: Long, contentPrice: Int): Int {
        val now = LocalDateTime.now()
        val maxUsablePoint = contentPrice * 10

        val points = memberPointRepository.findByMemberIdAndExpiresAtAfterOrderByExpiresAtAsc(
            memberId = memberId,
            expiresAt = now
        )

        val totalAvailable = points.sumOf { it.point }
        val usablePoint = minOf(totalAvailable, maxUsablePoint).floorToNearest10()

        var remaining = usablePoint
        var used = 0

        for (p in points) {
            if (remaining <= 0) break
            val usable = minOf(p.point, remaining)
            p.point -= usable
            remaining -= usable
            used += usable
        }

        if (used > 0) {
            memberPointRepository.saveAll(points)
            usePointRepository.save(UsePoint(memberId = memberId, amount = used))
        }

        return used
    }

    private fun Int.floorToNearest10(): Int = (this / 10) * 10
}